Focusing at the right distance with lots of DOF keeps everything in focus

Will Back-Button Focusing Make Me a Better Photographer?

All right, DSLR owners. I’ve had so many people ask me this summer about back-button focus and how and why to use it that I thought it would make a good post. Since this is (as usual) a long post, let me just summarize by saying if you don’t understand “focus-and-recompose,” focusing modes, focus selection points, critical focus, the focal plane, depth of field, and how to control all of these things, you probably should worry about those before you worry about using the back button to find focus. Back-button focusing is a great tool to achieve better control over autofocusing, but if you don’t understand how to control focus and what settings and techniques allow you to do that with autofocus now, it’s really not going to make a big difference for you.

That said, here goes my explanation of what back-button focusing is, why I use it, and some pointers on how to enable it on your camera if you want to give it a whirl.

First, what the heck are people talking about?

Back button focus means using a button on the back of your camera body to autofocus instead of autofocusing when you half-press/press the shutter button.

Why would you want to do that?

By separating autofocus from the button that also releases the shutter, you gain complete control over when your camera is focusing and when it isn’t, you can stop switching between autofocus modes and leave your camera in continuous focusing mode, and you make it easier to avoid releasing the shutter when you don’t mean to.

Why wouldn’t you want to do that?

Well, personally, I think back-button focusing is the bomb and I’ve been using it for so many years that it’s the first setting I adjust when I buy a new camera body because I can’t handle focusing via the shutter button.

That said, I have one big caution for you when it comes to switching to back-button focusing: choose when to make the switch cautiously. Your brain is programed to believe that the shutter button autofocuses right now. If you switch to back button, you will need to practice daily for about 2 weeks (depending on the neuroplasticity of your particular brain) to retrain yourself to go for the back button to find focus before you press the shutter. You would not want to make the switch and then go on the once-in-a-lifetime trip and/or to a once-in-a-lifetime event without having taught yourself this new habit before you get there–you will forget to focus and make a bunch of blurry photos at first.

Also, because of this need to create an unconscious habit, you don’t want to switch back and forth between using the back button technique vs the shutter button–you will get yourself very confused.

I Don’t Get It–Why is Back-Button Better?

In spite of all the hype about back-button focusing, a lot of students don’t get it at first. They look at me puzzled and try to understand why they would care which button causes the camera to focus.

So, let me tell you a little story about why I was so enthused when I learned about back-button focusing.

Back when DSLR screens weren’t so big or bright, I was doing a lot of landscape photography on a tripod. I found manual focus to be extremely difficult because the viewfinder focusing screen was terrible and I hadn’t yet invested in a loupe for my LCD screen, so I couldn’t see if I was in focus in daylight. So, I would put my camera on the tripod, compose my image, and then decide where I should focus based on DOF and hyperfocal distance. Then, I would begin the struggle of turning the camera to point at the place where I wanted to focus, hold the shutter button halfway, and then try to recompose the image back to what I wanted without releasing the shutter. I invariably either took the shot while still adjusting or lifted my finger and my focus unlocked. When you lose focus lock and then press the shutter button again, the camera re-focuses on whatever it picks to focus on instead of where you want to focus.

I then discovered there is a little focus lock button on Canon’s that if you press it, focus will remained locked “for a few seconds” giving you an unspecified amount of time to reset and shoot before it turns off. This little button just stressed me out because I was racing against a clock and I didn’t know how much time I actually had before the focus would unlock.

Then, I learned about back button focus. And, ahhhh, breathed a sigh of relief. I could still autofocus, but once I found focus with the back button, I was free to move the camera with both hands for as long as I wanted until I was ready and could get the shot I wanted. And so my love of back-button focusing was born.

If you’re not using autofocus on a tripod a lot (Manual focus avoids this problem), you will not have the same appreciation for this struggle. That doesn’t mean back-button focusing doesn’t still have many advantages.

By the way, even though I now have the tools to manually focus on a tripod, my lenses allow full time manual focus, meaning I can manually focus even when the lens is set to AF. By using back-button focus, I can leave my lenses on AF at all times and I don’t have to worry about undoing my manual focus when I press the shutter button.

I’m Not Autofocusing on a Tripod–Why Would I Care?

A big reason it can be hard to grasp why back-button focusing is so powerful is if you haven’t spent much time working on gaining control over focus in general. If you’re going around autofocusing with all your selection points turned on in single focus/one-shot focus mode (or if this sounds like gibberish to you), you actually have no idea where you are focusing. If you have no idea where you are focusing, back-button focusing probably isn’t the first step you need to take to get control of focus.

Personally, I have 3 bodies that have 61 focus selection points. Those 61 focus selection points are handy when I’m trying to get a shot of, say, a Cliff Swallow in flight. It’s a tiny bird that swoops and dives erratically and I cannot pan with it well enough to keep it in focus using my normal technique. As such, those 61 focus points become very handy when the bird is against a sky or other background that doesn’t fool my camera into focusing on the background (and I’m in continuous focusing mode and I have tracking set properly for such a subject).

The rest of the time, I use either 1 or 9 focus selection points. If I’m shooting landscape, portraits, etc, I use 1 focus selection point. If I am shooting moving subjects like birds that aren’t as erratic or small as swallows but are likely to fly, I turn on focus point expansion that allows me to find focus using the center point, but will activate the surrounding 8 points if the subject moves to help keep the subject in focus.

Now, this is about when students ask, “But I want more than one thing in focus. How am I supposed to get multiple people in focus if I only find focus in one place?” Well, I have news for you: critical focus only occurs at one distance from the camera. If 4 focus points light up when you press the button, it’s because the camera thinks all four of those things are the same distance away. If you want multiple people in focus, you need to understand DOF. This is the diagram I use to explain the relationship between where you find focus and how DOF keeps more than that distance sharp to students:

DOF and Focal Plane Diagram.001

So, first understand how focus works and how DOF helps you get what you want sharp, then worry about whether you should be using the back button to find focus or not.

Once you are very clear on what the focal plane is (which is technically where your camera sensor is positioned in your camera body, but is also often used to mean the plane of critical focus in the scene/subject you are shooting) and how to control DOF, you will realize the advantage of using one focus selection point whenever possible: it let’s you decide what should be sharpest in your image instead of your camera.

All of the Images in this Gallery Used the Focus-and-Recompose Technique (All of my Images are Made Using Back-Button Focusing)

Once you make the switch to using only one focus selection point, you then will want to make a lot of use of “focus-and-recompose,” which is what I was doing in the tripod example. However, focus-and-recompose is a fundamental technique  whether you’re on a tripod or hand-holding. It allows you to get both the focus you want and the composition you want without being dependent on a focus selection point being in the right place (if you are in one shot/single focusing mode). It means that, for example, you can use the center focus selection point (which always has the greatest ability to focus the most precisely in all cameras) to autofocus on a subject’s eyes and then lock focus and recompose so that your subject is artistically framed in your image. It gives you the ability to control critical focus without losing control over composition. The key is to ensure that when you recompose, you don’t change your distance from the subject as this will cause focus to shift forward or backward based on your movement.

The other key is that if you recompose, you must hold the focus. And this is where back-button focus becomes a life saver. If you have to half-press the shutter and hold it while you shift, you may either accidentally press the shutter all the way or let go of the shutter all together. Then you have to start over. With the back button, you can simply press the back button to find focus, release, and then concentrate on recomposing. When you press the shutter, because you have turned off focusing on the shutter button, your focus does not change and, as long as you also haven’t changed the distance from you to the subject, their eyes will be the sharpest thing in the image even though the focus selection point is no where near their eyes when you eventually do press the shutter button.

There are also advantages to using back button focusing when you are continuously focusing (AF-C on Nikon, AI Servo on Canon). As you track a subject in motion, you hold the back button and it keeps focusing, giving you more control on when you focus vs fire (it can be challenging to pan while holding the shutter button half way without firing). If the subject stops, you can release the back button, locking focus as if you were in one-shot/single mode and fire away. Essentially, you gain total control over when the camera is autofocusing and when it is not. It’s a beautiful thing once it clicks in your head how much easier it is to control focus this way.

This also means you never have to switch between one-shot/single focusing mode and continuous focusing mode–if you’re not pressing the back button, your focus is locked regardless of which focusing mode you’re in. By comparison, when you use the half-press of the shutter to focus, if you’re in continuous focusing, it keeps refocusing until the shutter releases, meaning it’s not possible to focus-and-recompose.

To summarize, back-button focusing is an advantage in all situations. There are fewer settings you have to use to control focus when you back-button focus and you gain greater control with less coordination. I honestly cannot think of any reason not to switch to back-button focusing other than ensuring you have the time to develop the habit before you make the switch.

You Convinced Me–Now What?

Remember, if you make the switch, you will forget to focus at first. Do not, say, decide you are going to make the switch because you are shooting a wedding tomorrow and you want to give it a try. Make the switch and really pay attention to whether you are finding focus when and where you want until you find yourself automatically pushing the back button without thinking about it and getting the results you want. Then, you can go shoot a wedding with back-button focus. 🙂

Now, the remaining question is, how do you turn it on/disable the shutter button focus? This requires finding the setting in your manual (which is usually different for each camera) that will allow you to assign functions to your buttons. You will, unfortunately, not find anything called “back-button focusing” in your manual.

In Canons, these settings are in the custom function menus and are pretty obtuse. Once you find a setting for the shutter button in custom controls, set it for “Metering Start” (or another setting that doesn’t include anything with AF in it) which will disable focusing with the shutter button. Find the settings for the AF-On button (the button is in upper right corner of camera back and furthest to the left of those 3 buttons—very convenient to find with your thumb once you get used to it). Make sure the AF-On button is set to “Metering and AF Start.”

In Nikons, it’s even more obtuse, but I don’t look at Nikons every day, so maybe it makes more sense to a Nikon shooter. In any case, you also need to go to the custom setting menu, to controls, and then go to assign AE-L/AF-L button. Choose AF-On from that menu. If the shutter button is also in that menu, check to make sure it isn’t enabled for AF-On as well. I’ve been told that in many Nikons you also need to set the camera so that the camera will still fire if it hasn’t been focused in order to get it to fire when it doesn’t know that you don’t want to refocus. That setting is also in the Custom Setting Menus under Autofocus and you want to set AF-C and AF-S priority selection to “release.”

Now, go practice, practice, practice! 🙂

 

 

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Why does a 22.3 MP camera produce a 7 MB file size?

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This file, after being resized to a small JPEG for sharing on the web, is now only 117 KB. The RAW version recorded in my camera was a whooping 28.6 MB.

First, let’s understand that megapixels refers to how many photo sites are in your camera sensor recording data to create an image. The number of photo sites equals the number of pixels (“dots”) in your image. The more dots, the smaller the dots are at any given print size, and therefore the greater the detail and resolution in your image.

So, many folks assume that if they have a 22.3 MP camera, they will get 22.3 MB files. There are many reasons why this likely won’t be true.

First, a mega pixel does NOT necessarily equate to a megabyte of data. How much data is recorded by a pixel (or, more correctly, a photo site on your sensor) varies. Brighter areas in an image record more data than darker areas. Also, badly over exposed or under exposed images record less data—the white goes to pure white and the black goes to pure black with no details. The same number of megapixels will produce different numbers of megabytes in different circumstances. Ultimately, the file size in MB is the total amount of data recorded by all pixels plus any “overhead” data added by the proprietary format.

Second, your camera has choices on how you want to record your image files. Some cameras have options to save different sizes of RAW format files and/or different sizes of JPEG format files (some even have TIFF choices). Here is an example of the different settings and the resulting file sizes from the Canon 5D Mark III manual:

Screen Shot 2015-02-18 at 12.03.26 PM

The different settings affect how many megapixels are turned on to record data as well as what file format the data is saved in, creating different file sizes.

So, what the heck does all this mean? RAW is a proprietary format that is unique for each camera vendor. It’s essentially your photo negative. It cannot be directly altered—if you edit a RAW file in software, you actually create a new file to save the changes. To share a photo, you have to convert to a standard file format such as JPEG eventually.

So, why not save all your images to JPEG in the camera to begin with? Well, there are good reasons to save JPEGs. For example, let’s say your shooting in completely predictable conditions (like a studio), you have all your settings dialed in and you know nothing is going to change on you. Shooting in JPEG can save a lot of space and allow your camera to shoot faster without having to stop and catch up periodically.

However, if you don’t feel confident that you know how to “dial-in” all of your settings (including the post-processing settings in your camera that determine things like brightness, contrast, saturation as well as the white balance setting), you might not want to risk losing data for the sake of saving space.

JPEG files are compressed. However, some of the data is thrown away when the file is compressed. So, the file size you get is significantly smaller than the RAW file, but some of that is because the data has been squished together (but is still there) and some of it is because data has been thrown away, never to be seen again.

Notice that the largest JPEG file in this example is 7 MB for a 22 MP image. This does NOT mean that 15 MP were thrown away. All 22 MP were used to record data, but that data got compressed into 7 MB. By comparison, the full RAW format would produce a 27.1 MB file. This difference does not indicate how much data was actually lost.

While JPEG is “lossy,” it also reduces file sizes by compressing data in ways that don’t necessarily result in a loss of quality. For example, instead of recording 1000 pixels individually are a particular shade of red, the JPEG file might just record that these 1000 pixels are red collectively. In that sense, the data isn’t “lost,” it’s just consolidated. However, some data is lost and repeatedly editing a JPEG causes the losses to be more significant. Also, the quality settings you choose when saving a JPEG have a significant impact.

Two areas of data loss that frequently limit what you can do with a JPEG image are data that falls outside the dynamic range of the JPEG file (pure black and pure white areas with no details) and in color casts. If you have an over-exposed sky in a JPEG file and you try to reduce the exposure in software, the sky turns gray. If you have a RAW file, it might bring back the blue—it depends on how badly over exposed it is.

White balance doesn’t fix well in a JPEG file either. If you don’t have your white balance just right, it can come out quite odd looking if you’re editing a JPEG. It can also be impossible to get the white back to white. Color-casts can ruin otherwise good images and are commonly seen in the images produced by beginning photographers.

As a general rule, if you want to do post-processing on your computer and you’re not overly concerned with hard drive space or memory, save the largest RAW files to get the maximum amount of data and the highest resolution images.

If you are confident you know how to control all the settings in the your camera properly so that you can produce final images with only the settings your camera provides and that the situation isn’t going to change suddenly (e.g., the sun coming out from behind the clouds can totally change your white balance), then you can save time and space by saving JPEGs.

Or, a simpler way to decide: are you a control freak? Save to the largest RAW format. Are you an efficiency freak? Save to the largest JPEG format. Do you not care at all how your images look? Save to the smallest JPEG format.

Frankly, I don’t know what to do with all those other choices. If you have to hand photos in JPEG format to people immediately while at a shoot, saving both RAW and JPEG makes sense to me. I haven’t come up with a use case that works for me for using smaller file sizes, however. And I sure don’t want to turn off a portion of the pixels I paid so much to have!

That said, camera makers don’t make up features just for the sake of adding features, so I’m sure there are use cases that make perfect sense for those settings as well.

This is how the birds and sky really looked in the golden hour glow. This also happens to be what Auto White Balance captured.

Weird Colors and White Balance

During a workshop this past weekend, several folks commented about having trouble with their images looking yellow or having other weird color casts. This is generally solved by changing your White Balance Settings.

What is White Balance? Back before we had miniature super computers in our cameras, film photographers would use different film or filters to prevent photos from getting weird color casts based on the temperature of the light they were shooting in. Being able to adjust white balance in your camera is one of the great advantages of digital photography.

However, if you think about your camera as a computer, it has to be programmed to mathematically recognize white, which sometimes it does quite well. White balance basically tells the camera “this is white” and it then shifts all colors based on what it believes is white.

So, why is white not always white? Light has a temperature. That temperature causes us to see the light as more blue or more yellow and it can dramatically impact how all colors look.

For example,we once lived in a house where we’d painted every other wall  a nice, neutral gray. One of those walls was in the kitchen, which was open to the great room where two more of the gray walls were located. If we had florescent lighting turned on in the kitchen only, the gray wall in the kitchen looked robin-egg blue while, in golden morning light, the gray walls in the great room turned a soft lavender. The difference was so striking that we once had a guest ask us why we had painted the walls different colors.

The walls were painted the exact same color from the exact same paint can. The difference in color that we see is caused by the difference in the color of the light striking the walls.

This means that in the great room, I needed a different white balance setting from the kitchen to make white look white.

Auto White Balance usually works great in my camera. It has worked great for me most of the time in 5 different models of digital cameras now, even going back to the early 2000’s. As the algorithms in the camera’s computer have improved with each camera upgrade, the percent has probably gone from 75% of the time to 90% for casual shooting.

But then there are the times when it doesn’t work so well.

Auto White balance often fails when:

  • The temperature of the light is outside the range of temperatures your camera’s Auto White Balance is programed to deal with.
  • There are multiple sources of light with different temperatures lighting your subject (e.g., daylight coming through a window plus incandescent bulbs plus florescent bulbs all in the same room. Or, if you’re using flash indoors, most flash units are the temperature of daylight, so that will also create the same kind of mix as in the first example.)
  • Your subject contains a lot of one color or a limited range of colors, which can fool your auto white balance into thinking the light is cooler or warmer than it is, depending on the dominant color(s) in your subject.
  • You are shooting in the golden hour around sunrise or sunset. This is not so much a failure of auto white balance as an over application. Auto white balance will often eliminate the golden cast to the light, removing the warm glow that we usually find quite pleasing.
  • You need the white balance to be absolutely accurate so that colors are represented truly (e.g., a product photo).

So, let’s say you’re shooting away and all your images look really yellow. What to do?

Before we go through the white balance adjustment options, let’s start by saying if you have set your camera to save your images in the RAW format, one option is not to worry about white balance and to set it in post-processing on the computer later. The down side to this is that your white balance accuracy will be dependent on your eye, your memory, and your monitor. If you really need exact colors, this is not the best way to achieve white balance (e.g., product photography, art reproduction, etc). If you just need it to look good, this works very well and can save you some headaches.

That said, even if you are using the RAW format, you may prefer to have good white balance in camera as well. It can make it easier to judge your images when you are not distracted by strange color casts. So here are some options:

First, check to see what White Balance Setting you’re currently on. If you’re on Auto, try picking another pre-programmed setting that best matches your situation. Indoors this gets trickier all the time because we now have all kinds of bulbs that come in all kinds of temperatures. So if your light looks warm to you, try setting the white balance to tungsten (incandescent bulbs). If the light looks cool, try florescent.

Second, you can try setting the temperature of your white balance using the “K” option for Kelvin temperature. Daylight during mid-day is around 5000-5500K. If you change the K value to something higher, your image will look warmer (more yellow). If you change the K value to something lower, your image will look cooler (bluer). You can experiment with this to see if there is a value that works particularly well for your situation, but I find the next method to work better.

Third, if you don’t need the colors to be absolutely correct but you’d like to be able to get your white balance pretty darn close in-camera without having to depend on your eye/monitor later, use a white balance target and take a picture of it in the same lighting conditions you’re going to shoot in. You can purchase a very exact neutral target for this purpose, you can use a white sheet of paper, or you can simply look for something in the same light that is neutral (white works very well for me). The target will be more accurate, but under most circumstances, anything white is good enough. The target must occupy a good portion of the frame for this to work, so zoom in.

Follow your camera’s instructions to set the photo of your target as your custom (Canon) or preset (Nikon) white balance. This will tell your camera “this is white in these lighting conditions” and your camera will measure what white is from that image and then adjust the white balance accordingly. This is a 3 step process:

  1. take a shot of something white/neutral
  2. tell your camera “use this image to determine what’s white,”
  3. set your white balance setting to use the “custom” (Canon) or “PRE” (Nikon) white balance.

This is a really important thing to do if your other white balance settings aren’t working well and you’re saving your images as JPEGs. It’s more difficult and sometimes impossible to fix white balance in JPEG images later.

Fourth, if you are shooting in circumstances where the color must be absolutely correct (i.e., mathematically correct vs to your eye) such as product photography, use a tool like the X-Rite ColorChecker Passport to set your white balance in camera and to also calibrate individual colors during post processing. This is a combination of exactly calibrated targets and software used in post-processing to ensure your white balance and colors are correct. Most people do not need this tool. However, if you do any product photography or art reproduction work, as I do, it is a huge time/headache saver.

But what if you’re white balance is making white too white? This used to be a problem in older camera models. I would get up at the crack of dawn or time my shoot around sunset to get that beautiful golden glow in the light and then my white balance would take it away! My 5D Mark III seems to leave my images nice and warm in Auto White Balance. But, if your camera is off-setting the light more than you want it to, try setting your white balance to florescent. Or, set a Kelvin temperature for the white balance that gives you the nice warm glow you’re looking for.

Finally, a word about flash. When you are using flash indoors, you can help prevent white balance confusion by using gels on your flash to match the temperature of your flash to the indoor light. If we revisit my first example:

Even though I was able to get the skin tones back to natural looking, the rest of the scene still looks a bit warmer than it did in real life. If I had gelled my flash to make the light temperature of the flash match the light temperature in the room, all of the colors could have been white balanced to look right. As it is, because some areas are more lit by the lighting in the building while others are more lit by my flash, it’s harder to achieve good white balance consistently throughout the image. Of course, there are many other problems with this image, so imperfect color temperature is the least of my concerns! 🙂

If your only flash is your pop-up flash built into your camera, here is a do-it-yourself project to create gels for a pop-up flash, but you can also buy gels. Here is a set available for pop-up at Adorama.

For speedlites/speedlights and other strobes, there are lots of options out there for gels.

There are a lot of great resources out there on how to gel your flashes. Since this post is already too long, here’s an article by the Strobist, who has many, many great articles on using speedlites.

Star Trails

Long Exposures: Part V

I’ve done many posts on things you can do with long exposures (see Disappearing Act and Long Exposures, DSLRs: Photographing Fireworks, Lightening and Long Exposure, and Long Exposures), but here in another one: Star Trails.

First, what is “a long exposure”?

When we talk about the length of exposure, we’re talking about how long the shutter is open in your camera to allow light in. Now, you may already know that how “bright” the image ends up being (or the exposure value) is dependent on the combination of shutter, aperture, and ISO settings. These 3 settings in combination control how much light reaches the sensor as well as how much light is required to get a given exposure value.

So, why would we talk about the length of the exposure separately?

How long you open the shutter determines whether you freeze motion or show motion blur and how much. So, when we talk about a long exposure, we’re really talking about showing motion in our images. Getting good exposure still requires a combination of setting the shutter, aperture, and ISO appropriately.

So, now that we’ve reviewed the basics, let’s get into a couple of examples of what you can do with long exposures (slow shutter speeds).

Star Trails

When we look at the stars, if we look at them long enough, then appear to move in the sky. This is because the earth is rotating so the stars rise and set just like our closest star, the sun. They actually move fast enough that we can record their path as a “star trail” if we leave our shutter open long enough. You can also take a series of photos and use software to combine them.

For the purpose of this blog, I’ll just tell you what I did to get this image:

Star Trails

  1. Find a location where it’s very dark and you are far from the city so you can see lots of brilliant stars in the sky.
  2. Attach remote control to camera (a remote is an absolute requirement for star trails).
  3. Place the camera on a tripod and frame what you want in the image and determine how/where you will need to focus (see next step).
  4. If you have something in the foreground on earth (like the trees in my image above), you might want to check a depth of field calculator to determine whether you need to find focus on the trees of whether you can simply focus at infinity. If you are focusing on something fairly close, you may need to use a flashlight or focus assist on your flash to find focus in the dark if you cannot see well enough to focus manually and your camera can’t see well enough with the available light to focus automatically. Just shine the flashlight on the thing you want to focus on, point your camera at that thing and lock focus (hint: this is easiest if you’re using back-button focusing, but that’s a subject for another blog post). In most cases, you will be shooting wide enough and at objects far enough away that you can simply manually set the focus at infinity and everything will look sharp. In my case, I was using a full-frame camera with a zoom lens at 27mm and my aperture at f/11. Worst case, focusing at infinity would keep everything 8 feet and further sharp. Since the trees were more than 8 ft above my head, I just set my focus at infinity.
  5. Now that you’ve found focus and locked focus, you can get your camera set on your tripod and framed the way you want again.
  6. Make sure your camera is set to “Bulb.” For some cameras, this is a setting on the shooting mode dial (where you pick Auto or Manual). For other cameras, this is an option in the shutter speed selection.
  7. Make sure your remote is set to “Bulb” as well. Bulb allows you to manually open the shutter and then manually close it.
  8. I personally like to just take a shot based on feel and then adjust from there. I started by trying to get a shot that just looked realistic. I left the shutter open about 70 seconds and this is what I got:

How the Sky Looked

  1. Because there was so little light in the area I was shooting in, I wasn’t worried about over exposing the trees with a very long exposure. If you have more ambient light, you might want to stop down more or turn down the ISO. In my case, I did f/11 for aperture and 1600 ISO. I used a higher ISO than usual because I wanted to ensure the sky registered enough light to clearly show the silhouette of the trees. Had I not been so sleepy by the time this shot completed and keeping my husband awake getting in and out of the tent to tend to the camera, I probably would have tried another shot with a lower ISO and longer exposure time to see how long I could get the star trails and if I could reduce the noise.
  2. Make sure you have a comfortable and warm place to sit where you can keep an eye on your camera. I was more worried about curious bears than people at our campsite since there wasn’t anyone else around. Also, set an alarm on your phone so you don’t forget when it’s time to close the shutter. For my example, I opened the shutter (by pressing the button on the remote 1x) and then set the timer for 30 minutes. However, I must have bumped the shutter button early because my metadata says the total exposure time was actually 1275.9 sec (21.26 minutes). The longer you leave the shutter open, the longer your star trails will be. However, be aware that extremely long exposures create more noise in the image and can build enough heat in the camera that it will shut itself off (hopefully) to avoid damage. At one time I recall reading a warning that there is a maximum limit to how long you can safely leave your shutter open on a digital camera, but I have not seen anything like that in years so this may be something only relevant for older DSLRs (or perhaps it was just a rumor).
  3. When your timer goes off, click the button again to close the shutter and go see what you got!

Trivia question: why do the star trails appear in a semi-circular pattern?

 

 

 

A 7-sec exposure captured a combination of fireworks that never appeared to the human eye

DSLRs: Photographing Fireworks

It’s that time of year again here in the US. The 4th of July promises 2-3 days of fireworks displays in many areas. For photographers, that means lots of opportunities to get shots of fireworks.

Having shot more fireworks than I know what to do with the past few years, I have several tips you may find helpful.

Here’s the short form:

  1. Pick a location upwind and preferably high enough to get a view above the crowd and the trees.
  2. Use Manual or Bulb exposure. Don’t worry much about depth of field. Keep ISO low and shutter speed long. Use primarily Aperture and/or secondarily ISO to brighten or darken the fireworks if they’re getting under or overexposed.
  3. Use a wide angle zoom lens (16-35mm works well if you’re close; 24-70mm if your further away; if you’re really far away, you might need a telephoto lens) on a tripod and a remote to release the shutter.
  4. Setup with a wider angle than you think you need–this will help you catch fireworks that go off in different positions more easily.
  5. Manually focus on infinity unless you’re closer than 2 football fields and using a telephoto lens.
  6. Speed up your shutter a lot for the finale when many fireworks go off at the same time.
  7. Try to let your camera have a short rest between shots when you can–this will help it keep up with writing image files, preventing it from not firing when you least expect it, and help keep it cooler, reducing noise.

Planning Tips:  Location, Location, Location

Find out where and when the fireworks will start. Look at the location on Google Earth. Even better, go to the location and check it out ahead of time. Look for a good vantage point that will give you a view of the fireworks and, preferably, the ground–you may need to get yourself invited to a rooftop party for the best view. 🙂 If you have trees between you and the fireworks, you will be limited to shots of the fireworks above the trees.

Alternatively, look for an interesting foreground subject you can put fireworks behind. Check out this famous photo by Jim Zuckerman of the Statue of Liberty surrounded by fireworks for inspiration.

Additionally, consider smoke when choosing a location. Check the weather forecast for the wind direction and speed. Hopefully there will be a light breeze that will dissipate the smoke. You want to be upwind of the fireworks with the hope that the wind will carry the smoke behind the fireworks and keep your photos clean.

Have an idea of how you’re going to get to your chosen location, how bad traffic will be, and when you will need to get there to ensure a place to setup a tripod. You will need a tripod.

Exposure Settings

Shooting fireworks is similar to shooting lightening except it’s easier because you can predict fireworks better. (See Lesson: 109 Long Exposures and Lightening).

There are two methods I have used with success. I prefer the second one, which is how I shoot lightening, but it requires imagining how much you’ve captured, so you might find the first one easier.

Method One: Manual Shooting Mode

In this method, you choose an aperture, shutter speed, and ISO setting that you think will give you good exposure of the fireworks. You then adjust your shutter speed longer or slower to get what you want and adjust aperture and ISO accordingly.

Most of my single-firework examples (in the gallery above) are ¼ to 1/13 of a second long using this method, but how fast or slow your shutter needs to be is partly dependent on how large the fireworks are in your frame, partly dependent on personal preference, and partly dependent on whether you want to get multiple fireworks in the same shot. Most people shoot fireworks with much longer shutter speeds.

You will likely want shutter speeds of 5-15 seconds or even longer to get multiples, but this is, of course, dependent on how frequently fireworks are being fired.

Note that you will not be able to use your light meter. You can meter while a firework is firing, but the brightness of one firework to another is quite variable and the percentage of the sky that is firework vs dark may make your meter reading deceptive. Also, during the finale, you will need a much shorter shutter speed because many fireworks are going off simultaneously–you may end up with a massive jumble with a very slow shutter.

As far as aperture goes, for fireworks it is more a factor of getting the exposure you want than getting depth of field–you are likely to have all the DOF you need (if you’re shooting wide and not too close). Because fireworks are a lot like light painting, the maximum amount of light you can capture is determined more by how long the firework is glowing, how wide your aperture is open, and how high your ISO is than what you’re shutter speed is. The one thing to be cautious of is if you use a very slow shutter and one firework goes off after another in the exact same spot, not only will they not look so good together in the same frame, but you will probably blow out the highlights where the brightest part of each firework ended up overlapping. This is one of the reasons I prefer using the bulb mode.

ISO can be minimized to reduce noise in most cases, although ISO 800 works for me when shooting single fireworks at shorter shutter speeds. But, bear in mind the longer the shutter speed, the more noise you will have.

Method 2:  Bulb Shooting Mode

Bulb simply allows you to manually open and close the shutter instead of setting the shutter speed ahead of time. Some cameras have an actual “Bulb” shooting mode (“B”) on the shooting mode dial. If yours doesn’t, bulb is probably selected by being in Manual Shooting mode and changing the shutter speed–it’s usually the one after 30 seconds.

I prefer this method. The advantage is that it allows you to control the shutter speed based on how bright particular fireworks are, how many have gone off, etc. Instead of guessing ahead of time what’s going to be fired, you can imagine how much light has reached your sensor and how many individual fireworks have been included in the shot.

Use your eyes and brain to “measure” the amount of light that has been produced by the total number of fireworks that have gone off since you opened your shutter. Mentally picture the combination of fireworks that have gone off in the image. This takes getting a feel for when to close the shutter, but isn’t that hard to do because each firework fades rather than continually adding light, meaning there’s a lot of leeway from an exposure perspective as long as ambient light from sources other than the fireworks is minimal.

To maximize the length of time you can leave your shutter open, you can set your ISO to 100 and stop down to f/22. However, you may find the fireworks look at bit dim. Each firework only emits light for so long, so you want enough light to reach your sensor to record each one brightly. For these examples, I used ISO 100 and f/16.

If you have a remote for your camera, this is a good time to use it. Pressing the shutter button can introduce vibration into your shot, which may cause some blur. In fact, it’s preferable to use a remote even if you’re not in Bulb mode. But it’s doubly important when using bulb mode.

Focus

The short answer is manually focus your lens at infinity (there should be a mark on your lens that is an infinity symbol with a line showing you where to turn the focus ring to). This will yield sharp fireworks the vast majority of the time.

If this makes you nervous, you can refer to Lesson 106: Focusing in the Dark. Or, you can point your camera at a bright object that is about the distance you expect the fireworks to be, if your lens has a distance meter you can look at the distance meter to see how far away that is and if your lens is focused at infinity. If you are shooting wide, you may be surprised to discover how close a subject can be and still result in focusing at infinity.

If there is nothing bright enough to focus automatically on, you can focus on infinity and check to make sure the first image you take is sharp.

If you are very close to the fireworks and using a lens that is longer (where infinity focus is much further away) you can autofocus on the first firework itself.

Realistically, you are likely to have so much DOF that accurate focusing is less important. I cannot say I’ve ever had a problem with focus, but then, I typically shoot wide. Focusing at infinity at 16mm, for example, with my full-frame camera at f/16 everything will stay in focus from less than 2 feet away to infinity. I have no desire to be that close to fireworks!

By comparison, if everything were the same except my focal length, at 100mm, I would need to be at least 70 feet from the fireworks. We are not usually that close either, so focusing at infinity will usually work. But, if you’re using a 300mm lens, you’d need to be over 600 feet away for infinity focus to work well. This is still pretty darn close for fireworks, but just keep in mind that if you’re using a 300mm lens and are less than 2 football fields away from the fireworks, that might be a time to worry about this–you might also want to keep a fire extinguisher handy.

Focal Length and Framing

Fireworks are a good time to have a zoom lens on your camera in my opinion. Especially if you are in close proximity. The first time I shot fireworks, I put my 100mm prime lens on my camera and was surprised when the fireworks didn’t fit in my frame–they were much larger than I expected shooting from about a quarter mile away. I ended up scrambling to change lenses.

Using a zoom gives you room to adjust for such misjudgments since you can’t tell how big the fireworks will be until they start going off.

If you like to include the landscape in the shot, you will definitely want to shoot wider. The other thing to be aware of is that you are setting up on a tripod and you will not have a lot of time to adjust between shots. In fact, my preference is to shoot wide enough that I never change the camera position once the show starts. I prefer not to miss shots by fussing with the tripod.

I do miss shots when the fireworks suddenly get fired in a different direction or the wind blows them out of the frame. But, this happens infrequently when I’m shooting wide.

Cautions

If you are firing off a series of long exposures one after another, there are a couple of things to be cautious about. First, you can fill your memory buffer in your camera. This is a little hard to predict when you are doing long exposures. For example, my camera can shoot 6 frames per second but if I fire 18 shots in 3 seconds, the memory buffer will fill and I will have to wait for the camera to catch up writing the images to the memory card. Theoretically, one would think if you are firing off a long exposure followed by another the camera would be able to write the first image while exposing the second and keep up. However, I have run my camera out of memory right before the finale and missed the entire finale while it was catching up. I was not happy.

Just pause every once in a while to see how long it takes for the busy light to go off–if it’s a really long time, you might want to space your shots a bit more.

The other thing to be aware of is that long exposures produce a lot of heat in your camera. This is why long exposures tend to be noisier than short exposures. Giving your camera a little time between shots may also help keep it cooler, keeping noise to a minimum.

Post Processing

Smoke is quite detrimental. You can use curves and levels in Aperture or Lightroom to darken the smoke and make it less obvious to the eye. However, you also loose some of the light in the fireworks in the process and can substantially change the texture of the light trails.

Here’s an example of before and after:

I like the way the fireworks look better in the before image, but the smoke is distracting and lowers the contrast.

Sometimes, a puff of smoke in the wrong place ruins an image no matter what you do in post-processing (well, what I do in post-processing; Photoshop gurus may be able to deal with this). And sometimes the smoke is positioned so that you can still enjoy the image (even if you’d like it better without the smoke):

Conclusion

Do not stress about shooting fireworks. It’s not hard and you’ll get a better view of the fireworks if you plan ahead a little bit whether your images turn out or not. Just don’t forget you’re having fun!

And this is one of many shots of Osprey in flight that I did the crawl through poison ivy for

Recovering “Erased” Photos

Hopefully, you are all well-organized and have never gotten confused about which images on your memory card have been saved to your computer and which haven’t. In my case, I recently had a brain malfunction known as “brain flatulence” causing me to reformat a memory card containing about 1000 images I hadn’t uploaded yet.

It happened in a moment of distraction. I was checking to see how much space was left on the memory card in my camera in preparation for a shoot just to see if I needed to swap out the card before I started. I knew I hadn’t uploaded the images yet. I made several mistakes:

  1. I went to the format card menu to see how full the card is because it’s easier for me to see the big bar graph displayed on my LCD than the counter that tells you how many images you have room for. Putting on my reading glasses and looking at the counter would have been safer.
  2. I was sitting in my car waiting to meet someone with traffic zooming by and other distractions. In the moment when I should have selected “cancel,” a loud vehicle grabbed my attention.
  3. I use the format card menu every time I want to erase images. My muscle memory is to select “format card,” not to select “cancel”–I have to pay close attention when in the format card menu.

In the moment the loud vehicle captured my mind, my muscle memory took over and gone were all my images! Mind you, I had bushwacked through thick undergrowth, dragged myself through poison ivy, and braved the aerial version of a mine field walking under a heron rookery to get some of the images on that card. I was not a happy camper.

But, here’s the good news! When you delete images or format your card, no data is actually lost. Rather, the existing data is marked as eligible for being overwritten. This means that as long as you set that card aside and don’t write any photos on top of your “deleted” data, your images can easily be recovered with the right software.

The software I chose first was Lexar’s Image Recovery 4. My main reason for choosing this software was because it is a) available for a mac (and windows), and b) free because I own several Lexar memory cards. This software claims to work on all memory cards, but it was a Lexar card I used it with.

Unfortunately, Lexar does not have the best ordering process. You can download the trial version of the software for free, but you can only get a key by contacting support. Alternatively, you can pay $40 for their newest version, IR 5.

I recommend NOT scanning your memory card with the trial version–you can only restore one image. After I had successfully scanned my card and restored one image, I was stuck waiting for a license key. Support told me it could take up to 48 hours to get it. When I finally got the license key and rescanned the card, the software couldn’t find any images. Yes, I freaked.

Fortunately, support provided me with a key for IR5 because I had recently bought one of my Lexar cards. Once I had IR5, I had no trouble restoring all of the images. The interface is intuitive and although running the scan on a full 32GB card and restoring the images does take a significant amount of time to run, all I had to do was click a couple of buttons.

So, if you own a recent Lexar card, download the IR5 version and send support a request for a free license key (you will probably need to tell them what card you have that entitles you to the software). Wait to run the software until you receive the key and then you should have no problems.

If you don’t own a Lexar card, there are other software options out there. I was unable to find a reliable source I’m familiar with for reviews of these software options, so I went with Lexar. My logic was that they have a major stake in making sure I recover my photos successfully and they are a company I’ve already trusted with my images for many years. While they have logistics issues with giving out licenses, they were helpful and supportive, the software worked, and it didn’t cost me anything but time.

By the way, for iPhoneographers, I stumbled across software that is supposed to recover deleted data on the iPhone, including photos. I cannot vouch for the product, but here is a review on CNET: http://download.cnet.com/Data-Recovery-for-iPhone/3000-2242_4-75856767.html

Same grass, same lens with the same dirt, but shot at f/5.6 and 65mm and with a different angle to the sun.  I did not remove any flare spots in post processing--there was only one and it disappeared when I converted to B&W

Lesson 110 (DSLRs): How Clean Does Your Lens Need to Be?

For those of you who don’t have time to read a long post, here’s a summary so you can decide what’s relevant to you:

  1. Don’t clean your lens unless you’re actually seeing spots, areas of low contrast or fuzziness in your images.  The first part of this post provides an example and links to other examples on what it looks like when stuff on your lens shows up in your images.
  2. If you do clean your lens, be gentle to avoid doing more harm than good.  Take the time to go to the second part of this post and read the referenced article before you start cleaning.
  3. Before you have your sensor cleaned, make sure your problem really is dirt on your sensor.  The last part of this post provides a tip and a link to step-by-step instructions on testing whether your sensor is dirty.

Recognizing When You Need to Clean the Lens

It always amazes me how much debate there can be over seemingly simple topics in photography.  However, most experienced photographers tend to agree on this one:  your lens doesn’t usually need to be all that clean.

I confess, I hate to clean a lens.  I don’t do it unless I really have to.  When it comes to my lenses, when I first started getting “serious” about photography, one of my mentors warned me that cleaning a lens too vigorously could damage the coatings on the lens and cause more problems than the dirt.

This made me so paranoid that I was afraid to clean my lenses.  What I discovered was that the crud on my lens didn’t show up in my images, so I was convinced it really wasn’t worth risking damaging the lens to clean it.

Then, a few years ago, I found myself shooting outdoors in the middle of the day a lot more frequently than I would prefer.  When this led to experimenting with more shots that include a lot of bright sunlight, I suddenly started getting images with blurry flare spots all over the place.  Advised that I had a dirty sensor, I took my camera in and had the sensor cleaned.  But that didn’t solve the problem.  My problem was the dust on my lens.

Since then, I’ve learned a few things about troubleshooting spots in your images.  First, there’s lens flare, which can occur regardless of how clean your equipment is.  But, when you have dust on your lens, if light strikes the front lens at the wrong angle, the dust can also contribute to seeing lots of flare spots in your image.

In the following example, some of the flare is not attributable to dust, but the large number of large, bright blurry spots indicate there was dust on my lens and the sun was hitting them just right:

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One of the challenges of this problem is that it may occur quite infrequently.  This was shot at 28mm and f/20–both the wide angle and the stopped down aperture make it more likely that flare will turn up in the image.  The inclusion of the sun in the image also meant my lens hood wasn’t going to block direct light from hitting the front lens element, which is the root of flare problems.  However, in this case, I wanted lens flare to show in the image.  I wasn’t, however, bargaining for an entire sky full of blurry bright spots!

Since cleaning the lens, the problem has been reduced to “normal” lens flare.

But the caution I received so many years ago remains true–over cleaning your lens is more damaging than under cleaning–you really only need to clean the lens if your images are affected.

Here is an amazing article that shows just how little stuff on your lens may show up in your images–it’s definitely worth the read:  Dirty Lens Article.

In spite of what the Dirty Lens Article demonstrates, this is not a justification for abusing your lens.

First, just like the dust on my lens did not show in my images the vast majority of the time, damage to the lens will also show up under different circumstances.  Note that Munger’s examples with named aperture settings were all at f/5.6.  As mentioned earlier, flares are more likely to show up when you’re stopped down.

Second, even if you don’t care if your lens is in pristine condition, should you ever want to sell your lens, your buyer probably will.

How to Clean the Lens

When you do clean your lens, remember that less is more.  You don’t want to rub at the lens like you’re cleaning a window.  Instead, try starting with a fun little toy called a blower.  I particularly like the Giottos Rocket Air Blaster.  It doubles as a fascinating conversation piece should you decide to keep it on display in your living room.

By using a blower, you can shoot dry air (unlike when you blow with your mouth) across the lens to blow away any loose dust on the lens.  Dry air does a better job lifting away dust than moist air.  Plus, do you really want to know how much spit you spray when you blow on something?

Some people like to use a very soft brush after the blower to brush away more stubborn dust.  The idea is to remove anything that might be abrasive gently so that it doesn’t scratch the lens or the coatings on the lens.  When you start rubbing at the lens with a cloth, you can effectively turn dust particles into sand paper, abrading those special coating that do things like reduce flare.

I skip the brush step and do the next step very, very gently.

When I first attempted lens cleaning, I bought fancy lens cleaning fluid and cleaning papers.  I put a few drops of cleaning fluid on the paper and gently wiped the lens.  Later, I adopted Ken Rockwell’s approach of breathing on the lens to fog it up instead of using cleaning fluid.  (That article is still available and includes additional tips for using methyl alcohol to clean stubborn spots:  How to Clean Lenses, Monitors, Filters and CCDs.)  I also switched from using cleaning papers to microfiber chamois clothes–the main problem with the paper for me was gently getting rid of streaks without having my fingers slip off the paper and create new fingerprints.  But then, I have below-average coordination.

If you are going to go to the trouble of cleaning your lens, clean the back element as well as the front (at the end that attaches to the camera).  According to Nasim Mansurov, rear element dust shows up as dark specks in the out-of-focus portions of the image. He shows an example in this article.

Dust on the Rear Element vs Dust on the Sensor

Since dust on the sensor also shows up as dark spots on images, it’s probably worth cleaning the rear element before having your sensor cleaned (or cleaning it yourself).  If you want to be positive whether it’s the lens or the sensor, take test shots using two different lenses based on the instructions in this article from Jeff Guyer, Got Sensor Dust?  Check.  See if the spots show in the same places even when you switch lenses.  This will guarantee there’s no confusion between lens dust and sensor dust.