A High Dynamic Range (HDR) photograph is really a set of photos, that you merge into one photo. If you are unsure of what HDR photos really are, you can read my introduction here.
The requirements to make an HDR photo out of e.g. three photos, is that the three photos are identical, except for the fact, that one is under exposed (dark), one is over exposed (bright) and one is normally exposed. A DSLR camera and most mirrorless system cameras, can be configured to do these three photos automatically, but only a very few snapshot cameras can do it.
In order to take a set of photos for an HDR photo, you need to:
- Set your camera to Aperture mode to keep the depth of field constant.
- Set Auto Exposure Bracketing (AEB) to take more than one shot, each a with different exposure.
- Don’t use Auto Focus Control (AFC), you might get different focus points and thus different photos.
- Set your camera to Timer mode, if on a tripod to make sure the tripod has stopped shaking.
If you can not find this setting immediately this is probably one of the few things, you will need your manual for your camera. Most cameras has got a dial on top of the body, where you can set the camera into different modes. Typically modes are: Auto, P, A, T, M and then some scenes.
Auto: The ‘auto’-mode does what it says, it does adjusts everything automatically. This you can’t use to shoot HDR photos.
P: Program-mode. This is semi-auto. It does set the aperture and the shutter speed automatically, but other settings you can set as you like. This you can’t use to shoot HDR photos.
A: This is the Aperture-mode. When you use this setting, the aperture is fixed, but the camera does the rest automatically. The aperture controls the depth of field, and if you keep this fixed, you make sure, that the depth of field is fixed and that you get photos with the exact same focus all over the image. This is the setting you will need to use for HDR photography.
T: Time-mode. This mode fixes the shutter speed, but everything else is automatically set by your camera. This you cannot use for HDR photos.
M: Manual mode. You can use this for HDR too, because the aperture is fixed, but I personally prefer to use Aperture mode. Only in really extreme situations where the camera gets really confused would I consider using the manual mode.
Scene modes: These you can’t really use for anything as a serious photographer. The camera makes some adjustments you do not control. You can do a much better job your self. And I believe in ‘just pressing a button’.
What f-stop should you use?
When shooting in aperture mode the f-stop is fixed to whatever value you select. The camera will adjust the shutter time to get the right exposure. But what f-stop should you use? “It depends” is the really unusable, but correct answer. The f-stop controls the depth of field. In other words how much is in focus.
What is really confusing is that large f-stops, have got the smallest numbers on your camera. That is because the number is shortened, it really should be f/4.0, f/5.6, f/11, f/16, f/22 etc, and if you remember your math and you see f as a number you can see that f diveded by 4 is a larger value than f diveded by 22.
Large f-stop let’s in a lot of light, gives a fast shutter speed and it gives a shallow field of depth, while small f-stops gives large depth of field. If you want something to be blurred in the background you want to use a large f-stop (4.0 or 3.2, 2.8 or even 1.4).
Setup your camera to Auto Exposure Bracketing (AEB)
This is the essential setting that gives you the under exposed, normally exposed and over exposed photos you need for your HDR photo. You may need to grab the manual of your camera to figure out how to set up this.
Somewhere, typically in the menu, you will find the setting Auto Exposure Bracketing. When you adjust this, you will see three markers: One will be on 0 and the two others will move symmetrically in each direction. There will be numbers above the scale, typically –2, –1, 0, +1, +2.
Each marker represents a photo that will be taken. If you place the markers on –2, 0 and +2 you will get a photo that has an exposure compensation of –2, one normal and one that has an exposure compensation of +2. The –2 will be an under exposed photo while the +2 will be the over exposed photo.
You want to use –2, 0 and +2. If you go with less, you don’t cover as much dynamic range.
Turn of the Auto Focus Control (AFC)
You must make sure that you have your camera in either manual focus mode or in auto focus mode (AF). Auto Focus Control (AFC) is intended for sports and other moving targets. The camera will refocus constantly. If there is something you don’t want, when you shoot bracketed photos to use for an HDR it is photos with different focus points. Different focus points is the same as photos that are not identical.
This is usually a button or a switch somewhere on your camera body that decides which one to use, and you may need to consult your manual to find it.
Optional: Use the timer if you use a tripod
If you have your camera on a tripod, while you are shooting your three shots, you can use the timer to trigger the shots. When you let go of the camera, the tripod unless very sturdy, will typically shake slightly. By using a timer the tripod gets a little while to become steady before the camera starts shooting. Usually a timer set to 2 seconds is plenty of time.
On many cameras including Canon and Nikon you get the advantage, that the camera shoots the 3 bracketed photos automatically too.
If I shoot bracketed photos hand held I find the timer annoying and I just keep the trigger down until my 3 shots are fired.
When you have your bracketed photos you need to merge them, which you can read about here.