Exposure Bracketing is the process of taking a series of shots of the same scene at different Exposure Values (EV).
Although Exposure Bracketing can be done manually. Here we only going to talk about Automatic Exposure Bracketing using the camera’s menu system.
- EV (Exposure Value) is the same as a Stop of Light. 1 EV = 1 Stop.
- HDR (High Dynamic Range) is a software process of merging two or more shots taken at different EVs into one image.
- Exposure Blending is a software process using layers and masks to blend images with different exposure values.
- Luminosity Masking is an Exposure blending method using areas of share luminosity as masks.
If you want to read about Luminosity Masking I’ve covered it before.
Why use Exposure Bracketing?
In scenes where there is a wide dynamic range that one shot alone cannot capture. We can use Exposure Bracketing to capture the full dynamic range of a scene across several shots.
Those differently exposed shots can be blended together post-processing by either using HDR (High Dynamic Range) or Exposure Blending techniques.
What is taking place?
A common scenario is three shots at 2 EV apart.
The first shot will be what the camera thinks to be balanced exposure this will be the 0 EV shot.
The second shot will be at two Stops/EV below. This will be the -2 EV shot.
The third shot will be at 2 EV above. There is no plus (+) prefix
Who needs Exposure Bracketing?
Mainly Landscape and Real Estate Photographers.
A common scenario could be a sunset or sunrise with a dark foreground and a bright sky.
Another scenario is a room that is very bright near the windows and very dark in other places.
What should I be aware of
- Ideally, you should be using a tripod. It is still possible to shoot hand-held and get ok results post-processing.
- Use manual focus or back-button focus.
- Deciding on how many stops or EV’s apart you should use can be calculated. In reality, we are not going to do that. So, three shots at 2 EV apart is seen as the standard for capturing the dynamic range of most scenes.
- Shooting all the time in Exposure Bracketing is pointless. When the conditions become challenging light wise, then use Exposure Bracketing.
- Remember that HDR should not mean Horrible Dynamic Range. So, maybe shooting three shots at One EV apart could lead to better results.
The Many Permutations
With automatic Bracketing, the camera will underexpose and overexpose an image by changing the f/stop, shutter speed, or ISO?
- In Aperture Priority, the camera keeps the aperture the same and changes the shutter speed.
- In Shutter Priority, the camera keeps the shutter speed the same and changes the f/stop.
- In Program, the camera changes both the f/stop and shutter speed
- In Manual, if Auto ISO is set, then the camera changes the ISO. If ISO is set to something fixed, then the camera modifies the shutter speed.
The only practical setting for most for those of us that shoot Landscapes or Real Estate photography is using Aperture Priority. Personally, I tie down my ISO to the native ISO of my camera which is 100.
I will move my ISO higher as the light fades.
I don’t have the luxury of owning an expensive light meter. For Landscape photography, although a light meter would just slow you down. As we are normally struggling with the fading light.
Start in Aperture Priority, then raise the ISO as the scene gets darker. Maybe call it a day when you reach 1000 ISO. Unless you are shooting the Milky Way.
- Use a tripod is possible.
- Shoot in Aperture Priority for Landscape and Real Estate photography.
- If using an Auto-Focus lens shoot in manual focus, or use back-button focusing.
- Three shots at 2 EV apart will cover the dynamic range of most scenes. Experiment by using 1 EV apart.
- Tie your ISO down but be willing to move it up to cope with fading light.
- Shooting for HDR? Use Aperture Priority with a fixed ISO (not auto). Set the bracketing at 3 Shots at 2 EV apart. This is not fixed in stone, it’s just a recommendation. You try 3 Shots at 1 EV apart.
How you decide to use your shots is up to you. It’s worth learning Luminosity Blending over using HDR as you have far more control.