In this article we’ll look at how to Expose to the Right (ETTR) using the Sony a7R II and Sony a7S II. I’ve used the a7R II for comparisons, though I own both cameras and the same principles apply.
What is ETTR?
Exposing to the right (ETTR) is the way to get the best image quality for still photographs (or video, but not on the a7R II and a7S II cameras) if you’re shooting RAW.
The principle is simple. When you raise your exposure to just before it clips, and shoot your image in this overexposed state, you get the least noise. You’re basically raising the noise floor so that when you later bring the levels down in your RAW processor, the noise will effectively get crushed – without affecting anything else.
Here’s an example of a RAW image shot at standard exposure vs one that was exposed to the right (right click to open in 100% view):
Note: JPEG compression doesn’t really do it justice, but you can see the extra noise in the ‘correctly’ exposed image. Whether or not this tiny difference makes sense to you, is your call.
Original RAW files are available for download in the Sony a7R II Guide.
When would you use ETTR?
You would use ETTR when you want the best signal to noise ratio. This is handy when you’re printing or interpolating your images. When you do these things, the noise becomes even more obvious in your final print or file, and ETTR is the way to minimize it.
The added benefit of ETTR is you get cleaner and more natural tonality and gradations in your shadow regions, as you can see in the above image. Here are some scenarios where ETTR works best:
- Fine art photography
- Astrophotography and general nighttime photography (though specular highlights are a pain to deal with)
- Photographic reproduction of artwork for archival
- Military, scientific and medical imaging
For most of us, and even for most photographic purposes, ETTR is overkill. If you ETTR, you need to take care while shooting and spend time for an extra step in RAW processing. For some, this is a negligible issue, because RAW shooters need to process their images anyway.
Let’s see how best to ETTR with the Sony a7R II and a7S II, so we don’t screw up the process.
How to ETTR with the Sony a7R II
Here’s the best way I could find:
- I’m pretty sure you can get close with any other creative style, not just Neutral. But this lesson was about finding the best possible method, then Neutral it is.
- To get uncompressed RAW on the a7R II, you need to upgrade to firmware version 2.0.
- The color space doesn’t matter.
- Sometimes, a certain color channel clips first, and this is normal. For real world images, the histogram does a good enough job of assimilating this. I’ve found it clips as soon as one channel clips.
So what’s the formula? You need to:
- Shoot uncompressed RAW only.
- Switch to neutral creative style and reduce the contrast to -3. The color space doesn’t matter.
- Use just the histogram to make sure your scene doesn’t clip. You can quickly raise the exposure from middle grey by two stops, and then work from there.
- Ignore the highlight exposure warnings. Don’t use the zebras!
- Until I get some clarity on Capture One, process RAW images in Lightroom or ACR.
The formula, just for fun:
[N-3] ±2/3EV ?1/3EV
- N-3 is neutral creative style -3 contrast
- ±2/3EV is the headroom you can expect above this, but remember, it’s also a -2/3 (zero, but where’s the drama in that?), so you might not get headroom, because of the next factor:
- ?1/3EV Error. This stands for two things. One, it is highly likely that you might make a human error in judging the histogram, probably a third of a stop, and this might only result in a headroom of +1/3 EV instead of +2/3EV (or at worst an overexposure by 1/3 EV). However, a headroom of only +1/3 EV is the second delta, because it is the smallest EV possible, and is within the margin of error. The point being, do not overexpose by +2/3EV over ETTR to get that headroom, because the errors might ruin your shot.
Don’t worry if this confuses you, just use the guidelines above the formula and keep it simple!
I hope you’ve found this lesson useful. Do you think ETTR is right for you?