D850 exposure strategy — auto-exposure settings

This is the 73rd in a series of posts on the Nikon D850. You should be able to find all the posts about that camera in the Category List on the right sidebar, below the Articles widget. There’s a drop-down menu there that you can use to get to all the posts in this series; just look for “D850”. If you’re new to this thread, it’s a good idea to start reading here.

The last post proposed a strategy for managing ISO settings and exposure on the D850 when setting the exposure manually. I think this is an excellent way to do things with a camera whose read noise relates to the ISO setting as we saw here. But it’s quite different from the way most folks use their cameras. Now I’ll write about a way that should be a bit more familiar that gets most (but not all) of the same benefits and the purely-manual approach.

The cardinal rule remains the same: If you can, expose to the right (ETTR) at base ISO. With the D850, you can use the live view histogram, or take shot and look at the histogram as you review the capture. Set your exposure compensation (EC) so that your meter will give you that exposure. You might want to bias the exposure slightly towards underexposure if the light is changing, since it’s easier to deal with a bit more noise in the shadows than blown highlights.

But let’s ask what you should so if the ETTR exposure is too long for you or requires a wider lens opening than you want to use. If the lens opening is the most important thing to you:

• Set the ISO to base ISO
• Set the camera to aperture-priority exposure mode
• Set the aperture to whatever you wish
• If the ETTR exposure is acceptable, you’re done; take the shot
• If the shutter speed is too long, and you want some extra highlight protection, crank the EC down (make the numbers more negative) until you get an acceptable shutter speed.
• Stop when you get to two stops underexposed from the ETTR setting.
• If that gets you an acceptable shutter speed, you’re done; take the shot.
• If not, set the ISO to 400
• If the exposure is acceptable, you’re done; take the shot.
• If the shutter speed is too long, and you want some extra highlight protection, crank the EC down (make the numbers more negative) until you get an acceptable shutter speed.
• Stop when you get to three stops underexposed.
• If that’s still a short enough exposure, increase ISO until you get a shutter speed you can live with, keeping the EC three stops undersxposed.

Sounds like a lot of fiddling, but after you’ve painstakingly follow the steps above a few times, you’ll get a feel for it and will be able to take many shortcuts. The idea is to make use of the highlight protection that comes with what would generally be called underexposure, and boost the gain in postproduction, which, thanks to the nature of the D850 sensor, has practically no noise penalty.

If the shutter speed is what’s key for you, use the above procedure, but set the camera to S mode and swap aperture and shutter speed in the protocol.