I think what you are talking about is typically called ETTR (Expose to the right), ie expose according to highlights.
The basic idea is fine, although the back-of-camera histogram can be deceiving because it is based on the camera jpg. More (much more) is available here: https://blog.kasson.com/using-in-caera-histograms-for-ettr/
(I copied & pasted the url, so the missing m is correct)
Otherwise, it can happen that you want the background to clip. Shooting at 5pm in winter in Lyon, there are lots of times when you are going to have way more than 14 bits worth of DR in front of you, and you’ll need to decide what you want. You might be shooting with a plain white background in studio, and you want the entire background to be paper-white: so whether all channels are at 255, or one or all is way over, you’re going to push them into clipping with the tone curve or similar. It doesn’t matter. You can easily have a super-bright reflection off a belt-buckle that doesn’t matter… or it might be off a belt-buckle just in front of the face of the subject and it does matter… but maybe then you need to mask it. Good luck.
For more exotic artistic reasons, you might want the main subject clipped… but yes, you should know what this is going to mean for processing. It will be easier if you are going to convert to B&W.
So here’s an example a) of where clipping is unavoidable if you want more than silhouettes; and b) when it’s deeply annoying bacause it’s small, but irregular, against a dark background and in a bad spot…
Pretty much standard with many cameras that have DRO options - underexpose by 1-2 stops and tonemap the shadows up in the SOOC JPEG. Since the raw image isn’t tonemapped, you see the original highlight-preserving underexposure.
There was recently some good discussion on DPReview on how to set Sonys up to have the in-camera highlight clipping warning be close to the RAW clipping threshold, I’ll try and dig that up.
Someone correct me if I’m wrong, but isn’t ETTR different to exposing for the highlights? When exposing for the highlights, you will often end up with an underexposed overall scene out of camera as the highlights should have the correct exposure. On the other hand, when exposing to the right, you are over-exposing as much as possible (without clipping) to capture as much data as possible to the right of the histogram, because digital sensors are better at capturing brighter details than dark details.
I agree. Exposing for the highlights is a bit of a vague term and I think different people mean different things when they say it. I suppose the one thing everyone agrees on is that exposing for the highlights means not clipping them, but apart from that the definition is a bit fluid. ETTR is much more specific.
BTW exposing-to-the-right is less to do with compensating for a property of the digital sensors and more to do with the properties of the light itself (shot noise). The more light you capture, the higher the signal-to-noise ratio and the more information you are capturing.
No, they’re chasing the same objective. In both, the object is to put the highlights right at or just under the sensor saturation point. For some scenes, that’s a +EV from the “standard” exposure, for others it’s a -EV.
ETTR is a special case of exposing for the highlights, as a square is to a rectangle. Moreoever, when you have specular or bright sources, you can’t do strict ETTR. The rest of your image would be woefully near the noise floor.
Sony cameras allow you to change the settings that you get an “hdr” histogram which isn’t based on the developed jpeg. Take a look at DRO and Creative style settings
@anon41087856 is right about Fujifilm cameras. At least some of their X series are know to underexpose by about 2/3 of a stop. It was evidenced in comparison shots on review sites such as dpreview, to compare Fuji cameras with other cameras they had to lower the shutter speed by 2/3 stops to get a similar brightness. It’s not a metering nor a DR thing. Take a shot at 1/125, f/11, iso 200 on a Fuji X, and same settings on a Sony or whatever, the Fuji will look less exposed.
The realization that slapped me in the face is that there really is no “correct” exposure. For a low-dynamic-range scene, you can “move” the raw data across the face of the sensor a few stops for a set of images, and when in post you anchor each’s highest value to white, they’ll all look pretty much the same.
It’s the middle gray reference to which most meters are anchored that determines how the rest of the data lays on the sensor. What’s the number I saw recently, about 2.4 stops from gray to saturation in most sensors, so any light that goes past that will just saturate the sensel. In Watership Down terms, the “hrair limit”…
A lot of the time, the data past the hrair limit is just specular, in-scene light sources. But sometimes, it’s brightly-lit objects; go see my “Afternoon Snack” PlayRaw for a good example. In those cases, one might want to underexpose from the camera’s assertion, pull those bright bits into resolution. But that will push shadows down toward black, and into the noise floor of the sensor, if they weren’t already there. Sometimes, the photographer is hungry, and wants to eat more than wanting to mess with the exposure…
Soooo… pick your poison, I guess. This is why I’ve bought each successive camera, chasing dynamic range, so when I pushed shadows further into the well, the sensor tolerated it a bit better…
I’ve never really thought of it like that, but I see what you mean.
Even if the objective is similar, I’d always thought they were two different approaches.
With ETTR, I’d always considered it primarily as an approach for dark scenes where you are deliberating over-exposing to try and capture as much light as possible, which you can then darken in post to get the “right” exposure while keeping noise to a minimum.
With exposing for the highlights, I’d considered it simply as an approach for bright scenes where you prevent clipping by exposing for the brightest part.
But on reflection, you are essentially just doing the same: exposing as much as possible just below the clipping threshold. Thx.
Hmm, I didn’t see anything about setting up the zebras there.
The issue with zebras is that they’re derived from the JPEG settings of the camera - so having them set improperly can result in the camera underexposed significantly compared to what would put the highlights just under the RAW saturation threshold.
I had missed the interesting observation that zebras are only calculated from the green channel before - that explains why I’ve so frequently had issues with blue/red LED lighting looking horrible despite no apparent zebras!
Yeah, it’s pretty much like setting up the gain for a microphone: increase it as much as possible to optimize the PSNR, but keep it -3 dB under clipping. Every anchor number such as grey = 18% or white = 100% = log2(grey) + 2.43 EV is merely conventional, and useful only if no post-processing is performed.
When I first bought my Nikon a couple of years ago, first thing I did was set the default exposure to -0.3 and default flash exposure to -0.7, along with using a Neutral profile. Defaults seemed completely unrealistic, but eye-candy pleasing for Internet posting photos.
Nikon’s Matrix metering is good for taking photos of black cats or other black objects, as matrix metering automatically compensates for such lighting abnomalies, rather than using center weighted or spot metering. (Can be worked around by using spot metering, but takes a few more seconds.) Or, if you find yourself always applying a curve within your editor to increase contrast/saturation for bringing-out shadows, etc, Matrix metering also does a pretty good job for sufficing for such a time consuming post processing within your editor.
You make this sound trivial, but it’s one of those hard learning curves I always have trouble getting over when starting a RAW post-prod in Darktable. Thankfully your filmic stuff makes that easier, but it’s still a challenge to “get back to the JPG”, so to speak, when starting from a “bland” and underexposed RAW…
