Camera histograms - are they useful?

pdk42

All-Pro
Location
Royal Leamington Spa, UK
Name
Paul
I had an outing with another photographer last week and we had a little discussion on whether the in-camera histogram is useful or not. He says "yes", I say "no". It would be interesting to hear your views. The discussion applies to raw shooting only, and probably mainly to landscapes where preservation of highlights is essential. Here's my case:

  • Since we're talking raw, the brightness of the image can be corrected in PP later.
  • To minimise noise, we want to increase the exposure as much as we can, but not to the point of clipping highlights (i.e. ETTR).
  • GIven that, what we need is something that tells us when highlights are clipped.

OK, so we need a histogram then? Well, maybe, but I contend that the histogram is too crude:

  • Clipping is shown by the highlights pushing up to the right edge of the graph.
  • But the difference between clipping and not clipping isn't that obvious.
  • The amount of clipping is hard to assess.
  • And you have little idea WHAT is clipping in the image.

So, what's the alternative?

Zebras, or "blinkies" (over-exposure indicators) of course!

  • They not only tell you that you're clipping highlights, but they show you WHERE the clipped highlights are.
  • So, you can choose to perhaps leave some clipped by a quick assessment of the EVF/screen. Like the sun for instance, but not the clouds.
  • They overlay nicely on the image. By contrast, the histogram is some alien graph that's splatted somewhere you probably don't want it!

I rest my case!
 
Last edited:
It is also useful to note that in many (most? all? not sure) cases the histogram is based on processed data, i.e. as if you were shooting jpeg, even when actually shooting raw. That may or may not be accurate, but one should be aware of the potential to mislead.

I will sometimes look at a histogram particularly if I am chimping, but during shooting if concerned about clipping I most often use zebras/blinkies. I am not big on ETTR but do not like to blow highlights as they are much less recoverable versus pulling up shadows. So I much prefer zebras and on my camera can customize at what relative exposure level they kick in. It can get a bit overpowering if over-exposing large areas on purpose (rare) and have enabled my usually red focus peaking because I am using a manual lens... but I have custom buttons and menus to turn things off/on.
 
I'm probably guilty of using the clipping warnings more than the histogram, especially for wildlife, but, even so, I find the histogram just as useful. The observation that one can't tell where clipping is occurring is equally true of the under/overexposure warnings when the clipping is located in pixel-patches small enough to be averaged out to not-clipping when downsized for display in the viewfinder or on the monitor panel. I find the histogram very useful to avoid underexposure when I'm shooting, for example, critters in shade or forest scenes. I've learned to avoid having the rightmost column (the red one) brightly lit. Since I have my histogram warning thresholds set to 2 and 253, I can tolerate a little red ember at the right side. I've been riding the histogram for about ten years now (since I acquired the original E-M 5) and I've become comfortable using it. Horses for courses. ;)
 
Depends on how the camera maker implements the histogram. Some show what the raw data is, others show the exposure based on the jpg preview.

I use histograms, blinkies, zebras as a guide, but never fully rely on the automation.

I will say that I do shoot a LOT of jpg, so the histograms are probably a lot more useful to me than when shooting raw.
 
No. For my purposes the histogram isn’t useful. Blinkies are better but still not great. What works for me is that over time I’ve learned how my camera over/underexposes and I adjust the exposure comp as needed. If I have the time I’ll take a few photos at different exposures, otherwise I may underexpose slightly to be on the safe side.
 
Shooting a lot in manual mode, I keep recurring to histogram and clipping warnings from time to time depending on the motif just to make sure. Of course you can repair some issues in PP, but physics has its limits.
 
I agree with your original post. Blinkies are more obvious to me than reading a histogram. Plus the histogram seems to take more screen space and more distracting when composing.

I prefer the red olympus blinkies over panasonic zebras. The red is just more obvious while with the zebra's small patches of over exposure are less noticeable.
 
Add another here for Team Blinkies.

I almost never look at a histogram in camera. Partially, that's because I don't do much "chimping" in general, but to @fredlong's point that may be partially to my own lack of a really thorough understanding of the information the histogram conveys, if I'm being very honest.

- K
 
Yet another for team blinkie, they have been much more useful for me. Having said that, I do use the histogram to check my general exposure in very dim lighting, where I’m using manual modes. The EVF boosts the lighting enough to fool me into thinking the exposure is bright enough sometimes, when the exposure is all on the left half of the histogram.
 
I'm a histogram guy, or at least I was. I started using mirrorless bodies recently with exposure simulation in the viewfinder, so they're not as important to me now. But I still watch the scene with the histogram in mind.

I shoot raw for post. My goal is a raw file with a big gray blob in the middle of the histogram. That gives me a sturdy lump of clay to massage out to the edges in post. I tend to expose to the left (ETTL?). You can't fix blown highlights. You can dial them down, but there's no color information. Dropped shadows can be a problem too, but there was probably less useful color information in there to start with. I use Topaz to clean up noisy shadows.

If I can, I bracket exposures -- a lot. Then I look for the shot with the most malleable histogram to work with in post. If I had to guess, I'd say the best ones tend to be a little underexposed.
 
In low light, once your eyes have adjusted to ambient conditions the screen will look VERY bright.
A histogram is pretty mush essential to judge exposure under these conditions (astrophotography etc).
 
In-camera histogram is based on JPEG output, so for them to be useful while shooting, the JPEG settings need to reflective the actual capability of the camera.

For example, with my Olympus E-M1 II, this means Contrast -2, Saturation -2, Gradation Normal, Picture Mode 4 Muted. With the default settings, the histogram will show erroneously clipping of the highlights and result in underexposed images when I try to "expose to the right".
 
@doady I’ve never considered downgrading contrast, saturation and picture style to muted to get a feel for what the raw may be capable of, thanks for pointing that out.

You will still have the problem of color channel saturation that the WB hides, thus the use of uni-WB. I think the two ideas could be used in conjunction for a raw flow in a difficult lighting scenario.

edited to add: I would still use blinkies over the histogram even with all of that, back to the original topic.
 
Back
Top