DPR Article: What is a histogram, and how do you use it?

[Mathew Anderson]

No matter what type(s) of photography you like to pursue, mastering exposure is key to creating successful images. While it can be tempting to use your camera's screen to judge exposure, that display can be quite unreliable for such a task. Instead, one of the most useful tools for evaluating exposure in digital photography is the histogram, a graph that reveals the distribution of brightness levels across the image. Understanding how (and why) to use the histogram can help prevent accidentally losing details in the highlights or shadows, allowing you to get consistent, quality exposures.

What is the histogram?

Histograms are not specific to photography and are simply graphs that show the distribution of continuous numerical data. They help visualize data by revealing a shape, spread and central tendency in a dataset.

In digital photography, the histogram is an exposure-assessment tool.

Check out the complete article by Abby Ferguson!

 

[alcelc]

Before the quality of Live View had reached standard of nowadays, histrogram was once my key tool on exposure setting.

However, having live view improved and availability of new tools, e.g. highlight alert and or shadow alert, usefulness of histrogram has been lowered.

Histrogram can provide good information on the lightness distribution of the frame at the set parameters. However it is on statistical base only such that we have to understand what it means to the frame. While we know there could be overblown highlight under the used parameters, we have to look for it. To the most we can only guess the affected area.

Live view, can tell roughly the lightness condition across the frame. Specially highlight alert shows where it (also the exact piece of affected area) will be. I can therefore decide how much to push (give up the meaningless highlight area by overblown it to trade for brighter shadow (more important area)). As a result, I can set up exposure a lot faster. I can also produce more useful SOOC output for less editing in post too.

Histrogram is now my secondary reference tool.

 

[chrisfisheye]

In digital photography, the histogram is an exposure-assessment tool.

Not really. Histogram is about brightness, not exposure.

 

[Zeee]

I posted this reply. It was crucial to me for event photography when in a hurry and using ETTL (Canon's auto flash). I often bounced off ceilings and walls. Most of the time I could get a second shot in after observing the results and then tweaking FEC.

Another use of the histogram is for flash photography. From one of my on camera flash gurus. Neil van Niekerk. Great way to get good exposures at events was a brides white dress. I used anything that was white at any event. Shirts, sweaters, purses and even table cloth at times. Sure you had to take a shot first to see the results but I just used it as an excuse to take another shot. In a less critical environment you could use a white piece of paper as guide if you don't have a meter or you weren't sure.

Get the histogram to the far right as possible but don't let it touch the wall. Get the whites right and the rest of the exposure falls right into place. This was best suited when you used your flash systems auto setting and then used Flash Exposure Compensation to tweak. Worked good with flash on manual if you don't have a meter and have the time.

 

[Mathew Anderson]

Before the quality of Live View had reached standard of nowadays, histrogram was once my key tool on exposure setting.

However, having live view improved and availability of new tools, e.g. highlight alert and or shadow alert, usefulness of histrogram has been lowered.

Histrogram can provide good information on the lightness distribution of the frame at the set parameters. However it is on statistical base only such that we have to understand what it means to the frame. While we know there could be overblown highlight under the used parameters, we have to look for it. To the most we can only guess the affected area.

Live view, can tell roughly the lightness condition across the frame. Specially highlight alert shows where it (also the exact piece of affected area) will be. I can therefore decide how much to push (give up the meaningless highlight area by overblown it to trade for brighter shadow (more important area)). As a result, I can set up exposure a lot faster. I can also produce more useful SOOC output for less editing in post too.

Histrogram is now my secondary reference tool.

An interesting comparison. I'm still getting used to how histograms compare to newer tech like Liveview. Supposedly, a histogram is a more accurate, objective assessment of exposure, but a subjective view is important too, imo.

 

[Mathew Anderson]

In digital photography, the histogram is an exposure-assessment tool.

Not really. Histogram is about brightness, not exposure.

Is it? It seems a histogram, as we've written about, showcases the potential for blowout, which would be more indicative of exposure issues than an overall image brightness issue.

 

[Ysarex]

Before the quality of Live View had reached standard of nowadays, histrogram was once my key tool on exposure setting.

However, having live view improved and availability of new tools, e.g. highlight alert and or shadow alert, usefulness of histrogram has been lowered.

Histrogram can provide good information on the lightness distribution of the frame at the set parameters. However it is on statistical base only such that we have to understand what it means to the frame. While we know there could be overblown highlight under the used parameters, we have to look for it. To the most we can only guess the affected area.

Live view, can tell roughly the lightness condition across the frame. Specially highlight alert shows where it (also the exact piece of affected area) will be. I can therefore decide how much to push (give up the meaningless highlight area by overblown it to trade for brighter shadow (more important area)). As a result, I can set up exposure a lot faster. I can also produce more useful SOOC output for less editing in post too.

Histrogram is now my secondary reference tool.

An interesting comparison. I'm still getting used to how histograms compare to newer tech like Liveview. Supposedly, a histogram is a more accurate, objective assessment of exposure, but a subjective view is important too, imo.

I'm going to go with the histogram is less accurate and less useful. First of all there's the question of what kind of histogram is it? And that's going to be camera make/model specific. The two histograms below are from the same image.



If you don't know what type of histogram the camera is presenting you can't interpret it correctly and obviously those two histograms above are telling different stories. Which story do you want to know.

Some cameras present RGB composite histograms while some cameras present luminosity histograms while some cameras do and don't have an option to see the three color channel histograms. What's in your camera?

Most modern MILCs include a live-view highlight alert. The highlight alert always shows you what's the brightest highlight in the scene as well as showing you if that highlight is diffuse or specular (not possible with a histogram) -- awesome! All my cameras are now MILCs and I set all exposures using only the camera's highlight alert. I ignore the meter, metering mode, live-view simulation, and histogram. My exposures are now more accurate than they have ever been over the course of more than 50 years taking photos.

 

[chrisfisheye]

In digital photography, the histogram is an exposure-assessment tool.

Not really. Histogram is about brightness, not exposure.

Is it? It seems a histogram, as we've written about, showcases the potential for blowout, which would be more indicative of exposure issues than an overall image brightness issue.

 

[Mathew Anderson]

In digital photography, the histogram is an exposure-assessment tool.

Not really. Histogram is about brightness, not exposure.

Is it? It seems a histogram, as we've written about, showcases the potential for blowout, which would be more indicative of exposure issues than an overall image brightness issue.

Could be simply due to an ISO value too high but the exposure may have no issue at all.

If you shoot at f/4, 1/100s ISO3200 then maybe you just have to use ISO1600 (with same f# and SS) to avoid blowout.

What I mean is that the histogram shows a lightness issue. Then maybe it can be an exposure issue, but not necessarily.

Ah! I understand. Thanks for clarifying.

 

[alcelc]

[No message]

 

[MJ_Photo38]

I generally shoot without it, but I sometimes use it to make sure I'm not clipping my highlights. It's not a be-all and end all because I know I have additional headroom in exposure compensation for RAW files since the Live Histogram on pretty much every camera displays the JPEG histogram, which has lower dynamic range compared to the RAW file.

But it's still nice to have it in camera sometimes. I don't think I ever used it seriously in an editing software, I generally edit to taste, and sometimes clipped highlights is exactly what I go for.