Question on interpreting the histogram in LR3.

jwbryson1 · Oct 19, 2011

Briefly, when I set the exposure in LR3 under the basic tab in the develop module, if I slide the tool bar to the right to add exposure the histogram responds accordingly. However, when the histogram gets to the far right side ("exposing to the right" as I have heard it called), often times the photo appears to be overexposed, in some cases dramatically. How am I supposed to interpret that?

To my amateur eye, my photos can appear properly exposed when the histogram is 1/4" from the right side of the diagram. Can that be correct? Or should I expose to the far right side and then dial it back with other controls?

Thanks!

analog.universe · Oct 19, 2011

Exposing to the right is a technique you employ when you're shooting to get the best signal to noise ratio from your sensor. Once it comes to post process, you can do whatever you want with the data you've captured. Exposing to the right is purely about capturing the most data. I'm not familiar with the lightroom interface specifically, but I would imagine that there are separate controls for exposure, and the shape of the gamma curve. There are likely even controls for the curve that the exposure control acts on. So the subjective appearance of proper exposure isn't only determined by how far to the right the data makes it, as much as it is how that data is distributed across the curve. So essentially, exposing to the right when you shoot gives you the most flexibility when it comes time to post process. Once you're actually in post, use your copious data to make the end result look however you want.

2WheelPhoto · Oct 19, 2011

This may help you tremendously with initially shooting the shot and the LR3 Histogram

Big Mike · Oct 19, 2011

Yes.....'shoot to the right' is carried out by 'SHOOTING' to the right (slightly overexposed), which gives you the best signal to noise ratio, and then adjusting the exposure DOWN in processing.

The big thing to remember is that it's easier/better to slightly overexpose then darken in post, than to underexpose and brighten in post. If you underexpose and brighten in post, you will see a lot more noise in your images.

As for interpreting the histogram...try not to think that it has to look a certain way. You need to be able to relate the histogram to the image. If the image looks OK, then the histogram is probably OK, however it looks.

Another way to think about it, is by breaking the histogram into 6 sections or zones;
Black clipped (piled up on the left)
Dark (left 1\4 section)
Mid-Dark
Mid-bright
Bright (right 1/4 section)
White clipped (piled up on the right)
Now looking at your images, try to place your blacks so that they are close to the left edge, try to place you whites close to the right edge, the rest should fall into place.

Scuba · Oct 19, 2011

interesting I haven't heard of this before....that is why you read random stuff on forums I guess. Have to give this a try

Big Mike · Oct 19, 2011

Understanding Histograms
Expose Right

MTVision · Oct 19, 2011

http://www.luminous-landscape.com/tutorials/expose-right.shtml

This site has some information about exposing to the right.

jwbryson1 · Oct 19, 2011

This is a terrific thread. Thanks so much to Mike and 2wheel for the explanations and the video. I really appreciate the feedback! :thumbup:

Truth be told, before I found this forum I spent a LOT of time reading one other specific forum that is documented on this website. That particular photographer makes the case that it's better to be slightly underexposed (-2/3) on your shots than overexposed. So for the first few years of me learning to shoot my DSLR, I've been scared away from overexposing my shots and as a result I'm probably underexposing way too often. It seems I may have learned a ton here today in about 10 minutes time.

Kewl.

clanthar · Oct 19, 2011

The theory behind "expose to the right" is sound. However I have a problem with the language used to describe it. Exposing to the right isn't overexposing it's getting the exposure right.

Back in the day (film) folks would talk about different films having exposure latitude. What that really meant was if you got the exposure wrong, but close enough, you could still save your *ss and get a print you could sell to someone who didn't know any better. When I used to hear my students in class say film had latitude, I would respond with, "Film has latitude for people who think excellence has latitude."

A correct exposure places the diffuse highlight just below white. PERIOD. If you do that you've got a correct exposure. The problem today with digital is it's really hard to know if you've done that because you can't see it. Again back in the day, when you got the lighting right and nailed the exposure and didn't screw up the chemicals you could look at that finished negative or transparency and know you'd nailed it. It took some time to learn to read a neg but after a few thousand you got to where you could see it. You knew when it was right.

Today you have to look at an interpretation of what your camera captured. Even a RAW file in LR without any applied adjustments is being interpreted by the software. LR and/or ACR is applying tonal adjustment curves to your data just to get it on the screen for you. You look at that image and say, Oops! looks like I overexposed. Did you? How do you know you overexposed? You're looking at a software interpreted image. Your original data has already been manipulated. Maybe you did just fine and the software is screwing up. All of the software is programmed to manipulate your data in accordance with assumptions that in many cases may not fit your intention. Just to see your photo in LR your data has to undergo manipulation based on the programers/engineers adopted assumptions.

Going back to JW's original question -- How to interpret LR's histogram -- begs another question: How has LR interpreted the RAW data?

I switch between different RAW converters with some regularity. In principle, you'd think that a RAW converter would display your photo without first adjusting it -- after all you shot the photo in RAW so YOU could adjust it. Look at this example:

I opened the same file "as shot" in three different RAW converters: Adobe Camera RAW, Capture One and Raw Therapee. I pasted in each programs histogram window for reference. C1 right out of the gate says I overexposed this shot. The highlight clipping warning is active in the flowers. ACR says I got a pretty good exposure and RT says I underexposed the photo quite a lot. How about that: I underexposed, overexposed and correctly exposed all with the same RAW file!

Above I said this, "Just to see your photo in LR your data has to undergo manipulation based on the programers/engineers adopted assumptions." Well photography has standards. It's fair to expect that those software engineers are adhering to industry standards isn't it? Look at the above photos.

This is not a encouraging answer. Never again can we put a loupe over that neg or transparency on the light table and say, "nailed it!" So first step in interpreting LR's histogram is to recognize that LR's histogram is itself an interpretation that you should immediately hold suspicious.

Joe

MTVision · Oct 19, 2011

jwbryson1 said:
This is a terrific thread. Thanks so much to Mike and 2wheel for the explanations and the video. I really appreciate the feedback! :thumbup:

Truth be told, before I found this forum I spent a LOT of time reading one other specific forum that is documented on this website. That particular photographer makes the case that it's better to be slightly underexposed (-2/3) on your shots than overexposed. So for the first few years of me learning to shoot my DSLR, I've been scared away from overexposing my shots and as a result I'm probably underexposing way too often. It seems I may have learned a ton here today in about 10 minutes time.

Kewl.

From what I've read you want to expose as far right as you can before blowing. I'm sure it takes a lot of experience because you have to be very familiar with your camera. The histogram on the LCD isn't a true representation of your raw file! Highlights could possibly blow out on the jpeg before the RAW so I'm assuming it takes alot of trial and error.

jwbryson1 · Oct 20, 2011

Clanthar, do you have LR3 that would permit you to add a 4th comparison alongside the 3 shots above? That would be interesting.

Thinking about what you posted, I understand your point but in the end if you have a good monitor and are able to adjust the photo to the point where you find the photo is properly exposed, does it really matter how the RAW image was manipulated by the S/W in the first place?

Big Mike · Oct 20, 2011

Thinking about what you posted, I understand your point but in the end if you have a good monitor and are able to adjust the photo to the point where you find the photo is properly exposed, does it really matter how the RAW image was manipulated by the S/W in the first place?

Just a point of clarification...when we talk about adjusting 'exposure'....we should be talking about the camera settings used when the photo was created. You don't change/adjust the exposure with software. I know that LR/ACR etc. have an 'exposure' slider...but to me, that is simply using the software to brighten/darken the image. Which will hurt your image either way.

analog.universe · Oct 20, 2011

There are differences between RAW converters because each employs it's own customized algorithms for decoding the RAW data. Even if you use the defaults in all programs, or the "as in camera" or whatever, they still arrive at the result based on the biases of the software developers. This doesn't necessarily imply that you can't know if you've exposed properly. I've not used the specific software in the comparison above, but the software that I do use, UFRAW, provides separate input and output histograms. If the input histogram taps the right edge, you've overexposed, if you're close without touching, then you've done fine. The output histogram represents the image you see after the decoding has occurred, but you still have both views to work with. You can't look at the negative anymore, so instead you have histograms, which are essentially a mathematical analysis of the data you're working with. The process has changed, but you have just as much ability to evaluate your accuracy at each step.

I also believe there are exceptions to every rule, no matter how sound. So while in most situations, a proper exposure puts the highlights just shy of clipping, in certain situations, it may actually be ideal to blow out a large number of pixels in order to preserve shadow detail. The proper value for any variable in photography is always dependant on the scene at hand.

clanthar · Oct 20, 2011

jwbryson1 said:
Clanthar, do you have LR3 that would permit you to add a 4th comparison alongside the 3 shots above? That would be interesting.

Thinking about what you posted, I understand your point but in the end if you have a good monitor and are able to adjust the photo to the point where you find the photo is properly exposed, does it really matter how the RAW image was manipulated by the S/W in the first place?

ACR and Lightroom are the same software. LR3 is Adobe Camera RAW with a database attached.

It does matter how the software is manipulating the RAW data. The software gives us access to make our own adjustments and in effect adjust what the software has already adjusted, but the end result is often irrevocably altered by the initial software algorithms as applied.

In practical terms: I take a RAW file into ACR/LR and begin processing it. I find it difficult and don't manage to get the end result I'd like.

Stop right here and ask:
Did I screw up behind the camera?
Did my camera screw up?
Is it my lack of skill using ACR/LR?

I take the same RAW file into Capture One and out comes the photo exactly as I had intended with little effort. And with this added info we go back to those three questions above.

I've tested this time and again. No two RAW file converters function the same and that means whatever software you select to use is operating in the background in ways you may prefer it didn't. So when I start to work with a photo I'm always holding the software suspect. If I'm not getting the result I want from ACR/LR my first assumption is it's ACR's fault not mine and I switch converters.

You embrace the theory behind "expose to the right" for example. How do you know you actually did that if one RAW converter indicates you did while another indicates you didn't?

============================================

Take your monitor point one step further. If you've made an excellent print and can repeat that at will that's hard verification that you're managing the entire process well.

This problem has existed since photography was invented. The image is a product of the photographer's intention but mediated by the technology. As the technology has become increasingly sophisticated the photographer has been losing control. In the past the problem may have been that the technology was too crude to realize the photographer's intention. Now the photographer doesn't have a clue what the technology is doing.

Joe

analog.universe · Oct 20, 2011

clanthar said:
This problem has existed since photography was invented. The image is a product of the photographer's intention but mediated by the technology. As the technology has become increasingly sophisticated the photographer has been losing control. In the past the problem may have been that the technology was too crude to realize the photographer's intention. Now the photographer doesn't have a clue what the technology is doing.

I have to disagree with this, I feel like we have more control than ever. The technology used to be chemicals and timings and temperatures, and if you got it wrong, it took a while to find out and you couldn't "undo". Now you have complete control over the process of getting the image from the camera to it's delivery medium, coupled with instant feedback and the ability to try anything any number of times at any step in the process. You say that the photographer doesn't have a clue what the technology is doing... I think there are two points to be made about that. The first is, how much does the photographer need to know? Understanding the intricacies of computer programming languages and data management may provide a certain intuitive advantage, but I wouldn't consider it necessary to understand completely how to use the software tools available. Just as film photogs didn't _need_ 6 years of college chemistry to understand the development process, though it likely helped. Now the other side of the photographers not understanding, is that it's not the technology's responsibility to be self explanatory. Every photographer has the choice to learn the technology or not.. If all someone is doing is poking at a piece of software without learning in depth about why it does what it does and what options are available, then that person has simply opted to "noodle around" instead of learn. It's not the developers fault that people don't have a clue what the software is doing, all information to that end is readily available to anyone with an internet connection. A situation vastly superior to what a person had to do in order to learn how to properly develop film.