RAW images and the histogram

[djotaku]

I'm going to play with this a bit more when I get home today, but I thought I'd get some answers from the DPS crowd in the meanwhile. I'm currently going through the AWESOME "The Adobe Photoshop Lightroom 2 Book" by Martin Evening and I'm reading the section on the develop module. He mentions upping (or lowering) the exposure slider until the highlights are just about to be clipped. Then do the same for blacks. I've seen this advice many, many times in Photoshop RAW books (of which I own a few).

My question stems from the fact that I often have photos that look just fine even though the histogram doesn't go ALL the way to the right (I think...I have to check for sure when I get home) - at least that's the way I remember it. If I move it over to the right, the image would look overexposed. So most of the time, if the picture doesn't look dark, I just leave exposure alone. What am I missing out by not pushing exposure until the histogram hits the right. Do you do push the histogram to the right on EVERY image? (I understand these types of things can get tricked on photos with lots of black, night shots, etc - I mean "regular" photos)

Thanks!

[djotaku]

I see. Upon reading further, I finally understand. He's not saying push the histogram all the way to the right, just until there appears to be some clipping.

[fletch]

It seems the instruction is to increase the contrast of the image so the blacks are black and the whites are white. Seems sensible but you could go too far very easily if there is only a very small number of pixels in the image that are at the darkest or brightest edges. I don't have lightroom yet but so I don't know how it would flag the number of pixels that are clipping but if it is just the graphical histogram then it would be easy to miss some cliiping and go too far. There will also be some scenes that are naturally low contrast and need to remain so.

[djotaku]

With LR and PS you can have it turn the blacks blue and the highlights red when they clip. Also, can you post a low contrast photo that should stay that way, as an example?

Thanks,

[djotaku]

Ok, so I decided to experiment at home. Please comment.

Here I adjusted until the highlights were blown, then came back a bit.


Here I adjusted as I usually would:


For further comparison, using Canon's portrait setting then blowing the highlights and coming back a bit:

which I don't like because it appears to really redden the image

Here's Lightroom's auto-tone:


So what do you guys think? I mostly like the hightlights blown one, but I feel like I'm losing detail in teh face compared to my usual way of processing the files. I'm not as much of a fan of auto-tone or Canon's portrait setting in Lightroom.

[djotaku]

and here's the way it came out of the camera without any adjustments:

[Snowdust]

I find it really depends on the look you are going for. Yes, the one that you increased the exposure on to the point of clipping does spread the histogram out and represents more of the spectrum, while the second one is a little darker and portrays a better mode for the subject.

You will find that if you have to add alot of exposure, +1 or more, it comes at a sacrifice. It is always better to try to expose correctly at time of shot. The recovery slider will help bring back some of the lost detail. You could also selectivly apply exposore with the adjustment brush, rather than effect the entire picture.

[OsmosisStudios]

I far prefer the 1st to any of them. It seems the most natural to me.

[djotaku]

Originally Posted by Snowdust

I find it really depends on the look you are going for. Yes, the one that you increased the exposure on to the point of clipping does spread the histogram out and represents more of the spectrum, while the second one is a little darker and portrays a better mode for the subject.

You will find that if you have to add alot of exposure, +1 or more, it comes at a sacrifice. It is always better to try to expose correctly at time of shot. The recovery slider will help bring back some of the lost detail. You could also selectivly apply exposore with the adjustment brush, rather than effect the entire picture.

Well, technically the RAW without adjustments *should* be properly exposed. I didn't have the camera set to + or - ev. I find that I like my colour balance a lot better, which is more of an indoor than an outdoor colour balance. I think all of the ones I adjusted had some amount of exposure increase. The thing is, the photo straight out of the camera is technically a perfectly fine exposure and could maybe use a touch of an increase. But, as I said in the top post - every book says you should increase the exposure until you're just about the clip the highlights. But when I did that, even using the recovery slider, I didn't have as much detail in my face. So which is the better picture? Which is truly properly exposed?

Interestingly, the photo out of the raw without adjustments has a very different mood as a photo compared to the adjusted one.

Originally Posted by OsmosisStudios

I far prefer the 1st to any of them. It seems the most natural to me.

I'm really torn between the top two. I like how the top one really pops, but I like how the second one has more shadow detail.

[PrimeTime]

Originally Posted by djotaku

I'm going to play with this a bit more when I get home today, but I thought I'd get some answers from the DPS crowd in the meanwhile. I'm currently going through the AWESOME "The Adobe Photoshop Lightroom 2 Book" by Martin Evening and I'm reading the section on the develop module. He mentions upping (or lowering) the exposure slider until the highlights are just about to be clipped. Then do the same for blacks. I've seen this advice many, many times in Photoshop RAW books (of which I own a few).

My question stems from the fact that I often have photos that look just fine even though the histogram doesn't go ALL the way to the right (I think...I have to check for sure when I get home) - at least that's the way I remember it. If I move it over to the right, the image would look overexposed. So most of the time, if the picture doesn't look dark, I just leave exposure alone. What am I missing out by not pushing exposure until the histogram hits the right. Do you do push the histogram to the right on EVERY image? (I understand these types of things can get tricked on photos with lots of black, night shots, etc - I mean "regular" photos)

Thanks!

I think what they are talking about are the slider's on the levels tool. The left slider is for the black's and the right slider is for the white's. There is also a slider in the middle for the midrange tones. The two sliders on the ends should be slid up close to the edge of the histogram on both sides, without clipping. You can do the same thing with the curves tool, just move the end dot of the line close to the edge of the histogram on both ends. If you change the graph to logorhythem, you can see the ends better.

What that does is resets your histogram and spreads it back out across the 5 full stops of range.