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07-14-2008, 03:55 AM   #16
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IMHO, if you wanted the Canon look, you should get a Canon (like 66% of flickr it seems) rather than try to recreate the look via curves.

a little dab will do ya, those are good photos.

07-14-2008, 04:55 AM   #17
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QuoteOriginally posted by Nesster Quote
IMHO, if you wanted the Canon look, you should get a Canon (like 66% of flickr it seems) rather than try to recreate the look via curves.
Pentax doesn't even show up.

Yesterday's Canon Rebel XTi uploads: about 108,000.

K10D: about 8,000
K100D: about 4,000
K100D Super: about 1,000
*ist DL: about 1,700
K20D: about 770

Total average daily users: somewhere around 1,000

For the Rebel XTi alone? Over 6,000. The uploads and daily average users from any one of the top 5 Canon models exceeds the uploads and total daily users from the top 5 Pentax models combined.

Good deal. Less chance anybody will ever try to borrow my stuff.

To be on topic..... Yes, the histogram is your good friend. But like any other good friend, turn to it for guidance but don't let it talk you into something that goes against your better judgment.
07-15-2008, 07:16 AM   #18
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QuoteOriginally posted by cputeq Quote
Thanks for the inputs everyone! I think maybe I did push it too far, and I'm going to keep the curve nudged a little left. instead of centered, eyeballing it for each picture of course.
I highly recommend these two articles about histograms:
Expose Right
Understanding Histograms

In the first, Michael suggests shooting right because "if you do not use the right-hand fifth of the histogram for recording some of your image you are in fact wasting fully half of the available encoding levels of your camera."

In the second, he notes that "with the possible exception of showing badly blown out highlights there really is no such thing as a bad histogram. They just are."

I've noticed that when I remember his tips that I have to do less pp work to make the image look like I recall the scene. Not at the point of none at all though, I'd bust out the K1000 and a roll of film for that.
07-15-2008, 07:50 AM   #19
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The after shots looks better on my monitor

07-15-2008, 08:50 AM   #20
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QuoteOriginally posted by cputeq Quote
Nope -- I'm moving the histogram to where the majority of the curve (if there is a curve) sits right in the middle, minding blown highlights as much as I can.

According to clipping alert in Lightroom, the only picture I posted that even has a blown highlight is the Parrot, and it's just a few pixels on his beak and under his eye a little.
I agree with the others that the best result in the parrot photo would probably be somewhere in between your before and after.

*

There is no rule that says the histogram for the processed photo has to peak exactly in the middle of the graph. A picture of something very dark SHOULD probably have a histogram that peaks strongly on the left; a portrait of a bride in her white dress, with a bright background, should probably peak strongly to the right.

There are three quasi-rules about exposure that relate to the histogram. Perhaps they should be called "goals" rather than quasi-rules.

First, you don't want to lose important data at either end of the histogram. Losing unimportant data is okay because, well, because it's unimportant. In many photos, you can push the histogram to the right and blow certain highlights without damaging the photo, because the blown highlights are not important - they're bits of reflection off the shiny fenders of a white car, or touches of cloud in the sky. A lot of the time, especially when you shoot outdoors, you may not have any choice but to lose something at one end of the histogram or both, because many scenes in real life have greater dynamic range than your camera can capture.

Second, to the degree possible, you do not want the histogram on your camera's LCD to be balanced in the middle: you want it to start out pushed as far to the right as you can get it without running afoul of goal #1. You want this not because you're always going to leave the photo looking that way but for technical reasons having to do with the way that data is stored in digital photos. See the famous (and I think often misunderstood) article "Expose to the Right" over at Luminous Landscape. Basic idea: Your camera stores data with much greater sensitivity at the right side of the histogram than on the left, so in order to preserve as many tonal gradations, you want to capture the data on the right. You can pull the levels down (move the histogram to the left) in post with little or no penalty. If you expose to the left (darker than necessary) and decide later to lighten the picture up, well, you have less info to start with, so you end up getting results that seem flat, plus, you're going to end up increasing the noise in the photo. We used to say for black and white film photography, Expose for the shadows, develop for the highlights. But when you're shooting digital, the formula is reversed: Expose for the (important) highlights, process for the shadows. When you're lucky, you'll find yourself darkening the shadows in post, rather than trying to lighten them.

Finally, your third goal is simply to give yourself the data you need to produce a final result that looks right. This relates to the histogram too although this goal simply says that, goals 1 and 2 notwithstanding, whatever works best is the right way to go. If the histogram ends up piled up on the left side but the result is what you're after, then go for it. But this goal really looks forward to what you do AFTER you take the photo.

*

And that raises another key point: You have to understand that the goals above - especially 1 and 2 - apply to the capture, not to the processing.

If you want to take the best photos possible, don't think of your camera as a machine for making photos. Think of it as a data-capture device. Your computer and software are a tool that you use for actually generating actual photos, prints, or files for viewing say on a web page. Data capture and file output are different processes and you have to think a bit differently for each process. The goal for capture (shooting) is basically: save as much important data as possible. This sums up goals #1 and #2 above. (I'd throw in here that you will save as much important data as possible by shooting raw, but that should be obvious.) But your goal in processing is simply to produce a result that looks right, looks the way it should look or the way you want it to look. So the histogram in the camera does not need to look like the histogram of the final output, indeed, it often will not.

Personally, I find the histogram in the camera much more useful if I also have enabled the feature where blown shadows and highlights blink. If the histogram is well to the right but there is no blinking, I know I'm doing okay. Even if there is blinking, but the parts of the photo that are blinking are not important, that's okay, too.

Will
07-15-2008, 01:42 PM   #21
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Well written, Will.
07-17-2008, 01:14 AM   #22
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With regards to the above and having practised - I would have to dial in a minimum of +1 to +1.5 ev for just about every shot (also after reading the LL article) - having done this and seeing the results, just didn't do it for me to my eye anyway

I find if I have say .5 cm left blank to the right on the camera histogram (I do run +.03 ev permanantly) is fine for me - a little tweak of the curve (slight S curve) pp - does fine for me.
07-17-2008, 06:56 AM   #23
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QuoteOriginally posted by dylansalt Quote
With regards to the above and having practised - I would have to dial in a minimum of +1 to +1.5 ev for just about every shot (also after reading the LL article) - having done this and seeing the results, just didn't do it for me to my eye anyway.
What was your dissatisfied eye looking at? The histogram on the camera? Or the computer screen after you processed the photo?

If you were just looking at the histogram on the camera - and assuming that your +1 EV didn't cause important highlights to be clipped - then it's possible that you don't understand the point of the "Expose Right" article or you missed my comment above that capture and processing are two entirely different problems. If the photo has a normal, full dynamic range, and again assuming that you don't clip important highlights, then exposing to the right may indeed make the photo look overexposed on the camera's LCD. Never mind that. What you see on the LCD is NOT the result you're after. The result comes from the computer, after you've processed it.

If you're looking at the photo after you've processed it, then I guessed I'd want to know what "didn't do it for me" means. If the photo seems overexposed, um, you should pull the exposure down in your software. This works extremely well.

I want to add that, with my K10D and K20D, I seldom expose at +1 EV. If I did that, I would probably clip important highlights, at least in a lot of the photos that I take. So for me, much of the time, the technical ideas in the "Expose Right" article remain a bit theoretical, since I don't always have a lot of choice about the matter. In fact, since I shoot a lot of low-light stuff, I often do not have the ability to push the histogram to the right at all. If I'm shooting in a church, I may already be shooting at max aperture, at slowest usable shutter speed and at highest acceptable ISO - so there's not much I can do (if I can't use flash).

Will

07-17-2008, 11:28 AM   #24
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Hi

I basically took a number of shots of the same scene utilizing the camera histogram alone - thinking that the expose right theory was all about that.

Comparing the shots on my corrected 17" lcd I found the shots that were exposed to the right to be washed out which for me effected the tonality and the colour punch I kinda like - even by using curves/levels I couldn't get the look I was after - so just gave up by exposing by the camera histogram alone - so as mentioned above, as long as my histogram on camera is a little to the left I'm happpy with a constant +.03 ev.
07-17-2008, 06:25 PM   #25
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Someone above mentions "the perfect histogram" Is there a picture or desription of this perfect beast.
07-17-2008, 07:12 PM   #26
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QuoteOriginally posted by mi2nc Quote
Someone above mentions "the perfect histogram" Is there a picture or desription of this perfect beast.
I don't think it really exists, as discussed above, but for what people mean when they say that, see the first histogram in the previously mentioned link.

Dylansalt: Did you try just using the exposure adjustment on your "exposed right" photos. Levels/curves might work too, but I think in theory even the simple process of exposing +1.0 ev on the camera then adjusting -1.0 ev in software should result in a better result*.

*as long as you don't blow the highlights too much, which I agree with WMBP is not necessarily so easy to avoid.
07-17-2008, 08:54 PM   #27
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QuoteOriginally posted by dylansalt Quote
I basically took a number of shots of the same scene utilizing the camera histogram alone - thinking that the expose right theory was all about that.
Well, um, not exactly. The expose right theory is all about the fact that the structure used to organize the data that your camera captures is organized so that there is WAY more info stored for the right side of the histogram than for the left. So in order to capture and save as much info as possible, you want to make sure you aren't UNDER-exposing your shots.


QuoteQuote:
Comparing the shots on my corrected 17" lcd I found the shots that were exposed to the right to be washed out which for me effected the tonality and the colour punch I kinda like - even by using curves/levels I couldn't get the look I was after - so just gave up by exposing by the camera histogram alone - so as mentioned above, as long as my histogram on camera is a little to the left I'm happpy with a constant +.03 ev.
The problem you report is a very common one with raw files: The files, when first viewed on the computer, look "washed out." I see the same thing with my own files but I'm used to it and know what to do. Setting the black point (say, in Photoshop or in Bibble Pro) almost instantly causes the photo to get some depth and punch. In Lightroom, I very frequently adjust the black slider from the default of 5 to 6, or 8, or something like that. The clarity setting in Lightroom - a special midtone contrast control - also helps a great deal. Occasionally I also tweak the tone curves - especially bringing down either the shadows or midtones - and this too can make a difference.

Whatever works for you is great, so I'm not trying to persuade you personally to do anything differently if you're happy with the results you're getting now. The proof is in the pudding, but because we don't all cook the same way, it's hard to give a completely persuasive demonstration of the expose right idea. Nevertheless, the idea itself isn't really something about which there's room for personal opinion. It's rather like the raw vs jpeg-in-camera discussion: at least in terms of image quality, there is not good reason NOT to shoot raw, because the unconverted raw file undeniably contains more information. In the same way, by exposing to the right, you get more data - more tonal variations, for example - because that's simply how raw output is structured. So WHEN YOU CAN, you want to push the histogram to the right. And if you capture more data, with greater tonal range, then it is both logical and obvious that you'll be able to do more with it. Once you've got all that data, you can pull the exposure down in post-processing and get a really great result. Pulling the exposure down in a photo pretty much always produces a better result than pulling the exposure UP (which generally introduces noise).

*

I shot a few test shots to illustrate the principle. You can see them here:

Picasa Web Albums - William - 20080717 expo...

Note that what I call shot #1 here - the one where I let the histogram lean to the left - is already moving to the right. I threw out an earlier shot that represented the camera's own preferred exposure, because it was too far to the left. And why did the camera suggest an exposure so far to the left? Because the Pentax K20D does its best to avoid clipping highlights, even if it means badly clipping shadows. This is, I think, the right thing for the camera to do, because for ordinary users, it's probably the safest thing to do. Highlights usually matter more than shadows, so if you're going to lose something, lose it in the shadows.

But if you aspire to being something more than an ordinary photographer, then you will want to make judgments for yourself about whether you'll tolerate blown highlights and to what extent. And that means that, whenever you can do so and to the extent you can tolerate, you'll want to push the histogram to the right. That's what I did in shot #2.

The differences in result are not huge. When processing a raw file from a 14.6 MP camera like the K20D, you end up with a good bit of info to work with even at the dark end of the dynamic range, certainly more than enough to process the photo for effective display on a computer screen. Perhaps I should have done the test with the *ist DS (6 MP) instead. Even so, shot #1 (histogram to the left) does indeed, after post-processing, end up noisier than shot #2 (histogram to the right), and in a good print, especially at a somewhat larger resolution, this difference would be noticeable and important.

Will
07-17-2008, 09:16 PM   #28
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cputeq:


I prefer the 3 before shots.


Regards,

Ernest
07-18-2008, 01:05 PM   #29
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Prefer all the "before" photos here. Especially the elephant shot...

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07-18-2008, 01:12 PM   #30
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Will - Thanks for the time and effort for the explanation - much appreciated

Was very informative especially re: increased noise with pp when exposed to the left.

Will definately practice this method more.

Regards

DS
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