Any simple good tutorials on Dynamic Range in post processing out there?

Donnie

Donnie

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Just want to make sure im not missing something as a couple of pics ive put up for critique recently have attracted feedback that Im possibly neglecting this?

any youtube vids or blogs that others have found useful would be great.
 
Donnie said:
Just want to make sure im not missing something as a couple of pics ive put up for critique recently have attracted feedback that Im possibly neglecting this?

any youtube vids or blogs that others have found useful would be great.
Click to expand...

Let me guess.. KQC has been offering critique?

It's a convention that images should have a full range of tones from black to white. In that case you'll see that the histogram stretches from one side to the other. Contrast can be regarded as the width of the histogram. You can make an image fill that range by tweaking the exposure, black levels and white levels and / or contrast. Doing so will inevitably affect the perceived saturation and colours.

I reckon you should feel free to disregard this convention. Hazy sunshine, fog, low key and high key images are all inherently low contrast images, to name just a few. There's no reason why an image should fill the histogram unless you're after a 'record' shot. Just ensure that the main subject is exposed as _you_ want it to be.

You could read up on the zone system as devised by Ansel Adams. Michael Freeman's book Perfect Exposure may give you some insights too. I can't whole-heartedly recommend buying it but it's definitely worth getting out of your local library.
 
juggler said:
Let me guess.. KQC has been offering critique?

It's a convention that images should have a full range of tones from black to white. In that case you'll see that the histogram stretches from one side to the other. Contrast can be regarded as the width of the histogram. You can make an image fill that range by tweaking the exposure, black levels and white levels and / or contrast. Doing so will inevitably affect the perceived saturation and colours.

I reckon you should feel free to disregard this convention. Hazy sunshine, fog, low key and high key images are all inherently low contrast images, to name just a few. There's no reason why an image should fill the histogram unless you're after a 'record' shot. Just ensure that the main subject is exposed as _you_ want it to be.

You could read up on the zone system as devised by Ansel Adams. Michael Freeman's book Perfect Exposure may give you some insights too. I can't whole-heartedly recommend buying it but it's definitely worth getting out of your local library.
Click to expand...

:D:D:D
 
Just to flip the coin; whilst I agree totally with Juggler when talking about those specific instances of low contrast situations, I don't think it's fair to say "disregard this convention" when talking about a lot of other images.
There are times where utilising the full dynamic range will make a good shot better.
There are many examples in TP of shots which could be improved massively by simply setting the black and the white points correctly.
Apart from the type of low contrast shots mentioned, and of course, if you want a low DR for a specific shot, then learning how to set the points correctly will help you.
Just remember, just because you can doesn't mean you have to include the full range in an image.
(BTW, high and low key images aren't necessarily low contrast. They can also include the full dynamic range, especially in B&W. IMHO of course.)
 
juggler said:
Let me guess.. KQC has been offering critique?

It's a convention that images should have a full range of tones from black to white. In that case you'll see that the histogram stretches from one side to the other. Contrast can be regarded as the width of the histogram. You can make an image fill that range by tweaking the exposure, black levels and white levels and / or contrast. Doing so will inevitably affect the perceived saturation and colours.

I reckon you should feel free to disregard this convention. Hazy sunshine, fog, low key and high key images are all inherently low contrast images, to name just a few. There's no reason why an image should fill the histogram unless you're after a 'record' shot. Just ensure that the main subject is exposed as _you_ want it to be.

You could read up on the zone system as devised by Ansel Adams. Michael Freeman's book Perfect Exposure may give you some insights too. I can't whole-heartedly recommend buying it but it's definitely worth getting out of your local library.
Click to expand...

Spot on. In no way should a Histogram HAVE to touch either end of the scale.

What were the pics in question?
 
GHP said:
Just to flip the coin; whilst I agree totally with Juggler when talking about those specific instances of low contrast situations, I don't think it's fair to say "disregard this convention" when talking about a lot of other images.
There are times where utilising the full dynamic range will make a good shot better.
There are many examples in TP of shots which could be improved massively by simply setting the black and the white points correctly.
Apart from the type of low contrast shots mentioned, and of course, if you want a low DR for a specific shot, then learning how to set the points correctly will help you.
Just remember, just because you can doesn't mean you have to include the full range in an image.
(BTW, high and low key images aren't necessarily low contrast. They can also include the full dynamic range, especially in B&W. IMHO of course.)
Click to expand...

I take your point.. but still think that tweaking the black and white points is less satisfactory than altering the exposure - ideally at the time, alternatively in post. As soon as you start stretching or compressing the histogram you reduce quality and the familiar comb-like chart makes an appearance. Altering contrast also alters colours and saturation. Adjusting the exposure slider does a much better job of keeping things where they should be relative to one another. Unless of course you want to adjust the contrast and colours.

(fwiw there are a lot of different definitions of high and low key. I'm not that bothered about finding the 'correct' definition but I was using the one which states that in low key images there are no tones above middle grey, and conversely for high key.)
 
just find your own way of doing it and one that suits your style there is no magic formula or way of doing it if there was everyones photos would be the same ............. just enjoy experimenting
 
juggler said:
I take your point.. but still think that tweaking the black and white points is less satisfactory than altering the exposure - ideally at the time, alternatively in post. As soon as you start stretching or compressing the histogram you reduce quality and the familiar comb-like chart makes an appearance. Altering contrast also alters colours and saturation. Adjusting the exposure slider does a much better job of keeping things where they should be relative to one another. Unless of course you want to adjust the contrast and colours.

(fwiw there are a lot of different definitions of high and low key. I'm not that bothered about finding the 'correct' definition but I was using the one which states that in low key images there are no tones above middle grey, and conversely for high key.)
Click to expand...

Don't get me wrong, I'm not disagreeing with you.
My point is, the OP needs to understand dynamic range, and exposure, and contrast etc etc, in order to know how best to adjust for the effect he wants for that shot.
As said many times, understanding these factors, and aiming to get it right in camera is the best way to work.
And, as the many different definitions of (for example) high and low key show, there is no right or wrong for each technique, only what works or not for the shot you see and want to take.
 
Fact is, a scene only contains a certain DR, and a camera can only record a certain DR. If you want to *record* a different DR you have to shift the exposure. The rest is about artificially stretching the exposure (histogram) in post.

I recently saw a Phlern tutorial on doing it in PS... he was using 8bit jpegs, which should be avoided for this. But it really makes the point as to what is actually going on when you "stretch" DR in post.
 
AFAIK, there are only two definitions for High/Low Key.

There is a definition for lighting: High = low contrast, and Low = high contrast.
And there is a definition for images: High = above mid, and Low = below mid.

But often images that are "mostly" High/Low Key are called that even though they are not technically (i.e. most "low key images" also include white, and many "high key images" also include black). Combine that with the fact it requires high key lighting to create both high and low key images (technically), and it get's convoluted.
 
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