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Controlling Contrast

OllieNZ

OllieNZ

Member
Joined
11 Nov 2009
Messages
990
Location
Witney, UK
Hi All,
I'm after some advice on controlling or minimising the whiteout caused by brightly lit areas of lighter colour. This is an issue I've had in the past a lot with light coloured substrates but now I have a DSLR which seems to handle this a lot better. I was messing around the other night trying to get a decent picture of my cat on top of my tank and well the issue I was having is fairly obvious.
0152_zps99a98955.jpg
 
The least expensive and easiest way is via Photoshop or similar. Boost shadows, reduce highlights. Curves are also very effective.

The other method is to equalize the lighting by using flash or another light source to fill the shadows.

Lovely capture, and scape, by the way. :)
 
I hope you don't mind but here's a quick example using Photoshop CS3. Boosted shadows, reduced highlight, small 'S' curve and unsharp mask.

Because I on'y processed the small image direct from the forum, there's a lot of noise in the shadows, and the blown highlights in your cat are unrecoverable. By processing the original image from camera this would likely be much better.

0152_zps99a98955.jpg
 
Thanks George,
I really need to get photoshop and learn how to use it properly. The Blown Highlights are my major issue is the anything hardware wise you can use to tone these down to give you an image you can then edit without losing the detail?
I can email you the original I you'd like to have a play.
 
This is a better capture from the tank point of view but still the same issue with the highlights. Guess I'll have to dye him black:banghead:
010_zpsed9d31e0.jpg
 
This sort of scene is asking a lot from any sensor - a pure white object in bright light and dark objects in shadow. I hate to think how many stops the dynamic range is.

You have to expose for the cat - spot meter on its fur, or go by trial and error. And then as George said, either use directed flash to light up the tank, or do it in software. You can recover quite a lot of shadow detail these days if you're shooting in RAW. Personally though I'd shoot two frames (one exposed for the cat and one for the tank) and combine them in PS.

You can see instantly from looking at the histogram on your camera (I believe the 1100D has a live histogram which is very useful) that the highlights are blown - as soon as stuff falls off the right hand side of the graph (as shown below for your first image) you're never getting them back:

jywu.jpg
 
That's a nice scape and some great digital adjustments by George... What a difference photoshop can do, mind you you still have to know what your doing. My Christmas list is growing now: Canon DLSR, tripod and Photoshop ;)
 
BigTom said:
This sort of scene is asking a lot from any sensor - a pure white object in bright light and dark objects in shadow. I hate to think how many stops the dynamic range is. You have to expose for the cat - spot meter on its fur, or go by trial and error. And then as George said, either use directed flash to light up the tank, or do it in software. You can recover quite a lot of shadow detail these days if you're shooting in RAW. Personally though I'd shoot two frames (one exposed for the cat and one for the tank) and combine them in PS. You can see instantly from looking at the histogram on your camera (I believe the 1100D has a live histogram which is very useful) that the highlights are blown - as soon as stuff falls off the right hand side of the graph (as shown below for your first image) you're never getting them back:
Click to expand...

Can you please explain what the axis on the graph represent and where you pulled it from (trying to get my head around the technical aspects of the situation) The two photo technique is something I have seen before but as I don't have a tripod, not something I've tried. (Chrimbo list gets even bigger lol)
 
OllieNZ said:
Can you please explain what the axis on the graph represent and where you pulled it from (trying to get my head around the technical aspects of the situation) The two photo technique is something I have seen before but as I don't have a tripod, not something I've tried. (Chrimbo list gets even bigger lol)
Click to expand...


Somewhere on your Canon will be a setting for displaying a live histogram. This is a graph that shows the distribution of the brightness of all the pixels on your sensor. At the left hand side of the graph is pure black, at the right hand side is pure white. The graph I linked was from one of your cat photos which I'd viewed in Photoshop, but you should be able to view it live in the camera before you even take the photo, or when reviewing a photo you've already taken.

jywu.jpg


You can see in this example that a lot of the pixels fall near the left hand side of the graph. This means that a large amount of the photo will be under exposed - this is the dark tank and the unlit areas above and below the tank.

If you look at the right hand side of the graph, you will see that some of the pixels are right up against the edge - they have 'fallen off' and will show as pure white with no detail. This is your cat.

More here - Understanding Histograms
 
That's all clever stuff you've done there. I don't understand most of it. That cats got it good.:) on my phone the cats face doesn'. Look right, reminds me of the fatboy slim video where's your head at with the monkeys.
 
kirk said:
That's all clever stuff you've done there. I don't understand most of it. That cats got it good.:) on my phone the cats face doesn'. Look right, reminds me of the fatboy slim video where's your head at with the monkeys.
Click to expand...


Maybe it's FUGLY!
 
Lol. It must get warm up there surely with all that fur under the lights? Ollie just out of curiosity is your white cat deff? We had a white cat who was bannanas as he couldn't hear anything couldn't let it out of the house, it soon went back to the shelter it came from as we moved to fast around it poor thing. It was psychotic if you startled it.
 
kirk said:
Lol. It must get warm up there surely with all that fur under the lights? Ollie just out of curiosity is your white cat deff? We had a white cat who was bannanas as he couldn't hear anything couldn't let it out of the house, it soon went back to the shelter it came from as we moved to fast around it poor thing. It was psychotic if you startled it.
Click to expand...

He loves sitting up there. Certainly not deaf but pretty stupid nonetheless. He's a flame point ragdoll and the cuddliest cat I have ever met.

@BigTom Thanks for the link, I now understand how it works It will certainly be a useful tool.
 
a physical but probably impractical way to improve this would be using a half tinted or gradient filter on your lens?
it would mean you could get a stop or two less exposure on the cat buy keep the tank as it, but only if the composition would fit :)
 
Nutty said:
a physical but probably impractical way to improve this would be using a half tinted or gradient filter on your lens?
it would mean you could get a stop or two less exposure on the cat buy keep the tank as it, but only if the composition would fit :)
Click to expand...


Yeah a hard ND grad might do the trick. I'd rather do it in post 99% of the time though.
 
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