# Controlling Contrast



## OllieNZ (29 Oct 2013)

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.


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## George Farmer (29 Oct 2013)

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.


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## George Farmer (29 Oct 2013)

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.


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## OllieNZ (29 Oct 2013)

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.


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## OllieNZ (29 Oct 2013)

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


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## BigTom (29 Oct 2013)

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:


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## Gary Nelson (29 Oct 2013)

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


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## Yo-han (29 Oct 2013)

Or use the HDR option if your camera has this. This basically does what BigTom describes. Take two pictures and blend the pieces with the right exposure together. I always use it to take pictures from my tank with the lights above it.


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## BigTom (29 Oct 2013)

PS, you can clean up noise pretty easily these days (excuse the lazy blending, you could make a much neater job with the full size file) -

Here's George's brightened shot after noise removal and removing the blue cast -





You'll never recover those blown highlights though, which is why you need to expose for the cat.


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## Nathaniel Whiteside (29 Oct 2013)

This threads in Chinese isn't it?


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## OllieNZ (29 Oct 2013)

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:


 
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)


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## OllieNZ (29 Oct 2013)

Nathaniel Whiteside said:


> This threads in Chinese isn't it?


I was thinking the same thing that's why I'm seeking translation lol


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## BigTom (29 Oct 2013)

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)


 

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.





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


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## kirk (29 Oct 2013)

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.


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## Nathaniel Whiteside (29 Oct 2013)

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.




Maybe it's FUGLY!


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## kirk (29 Oct 2013)

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.


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## OllieNZ (29 Oct 2013)

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.


 
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.


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## Nutty (29 Oct 2013)

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


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## foxfish (29 Oct 2013)

OllieNZ said:


> 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..


 Does he ever go outside?


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## BigTom (29 Oct 2013)

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


 

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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## sparkyweasel (30 Oct 2013)

The Gimp can do most of what Photoshop can do, with the advantage of being FREE. 

GIMP - The GNU Image Manipulation Program


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## OllieNZ (30 Oct 2013)

foxfish said:


> Does he ever go outside?


All the time. Hes pretty skittish outside and doesnt like strangers so were not overly worried about him getting nicked. He does like getting in vehicles though I've had to get him out of the grocery delivery van a couple of times and he always sneeks onto my daughters school bus which all the kids love.


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## wijnands (30 Oct 2013)

Why doesn't anyone mention metering? A DSLR comes out of the box configured to meter the entire picture and find a value to minimize over and under exposed parts in the scene.
Most of you guys run tanks with a LOT of light which makes for a big contrast between light and dark in the scene. One way of dealing with that is to switch to spot metering and meter on the sand in the tank. Anything light grey or brown will work,. Of course the result will be a cat that's massivly overexposed but you'd get proper exposure in the tank.


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## OllieNZ (30 Oct 2013)

wijnands said:


> Why doesn't anyone mention metering? A DSLR comes out of the box configured to meter the entire picture and find a value to minimize over and under exposed parts in the scene. Most of you guys run tanks with a LOT of light which makes for a big contrast between light and dark in the scene. One way of dealing with that is to switch to spot metering and meter on the sand in the tank. Anything light grey or brown will work,. Of course the result will be a cat that's massivly overexposed but you'd get proper exposure in the tank.


I was trying to see if I could get the shot as a whole correctly exposed it seems the only way to do this is to create a composite of two images. I have no issues obtaining correct exposure for the tank I just need to kick the cat off first.



sparkyweasel said:


> The Gimp can do most of what Photoshop can do, with the advantage of being FREE. GIMP - The GNU Image Manipulation Program


Now downloaded  May not get a chance for a proper play for a few days, will it use RAW image files?

Also do people use/recommend separate de-noise software?


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## wijnands (30 Oct 2013)

Gimp should offer some raw support. If not there's raw therapee. For nikon the free view nx will at least do a decent conversion to tiff.

As noise reduction tool I've settled on Nik's Dfine. Tried a few others but I couldn't get my head around the interface or it did horrible detail smearing.


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## OllieNZ (30 Oct 2013)

wijnands said:


> Gimp should offer some raw support. If not there's raw therapee. For nikon the free view nx will at least do a decent conversion to tiff. As noise reduction tool I've settled on Nik's Dfine. Tried a few others but I couldn't get my head around the interface or it did horrible detail smearing.


I'm using a cannon 1100d. Is Dfine freely available?


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## wijnands (30 Oct 2013)

Not legally. But there's a 30 day trial


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## sparkyweasel (4 Nov 2013)

There's a plug-in for GIMP to handle RAW;
Opening RAW Images In GIMP with UFRaw For Windows - The Basics - Digital Photography School


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