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Old Thursday 1st January 2004, 23:42   #1
paul_j_c2000
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exposure

Hi i am posting a picture with this message hoping that someone can give me some advice on how to overcome this problem,this picture was taken in the afternoon quite bright the sun was low and behind me,as you can see it is washed out and the detail seems lost,i am assuming the camera has set exposure from the light background is this something i can correct in taking the picture or can it be corrected in photoshop ,i am using a canon 10D with a 300 f4 prime +1.4 converter,i am no expert in photography and like most people i come across problems ,persevere and you win ,this problem has bugged me for ages always shooting up at a bird in tree with sky as background any help will be much appreciated thanks paul
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Old Friday 2nd January 2004, 00:44   #2
Doug Greenberg
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Hello,
You aren't alone in being frustrated with this issue. High contrast situations are particularly difficult in digital photography. What I see in this picture really isn't that bad, frankly.

Some suggestions:
First, you should try using the spot metering function on your camera if there is one. If you can't do this, think in terms of getting the exposure right *for the bird* and letting the background "go." A typical camera metering system, even an "evaluative" one, will tend to underexposure the bird so as to protect some of the fidelity of the background. But you don't care about this, you want a correctly exposed cormorant. In situations where you know the metering system will underexpose your bird, you should try setting your exposure compensation to +0.7 and even +1.0 or higher. By "overexposing" you have a better chance of bringing out the details in the dark bird's plumage.

Experiment until it comes out the way you want it! That's the advantage of a digital camera. Take six or seven different exposures (looks like this bird wasn't going anywhere quickly), go home, download them, and see which one finally is easiest to work with to produce a finished print. Trash the rest!

In Photoshop you have a feature called "fill flash." By using this gently (!) you can bring up the light level on an underexposed dark bird. Don't overdo it! The problem usually is that once a portion of a photo is underexposed the "noise" level is pretty hard to cope with, even if you can adjust the darkness level to where you want it to be. Perhaps someone else will have more insight/experience regarding this issue.

Bring up the brightness/contrast adjustment settings and play with the sliders that accompany the histogram that is provided. This can improve your image.

What you don't want to do in this situation is use the "auto levels" adjustment in Photoshop. This will invariably *increase* your contrast level, something you don't need.

Another thing you might try in these situations is setting your in-camera contrast level to "low contrast." This will alleviate (a little) the stark difference between bird and background.

That's what I can suggest. I'll bet someone else will come up with something better
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Old Friday 2nd January 2004, 09:27   #3
Jay Turberville
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Quote:
Originally Posted by paul_j_c2000
Hi i am posting a picture with this message hoping that someone can give me some advice on how to overcome this problem,this picture was taken in the afternoon quite bright the sun was low and behind me,as you can see it is washed out and the detail seems lost,i am assuming the camera has set exposure from the light background is this something i can correct in taking the picture or can it be corrected in photoshop ,i am using a canon 10D with a 300 f4 prime +1.4 converter,i am no expert in photography and like most people i come across problems ,persevere and you win ,this problem has bugged me for ages always shooting up at a bird in tree with sky as background any help will be much appreciated thanks paul
Well, it is my opinion that if you want good results, you simply have to invest in learning the craft to some extent. There are a number of ways to approach this, but here is the way I suggest for a "non-expert".

Whenever the background is relatively bright, increase the exposure by a stop or so. This is pretty much what Doug G. also said. But the real question is how much? At this point you have a choice. You can learn some of the "whys and hows" of photography and increase your expertise ... or not. If not, bump the exposure up a stop or so and you'll probably get better results. No need to read further. But if you want to understand it more, read on.

Well Ansel Adams used a spot meter to analyze such situations and that certainly will work if you have one and are willing to use the Zone system or some variant. I'm going to assume that you'd rather not. And in fact, you don't really need to since you have a tool built into your camera that is much more sophisticated. It is the camera's histogram function.

The camera histogram should give you a display that looks something like this:
http://www.jayandwanda.com/digiscope.../histogram.jpg

What this graph tells us is that no detail is being recorded in the lightest portion of the image. This pretty much confirms what we can see in the image. The value of the histogram is it gives us a means to measure when our exposure compensation is about right. We should increase our exposure so that we push that large thick bar (which is caused by the sky in this picture) almost all the way to the right as represented by this image.

http://www.jayandwanda.com/digiscope...erexposure.jpg

You might even want to push it further or even fully off the right side of the scale. But beware of such a move since the "overexposed" areas might "spill" or "bloom" into the edges of your main subject. Do some tests of this kind of overexposure in your backyard as an experiment to see how your equipment reacts. Then you'll have a good idea of how far you can go if necessary.

This better exposure doesn't completely fix your problem though. The simple fact is that you have an image with a very broad brightness range. This is a place where using the RAW image format might be of use since it records more than 8 bits of data per pixel. But we'll leave that for another discussion.

The fact is that whether it is film or digital, we can only record a limited brightness range. And digital is a bit more limited than film. Our expert Ansel would have carefully recorded his exposure (your camera does that automatically for you) and would have then made notes on how to develope his negative to best exploit his exposure. But there is no developing stage for us. As Doug G. said, situations like this might very well call for setting the camera contrast to low. This is mildly analogous to development since this setting controls how the RAW image data is converted to 8 bit RGB data. So when a scene's contrast is very high, it is generally a good idea to set the camera to a lower contrast.

But while digital mostly takes away the developement stage as an opportunity to control our image, it also give us something very powerful. Photoshop!! (Or insert your favorite image manipulation software here.) Photoshop is our digital replacement for differing paper grades, special developing, and dodging and burning and other manipulations. Getting the exposure right is only the first step and sometimes it is not enough in order to get a good image. In fact, there are very few images that cannot benefit from a little adjustment in Photoshop.

There are many ways to approach this next step, but I generally prefer using Photoshop's "curves" feature. The point to keep in mind regardless of the tool we use is that we want to remap the detail that is in the dark area of the bird so that it covers a wider brightness range. We want to make the bird brighter and also keep its contrast looking more natural. The beauty of the curves tool is that it lets us interactively give different brightness regions of an image a differing level of adjustment. In this case, we try to leave the sky alone (about a 45 degree angle) but want to increase the contrast and elevate the levels of the darker regions (a very steep angle on the curve).

http://www.jayandwanda.com/digiscope/paulC/curves.jpg

You can see in the sample image that the peak at the far left of the histogram has now been spread out into the middle values and that the bird is beginning to look more like what we want. But it does seem to have a bit of a yellow cast to it and it is looking a bit soft. So I shifted the color balance a bit toward blue and sharpened the image a bit to increase the local contrast in the details of the feathers.

http://www.jayandwanda.com/digiscope...olor_sharp.jpg

More could be done. For instance, you might create a number of different layers with different curve treatments and blend them together. This technique could be used to bring out more detail in the very dark branch to the left of the bird.

These results aren't half bad. If the initial exposure had been better, then better results would be possible.

The important points to take from this are:

1) Learn to use historgrams to get a better exposure up front. More detail on histogram use can be found here: http://www.larry-bolch.com/histogram/

2) Photoshop is a necessary step. The picture isn't done until it has visited Photoshop (or a similar image processing program).

3) Just because we have item (2), don't think that item (1) isn't very important.
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Old Friday 2nd January 2004, 23:19   #4
paul_j_c2000
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Hi Doug thanks for your input,i am new to photoshop and still trying to get the best out of it,you mentioned using Fill Flash which i dont appear to be able to find any reference to it in my Sams teach yourself or in the help any thoughts thanks paul
Quote:
Originally Posted by Doug Greenberg
Hello,
You aren't alone in being frustrated with this issue. High contrast situations are particularly difficult in digital photography. What I see in this picture really isn't that bad, frankly.

Some suggestions:
First, you should try using the spot metering function on your camera if there is one. If you can't do this, think in terms of getting the exposure right *for the bird* and letting the background "go." A typical camera metering system, even an "evaluative" one, will tend to underexposure the bird so as to protect some of the fidelity of the background. But you don't care about this, you want a correctly exposed cormorant. In situations where you know the metering system will underexpose your bird, you should try setting your exposure compensation to +0.7 and even +1.0 or higher. By "overexposing" you have a better chance of bringing out the details in the dark bird's plumage.

Experiment until it comes out the way you want it! That's the advantage of a digital camera. Take six or seven different exposures (looks like this bird wasn't going anywhere quickly), go home, download them, and see which one finally is easiest to work with to produce a finished print. Trash the rest!

In Photoshop you have a feature called "fill flash." By using this gently (!) you can bring up the light level on an underexposed dark bird. Don't overdo it! The problem usually is that once a portion of a photo is underexposed the "noise" level is pretty hard to cope with, even if you can adjust the darkness level to where you want it to be. Perhaps someone else will have more insight/experience regarding this issue.

Bring up the brightness/contrast adjustment settings and play with the sliders that accompany the histogram that is provided. This can improve your image.

What you don't want to do in this situation is use the "auto levels" adjustment in Photoshop. This will invariably *increase* your contrast level, something you don't need.

Another thing you might try in these situations is setting your in-camera contrast level to "low contrast." This will alleviate (a little) the stark difference between bird and background.

That's what I can suggest. I'll bet someone else will come up with something better
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Old Friday 2nd January 2004, 23:35   #5
paul_j_c2000
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Hi Jay a very big thank you for writing this great piece as i said to Doug iam new to photoshop and still trying to master it,i have tried using the same picture to create your master piece following your notes,i dont seem to be able to get the exposure right in the histogram ,you are correct with your first j peg of original histogram i have mastered the curves and sharpening ok,i think i need to take more pictures and get more experience thank you very much for your help any more tips are always welcome thanks again paul
Quote:
Originally Posted by Jay Turberville
Well, it is my opinion that if you want good results, you simply have to invest in learning the craft to some extent. There are a number of ways to approach this, but here is the way I suggest for a "non-expert".

Whenever the background is relatively bright, increase the exposure by a stop or so. This is pretty much what Doug G. also said. But the real question is how much? At this point you have a choice. You can learn some of the "whys and hows" of photography and increase your expertise ... or not. If not, bump the exposure up a stop or so and you'll probably get better results. No need to read further. But if you want to understand it more, read on.

Well Ansel Adams used a spot meter to analyze such situations and that certainly will work if you have one and are willing to use the Zone system or some variant. I'm going to assume that you'd rather not. And in fact, you don't really need to since you have a tool built into your camera that is much more sophisticated. It is the camera's histogram function.

The camera histogram should give you a display that looks something like this:
http://www.jayandwanda.com/digiscope.../histogram.jpg

What this graph tells us is that no detail is being recorded in the lightest portion of the image. This pretty much confirms what we can see in the image. The value of the histogram is it gives us a means to measure when our exposure compensation is about right. We should increase our exposure so that we push that large thick bar (which is caused by the sky in this picture) almost all the way to the right as represented by this image.

http://www.jayandwanda.com/digiscope...erexposure.jpg

You might even want to push it further or even fully off the right side of the scale. But beware of such a move since the "overexposed" areas might "spill" or "bloom" into the edges of your main subject. Do some tests of this kind of overexposure in your backyard as an experiment to see how your equipment reacts. Then you'll have a good idea of how far you can go if necessary.

This better exposure doesn't completely fix your problem though. The simple fact is that you have an image with a very broad brightness range. This is a place where using the RAW image format might be of use since it records more than 8 bits of data per pixel. But we'll leave that for another discussion.

The fact is that whether it is film or digital, we can only record a limited brightness range. And digital is a bit more limited than film. Our expert Ansel would have carefully recorded his exposure (your camera does that automatically for you) and would have then made notes on how to develope his negative to best exploit his exposure. But there is no developing stage for us. As Doug G. said, situations like this might very well call for setting the camera contrast to low. This is mildly analogous to development since this setting controls how the RAW image data is converted to 8 bit RGB data. So when a scene's contrast is very high, it is generally a good idea to set the camera to a lower contrast.

But while digital mostly takes away the developement stage as an opportunity to control our image, it also give us something very powerful. Photoshop!! (Or insert your favorite image manipulation software here.) Photoshop is our digital replacement for differing paper grades, special developing, and dodging and burning and other manipulations. Getting the exposure right is only the first step and sometimes it is not enough in order to get a good image. In fact, there are very few images that cannot benefit from a little adjustment in Photoshop.

There are many ways to approach this next step, but I generally prefer using Photoshop's "curves" feature. The point to keep in mind regardless of the tool we use is that we want to remap the detail that is in the dark area of the bird so that it covers a wider brightness range. We want to make the bird brighter and also keep its contrast looking more natural. The beauty of the curves tool is that it lets us interactively give different brightness regions of an image a differing level of adjustment. In this case, we try to leave the sky alone (about a 45 degree angle) but want to increase the contrast and elevate the levels of the darker regions (a very steep angle on the curve).

http://www.jayandwanda.com/digiscope/paulC/curves.jpg

You can see in the sample image that the peak at the far left of the histogram has now been spread out into the middle values and that the bird is beginning to look more like what we want. But it does seem to have a bit of a yellow cast to it and it is looking a bit soft. So I shifted the color balance a bit toward blue and sharpened the image a bit to increase the local contrast in the details of the feathers.

http://www.jayandwanda.com/digiscope...olor_sharp.jpg

More could be done. For instance, you might create a number of different layers with different curve treatments and blend them together. This technique could be used to bring out more detail in the very dark branch to the left of the bird.

These results aren't half bad. If the initial exposure had been better, then better results would be possible.

The important points to take from this are:

1) Learn to use historgrams to get a better exposure up front. More detail on histogram use can be found here: http://www.larry-bolch.com/histogram/

2) Photoshop is a necessary step. The picture isn't done until it has visited Photoshop (or a similar image processing program).

3) Just because we have item (2), don't think that item (1) isn't very important.
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Old Saturday 3rd January 2004, 00:17   #6
Doug Greenberg
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Hello,
Actually, I use the cheapie version of Photoshop called "Photoshop Elements," which with various rebates is practically given away for free. I confess that I am fairly ignorant regarding which features of Photoshop Elements are present in the same form in the big version of Photoshop. I am now guessing that "fill flash," one of my favorite features of PE, is not present in Photoshop proper.

I did a quick web search using keywords "Photoshop fill flash," however, and found several references to "using Photoshop to create a fill flash effect."

Here's one example, which seems to necessitate ownership of version 8 of Photoshop:

http://www.techtv.com/screensavers/h...579825,00.html

There are other such articles online, plus references to some plug-ins that can perform a "fill flash" function.

I also confess that using those curves to which Jay refers is still beyond me, though I am starting to understand histograms just a bit.
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Old Monday 5th January 2004, 17:33   #7
Steve Gross
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Here's a tip for use in the field:

Arthur Morris, one of the US's premier bird photographers, sells an item called "Pocket Guide to Evaluative Metering Systems." It's a folded and laminated sheet which suggests the exposure compensation for a wide variety of lighting/subject/background combinations.

For example, on the shot posted in this thread (light background, dark subject), the recommended exposure compensation would be +1 EV. This (along with fill flash, if reasonable to use based on distance to subject, etc.) would bring out details in the subject without completely blowing out the sky.

Arthur uses some amount of exposure compensation on nearly every shot he takes, and I can tell you that his work is exceptional.

I believe that you can order this item through his web site: www.birdsasart.com

I have no affiliation with Arthur Morris (standard disclaimer), but find his work inspiring. He does a lot of field workshops, and I hope to attend one someday.

Steve in Houston
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