Old 08-06-2009, 02:48 AM   #1
jlev
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Default Cures for being rejected for underexposure and then bad color

Rejected for underexposure
http://www.railpictures.net/viewreje...5&key=25103366

Now, Bad color.
http://www.railpictures.net/viewreje...d=717142&key=0

I attached a shot with attempted changes. I hope I didn't make it worse
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Old 08-06-2009, 05:23 PM   #2
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Your attachment looks like a step in the right direction. The exposure is definitely better, but it doesn't have that 'washed out color' look that the bad color reject has.

One tip I learned is to take all the photos in question and put them in a slide show. This makes it easy to compare them, and small changes in exposure, contrast and color are easier to see.

Not to pile it on, but there's a bit of grain visible in the sky in your third shot. The locomotive looks sharper, but the sky is overdone. You might want to select it and use a noise filter like Despeckle, or better yet use selective sharpening to avoid the sky and sharpen the subject only. I used to have similar problems when shooting in the evening on warmer days (are you shooting with a Rebel XT?). I can't tell what the ISO for your shot is, but even around 400 I would start to have issues with noise in the sky.
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Old 08-06-2009, 06:00 PM   #3
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Hi John,

The first shot is underexposed, but the color looks reasonable. In the second attempt, it looks as if you might have overused shadow reduction and/or fill light in an attempt to try and brighten it up. Unfortunately, those had the effect of washing out the black stripes on the front of the locomotive....and other things....hence, the bad color rejection.

I do also notice the grain the Matt mentions. On this monitor, it doesn't look bad, just noticeable.

Is your original file a JPEG or raw? For a raw file, I'd normally start with an exposure adjustment, and then use levels, shadows, highlights, contrast etc to tweak it. On a JPEG, I'd start with levels. This image doesn't look that far off the mark that a JPEG couldn't be fixed. You just need to be careful what adjustments you make. If the blacks start to look grey or you start to see visible artifacts, it's a sign you're probably pushing it too far.

WRT exposure: What mode are you using when you shoot? I highly recommend shooting full manual exposure, especially if you are shooting JPEGs. You need to be pretty close on the exposure and letting your camera decide the parameters for you is too risky. At the very least, don't ever put your camera in a mode where it selects the ISO for you. Depending on how that function works in your camera, it might be able to select an ISO that's high enough to degrade the quality of your photo beyond what RP can accept.
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Old 08-06-2009, 09:07 PM   #4
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I am shooting on RAW for my original file. I use Picasa software. It's pretty good for RP.net, but unfortunately, it doesn't have elimination of noise software. I shoot at an ISO of 200 and aperture was about f10. I use a D70 and 200 is the lowest ISO. Even at that, on a bright day, I have gotten into noise trouble plenty. I am shooting on Aperture Priority.

No, I will never put my ISO on automatic.

To be honest, this shot has been rejected like six or seven times. I know I'm not too far off. I'm not always good with figuring out natural colors vs nonnatural.

Thank you for the help. I know I'm getting better, but I will always have my weaknesses.
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Old 08-06-2009, 09:25 PM   #5
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Quote:
Originally Posted by jlev View Post
I am shooting on RAW for my original file. I use Picasa software. It's pretty good for RP.net, but unfortunately, it doesn't have elimination of noise software. I shoot at an ISO of 200 and aperture was about f10. I use a D70 and 200 is the lowest ISO. Even at that, on a bright day, I have gotten into noise trouble plenty. I am shooting on Aperture Priority.
Yes, 200 is the base ISO for most Nikons, although the sensors get a bunch better with every generation. My D40x starts to have noise problems at ISO 400. With my D90, 400 is not a problem, but 800 becomes the borderline. Not much we can do with the hardware limitations

I would recommend trying full manual shooting. Take a couple test shots before the train comes and use the histogram to bracket in on the exact exposure. Postprocessing is sooooo much easier and quicker when the exposure is spot on. I've just discovered over time that any of the automatic modes leave open the possibility that the camera will misjudge the scene and blow it.....but if you're shooting raw, you do have a bit of a lifeboat.

Quote:
Originally Posted by jlev View Post
To be honest, this shot has been rejected like six or seven times. I know I'm not too far off. I'm not always good with figuring out natural colors vs nonnatural.
My rule of thumb....and this is just me.....is that four tries is about the max I'll ever do on one image....and I usually quit after three. If the issue is exposure or color and 3 sets of adjustments don't do it, I figure that I probably shouldn't have it in my portfolio. That rule keeps me from testing the patience of the Screeners....which is a good thing.
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Old 08-06-2009, 09:46 PM   #6
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Kevin,
I have used manual exposure mode, and unfortunately, I have gotten hit a lot. i think its just my lack of understanding the basic concepts at times such as aperture. I have to understand histograms.

What would a histogram look like if noise is evident in a shot, and what would it look like if the exposure is correct?
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Old 08-06-2009, 09:59 PM   #7
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Quote:
Originally Posted by KevinM View Post
I would recommend trying full manual shooting. Take a couple test shots before the train comes and use the histogram to bracket in on the exact exposure. Postprocessing is sooooo much easier and quicker when the exposure is spot on. I've just discovered over time that any of the automatic modes leave open the possibility that the camera will misjudge the scene and blow it.....but if you're shooting raw, you do have a bit of a lifeboat.
I think that is good advice. I used to shoot on Aperture or Shutter Priority all the time, but had similar experiences. You might as well go all the way and select both the shutter and aperture in manual. It's a few extra clicks worth of work, but it insures that you get complete control over the image.

Unfortunately I don't believe the histogram can help with the noise issue. It's more for insuring a correct exposure. Simply put the histogram should look balanced toward the middle. Peaks to far to either end and there may be too many light or dark areas (over or underexposed) in your image. Peaks with missing tops can mean there was data lost or not recorded on the image because of the limitations set by the exposure, ect.

It takes a little practice to understand histograms but it's well worth the time.

Edit: Here is a real basic example of what good and bad histograms look like:

http://www.cleanimages.com/articles/...icTutorial.jpg
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Old 08-06-2009, 10:28 PM   #8
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I'm going to railfan one of NJT's least frequent lines tomorrow during the p.m. rush, and I will only photograph like four trains, so I still might stick with aperture priority for most of the shots.
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Old 08-06-2009, 10:34 PM   #9
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Quote:
Originally Posted by jlev View Post
I'm going to railfan one of NJT's least frequent lines tomorrow during the p.m. rush, and I will only photograph like four trains, so I still might stick with aperture priority for most of the shots.
Why? Put it on manual, pick an aperture and then just adjust the shutter speed until the light meter (and histogram) reads a well-exposed shot.
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Old 08-06-2009, 10:54 PM   #10
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I will use Manual more. Here is an original attachment of the photograph of the train
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Old 08-07-2009, 12:49 AM   #11
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Here is an attempted attachment. This is not the original. I tried to make sure I didn't shadow it too much. The sky looks like a natural blue to me. I made sure I didn't oversharpen the photograph too much.
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