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DPChallenge Forums >> Hardware and Software >> 7D grain issues
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09/27/2010 02:52:35 AM · #1
This is a picture taken at 800 ISO, viewed at 100%. I thought the 7D was supposed to be good at low lighting. I never considered 800 ISO to be that low. If you have a 7D, are you getting grain like this in the 640-800 ISO range?


09/27/2010 03:29:50 AM · #2
Nope, especially not at that ISO. Looks more to what I get at 6400!
09/27/2010 04:18:37 AM · #3
Was this the image as shot or was it underexposed and you brought it up to this?
09/27/2010 06:46:09 AM · #4
I did a little highlight recovery in RAW.

Here's the original, unedited (except cropping it down.)


09/27/2010 06:52:37 AM · #5
Oh, my...no. Never seen that at 800. I've never seen grain that coarse on any ISO from my 7D. I have no idea what's going on there. :((
09/27/2010 07:14:29 AM · #6
any 7D owners out there. Could you please open some of your files in photoshop, bring them up to actual pixels, and crop out a section and post it here? I would love to know what they're supposed to look like at different ISOs

I'm really starting to panic. I'm doing a wedding on Saturday, and I should be using the 7D so that they can make enlargements, but I'm wondering whether I should switch back to my 40D.
09/27/2010 07:18:50 AM · #7
I will try and post a few when I get home. For right now I have this shot I can show from my port. Of course it is edited and resized but it is a significant crop and it was at iso 3200.
09/27/2010 07:22:45 AM · #8
If you have the original, unedited version that you could should at 100%, that would be helpful. I've been able to get things to look fine small, but when you enlarge, it's extremely obvious that there's an issue.
09/27/2010 07:27:38 AM · #9
This is an original viewed at actual pixels -- shot probably around 2000 ISO



This is the original shot shrunk down and even sharpened after the shrink, and it looks fine.


So small seems to be okay. But if I printed an enlargement on that shot, I assume it would look like the first image and look horrid.

I know I can do noise adjustment, but I thought the 7D was supposed to be better than this.

(now I realize that 2000 is more extreme -- but I'm getting this at 640 and 800 as well)

Here's two examples at actual pixels -- 320 ISO





Message edited by author 2010-09-27 07:36:53.
09/27/2010 08:07:58 AM · #10
Can you show a screen shot of the histogram of the original unedited shot with no adjustments made to it?
09/27/2010 08:24:16 AM · #11
.

Message edited by author 2010-09-27 08:25:35.
09/27/2010 08:25:13 AM · #12
The first shot is a little underexposed. Here's the histogram and the original shot (actual pixels):





I wouldn't have thought that the amount of underexposure would make that significant of grain. It's not that badly underexposed.

Here's a shot that's exposed better and it's corresponding histogram. There's still a lot of grain.



09/27/2010 08:25:15 AM · #13
Originally posted by vawendy:

I know I can do noise adjustment, but I thought the 7D was supposed to be better than this.

Do you have in-camera noise reduction (I think it's called "High ISO Noise Reduction" in the menu) turned off, by any chance? FWIW, Noiseware does a pretty good job of eliminating ISO grain without sacrificing too much detail. Have you done a side-by-side comparison with your 40D?
09/27/2010 08:27:23 AM · #14
Originally posted by david_c:

Originally posted by vawendy:

I know I can do noise adjustment, but I thought the 7D was supposed to be better than this.

Do you have in-camera noise reduction (I think it's called "High ISO Noise Reduction" in the menu) turned off, by any chance? FWIW, Noiseware does a pretty good job of eliminating ISO grain without sacrificing too much detail. Have you done a side-by-side comparison with your 40D?


The high ISO noise reduction is turned off. But I wouldn't have thought that 800 would be considered high ISO. I thought you used that for 2000-6400.

I'm in the process of comparing the 40D and the 7D. I just took some shots of a teacup, and I'm downloading them right now. It may not be a good object for the comparison -- but we'll see.
09/27/2010 09:25:27 AM · #15
Haven't really pushed my camera up in ISO that much but maybe these will be useful for you.

All shot at 1000 ISO - Full shot followed by crop



This had already been cropped a bit so this is a pretty heavy crop on the small pic



Edit to add: These are JPG images.

Message edited by author 2010-09-27 16:51:59.
09/27/2010 09:41:20 AM · #16
That's at 1000 ISO? I haven't had anything anywhere near that clean below 400 ISO.
09/27/2010 09:46:03 AM · #17
Wendy, looking at some of the shots in your portfolio taken with the 7d and a high ISO there doesn't seem to be a problem (but then again you may have used noise reduction).

Have you tried clearing your camera back to default settings and testing it again? Maybe a setting has caused the problem.

Message edited by author 2010-09-27 09:49:35.
09/27/2010 09:57:56 AM · #18
Originally posted by RamblinR:

Wendy, looking at some of the shots in your portfolio taken with the 7d and a high ISO there doesn't seem to be a problem (but then again you may have used noise reduction).

Have you tried clearing your camera back to default settings and testing it again? Maybe a setting has caused the problem.


I've denoised almost every shot that I've taken with the 7D -- at least in the last month or so.
Even if it's not denoised, you don't really see the problem when you're dealing with a smaller image. Here's the original of the first shot I posted, resized and sharpened -- not denoised.


09/27/2010 10:24:37 AM · #19
Originally posted by vawendy:

The first shot is a little underexposed. Here's the histogram and the original shot (actual pixels):





I wouldn't have thought that the amount of underexposure would make that significant of grain. It's not that badly underexposed.

Here's a shot that's exposed better and it's corresponding histogram. There's still a lot of grain.




Both of those shots are underexposed by at least 1/3 to 2/3 of a stop in my opinion. That is the problem with your noise.
09/27/2010 10:29:27 AM · #20
This is 1600ISO with a proper exposure. I can pull a 100% crop of it tonight if you would like. But I'm at work right now.
09/27/2010 10:50:00 AM · #21
Originally posted by MattO:

Originally posted by vawendy:

The first shot is a little underexposed. Here's the histogram and the original shot (actual pixels):





I wouldn't have thought that the amount of underexposure would make that significant of grain. It's not that badly underexposed.

Here's a shot that's exposed better and it's corresponding histogram. There's still a lot of grain.




Both of those shots are underexposed by at least 1/3 to 2/3 of a stop in my opinion. That is the problem with your noise.


But since I'm shooting in RAW, I should have the latitude to change it 1/3, yet it doesn't fix the grain issue.

Here is a shot that's obviously not underexposed, but see how bad the grain is in the background?



here's the histogram



and that's only at 640 ISO

Here's one that's even worse -- 640 ISO


Message edited by author 2010-09-27 10:54:08.
09/27/2010 10:57:55 AM · #22
When you shoot raw, you lose ALL in camera noise reduction, meaning that YOU then have to be the noise reduction software. IMHO todays cameras are very good at high ISO because of the IN CAMERA noise reduction done of JPEGs because of the software they use to help. You lose all of that with raw, UNLESS you use the manufacturers software to reduce the noise. Have you tried DPP to process the noise then move it to your regular software for processing? I only shoot the 7D in JPEG because of this. Underexposing any photo on the 7D is just asking for trouble. They did shove a few too many pixels on that sensor.

Matt
09/27/2010 11:05:36 AM · #23
You need a freckle filter. Even the BG has freckles.
09/27/2010 11:10:40 AM · #24
I have a 7D and I do not have that problem.... Something is definitely very wrong. Even at 64000 I do not get that kind of noise.
09/27/2010 11:12:54 AM · #25
Takes 7D off list.

Just kidding, Hope you resolve this and don't forget to let us know what it was. Good luck.
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