Why do my Nikon D7000 wildlife photos look noisy at ISO 640?
Asked 12/13/2011
4 views
2 answers
0
I'm new to photography and recently used a Nikon D7000 with a Sigma 150-500mm lens for wildlife shots. In some images, especially those taken at 500mm, the out-of-focus areas seem very noisy, and the effect gets worse when I add contrast in post-processing.
Example settings for one photo: aperture priority, 500mm, f/6.3, 1/320s, ISO 640, handheld. I expected the D7000 to perform better at this ISO, so I'm trying to understand the likely cause. Is this mainly sensor noise, underexposure, background blur/bokeh, low light, or something about the lens/settings?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
14y ago
2 Answers
5
I personally can't see much noise in the photo. I think you are confusing the blur of the background and foreground, or bokeh, with noise.
The long focal length of the lens and the distance you have taken the subject at has caused some nice blur before and after the subject. I am not personally familiar with the aperture of that lens, but if it has fewer aperture blades (5 or so) then any blur will be slightly less smooth than if it had 7 or more blades. When you have point light sources in the background this can look like hexagonal lights instead of smoother rounder ones, but when you have complicated backgrounds like the foliage in yours, this will make the blur ever so slightly more 'jagged' that it could be.
I think it is this 'jaggedness' to the blur of your photo that is making it look to you like the out of focus bits have noise, when really it is just an affect of the distances and background blur of that lens.
EDIT: I also think this may have been amplified a little by the other suggestions people have made on the not so low ISO and maybe a touch of auto sharpening added to the pictures
Originally by user3584. Source · Licensed CC BY-SA 4.0
user3584
14y ago
0
Generated from our catalog & community — verify before relying on it.
It’s probably not primarily a lens defect or unusually bad ISO 640 performance.
From the replies, two things are most likely happening:
-
You may be mistaking out-of-focus blur for noise. At 500mm and f/6.3, depth of field is very shallow, so foreground/background foliage will blur strongly. Busy natural backgrounds can make bokeh look rough or “jagged,” which can resemble noise.
-
The image may be slightly underexposed. If the histogram is weighted toward the darker half, lifting shadows or adding contrast in post will make real noise more visible. Even a good APS-C camera like the D7000 will show noise in darker areas if you brighten them later.
So the likely source is a combination of normal shadow noise plus underexposure, while some of what looks like noise is actually bokeh/blur texture.
To reduce the problem: expose a bit brighter when possible (“to the right” without clipping highlights), avoid heavy shadow lifting, and use a higher ISO if needed to get a better exposure in-camera. Also note that 1/320s at 500mm handheld is marginal, so softness/blur may add to the impression of poor image quality.
Recommended products
UniqueBot
AI14y ago
Your Answer
Related Questions
Why do full-frame and crop cameras need the same ISO for the same shutter speed and aperture?
Why do my GH1 night photos show heavy noise at ISO 320/640 and 15–25 second exposures?
Should I keep a Sigma 150-600mm for wildlife, or switch to a 300mm prime with a teleconverter?
Will a Sigma 150-500mm f/5-6.3 APO DG HSM autofocus on a Nikon D5500?
Will a Nikon D3300 autofocus with a Sigma 150-500mm f/5-6.3 at 500mm?