Canon EOS 7D: ISO Performance
|Northern Mockingbird #1 (2200 x 1385 crop)|
Canon EOS 7D with EF 400mm f/5.6L (ISO 250 | f5/6 | 1/500sec)
Sharpening: +25 | Luminance Noise Reduction: +10
Before I begin, though, it may be useful for me to make a couple points about how I will approach these reviews. First, while I have access to a studio, I don't plan to do much if any testing of the camera there. Studio tests have real value, but I will never be able to improve on the reviews on dpreview. I'm most concerned with its use in the field, and especially with how this camera performs in nature and wildlife photography. Second, pixel-peeping tests of image right out of the camera also have real value, since the "garbage in, garbage out" principle always applies. However, I'm not nearly as interested in this camera's image quality right out of the camera. I'm most interested in the camera's ability to give me images that I can turn into a final product. So the images I show will be edited images, and I will let you know what edits I made to each image. And if you click on any of them, you will be able to see the images larger on my smugmug site.
As a wildlife photographer, I often need to get out in the field early in the morning (when light is scarce) to find the wildlife I want to photograph. And while I'm a big believer in tripods, wildlife typically moves, so a tripod is not always practical. But in order to handhold my camera in low-light situations, I need to be able to crank up the ISO to get sharp images. Raising the ISO gives me faster shutter speeds, which allows me to "freeze" the motion of my subject (and my camera). But raising the ISO eventually brings diminishing returns, since the higher you raise your ISO, the more noise will appear in your images. The noisier your images become, the less detail will be retained in your pictures. In practical terms, this means you can't crop your image as much, and it means that you can't enlarge your images as much on screen and in prints. As a wildlife photographer, I almost always crop my images, sometimes very significantly, so I like to keep noise levels as low as possible.
I took these Northern Mockingbird photos all on the same morning of the same bird. I was standing in different places and the bird was in different poses, but I made the changes in exposure in these photos to account for the light coming out from behind the clouds between after around 8 am.
|Northern Mockingbird #2 (1760 x 1152 crop)|
Canon EOS 7D with EF 400mm f/5.6L (ISO 800 | f5/6 | 1/400sec)
Clarity: +24 | Vibrance +62
Sharpening: +25 | Luminance Noise Reduction: +17
Now that we've seen how the EOS 7D performs at moderatly high ISOs, let's look at how it performs with photographs between 1600 and 5000 ISO. These photos were taken on different days of different birds, but they were all taken under the cover of trees which allowed little light to fall on the bird. The shutter speeds on these images are pretty slow, and since I was shooting without a tripod, I braced my arms and took many shots in the hope that a few would turn out sharp.
|Ovenbird #1 (2233 x 1553 crop)|
Canon EOS 7D with EF 400mm f/5.6L (ISO 1600 | f5/6 | 1/80sec)
Shadows: +45 | Whites: +43 | Blacks: -29 | Vibrance +36
Sharpening: +25 | Luminance Noise Reduction: 0
|Ovenbird #2 (2076 x 1299 crop)|
Canon EOS 7D with EF 400mm f/5.6L (ISO 2500 | f5/6 | 1/60sec)
Sharpening: +25 | Luminance Noise Reduction: +0
At this moment in time, if you want better ISO performance from a Canon DSLR, you'll have to buy a full-frame camera (or a 1.3x crop like the 1D mark IV). That said, other current generation cameras, like the 60D and T4i should produce similar results to the 7D, since they use the same sensor.
In practical terms:
- ISOs up to 400 generally produce nice, clean, and relatively noise-free images. In this range, I don't mind at cropping down to 1 megapixel image for online viewing.
- I don't hesitate to raise my ISO up to 1600 when I need to. Noise becomes more noticeable, especially in the shadows and clean backgrounds, but I can deal with much of that in Lightroom. And noise is not as noticeable in my subject, since it is made less conspicuous by the details in the subject.
- When absolutely necessary, I'll take shots as high as 5000 ISO. I don't crop these as much, and I tend to work much more to make the image look respectable, but I can often come up with an image that I don't mind showing on screen. A sharp, noisy image at 5000 ISO is much better than no image at all.