XTi / XSi / 50D dark frame noise testing

Started Oct 14, 2008 | Discussions thread
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Johns a geek Regular Member • Posts: 188
XTi / XSi / 50D dark frame noise testing

These tests have been asked for on here, so I did them. I couldn't help myself - with no daylight free time to do actual photography, and a new toy to play with... I figure this may be of interest to folks who are thinking about upgrading from a rebel body, so I'm posting it here instead of on the 50D forum.

The question is, how do noise levels compare in the absence of light? Given that the shadow areas are where you notice the noise in a photo, this makes a certain amount of sense. It also made for an easy test, since the variables of lens, focus, lighting, etc. are all eliminated.

Basically, I shot RAW with the lens cap on in a dim room, all at 1/15th of a sec, and at the full range of native ISO for each body. I controlled for as many factors as I could think of, processed the data with Canon's Digital Photo Professional 3.5 in the exact same way, avoiding any adjustments. I used Photoshop to analyze the noise, first boosting it by using the levels command, and then using the histogram window to report the average pixel intensity. I also examined the histogram and looked at the other statistics provided, noting the brightest pixels in each image etc., but I'm not going to report them as the average gives a pretty fair idea of what's going on.

Basically, the XTi exhibited less noise than either of the other two cameras at ISO 100 and 200. All three were pretty even at 400, and then the XTi got very noisy while the XSi was quite a bit better and the 50D was definitely the best. The 50D at 3200 was about 50% as noisy as the XTi at 1600!

Unfortunately, I don't think these results hold up under real-world shooting conditions. I did one quick test when I first got my 50D, because I was very excited to see how stunning it's promised high-ISO performance was going to be, and it was a bit underwhelming. If I get bored, I'll probably do a more scientific test.

Anyway, the results are presented here as one image, which you should download to properly examine ( 600kb):

http://picasaweb.google.com/notisj/CameraTests#5257125311543715010

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