I see people on various photography forums discussing this subject, but I usually just refrain because usually these things end up being a pissing match. I shoot a variety of subjects, weddings, model portfolio work, headshots, sports (soccer games, some football). So in my personal opinion I have put these two cameras threw their paces fairly diligently. I also print many photos, I feel that many times people look at images on their computer screen which is really not an accurate representation of what final output should be.

If you really want to test the quality of a camera, or compare two camera bodies then set them up side by side. Use the same lens, the same lights, the same shutter speeds and aperture ranges, and the same ISO ranges. Then take all of those files, untouched, and unprocessed and create wet process photographic prints. In my personal opinion this is the only REAL way to test a camera’s capabilities.

That being said here is a small but fairly comprehensive comparison of the Canon 5D Mark II vs. the Canon 7D

Camera Image Quality

As far as image quality it’s VERY hard for me to tell the difference at low ISO. If you’re shooting at any thing below 600 ISO you will most likely not tell the difference between the two cameras. The file sizes that the 7D produces are actually almost as large as the 5D Mark ii.

Canon 5D Mark ii Pros

ISO: One of the pro’s of the 5Dii are ISO, yes it’s 100% noticeable at ISO values over 1000. The Noise levels on the 7D are noticeably grainy at 1200 even with noise reduction in the new version of Lightroom 3. I didn’t really notice how noisy it was until I started printing this year’s wedding albums. However the grain pattern on the 7D is actually very nice; it looks more like film in my opinion and has a better pattern then the 5D Mark ii. The 5D however has a very high quality picture even up to 3200 ISO, it takes very little noise reduction in LR3 to produce a very clean image at 3200 ISO.

Detail: The detail on the 5D Mark ii is almost to much. I frequently shoot with the CFV-39 backs on MF Hasselblad system and the 5Dii stands toe to toe with most MF format cameras I’ve seen with almost twice the Mega-pixels. I’m actually having a problem with my new work flow because in my beauty retouching the skin texture is simply to pronounced even with very soft lighting. If you’re a detail freak like me the 5Dii + the 70-200 Canon L can’t be beat for the price.

Canon 7D pros

AF: Not so much the speed of the auto focus, but the layout of the AF points is really great on the 7D. I was a bit disappointed by the speed of the 7D AF system when I first received my camera but I’ve learned to live with it. I really expected it to be more snappy then the 5D Mark ii’s AF system. The 5D is in my opinion just as quick as the 7D if you’re using the 5D’s center AF point. However the 7D’s AF layout grid allows for better photographic composition of the image in camera. I am not a fan of focusing and recomposing which is common because I like to shoot at very wide apertures so this method can lead to slightly out of focus images. If the 5D Mark III had the 7D’s AF system it would be the perfect camera in my opinion.

Exposure Brightness: This is something I would have never even expected to fluctuate so much from camera to camera; however my 5D Mark ii seems to consistently UNDER-expose by about 1/3 of a stop. My mark ii is actually at the Canon NJ repair shop to try and correct this issue. If you like bright images the 7D lends it self to that image style, where when I want something darker and moody I grab my 5Dii (for now)

Optional Considerations

I personally like having one of each camera; I can perform all my jobs with either camera. The question of the two cameras is like a carpenter deciding what file to shape a piece of wood with. Most fine files will work for a carpenters task, some files just make this or that job slightly easier based on the qualities of the wood.

The biggest factor I would advise people to take into consideration is how the sensor size will affect your focal lengths. I really like my 24-70 on my 7D, because I rarely shoot at 24mm so it works out well. When attaching my 24-70 the lens to the 7d it becomes a 38.4 mm – 112 mm focal length lens. I’ll then use my 70mm-200mm on my 5D Mark ii, this gives me a wonderful focal length combination for most events. If I find for some locations if I do need a longer reach the simply move my 70-200 over to my 7D so it equates to 112mm – 320mm.

If you’re in the market for two bodies, I’ve been very happy with one of each. The batteries are interchangeable, though the grips are not. Both cameras are fine tools for their respective jobs.