I made a comment in my last post that I felt the quality of images captured with a Canon 7D rivals that of the Canon 5D Mark II when equipped with an equivalent lens. I made this assumption based on my subjective observations from using both cameras. However since I have both cameras, it’s possible for me perform a quantitative analysis to back up my claim. Perhaps I’ll finally get some use out of that Master’s Degree I earned from Miami University years ago.

My plan was to shoot the same scene with the two different cameras and visually inspect the results. The cameras were set to manual, with ISO 640, iris at f/2.8, shutter at 60, and white balance set to cloudy. The scene was illuminated with natural light coming through a large window on an overcast day. I shot the photos as camera raw, and then scaled down the images in Photoshop. I then saved the images as a high quality JPEG for upload to Flickr. The downscaling and JPEG compression will degrade the images, but since we’re looking for relative differences between cameras this seemed reasonable since the two sets of images received the same treatment. I used a Canon 24-70mm f/2.8 L lens for this test. In my first test I set the lens to 50mm and utilized a tripod to position the cameras.

7D on Left, 5D Mark II on Right

As you can see in the above image, the 1.6 cropped sensor of the 7D has a zoom effect on the captured image. So when shooting with the 7D equipped with a 50mm lens, the camera behaves more like a 50mm x 1.6 = 80mm lens is attached. Instead of comparing different zoomed images, I decided to shoot images on the 7D at 24mm, 35mm, and 50mm. I would then compute the equivalent lens for the 5D Mark II and attempt to match up the images. In the picture below, the image on the left was shot with the 7D with lens set to 24mm. The image on the right was shot with the 5D Mark II with lens set approximately to 38mm. The images don’t line up exactly, but it’s close, and even in the scaled versions posted on this page it’s clear that the image on the right has a more narrow depth of field. Although I tried to set the cameras to be identical, the color saturation is not the same.

7D on Left, 5D Mark II on Right

The next set of images were shot with the 7D set to 35mm and the 5D Mark II set to approximately 56mm. As we saw in the first set of images, the picture on the right captured by the 5D Mark II has a more blurry background indicating a more narrow depth of field. Again we see a slight difference in color saturation.

7D on Left, 5D Mark II on Right

The final set of images were shot with the 7D set to 50mm and the 5D Mark II set to 80mm. In this case I had to use a different lens since the lens I used for the test stops at 70mm. Despite having used a different lens, we see the same behavior with the 5D Mark II showing a more shallow depth of field and a slight variation in color saturation.

7D on Left, 5D Mark II on Right

I doubt the science employed here would impress my former professors at Miami of Ohio or the National Science Foundation. Although I tried to configure the cameras in an identical manner, there is a difference in color saturation in the captured images. Since the 5D Mark II is focusing the image on a larger area then the 7D, one would expect a more shallow depth of field as seen here. So my method of visual inspection isn’t very quantitative, but it confirms my gut feeling that images captured with the 7D rival that of the 5D Mark II.