7D vs. Mark III

Test done when photographing raptors for 2 consecutive days in Halfmoon Bay. The following equipment was used for comparison:

1) 400mm DO
2) 1Ds Mark III, 21 Mb pixel, 1x crop
3) 7D, 18 Mb pixel, 1.6x crop

The emphasis was to evaluate the capture (how quickly the camera locks on moving subject) and the tracking (keeping accurate focus).

Observations:
1) Still subject, high ISO (1600), F7.1 1/800s
Single center point focus, AI Servo
(Photo #1, #2)
Both cameras performed really well, with slightly higher noise on the 7D. As I was able to approach the subject close, there was no need to crop the full frame image to match distance to subject.
Advantages: Mark III for noise level

2) Flying subject, 400 ISO, F6.3 1/1250s
Mark III: Single center point focus, AI Servo
7D: AF Point Extension, AI Servo
(Photo #3 to 7 (Mark III), Photo 8-13 (7D))
The tracking on the Mark III performed with higher a ccuracy. Didn’t loose focus on the subject even against a busy background.
The tracking on the 7D was not as accurate and provided some softness around the subject’s eye. Even against a plain background the AF Point Extension didn’t perform with high accuracy. Against a busy background, it started to loose focus on the main subject.
In this test, the subject couldn’t be approached as close. So to do a true side by side comparison the Mark III images had to be cropped to 2821x 2231 vs. 5184x3456 (on 7D). Sharpness is still better on the cropped image.
Advantages: Mark III when compared to the AF Point Extension from 7D

3) Flying subject, 400 ISO, F7.1 1/1000s
Mark III: Single center point focus, AI Servo
7D: AF Single Point, AI Servo
(Photo #14 to 17 (Mark III), Photo 18-20 (7D))
This test shows very good tracking for both systems. The full frame images had to be cropped extensively (and still provided good resolution) to match the 7D reach. With so much cropping, there is more capabilities for post processing with the 7D images (larger size).
Advantages: 7D

Overall results:
This test did put the 7D at slight disadvantage over the 1 Ds Mark III. Noise was higher and the new AF focusing system didn’t provide the expected easier tracking (new AF settings). On the other hand, the 1Ds lacked the reach.
The good news is that the 7D tracking system, when used in AF Single Point did not disappoint. I believe with more time with the camera and using additional custom settings, results can possibly be improved.
I also noticed that the tracking was pretty accurate on the 7D and rarely lost focus in a sequence of images (happened only one time).
All considered, the 7D is a viable body for moving subjects (e.g. birds in flight). Unfortunately, the new AF focus doesn’t replace the skills and practice needed to get sharp images ;-)

NOTE: Images were not retouched, just converted to jpeg.

Oliver Klink