Autofocus is one of the most important aspects of any camera. There has been much debate over the past few years about how well autofocus performs on the various camera models. We originally developed this AF torture test as part of an ongoing article about the autofocus problems that surrounded the original introduction of the Canon 1D MKIII. Using this test we were able to discern that there was most likely a hardware issue at the root of these AF problems. And, so there was. Anyway, people seemed highly interested in this particular autofocus test, so we continued to conduct this test during various camera reviews.
How we test:
The tests are fairly simple and straightforward. A camera is placed on a tripod and a runner runs directly at the camera at a steady pace. The tests are all performed using servo focus mode at f/2.8 using the best 300mm f/2.8 lenses available from the respective camera manufacturers. The camera exposure is set to ensure that a very high shutter speed (usually 1/2000 or higher) is achieved throughout the run. Normally, at least 5 test runs are conducted and then coded for the number of in focus images in each sequence. A percentage is then taken for each test run. These 5 percentages are then averaged to get an overall result. These tests are all done using the default camera settings and default custom function settings. Tests are done using the center focus point only.
This is a specific Auto Focus torture test, not an overall Auto-Focus score:
Please note that these results do not necessarily reflect the overall autofocus system performance of any particular camera. They do provide a lot of insight into how well the AF systems stand up to one of the toughest tasks they can possibly face.
Overall winner is denoted in red.
Results of Canon 1D MKIV and Nikon D3s
Canon 1D MKIV Results
45 in focus out of 50= 90% in focus
56 in focus out of 60= 93% in focus
48 in focus out of 55= 87% in focus
49 in focus out of 55= 89% in focus
52 in focus out of 58= 90% in focus
Canon 1D MKIV Overall= 89.4% in focus
Nikon D3s Results
29 in focus out of 46= 63% in focus
37 in focus out of 47= 79% in focus
46 in focus out of 53= 87% in focus
40 in focus out of 52= 77% in focus
38 in focus out of 47= 81% in focus
Nikon D3s Overall= 77.4% in focus
There has been lots of talk about whether the new Canon 1D MKIV auto-focus will outperform the poorly received Canon 1D MKIII auto-focus system. In actuality, our tests of a good Canon 1D MKIII body showed very good results on this test. However, the Canon 1D MKIII bodies that had hardware, and possibly other quality control issues, did not perform well at all. So, while the 1D MKIII was certainly capable of performing well on this test, some examples of the camera did not. As a result of these inconsistencies, the recalls by Canon, and a lot of internet discussion of poor auto-focus performance, the camera quickly gave Canon a black eye.
In the end, this test shows that the Canon 1D MKIV does indeed perform better than the best Canon 1DMKIII we tested. In fact, it turns in the best results we have ever seen from any camera. The surprising thing is really how well the Nikon D3s does on this test. While it does not produce the tack-sharp images of the 1D MKIV, it does perform very respectfully and has improved significantly over the prior Nikon performance levels.
You may view more detailed results for the previously tested cameras in this and other sections of the site.