Canon EOS 5D Mark II review
Performance Page 1
How good is that movie mode?
Having reviewed the Nikon D90, I came to the 5D Mark II with some expectations as to how its video functionality may perform. From a specifications point of view, the 5D Mark II has the advantage of allowing contrast-detect autofocusing while recording, though I soon found this to be of very little benefit. Anyone who has used contrast-detect autofocusing via the live view function on their DSLRs will know that the process works via a trial and error stepping of various points of focus. In the context of a video this looks unnatural and is only of any real use when predetermining focus prior to recording, although this may be done quicker via the mirror-moving phase detection mode before video recording is initiated.
The other problem with focusing during recording is that the camera's microphone picks up all manner of sounds, which include the whirring of the lens' motor, the tapping of each focusing step, the image stabilisation system (if using a lens with the function) and the beeping of focus confirmation (though this may be disabled). As may be expected, a comparison with the USM-enabled lenses I used during the test showed them to focus much more discretely, though as some sound was still noticeable (and given the stepping problem) I still wouldn't advise relying on their quieter AF systems for video recording. The manual advises that these sounds may be minimised, or even eliminated, via the use of an external microphone, though I didn't have one to hand to check by how much this would be the case.
Manual focusing is, therefore, a much more logical step to take when using video, ideally using prime lenses with either relatively wide or standard focal lengths, (and ones which can be supported easily while recording). It goes without saying that the design of these didn't take into account their use for video capture, which soon becomes apparent in use. For example, the EF 50mm f/1.8 Mark II lens features a shallow manual focusing ring towards the front of its barrel, and when focusing a stray finger would often be captured mid-recording. It's perhaps slightly ironic that I found the older Mark I version far better suited to the task, as its manual-focusing ring is not only positioned further towards the rear of the lens, but is also easier to operate while still supporting the camera in the left hand.
Despite this, once focused I found the video mode very capable, so long as I remained relatively immobile and I didn't need to change the focus too drastically. On a tripod, and handholding in more relaxed environments, I developed a more fluent differential focusing technique between two subjects, and it was clear that a bit of practice was all that was needed. So, the AF is useful for initially confirming focus but then a polished manual focusing technique is advised for optimum results.