Are there any users of this lens out there? I am very disappointed in the speed of focus acquisition. My trials produce 75% out of focus flight shots whereas I am right on target with the 500 f/4 lens. Is there something wrong or is it just inferior?
I assume you are using the same body, with the subject size similar to the 500mm within the frame? If so, the lens should not be producing a 75% OOF ratio. How does it work on static subjects?
I owned the 400 DO in the past and found it excellent for flight shooting, equal to the excellent 400 f5.6 in focus acquisition. Could you perhaps have the focus range switch set for close focus on the 400 DO and not on the 500? If not, I suspect there's something wrong with the 400.
Hi, Susan,
I own the 400DO and use it as my primary telephoto. My dad owns a 500 f/4 so I can offer some comparison of my own, and would agree that the 500 is "superior" in autofocus, although not as dramatically as you suggest the difference is between your own lenses.
What camera body are you using? In my own case, I use a 1DIIn and, like I said, there is a difference, but not nearly as steep as what you are experiencing.
I was having a problem focusing BIF as well for the first couple of my months with the 400 DO (with and without the 1.4TC). Then I had a professional photographer try my lens. Of course, he had no problem. It was brought to my attention that I needed to make sure the lens was manually focused outside of the minimum focusing distance before shooting. Since that time, I usually quickly manually set the focusing ring to somewhere between 10 meters and infiniti before the action begins to make sure the AF kicks in. Since I began this practice, few of my BIF are OOF.
Thanks to all of you. This to answer all your suggestions. I am using the 1D Mark III for all my BIF shots. I am taking the focus off the min. focus distance and have it on 8m-infinity as I always do. Still, I see a marked difference in speed of acquisition. My still shots are in focus although I think they are less sharp than with the 500. Do you think I should deal with Canon or work with Hunt's Photo?
If the lens is new, you might see if Hunt's will exchange it for a another one. Otherwise, I'd send it to Canon--many people have reported much improved lenses after having Canon Service work on them, Canon Service apparently producing lenses closer to spec than Canon factory assembly. It's also possible your mark III could be better calibrated to the 400 DO, but I doubt that would have any effect on acquisition speed.
Susan,
I don't own one, however I used Artie's 400 DO on a Mark III body.
As a Nikon guy, I found that combination to be very fast and sharp.
I was using the Mark III's AF set to center point sensor only.
James
A couple of quick suggestions before sending the camera in to Canon or returning to the store. Try the lens on a different body and also have someone else shoot with your camera/lens combination. Compare results with your previous. You should not see that much difference in the focus speed or acquisition between these lenses.
Have you dialed in any micro focus adjustment for the new lens via the camera body? That may also help. I have had to adjust each lens I use on my new 50D especially the 100-400L. Now that I have sorted that out the focus is quite reliable.
As much as we like to think we all know our gear inside and out and that we use flawless technique sometimes eliminating a few of these variables can determine if it is, in fact, us or the gear.
Canon 400mm f/4 DO lens
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