hollis_f
Well-known member
I was asked by somebody on PotN to try out the 7D's AF using a non-reporting TC on a 100-400. As I guess most people know, with the earlier xxD series it became increasingly difficult to use the non-reporting TC (or taping contacts on a TC) to fool the camera into AF. Was the 7D any better - worse?
The news is good - surprisingly good! I used an old Teleplus 1.5x TC - which doesn't report the decrease in aperture - on my 100-400. All the focus modes I tried (single, zone, expanded) focused quite quickly. Every point I tried was as good as the central one.
Indeed, the AF on the 7D was better than on my 20D (where it was just about usable) and loads better than the 40D (needed masses of light) or 50D (totally useless).
It's grey and overcast here today. At f8 (reported f5.6), ISO400, I'm getting shutter speeds of 1/120 to 1/60 - light that would have had all my previous cameras hunting all over the place. I wouldn't say the focus snapped - but it was certainly usable.
This gives me some incentive to try stacking 1.4x and 2x TCs on my 300 - when the light's a bit better.
The news is good - surprisingly good! I used an old Teleplus 1.5x TC - which doesn't report the decrease in aperture - on my 100-400. All the focus modes I tried (single, zone, expanded) focused quite quickly. Every point I tried was as good as the central one.
Indeed, the AF on the 7D was better than on my 20D (where it was just about usable) and loads better than the 40D (needed masses of light) or 50D (totally useless).
It's grey and overcast here today. At f8 (reported f5.6), ISO400, I'm getting shutter speeds of 1/120 to 1/60 - light that would have had all my previous cameras hunting all over the place. I wouldn't say the focus snapped - but it was certainly usable.
This gives me some incentive to try stacking 1.4x and 2x TCs on my 300 - when the light's a bit better.
