Special AF sensor on the 30D ?

[Nilsen]

I read this review lately ofthe 70-200 f4 L IS lens- since i am thinking of upgrade my 70-20 f4 L to the IS version.

http://www.slrgear.com/reviews/showproduct.php?product=999 (http://www.slrgear.com/reviews/showproduct.php?product=999)

I the first comment below the review it says---

"My only (small) niggle is, that the AF hit rate seems to be not as high as with the prime, probably because the special AF-Sensor of the 30d is only actitvated with f2,8 lenses.----"

Is it so that the 30D has an AF that isnt working properly with smaller aparture then f 2,8 ?

[Michael]

The 30D does have improved AF with f/2.8 or larger. But I don't fully understand it. Someone else should be able to help you though.

[crn3371]

The 30D will autofocus just fine with the 70-200 f4L IS. The comment is refering to the center focus point which becomes a high precision cross type autofocus sensor with f2.8 lenses or faster. The f4 will focus just fine.

[Nilsen]

The 30D will autofocus just fine with the 70-200 f4L IS. The comment is refering to the center focus point which becomes a high precision cross type autofocus sensor with f2.8 lenses or faster. The f4 will focus just fine.

Ok - but why is it so ? if it still AF fine at f4 ? Sorry if I am slow :rolleyes: - but does this mean that with my 35mm 1,4 the autofocus "works better " ? :)

[crn3371]

The center focus point just gets better with a f2.8 or faster lens. The 70-200 f4 will focus so fast your head will snap. Here's a link (http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=139&modelid=12929) to Canons 30D site.

[Nilsen]

The center focus point just gets better with a f2.8 or faster lens. The 70-200 f4 will focus so fast your head will snap. Here's a link (http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=139&modelid=12929) to Canons 30D site.

Thank you - i see the light :) :)