difference in AF speed noticeable?

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is the difference in AF speed between the 20d and the Rebel XT noticeable if using the same lense? is there a difference? or does it all depend on the lense?

after testing out my girlfriend's uncle's Nikon F5 :)drool:) I want a DSLR camera, mainly for the fast AF.
 
The 20D and Rebel XT should be similar in terms of how quickly they focus with a given lens. Although there are a different number of focusing points (9 on the 20D, 7 on the Rebel XT) the one that most people use (the Center one) is pretty much the same in performance. They're both very quick & responsive.


Note however that different lenses focus at different speeds, and use different focusing motors/systems that offer different features. Although all are pretty quick, some focusing motors like USM allow silent and quick operation with a full-time manual override and a front lens element that doesn't rotate during focusing. Others are slightly noisier and may rotate the front element & filter threads during focusing, although they are still plenty quick but do not allow full-time manual override (the lens needs to be switched into Manual Focus to change the position manually). A micro-USM is not a true USM in that there is no full-time override. You really need to read up on lenses before you buy them so you know what you're getting & if your photography style has any use for that focal length.

Also know that Nikon has their own terms for different focusing motors & their features. So if you decide to go with say a D70 and want to borrow lenses from your girlfriend's uncle's F5...it would more or less be compatible. :)
 
the big difference will be in focus tracking. more AF points on the 20D will allow it to track a moving subject better. If I remember correctly, the 20D might have a better spec for low-light AF.

on something like a Nikon camera with screw-driven lenses, the body makes a huge difference. take the legendary 80-200/2.8D ED AF, pre-AF-S. On a D70, the whimpy AF motor will struggle to rack that huge helical back and forth. The motor on something like an F5 or D2H will throw that glass around like a rag doll, as they have significantly more torque.
 
Keep in mind there is going to be a big difference between Nikon's flagship film body and Canon's entry level digital.

Even still though, focus speed on any SLR is bounds over P&S
 
so ive pretty much got my mind set on a D70 (After going to ritz and trying one out). so i just have one last question.

if i have an AF-S lense on it will there be a big difference in AF speed between the d70 and the canons with a equivalent lense?

:edit:
what about with a regular AF lense? (no -S)

also..think $1200 is a good deal for an F5? :p
thats what i was offered for his F5....although i wanna stay digital
 
You can often find F5's for $600-800. Look on ebay, nikonians, robgalbraith, and adorama used.

Speed on an AF-S lens will be comparable to Canon's ring USM lenses (micro USM lenses are a bit slower)
 
oh, and with a standard AF lens, focusing speed on a D70 will generally be a bit slower than a non-USM Canon equivalent. Even on in non-USM Canon lenses, the AF motor is built-into the lens. On big/long glass, the weak AF motor on the D70 will struggle to move the lens elements back and forth (this is especially important in lenses that require more rotations of the AF screw- those with longer focal lengths).

still, it shouldn't really be a problem unless you're shooting sports.
 
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