Re: Auto-focus on digital SLRs.

"____" <internetphobic@[EMAIL PROTECTED]
> wrote in message 
news:internetphobic-63B1EC.12595123022008@[EMAIL PROTECTED]
> In article <kkd0s3h7vjcej95rfvbgjk5naq980trj1s@[EMAIL PROTECTED]
>,
> Steve <steve@[EMAIL PROTECTED]
> wrote:
>
>>
>> A crank starter sure would be nice if you accidentally leave your
>> lights on.  And if the engine is too big to crank start, one of those
>> clockwork wind-up crank starters would work great.  Just like manual
>> focus can work great if the autofocus isn't doing what you want.
>>
>> Steve
>
> Good point, to place back in context any suggestions for speed focusing
> rings for manual control?
>
> -- 
If you really want to go that route, you could always place an object at 
various distances in a well lit setting, and then autofocus on it. 
Scribing 
a reference line at some point of the housing and a small mark on the 
focusing ring could help.

But, after playing around with a Rebel XT and trying to get it to exhibit 
similar behaviour, I have to say it actually is quite good.  The only time

it would hunt around was when I was pointing it at a white wall, or some 
other nondescript object with no texture or detail.  If there is something

to work with, the AF unit seemed to find it.

Also, if the AF unit couldn't find anything to focus on, it only went 
through its range twice -- once rotating out and once coming back in.  It 
took about a second, and it wouldn't try again if it wasn't initially 
successful.

Does the problem get worse as you zoom out?  If so, it could be the result

of the variable aperture of the zoom lens.

How old is the camera?  Could the sensor be dirty?

Lastly, it is im****tant to keep in mind that red-eye reduction features
tend 
to slow down camera operation in low light situations.  The camera might 
hunt a bit for focusing, and then sit there for another second with the 
red-eye reduction light eluminated even if you don't need it.  This might
be 
mistaken for slow AF performance.

I don't know if any of this applies, but it doesn't hurt to mention it.

Good Luck,
Dudley