Rob Studdert wrote:
>
> On 16 May 2001, at 9:26, tom wrote:
>
> > I know cameras can use an IR beam for focus assist, but I didn't think
> > they had this much sensitivity. The IR beam on the AF500FTZ isn't
> > totally IR, you can actually see some red, plus you're rarely doing it
> > in total darkness.
> >
> > You learn something new everyday...
>
> Hi Tom,
>
> To perpetuate the learning I have new question: does the focus distance on
> the lens scale differ when focussing with then without the IR filter in place?
Well, crap, now I have to get all methodical. Luckily I work from home,
so I can do that....
I just stuck the zx-5n on a tripod, and this time used the 85/1.4. I
pointed the lens at a vertical line in a window, manually focused at
infinity, turned on AF, and let it do it's thing. Then I tried it with
the filter. It locked on, and shifted it *more* then what the IR mark
would suggest. Almost twice as much.
I didn't see very much difference in the amount of time it took to lock
on.
Next time I have some HIE in the camera I'll test to see how accurate it
is...
tv
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