I frankly don't understand why there is any error at all. I would think
that when the camera decides that the contrast is at maximum that it
simply orders the lens to stop moving. Perhaps they tend to coast
beyond the point where they should have stopped. Maybe my Tokinas and
Tamrons work well since they don't have high speed ultrasonic focusing
motors. Maybe they can't go fast enough to coast on by the right spot. :-)
Chuck Norcutt
usher99@xxxxxxx wrote:
> Yes, but....
> With a poorly matched ZOOM/body, correction may not be accurate at both
> ends of the zoom--must settle for sort of OK at both ends and spot on
> focus in the middle.
> Why is that acceptable for an "L" zoom? That was my point but I did
> not articulate that clearly enough.
>
> Mike
>
>
>
>
>
>
> Canon has adopted that in the 5D Mk II and other cameras but,
> unfortunately, I have a 5D Mk I. The 5D Mk II supports custom focus
> data for 20 different lenses. But I doubt that it would work with my
> Tokina and Tamron lenses. Fortunately, I'm not aware of any focusing
> errors with those lenses.
>
> Chuck Norcutt
>
>
> manuel viet wrote:
>> That's part of the reasons why I loved my Pentax *istDL ; there was a
> hidden
>> maintenance menu where you could finely adjust the back or front
> focus of the
>> camera to match perfectly with your lens.
>>
>> It's a shame this kind of software knob isn't widespread and made
> accessible
>> to the ordinary user.
>>
>> Le mardi 11 mai 2010 02:02:23, usher99@xxxxxxx a Ãcrit :
>>
>>> I never understood why improvements (or even data) on sample
>>> variability and matching lenses/bodies for spot on AF is not
> demanded.
>>> Certainly abundant info that Canyon is no better in either
> department.
>>> Even Canyon microfocus adjustment for zooms doesn't really work
> that
>>> well at all FL's--fine for primes. Manufacturing tolerances seem to
>>> produce some bad matches. There should be a hardware/software fix or
>>> the body should be sent in for a good marriage. No excuses for any
>>> manufacturer not to have a flagship lens work well on a flagship
> body.
>>
> --
> _______________________
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