Re: canon-nikon AF technology- the difference

Kennedy McEwen wrote:
In article <1192409549.472040@ftpsrv1>, frederick <lost@xxxxxxx> writes
Aaaaarrrggghhh.

Can factory / service AF calibration always adjust accurately to remove ff/bf errors in a wide aperture lens at close and infinity, short and long focal length?

I expect that the answer is no.

Your expectation is wrong then. What the heck do you think happens when a user sends a camera with several lenses into the service centre for calibration against EACH lens, at different focal lengths (in the case of a zoom lens) and at different apertures? The service centre can reprogram the LUT for each specific lens, taking account of the SA in that particular lens - this is not (currently) available in user accessible micro-adjustment. Getting specific lenses (or all lenses) calibrated on a particular camera happens all the time and the reports from those users who have gone through it is that it is very successful.

So with a LUT for each lens as described the for sure, I agree It can be done!
Does every dslr come with such a feature? Canon or others?

So, if you buy a camera that is within factory specification, then can you expect that at wide aperture lens in your kit will focus to within those parameters at all times. I expect that the answer to that is also no.

I think you will find that most kit lenses aren't wide enough to suffer enough spherical aberration to make significant AF errors. The only people I have seen reporting problems needing calibration have been using much faster glass than a typical kit zoom. So I expect that the complete opposite of your suggestion is closer to reality.

Sure, I was thinking more of users with entry dslrs who buy aftermarket fast lenses in particular. Say typically 16/18 - 50/55 f 2.8 zooms, and primes such as the Sigma 30mm f1.4.
This could explain (at least in part) the large number of complaints about user variability - so-called "sample variation".

So it's back to my comment that the high precision AF calibration spec is mainly a marketing tool. I'm probably more cynical than you.

You are confused enough - don't add confusion of cynicism with stupidity!
>
I don't think I am. If a LUT storing calibration data for lens (es) at different fl/focus distance in particular, or sometime even aperture isn't used, then I stand by my comments.
.

Relevant Pages

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