Boris,
I hope the corrections at either end turns out to be on the same side
("plus" or "minus").
It is rather unlikely to find the same adjustment (let us say plus 5)
fits both ends.
The magnifications at zoom ends (17mm vs 70mm) differ significantly but the
step motor's hardware remains the same.
I also think that, of the two ends of the range, adjusting for the
tele end should be better.
The problems of focusing are a lot easier to spot there.
Have a photographically pleasing Sunday :)
Bulent
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2014-01-26 Boris Liberman <bori...@gmail.com>:
> Bulent, you really made me curious. So I went and looked up the focal length
> distribution of this zoom lens...
>
> This is what I've found:
>
> By far the most used FL is 17 mm, second most used is 70 mm, which is rather
> natural - as far as typical usage pattern of a zoom lens goes. Then the FLs
> from 34mm to 63mm together amount to approximately the same number of frames
> as 70mm...
>
> Nonetheless, I will do as Paul suggested. I will probably start with 70mm,
> then go down to 40mm and then finally try for 17mm hoping that by the time I
> arrive there no correction will be necessary and that correction at 70mm
> will be very close to that at 40mm...
>
> Boris
>
>
>
> On 1/25/2014 8:52 PM, Bulent Celasun wrote:
>>
>> Hi Boris,
>>
>> The sheet for a gadget (don't remember the name) I use for such
>> calibration says there is no right focal length.
>>
>> You can either select the length you use most frequently (perhaps better)
>> or,
>> select a length in the middle.
>> In any case, the calibration will not be perfect at 17mm and 70mm
>> (assuming you haven't calibrated for these).
>> In the absence of a physical defect and with a x3 zoom like yours, the
>> calibration should still work acceptably.
>>
>> Bulent
>
>
>
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