zoom lens calibration

[holty]

if you calibrate your zoom lens at what focl lenth do you do it ?
i have a 17-35mm 2.8 nikon
24-70mm 2.8 nikon
70-200mm 2.8 nikon
200-500 5.6 nikon

where do i check focus on these lens's ?

thanks

 

[Kodiak Qc]

•


With all my zooms, I zoomed in to the longest focal length
and at the closest focusing distance from the subject in a
tethered calibration at 100 % view.

 

[gramps]

Two schools of thought:

1. Tune at the focal length it will be most used.
2. Tune at both ends and use the average, e.g. 70-200 says +6 at 70 and +4 at 200 so tune to +5.

(This is for Nikon, IIRC Canon can do zoom tuning better.)

 

[sk66]

With a zoom lens I would use whatever combination of distance/FL will generate the least DOF. If you are using the zoom for different compositions from a general distance, us that distance and the longest FL. If using the zoom for different perspectives (distances) then the longest FL/shortest distance. The latter is probably most suited to a short zoom like that one.

 

[holty]

thanks to you all