Auto focus adjustment

[joe_cormier]

<p>Is there any value in using auto focusing equipment in a variable lens? If for example on my 70mm/200mm lens my sharpness<br>

is off at 200mm and I make an adjustment using my Nikon custom menu and adjust for perfect sharpness, Is my sharpness <br>

then off at all other focal distances? As always, thanks in advance. Joe </p>

 

[dbcooper]

<p>Why not take some test shots and see? It seems to me you'd get more meaningful information doing that rather than asking strangers on the internet how <em>your</em> particular gear will behave. If you adjust the AF compensation in-camera for some test shots, you can always return the setting to '0' if it doesn't solve the problem or if the problem gets worse.</p>

<p>By 'variable' lens did you mean a zoom lens? If so, I would mention that it's not uncommon for some zooms to be 'soft' (unsharp) at the long end of their focal range. My 18-200 DX VR and 80-400 VR are both soft at the long end of their zoom range. OTOH, my 70-200 VRII is pretty sharp at 200mm.</p>

<p>Camera movement can contribute to unsharpness as well. The longer the focal length, the worse that gets. Testing your rig on a tripod or some other solid rest eliminates movement as a variable, and helps reveal if the problem is focus related or if it's inherent 'softness' of the lens. It can also help you set the AF compensation more accurately. Railroad tracks, picket fences, or the like make good test targets since they show front or back focusing and DoF differences at a distance. A LensAlign or similar gadget can be a great AF calibration tool, but it isn't much use, say, at 15 yards...not really a big deal with a 17-35mm, but it can matter a lot at 200mm.</p>

<p>If you can't suitably adjust the AF and it isn't a lens softness problem, there's a chance the camera body and/or lens may be in need of service (e.g. CLA). HTH.</p>

[joe_cormier]

<p>D.B.<br>

Will take your advice. Thanks</p>