d800 focus testing with different targets

Started May 15, 2013 | Discussions thread
Per Baekgaard Senior Member • Posts: 1,268
Re: Your tests shows why...

olyflyer wrote:

...focus tuning is waste of time.

Probably no more than spending too much time on these fora...

[...] NOT to do it unless you are absolutely sure it solves a problem and you know what you are doing.

Which actually could be the case for some...

There is bound to be some variation between bodies and cameras and even with "properly" adjusted optics, small variations might have to be compensated for. I had small amounts of front-focus in practical use, and have fixed that for the distances I most often shoot at. This has significantly improved my focus in practical use -- I probably have 100x more "real world shots" than "test target shots".

So I'm happy that Nikon has given us the ability to do AF tune on the more recent bodies (I think my older D70 and D200 bodies didn't have this, D300 brought it to this range, IIRC).

If you don't want to use the feature, just leave it alone -- and if you do know why you want to use it, be prepared that it is more complex than you may think.

Anyway, a lens should be tested from a distance of 40-50 times the focal length, which means between 1.4-1.8 meters from the camera. Not very close in other words. Also the focus target must be large, quite a bit larger than the actual focus area marker. Another thing is the light. You can ONLY test focus in good light.

Completely agree -- unless of course you always use a lens at a specific setting for which you want to optimize its usage. And then you could even include compensation for focus shifting as you stop down (spherical aberration) to the equation if you want...

 Per Baekgaard's gear list:Per Baekgaard's gear list
Nikon D800 Nikon D500 Nikon AF-S Nikkor 70-200mm f/2.8G ED VR Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 24-70mm f/2.8G ED +17 more
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