Focus Issue Question

Started Nov 10, 2012 | Discussions thread
Fayard
Regular MemberPosts: 127
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Re: Focus Issue Question
In reply to painterdude, Nov 12, 2012

painterdude wrote:

Okay ..did a vat of chart tests ..Had lens open to 1.4 AF-S on tripod, re racking with each shot varied between LV vs AF center & left. about 30-40 tries

Conclusion ...Hum ..its hit and miss . Often the left AF and LV have the same perfect focus .Sometimes the left is slightly out of focus..though the LV always remains perfect.

What the heck do I make of this ?? I have a slight Left Focus issue ..like sometimes sometimes not ??

g

Painterdude,

Any Autofocus system will show some slight variation from shot to shot. Depending on the way your lens is fine tuned, this variation may have very little influence on the quality of the focus, or a huge importance.

You have to make sure that your target and the light is good to get a consistent autofocus. To be sure, use the following target that you can put on a book. Then follow the instructions here to fine tune your lens, for your central AF sensor, at 50 times the focal length.

Then post here the 100% crop oh the ruler for the central, left and right sensor. Always take multiple shots (6 is a good number), racking the focusing ring to infinity in between each shot. It might happen that one every 6 or 10 shots is quite different. Post one that you usually have and avoid these exceptional shots that should be ignored.

But be warned. If you are looking for misalignment of AF sensors, you'll find them, wether it is a D800, a D4, a D3 or a Canon. You just have to find out if it is within "specification", and wether of not it really affects your real life pictures.

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