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Focus micro-adjustment on A700
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SteveMRose View Drop Down
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Posts: 132 		Post Options Post Options   Quote SteveMRose Quote  Post ReplyReply Direct Link To This Post Topic: Focus micro-adjustment on A700
    Posted: 16 January 2012 at 17:00
I have read a lot about focus micro-adjustment for lenses when they seem to be out of focus after AF. Is this when you pull the sticker off the bottom and putz with the screws underneath or is there something else?

I am not sure my 16-105 is really spot on focus and as such I am trying to figure out what to do. I might just switch to DMF to allow refinement of the focus but would like to know if there is something I am missing that I could do to rectify this.

Thanks
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a700-VGC |Sig 10-20 f4-5.6 | Tam 17-50 f2.8 | Son 16-105 f3.5-5.6 | Sig 24-135 f2.8-4.5 | Min 35 f2 |Min 50 f/1.4 | Sig 70-210 f/2.8 APO | Min 100 f2.8 MACRO |Son 70-300G f4.5-5.6 |HVL-F58
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momech View Drop Down
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Posts: 1788 		Post Options Post Options   Quote momech Quote  Post ReplyReply Direct Link To This Post Posted: 16 January 2012 at 17:33
No, two different things
A number of later bodies - A900, A850, etc. - have AF micro-adjustment capability where you can adjust for individual lenses to provide more accurate AF, and the camera registers each individual lens and it's adjustment in it's memory. The adjustment you're talking about would affect not just one lens but every lens you use. If you are having consistent focus issues with a number of different lenses then your sensor may be positioned improperly; that's when you use the adjustment you're talkling about. If it's just the one lens then that lens has the problem. Maybe send it in for adjustment by the manufacturer.
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gaging View Drop Down
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Posts: 385 		Post Options Post Options   Quote gaging Quote  Post ReplyReply Direct Link To This Post Posted: 16 January 2012 at 18:26
I suggest you read page 121 from your manual and then search AF micro adjustment on this website for information on methods for doing it.

This is how I do it:
Mount the camera on a tripod. Focus on something with fine printing (I use a world globe) from about 10 feet away in good light. The lens should be zoomed all the way out, and the aperture should be wide open. If you take five photos at -20, -10, 0, +10, & +20 and view them while zoomed-in on your LCD, it will give you an idea of where the camera achieves the best focus. You can then fine tune from there.
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momech View Drop Down
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Posts: 1788 		Post Options Post Options   Quote momech Quote  Post ReplyReply Direct Link To This Post Posted: 16 January 2012 at 18:44
Originally posted by gaging gaging wrote:

I suggest you read page 121 from your manual and then search AF micro adjustment on this website for information on methods for doing it.

This is how I do it:
Mount the camera on a tripod. Focus on something with fine printing (I use a world globe) from about 10 feet away in good light. The lens should be zoomed all the way out, and the aperture should be wide open. If you take five photos at -20, -10, 0, +10, & +20 and view them while zoomed-in on your LCD, it will give you an idea of where the camera achieves the best focus. You can then fine tune from there.


This is the procedure for using the AF microadjust on later camera bodies. The A700 does not have this feature.
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gaging View Drop Down
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Posts: 385 		Post Options Post Options   Quote gaging Quote  Post ReplyReply Direct Link To This Post Posted: 16 January 2012 at 18:52
Originally posted by momech momech wrote:

This is the procedure for using the AF microadjust on later camera bodies. The A700 does not have this feature.


My mistake...I thought I had read the OP had an A77.

FWIW, I did do the FF/BF adjustment on my A350 with great success because it was front focusing with all of my lenses. But, as Momech mentioned, it will affect all of your lenses, so make sure this is what you need before proceeding.
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raaaaah View Drop Down
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Posts: 52 		Post Options Post Options   Quote raaaaah Quote  Post ReplyReply Direct Link To This Post Posted: 20 January 2012 at 15:50
I did it on my A300 to fix FF, but I think I ended up with blurry infinity instead. Make sure you write down what you are doing with those screws so that you can always 'reset' it.
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arj View Drop Down
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Posts: 100 		Post Options Post Options   Quote arj Quote  Post ReplyReply Direct Link To This Post Posted: 20 January 2012 at 20:53
Originally posted by raaaaah raaaaah wrote:

I did it on my A300 to fix FF, but I think I ended up with blurry infinity instead. Make sure you write down what you are doing with those screws so that you can always 'reset' it.


This is interesting. How can it be that you have blurry infinity? Even on MF? Because the adjustment modifies the AF sensor, but not the position of the image sensor.
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jenik.nk View Drop Down
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Posts: 587 		Post Options Post Options   Quote jenik.nk Quote  Post ReplyReply Direct Link To This Post Posted: 20 January 2012 at 21:39
I did some adjusting on my A200, to be frank I don't really know why (edit: not for fun, but I don't remember which lens was the reason). I am happy I did it carefully and slowly and because the AF was slightly worse I had to and managed to set it back.

What I find dangerous about it - the screws are hidden deep in the camera and I cannot see them when operating the screwdriver. I was never sure if I really touched and moved the screw. So I didn't know if I really changed every single screw.
α200 - Tamron 17-50 - Minolta 28-105, 35-105 (O), 35-70/4, Beercan, 135/2.8; Sony 18-70, 50/1.4 - Σ EF-500 DG SUPER
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