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a99ii focus and micro adjust

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SnowFella View Drop Down
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Post Options Post Options   Quote SnowFella Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2018 at 03:45
Never seen anything in a repair manual that hints at the sensor having back/forward adjustments with some kind of motor.
Moving the sensor likely also would introduce issues with MFD and infinity focus to my mind.

Should be kind of able to check how it does, take a macro lens (would need something with a long focus throw), set things up on a tripod and dial in +20 and see where the distance indicator on the lens lands. Now do -20.
With a long throw focus lens it's likely that you could detect a difference.
 



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stiuskr View Drop Down
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Post Options Post Options   Quote stiuskr Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2018 at 12:55
Just did that and you're right, there's a noticeable difference between + and - 20 on the distance scale with a macro lens.
Rob Suits Jr.
a99M2 a99 a77 a700 KM7D|Min24/2.8 Min35/2 So50/1.4 So50/2.8 Min85/1.4G Tam90/2.8 Tam180/3.5|Tam17-50 CZ24-70G2 KM28-75D So70-200G1 So70-300G So70-400G1| SonyF60 AD200R2
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Basil View Drop Down
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Post Options Post Options   Quote Basil Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2018 at 13:54
This sounds like an issue similar to one discussed in a previous thread
Try turning off the "stabilization with shutter" feature. It fixed the problem for me, and several others. These cameras are of similar generation, so hopefully that is your issue.
To see is to enjoy. To see beyond is to rejoice.

A77Mark II; A850; A700; A100; NEX 6; various film bodies and an ever-changing collection of lenses
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stiuskr View Drop Down
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Post Options Post Options   Quote stiuskr Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2018 at 18:33
The a99II does have viewfinder stabilization but the only way to disable it is to turn off Steady Shot, there is no menu setting for 'SteadyS.w/shut.' like there is with the a77II.
Rob Suits Jr.
a99M2 a99 a77 a700 KM7D|Min24/2.8 Min35/2 So50/1.4 So50/2.8 Min85/1.4G Tam90/2.8 Tam180/3.5|Tam17-50 CZ24-70G2 KM28-75D So70-200G1 So70-300G So70-400G1| SonyF60 AD200R2
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 11 December 2018 at 20:08
Originally posted by SnowFella SnowFella wrote:

Seriously doubt it moves anything inside the camera!

You're right. Nothing physically moves.

It rather remembers the MFA value for each lens recorded and tells the AF to drive the focus either past or closer to what the camera thinks is focused by the value set.

Details: AF is achieved by comparing the bit values in two different sensors and telling the lens to move until those two values match as closely as possible. The theoretical point of best focus is where subtracting one sensor's bit value from the other results in zero. The micro adjustment informs the system that an offset is necessary with a particular lens, so the point of best focus is then determined by a result that is to one side of zero or the other.
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amrep View Drop Down
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Post Options Post Options   Quote amrep Quote  Post ReplyReply Direct Link To This Post Posted: 15 December 2018 at 17:29
Originally posted by BridgetC BridgetC wrote:

I have recently bought the a99ii, and notice that when I press the shutter button halfway, teh image is not as sharp as it was through the viewfinder.
I wonder if this A99ii issue could be related to the A7iii problem discussed here:
https://www.dpreview.com/forums/thread/4344449
 



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UBO1 View Drop Down
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Post Options Post Options   Quote UBO1 Quote  Post ReplyReply Direct Link To This Post Posted: 07 January 2019 at 19:39
I don't know if the problem is with every lens, but my sigma 100-300 f/4 was perfectly sharp on my A77 but is not on my A99II. I bought a new telelens (Tamron 150-600) and I can shoot sharp pictures again :-)
Sony A99ii; Tamron 24-70 f/2.8; Tamron150-600G2; Tamron 90F/2.8Macro; Linkstar LF400A

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