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  1. #11
    Join Date
    Feb 2006
    Location
    Des Plaines, IL
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    9,554
    Look, my camera's issue is a lot more than just a focus adjustment problem ... which is relatively easy to do, whereas mine requires they split the camera open and start diggin' through it. Not a lot of fun with these devices unless you are patient and have some serious experience playing with them.

    Now, SONY directed me to send the A700 to Precision Camera, because they are now the regional repair center for the east coast, where Laredo, TX is a real SONY repair center. Still, even they return a lot of stuff to Japan for advanced work.

    Anyway, do not hesitate on getting your equipment up to standards. That's the most crucial aspect of having the equipment. It is aligned and operating without question. Then you can make real improvements in your photography, based on measured and with the ability to duplicate results.
    Don Schap - BFA, Digital Photography
    A Photographer Is Forever
    Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
    Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography.

    flickr & Sdi

  2. #12
    Join Date
    Mar 2007
    Posts
    2,132
    Let Tamron adjust it. It would be pointless to return a lens just because it has a front/back focus tendency. Tell them what camera it is being used on and they can adjust it.
    Nikon D300 | Tamron 17-50mm f/2.8 | Nikkor AF-S 70-300mm VR | Nikkor AF 35mm f/2 D | SB-600 | Lowepro Voyager C | Lowepro Slingshot 300 AW

    For Sale:
    Nikkor AF 35mm f/2 D - Like New (FX compatible)

    Wish List
    Nikkor AF-S 17-55 f/2.8
    Nikkor AF-S 70-200 f/4 VRII
    Tokina AF 11-16 f/2.8
    SB-900 (2)
    Umbrellas
    New Tripod

  3. #13
    Join Date
    Feb 2006
    Location
    Des Plaines, IL
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    9,554
    The fact is that TAMRON does it to a standard ... independent of the model of camera, because all the SONY & Minolta cameras have the identical measurement between the sensor and the back of the lens. Only the A900 (currently) can micro-adjust this measurement.
    Don Schap - BFA, Digital Photography
    A Photographer Is Forever
    Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
    Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography.

    flickr & Sdi

  4. #14
    Join Date
    Dec 2006
    Location
    God's Country - Australia
    Posts
    10,421
    don, i thought the a700 had micro focus adjustments ?
    D800e l V3 l AW1 l 16-35 l 35 l 50 l 85 l 105 l EM1 l 7.5 l 12-40 l 14 l 17 l 25 l 45 l 60 l 75
    flickr

  5. #15
    Join Date
    Nov 2008
    Location
    Monmouthshire, UK
    Posts
    2,152
    Well if you can't MF and I mean by tweaking the focus ring and not by measurement, I'm not sure.
    I would certainly advocate using the Tim Jackson Focus Chart in preference to the "battery" test. This will offer the AF system a single line with sharply defined contrast and no choices.

    More often than not F/B focus issues are down to camera alignment. You have to remember that the AF system is not a distance detector but simply a feedback loop that moves the lens element to a position where the sensor detects maximum contrast between adjacent pixels. The border between a black line on white paper is ideal. Out of focus the border is blurred and less contrasty; in focus gives a sharp divide and maximum contrast. A lens has to be seriously out of kilter to be the culprit and I think it would show up in many ways.

    If the AF sensors are misaligned, AF will be bad and MF will be good.
    If the APS-c sensor is misaligned, both AF and MF be bad.

  6. #16
    Join Date
    Jun 2008
    Posts
    2,204
    Yeah, too bad there's no micro adjust for the AF. That would be ideal.

    Quote Originally Posted by Peekayoh View Post
    Well if you can't MF and I mean by tweaking the focus ring and not by measurement, I'm not sure.
    I would certainly advocate using the Tim Jackson Focus Chart in preference to the "battery" test. This will offer the AF system a single line with sharply defined contrast and no choices.

    More often than not F/B focus issues are down to camera alignment. You have to remember that the AF system is not a distance detector but simply a feedback loop that moves the lens element to a position where the sensor detects maximum contrast between adjacent pixels. The border between a black line on white paper is ideal. Out of focus the border is blurred and less contrasty; in focus gives a sharp divide and maximum contrast. A lens has to be seriously out of kilter to be the culprit and I think it would show up in many ways.

    If the AF sensors are misaligned, AF will be bad and MF will be good.
    If the APS-c sensor is misaligned, both AF and MF be bad.
    I see what you are saying now. But if the sensor was misaligned, I would also not be getting good results with other lenses.

    I did try the focustestchart.com chart and it showed slight BF, but the results aren't as clear cut as the battery test since I have no idea how close I was to a 45 angle. Don't have a geared head which gives degree increments, just a ball head.
    flickr

    Canon 7D - 5D | 550EX - 430EX II - (2) PW FlexTT5 | 24-105 f4L | 70-200 f2.8L IS | 100 f2.8L IS | 50 f1.8 II

  7. #17
    Join Date
    Feb 2006
    Location
    Des Plaines, IL
    Posts
    9,554

    Red face Unfortunately not

    Quote Originally Posted by Rooz View Post
    don, i thought the a700 had micro focus adjustments ?
    No ... that was an A900 exclusive. On it, there are 20 stored adjustments you can make to allow for your different lenses. They are not a lot ... but some +/- adjustments can be made.
    Don Schap - BFA, Digital Photography
    A Photographer Is Forever
    Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
    Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography.

    flickr & Sdi

  8. #18
    Join Date
    Nov 2008
    Location
    Monmouthshire, UK
    Posts
    2,152
    Quote Originally Posted by dr4gon View Post
    Yeah, too bad there's no micro adjust for the AF. That would be ideal.

    I see what you are saying now. But if the sensor was misaligned, I would also not be getting good results with other lenses.

    I did try the focustestchart.com chart and it showed slight BF, but the results aren't as clear cut as the battery test since I have no idea how close I was to a 45 angle. Don't have a geared head which gives degree increments, just a ball head.
    The DOF may be disguising the results with other lenses.
    It's not crucial to be at 45. Near enough is good enough.

    What's generally not appreciated is that the AF system puts you "somewhere" within the DOF; the system has to lock on quickly rather than looking for the "absolute" point of clarity, otherwise it would be "hunting" interminably. Usually that, "somewhere", in the DOF is good enough, that is until you have a very thin DOF at which point you may be in trouble and need to fall back on MF to fine tune (or stop down).

    Another thing that's not appreciated (maybe) is that nothing in the DOF is in focus except at the actual plane of focus, the rest is "acceptably" in focus and whats acceptable is not the same to everyone.

    When you do the test I suggest you
    use a tripod (I know you are, dr4gon)
    get into bright sunlight if possible
    choose maximum aperture

    If you still can't MF, I'm stumped.

  9. #19
    Join Date
    Feb 2006
    Location
    Des Plaines, IL
    Posts
    9,554
    To be entirely accurate, guys, add some more light to your testing. The camera can be fooled into an incorrect center of focus if the contrast is "fuzzy."

    My personal recommendation is to use a 200-300 W bulb as your light source and keep it overhead or over your shoulder, behind you, striking your center of focus on the subject.

    Soft light is always rather "iffy" and not a true reflection (pardon the pun) of the actual point of focus.
    Don Schap - BFA, Digital Photography
    A Photographer Is Forever
    Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
    Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography.

    flickr & Sdi

  10. #20
    Join Date
    Jun 2008
    Posts
    2,204
    Alright, more light then lol.... but it's still quite unacceptable to me if it can't AF in what I would say is decent lighting.... doesn't make sense right? It's a low-light lens and if I have to have 300W+ of lighting, then it's just not up to par.

    But, I will try it again this weekend.
    flickr

    Canon 7D - 5D | 550EX - 430EX II - (2) PW FlexTT5 | 24-105 f4L | 70-200 f2.8L IS | 100 f2.8L IS | 50 f1.8 II

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