Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,493   Posts: 1,571,396   Online: 1095
      
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 26
  1. #11
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,324
    Images
    12
    Sounds like it has either a tilted element or bent mount, causing a similar effect to using a tilt lens, i.e. a plane of focus not parallel to the film. That would cause significant confusion to the AF module because of the way it samples rays from each side of the exit aperture to determine the focus offset.

    The other thing is that SLR viewfinders generally do not receive all the light that the film does - they are effectively vignetted. That means you see a DOF equivalent to something between f/3.5 and f/5.6 depending on the camera, and you won't really perceive small focus errors. You can check this by putting on a f/1.4 lens, setting it to f/2.8 or so, toggling DOF-preview and noting that nothing really changes at all in the viewfinder.

    There's also the matter of how the VF glass is ground. For brightness reasons, it's often receptive only to a narrow range of incident angles (this is a big contributor to the looks-more-stopped-down-than-it-really-is effect). That means the VF doesn't get rays from the far edges of the lens' exit aperture, which means you not only can't really see a focus error with a good lens, you can't see gross tilted/misfocus effects on a defective lens. You can MF with a good lens wide open because you pick the midpoint between where you see it go out of focus in each direction - with a misaligned lens, that all goes to pot. You might find that if you MF with a subject on one side of the frame, take the shot and them MF with a subject on the other side of the frame, the focus errors are significantly different.

    Since you have access to digital bodies, I'd do some rigorous testing with those, merely because it's free. Set up some test targets at 1m, 5m and near-infinity, do AF and MF tests with the targets at centre, top, left, bottom and right. The changes in the focus errors will tell you a lot about how the lens is misbehaving. Of course, do some control tests with some other lens just to make sure you've not suddenly gone blind

  2. #12
    df cardwell's Avatar
    Join Date
    Jul 2005
    Location
    Dearborn,Michigan & Cape Breton Island
    Shooter
    Multi Format
    Posts
    3,342
    Images
    8
    Tom

    No clue. You've suffered enough.

    If the EOS 3 is focusing the other lenses, replace the lens.
    "One of the painful things about our time is that those who feel certainty are stupid,
    and those with any imagination and understanding are filled with doubt and indecision"

    -Bertrand Russell

  3. #13

    Join Date
    Sep 2003
    Shooter
    Multi Format
    Posts
    2,025
    For those following this, I ran yest another roll thru the set up and will be returning this second copy. The test was better planned to test for all issues and revealed:

    The lens does begin to backfocus beyond about 1m. It is already noticeable at 1.5m and a real problem at 3m.
    The lens also suffers from decentering. Pin sharp on centre at 1m, also on left side. Really impressive levels of detail here. Right side softer, particularly lower right, which is terrible. Left side and centre hardly improve stopping down. Top right very sharp by f4. Lower right still obviously less sharp than rest of the frame at f8. Not talking extreme corner either, but quite a portion of the frame. This would make portraits with the eyes etc in the top 1/3 of the frame a real problem as the right side would be used.

    I give up. I have a stunning 135 f2 in the UK and will collect that next time I am back. Really I wanted to work with 85mm, but $1900 for a 85 1.2 II is beyond me right now and I have no faith that a third copy of the 1.8 EF will be any better. Such a shame. up close on centre and on the left, it is obvious what this this lens can do when it is put together right. I'm very disappointed with Canon and have no other SLR system to work with. For me, RFs and 90mm lenses is not going to work. I need quick AF for this job.

  4. #14
    df cardwell's Avatar
    Join Date
    Jul 2005
    Location
    Dearborn,Michigan & Cape Breton Island
    Shooter
    Multi Format
    Posts
    3,342
    Images
    8
    Tom

    Canon has been making the 85/1.8 for ages, and it has been a great lens.

    The 3 I have (different camera kits stashed in different places to make travel easier !) are dazzling.

    Faith shouldn't have anything to do with this: you've has had an amazing run of bad probability !
    Go for a third.

    Are you in the US now ?
    "One of the painful things about our time is that those who feel certainty are stupid,
    and those with any imagination and understanding are filled with doubt and indecision"

    -Bertrand Russell

  5. #15
    Andy38's Avatar
    Join Date
    Aug 2008
    Location
    Lyon , France
    Shooter
    Medium Format
    Posts
    158
    My first EF 85:1,8 was old , but sharp , with no AF problem ; but it has been stolen about one year ago .
    I have bought another and this new is not perfect , with short and long distance AF problems , on Eos 3 , 33 (Elan 7) and DSLRs .
    The first was my favourite lens , often used at full aperture ; now , I don't use this new one any more...

  6. #16
    lilmsmaggie's Avatar
    Join Date
    Mar 2009
    Shooter
    Multi Format
    Posts
    328
    I've noticed similar issues using this lens on a Canon EOS 7N. VF will show sharp image but when printed, images are sometimes soft. I especially noticed with head shots that there will be areas of the image that are razor sharp but softness in odd places.

    For example, I took a shot of tree bark lying on the ground that gave the impression of Bullwinkle the moose's head (I used this for an abstract composition). The outer edges and pretty much all of the image when printed was razor sharp except for a small portion in the center that was soft. Weird.

    I've stopped using the AF feature on the lens and just use MF which helps but IMHO is still inconsistent.
    I haven't tried this lens on a digital body yet. I'm hoping I get better results.

  7. #17

    Join Date
    Sep 2003
    Shooter
    Multi Format
    Posts
    2,025
    I'm in Afghanistan and buy from the US through military mail. These are the only two new lenses I have ever rejected in my life! Its such a pig to get to the military base and send mail out that returning faulty items is a real chore. I could exchange it but worry it is a batch issue or that the container full of lenses was dropped from a few metres at the docks! Might well not be Canon's fault, but something as simple as that!

    I'll decide in the next few days whether to exchange it or just send it back, but looking at the centre and left of those negs is torture because the lens evidently has the potential to be spectacular and at a decent price One thing really missing from my current project is portraits and with time dwindling the loss of two faulty lenses costing months of opportunity is particularly galling. At this point, I will do whatever it takes. If I have to fork out for a 85 1.2 then I will because I absolutely cannot let this project finish without some portrait work. Got to think on this...

    Thanks all for your help and listening to my rant!

  8. #18
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,324
    Images
    12
    Can you get a refund and buy one elsewhere that you know is from a different batch? Say a known-good second-hand one.

  9. #19
    df cardwell's Avatar
    Join Date
    Jul 2005
    Location
    Dearborn,Michigan & Cape Breton Island
    Shooter
    Multi Format
    Posts
    3,342
    Images
    8
    cannot let this project finish without some portrait work

    Got it. Can you swing the 70-200 zoom (non USM) ? Yeah, I know almost the same as the f/1.2,
    and the f/1.8 is supposed to be working !



    Good pictures, Tom.
    "One of the painful things about our time is that those who feel certainty are stupid,
    and those with any imagination and understanding are filled with doubt and indecision"

    -Bertrand Russell

  10. #20

    Join Date
    Oct 2003
    Location
    Århus, Denmark
    Shooter
    Medium Format
    Posts
    2,102
    Images
    16
    Quote Originally Posted by grompirx View Post
    Never had a focus issue with my EF 85 f 1.8. It is always fast and accurate.
    Same here. Great lens!

Page 2 of 3 FirstFirst 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin