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Focusing issues with my DSLR's VF, not sure what the problem is.

Discussion in 'Projects/Repair' started by TraamisVOS, Dec 8, 2013.

  1. TraamisVOS

    TraamisVOS SC Hall of Famer

    Nov 29, 2010
    Melboune, Australia
    I recently purchased a Zeiss ZE 50mm f/1.4 lens for my Canon 7D DSLR. Very good price, won the auction on eBay, the lens was in excellent condition. I met the buyer at his home and discovered that he was a photography nut like me but anyway that's another story.

    I am having difficulty focusing with the lens wide open. It gets easier as I go down to around f/2.8 of course. But I've tried taking test shots of stationary objects like a wood fence and even when I'm sure I've nailed the focus through the VF where I can see the grain of the wood in sharp focus, when I chimped it was not even close. I thought there was something wrong with the lens. I've had my 7D for a few years and never had focusing issues this bad. Sometimes I didn't think I've focused properly but then the photo comes up sharp. There are a few occasions when I've been able to nail focus through the VF and in the photo but it's rare. So I know that the lens is capable of being sharp wide open, beautifully sharp.

    I then switched over to Live View (LV) and tried taking photos that way and I discovered that I can nail focus every single time through the LV. Here's an example of some photos I took of my dog with the lens wide open, close up, razor thin depth of field and my dog was moving the whole time. I still managed to nail focus and the lens is proving itself capable of being sharp wide open:

    https://www.photographerslounge.org/showthread.php?t=1757&page=142&p=160535#post160535

    I don't understand it. It can't be the lens, and it can't be the camera. I thought it might have something to do with the diopter in the VF but I've never had a problem with it before and I can definitely see when the shot is in focus through the VF.

    Does anybody know what it can be?
     
  2. mikesul

    mikesul New to SC

    3
    Dec 8, 2013
    This is probably not the answer and I suspect you already know this, but just in case :) Could it be a function of the very narrow DOF at 1.4? Sometimes our problems are that simple.
     
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  3. entropic remnants

    entropic remnants SC All-Pro

    Mar 3, 2013
    John Griggs
    Simply stated: the focusing screens of digital SLR's are crap for manual focus. They are optimized for AF and bright view. On one of my NIkon's I changed the screen and it helped but you can't do that with many DSLR's. Sometimes though, when you change the ground glass you end up with AF problems which is not fun then either.

    This is why many manual glass afficionados go mirrorless. This is essentially what you did with LV.

    DSLR's as a class are not designed to optimize manual focus.
     
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  4. entropic remnants

    entropic remnants SC All-Pro

    Mar 3, 2013
    John Griggs
  5. TraamisVOS

    TraamisVOS SC Hall of Famer

    Nov 29, 2010
    Melboune, Australia
    Hi mikesul, no it's not the narrow DoF I'm having trouble with. I couldn't even achieve focus in the wood fence even though I was absolutely sure I nailed it in the VF.
     
  6. TraamisVOS

    TraamisVOS SC Hall of Famer

    Nov 29, 2010
    Melboune, Australia
    Oh dammit. What you're saying there makes a whole lot of sense. Not sure what to do in this case except to switch to LV only when I use this lens. :(

    What other alternatives do I have? Even if I bought the Sony A7, I can't do a simple thing like change apertures on this lens, electronically coupled adapters for EF lenses aren't available as I understand it.
     
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  7. TraamisVOS

    TraamisVOS SC Hall of Famer

    Nov 29, 2010
    Melboune, Australia
    Such a pity, it's a beautiful lens that produces photos with beautiful IQ.
     
    • Like Like x 1
  8. Jock Elliott

    Jock Elliott SC All-Pro

    Jan 3, 2012
    Troy, NY
    John,

    Those are excellent articles. I didn't realize this was an issue. It certainly would be a factor if I ever thought seriously about acquiring a DSLR.

    Cheers, Jock
     
    • Like Like x 1
  9. entropic remnants

    entropic remnants SC All-Pro

    Mar 3, 2013
    John Griggs
    There isn't any elegant solution with a DSLR. If you dig, you'll find people have been talking about this since back when AF SLR's and DSLR's came out.

    One other side effect if you change screens (if you can on that camera) is that metering can change as well. The Rockwell article on the old 5D says that there's a custom function item in the menu's that has to be changed to tell the camera what focus screen is in use.

    Focus screens are something we take for granted, but they're actually a much more complex item than most people realize.
     
    • Like Like x 1
  10. Yeats

    Yeats SC All-Pro

    Jul 31, 2012
    New Jersey, USA
    Chris
    I recall having read years ago that the OVF is generally only accurate down to f/2.8. That said, I was able to focus OK with a Pentax M 50/1.7 on my K100D because I learned how to compensate for the OVF's lack of precision.
     
    • Like Like x 1
  11. TraamisVOS

    TraamisVOS SC Hall of Famer

    Nov 29, 2010
    Melboune, Australia
    I just saw the articles you posted, thanks. Will read them in a minute.

    I'm really disappointed by this, it's such a good lens and I was really enjoying using it. It also got me playing with my DLSR again. I really don't want to keep using the LV and I can't really use it on any other still camera if I want aperture control.
     
  12. Armanius

    Armanius Bring Jack back!

    Jan 11, 2011
    Houston, Texas
    Jack
    I know you don't want to spend $1700 on a new A7 plus $400 on an adapter, but just in case ...

    http://www.bhphotovideo.com/c/product/983747-REG/metabones_mb_ef_e_bm3_canon_ef_to_e_mount_nex.html
     
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  13. TraamisVOS

    TraamisVOS SC Hall of Famer

    Nov 29, 2010
    Melboune, Australia
    • Like Like x 1
  14. TraamisVOS

    TraamisVOS SC Hall of Famer

    Nov 29, 2010
    Melboune, Australia
    That sounds like my experience with this lens.

    There's no compensating though, I can't work out exactly where is the focus is. Just when I think it's a tiny turn to the left, I find out it's a tiny turn to the right in the next photo (probably).
     
    • Like Like x 1
  15. Yeats

    Yeats SC All-Pro

    Jul 31, 2012
    New Jersey, USA
    Chris
    What I had to do was, once I thought I achieved focus, I needed to lean forward ever-so-slightly... but a 6MP Pentax K100D isn't nearly as exacting as your 7D.

    And, I'd take multiple shots. :wink:
     
    • Like Like x 2
  16. drd1135

    drd1135 SC Hall of Famer

    Jul 13, 2011
    Southwest Virginia
    Steve
    This is ironic since, in my mind, this would be the only significant reason to favor OVF. If you're mostly using an eye level finder for framing and a stable shooting position, I believe the EVF is actually superior in many ways.

     
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  17. serhan

    serhan SC All-Pro

    May 7, 2011
    NYC
    There are Canon matte screens for mf that you can change the one in your camera but they cannot be used w/ 7D and 5D3 which has new fast af system. I used them w/ 5D and 40D which makes the mf easier but still the best accurate method is mirrorless magnification+focus peaking for me... I see some people increase the sharpness of the jpg to manual focus w/ the evf but that is not possible w/ dslr's optical viewfinder either.
     
    • Like Like x 1
  18. wt21

    wt21 SC Hall of Famer

    Aug 15, 2010
    An EOS M gives you a better sensor, live view and electronic coupling via adapter :)
     
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  19. TraamisVOS

    TraamisVOS SC Hall of Famer

    Nov 29, 2010
    Melboune, Australia
    hmm.... I haven't really been a fan of DSLRs to begin with anyway.

    wt21 - I attempted to purchase the EOS M for my girlfriend during the Black Friday deals but the US website didn't deliver overseas. I thought the EOS M's sensor was the same as Canon's T models?

    I just learnt that Sony Australia is giving away a free adapter for every body-only Sony A7/A7r sold. As I understand it, the EF Metabones adapter will be the active one. Apparently when you buy the camera, there will be a redemption voucher included in the box and you can choose which adapter you want depending on the mount you're after.
     
  20. wt21

    wt21 SC Hall of Famer

    Aug 15, 2010
    I was only partially joking on the M, but for the record, yes, the M's sensor is the same as the latest Rebels AFAIK, and that is a generation newer than the 7D. I could be wrong, though.
     
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