Sigma 50mm f/1.4 EX DG HSM: Out of Focus?

Discussion in 'Digital Photography' started by Chris7, Jan 13, 2010.

  1. Chris7 macrumors 6502

    Joined:
    Aug 8, 2008
    Location:
    Lost in Thought
    #1
    Hello,

    Wondering if this Sigma consistently focuses accurately.

    The Digital Picture says,

    "I have thrown out as many as 70% or more images from a single shoot of over 100 non-action, wide aperture shots because they were very OOF (Out of Focus)... It is possible that another copy of this lens would focus more consistently, but my guess (helped by feedback from others) is that my lens is representative of this model.
    http://www.the-digital-picture.com/Reviews/Sigma-50mm-f-1.4-EX-DG-HSM-Lens-Review.aspx

    But, DP Preview says,
    "Focus accuracy was generally impressive, although with a certain tendency towards slight front-focus at close distances and F1.4, especially with low-contrast subjects. The lens also shows some evidence of a slight focus shift to the rear on stopping down, which meant our sample focused correctly when set to F2."
    http://www.dpreview.com/lensreviews/sigma_50_1p4_c16/

    So, is the problem generally inconsistent autofocus, or just a "slight" front-focus at f/1.4?

    If it does just front-focus slightly at f/1.4, how much is this?
    (I would want to use f/1.4, but generally no closer than 6 feet away on a crop sensor camera).

    Thanks.
     
  2. Edge100 macrumors 68000

    Joined:
    May 14, 2002
    Location:
    Where am I???
    #2
    I had a thread on this last week. I've been trying to decide whether to get the Sigma 50/1.4 or the Canon 50/1.4

    The Sigma undoubtedly has better IQ. That having been said, if it can't achieve proper focus, all the IQ in the world isn't going to help.

    It seems to me that virtually every review on the web mentions this AF problem; that is, it's not an isolated incident affecting one or two users. There are several threads at fredmiranda.com that describe the agony and ecstasy of using this lens. When it works, it's as good as the 50/1.2L. When it doesn't, it's useless. It seems to be a bit of a crap shoot; some copies are great and nail focus at all distances; some front-focus at short distances but do fine at infinity; some focus perfectly at short distances but have trouble at infinity.

    I ended up getting a great deal on a Canon 50/1.4, which is still a great lens. I didn't want to risk getting a bad copy and having that headache.
     
  3. Chris7 thread starter macrumors 6502

    Joined:
    Aug 8, 2008
    Location:
    Lost in Thought
    #3
    I'm a beginner and cannot afford to have an inconsistent lens be the problem when trying to get a shallow DOF field shot right (don't want to always wonder, "Is is me or the lens screwing up this time"). So I'll be skipping this one. Many thanks,
    Chris
     
  4. Edge100 macrumors 68000

    Joined:
    May 14, 2002
    Location:
    Where am I???
    #4
    No one can afford that. This issue is causing many people a lot of grief. The Sigma produces absolutely stunning IQ...but who cares if it's OOF.

    I agree; skip it. I did.
     
  5. wheelhot macrumors 68020

    Joined:
    Nov 23, 2007
    #5
    Hmm, I'm afraid this OOF issue is not limited to the 50mm, I own the Sigma 18-50 f/2.8 EX (just bought end of last year, so should be the latest one) and as other mentions, when it performs. It performs, I was in love with its sharpness and bokeh until...the AF Inconsistencies began and it costs me DEARLY!

    Firstly, I thought it was some Back/Front focusing issue, used AF Fine Tuning and it got better. Sadly it doesn't solve the problem. I do occasionally get severe OOF shots and I even tested the lens to see if it's the user error or the lens error by doing focus-recompose and placing the AF point right on the area I want to focus and guess what...BOTH gave me OOF photos. Totally unacceptable. Like the previous posters said, as great IQ a lens may have, but if we cant rely on its focus consistency, then it is just as good as a lens with poor IQ.

    You wont have problem if the subject you shoot is static subject cuz if this problem occur, you can take time to try and debug it but if you are shooting action, AF Inconsistency becomes a major issue.

    Also, due to sometime it tend to focus correct and sometime it doesn't, this became a definite problem for me to show to my dealer how severe this problem was, cuz it just happen randomly and hard to replicate it under fixed situation. I am soo sending this lens for servicing, but I will need to get another lens first or I will be lensless for a month :(
     
  6. toxic macrumors 68000

    Joined:
    Nov 9, 2008
    #6
    if you get one that doesn't focus properly, then get it calibrated and it will be fine. this is not a design issue, it has to do with QC and reverse-engineering.

    unless you absolutely need a 50mm in the next week, I don't see why you shouldn't take the extra couple weeks to get it calibrated. it's that much better than the Canon.
     
  7. Chris7 thread starter macrumors 6502

    Joined:
    Aug 8, 2008
    Location:
    Lost in Thought
    #7
    Thanks for the heads up.
    I guess if I were more experienced I might consider the lens. I just don't have the skill to deal with this kind of thing yet.
    Anyway, thanks for your time and thanks for the links re: dynamic range on another thread.

    -Chris
     
  8. gmehje macrumors member

    Joined:
    Jul 31, 2009
    #8
    I purchased the 50mm 1.4 a few month ago, so went through the reviews and agonized over whether to go ahead.
    I did and at first I was disappointed with focus - very disappointed. But all it took was some in-camera calibration (+16 on the Canon 7D) and it's wonderful. In fact it's never been off the camera once (mostly takes shots of my children so it's perfect.) I would say for these type of shots with the kids I have about a c.90% success on sharp focus with spot focusing on the 7D.

    Two samples (I'm not a professional at all so no need to critique!):
    Portrait: taken on Monday - very very little Photoshop sharpening. 1/125 sec, bounced 430EXII Flash, f4.5

    Food: handheld f1.4 ISO320 - quickly taken at party - no sharpening.

    The review are correct - it's reasonably soft at 1.4 but it's not bad!

    My advice - if you can get it calibrated (and can afford the lens) - buy.
    Ged
     

    Attached Files:

  9. Edge100 macrumors 68000

    Joined:
    May 14, 2002
    Location:
    Where am I???
    #9
    The problem is that 90% of people have DSLRs that don't support micro adjustment, in which case the lens is a huge risk.
     
  10. gmehje macrumors member

    Joined:
    Jul 31, 2009
    #10
    I agree. If you can't adjust - don't buy it.
    Complete waste of money (unless you can send it somewhere, somehow)
    Ged
     

Share This Page