help with Sigma 30mm 1.4

Discussion in 'Lens Lust' started by bill-e, Aug 14, 2008.

  1. bill-e

    bill-e

    516
    May 10, 2008
    New Hampshire
    Hi folks,

    Meet Mickensy, my granddaughters doll. I'm home alone and needed a model and one that doesn't move is even better.

    I need to make a decision if I'm keeping this copy (focus) of if I'm returning it for another so I set the doll up about 3 feet from the tripod mounted camera and started snapping. I re-focused between each shot. I took pictures at 1.4, 1.8, 2.8, 4 and 8 and here they are. The red focus brackets surrounded the dolls eyes.

    Pictures are unaltered 100% crops.

    What do you think, is this normal performance for this lens? Thanks.
    f/1.4
    f1.4.jpg
    f/1.8
    f1.8.jpg
    f/2.8
    f2.8.jpg
    f/4
    f4.jpg
    f/8
    f8.jpg
     
  2. Randy

    Randy

    May 11, 2006
    nice eyes, she takes after her great grandpa huh

    ask Nute, he'll know
     
  3. bill-e

    bill-e

    516
    May 10, 2008
    New Hampshire
    Focus. I don't actually know if there's anything wrong, hence the question. My noobness causes me to question myself and every picture I take with this lens seems to look better if I apply some sharpness.
     
  4. rotxlk82

    rotxlk82

    Jul 20, 2007
    UK
    If you're thinking there may be a front or backfocus error you can test using a special chart which can be downloaded and printed out.

    I'm sure you can find it via a search engine or someone may have a link for it here
     
  5. Phillip Ino

    Phillip Ino

    Nov 26, 2007
    Austin
    Looks okay to me. Try shooting a profile of the doll's head and focus on the eye again.
     
  6. bill-e

    bill-e

    516
    May 10, 2008
    New Hampshire
    Phillip so I just turned her head and cropped again. I hope this is adequate. I just posted the 2 extremes though I retook the series.

    f1.4p.jpg
    f8p.jpg
     
  7. bill-e

    bill-e

    516
    May 10, 2008
    New Hampshire
    Robert, I read a lot of pro's and cons about the chart and based on what I read I decided against using it for now. I figured a subject, albeit it not alive, would be a more reasonable test.
     
  8. rotxlk82

    rotxlk82

    Jul 20, 2007
    UK
    Fair enough Bill, I've not used it either. I was just making a suggestion. I don't think there is anything wrong with the doll test you're using

    To be honest there looks to be nothing wrong with the lens to me. Maybe you should give it a try with some 'real' everyday shooting before you make your final decision
     
  9. Nuteshack

    Nuteshack Guest

    the dirty thirty is a little iffy ona d40. the 40's focus system is the worst. this little lens is a much different animal on my d200. but on the 40 it's somewhat hit and miss.
     
  10. Phillip Ino

    Phillip Ino

    Nov 26, 2007
    Austin
    I still think it looks okay. You seriously should try using it in real world situations and see what you think then.
     
  11. Jim C

    Jim C Guest

    I was thinking of picking up on of these to use on my D80. The autofocus system in the D80 should be similar, but not identical, to the D200, so I should be OK?
     
  12. bill-e

    bill-e

    516
    May 10, 2008
    New Hampshire
    Philip,

    Thanks. I have been using it and I'm getting inconsistent results. I wanted to make sure it was me and not the lens before my 30 days is up.
     
  13. Phillip Ino

    Phillip Ino

    Nov 26, 2007
    Austin
    Should definitely be okay.
     
  14. Phillip Ino

    Phillip Ino

    Nov 26, 2007
    Austin
    Getting used to using a lens wide open, especially at 1.4 can take a little time. If you haven't already, try taking some shots in the day time, wide open, but with a high shutter speed to help reduce any motion blur. In the end, only you can decide whether or not you feel comfortable keeping the lens or exchanging it.