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Thread: pentax 50mm 1.4 faulty? help needed.

  1. #1

    Default pentax 50mm 1.4 faulty? help needed.

    i just purchased my first dslr, pentax kx for about a month now, bought a 50mm 1.4 yesterday. took some sample pictures with it. i realised that the pictures taken weren't quite as sharp as compared to the pictures on the internet. any possibility that the lens that i purchased was faulty? or are there any tips on using the lens?

  2. #2

    Default Re: pentax 50mm 1.4 faulty? help needed.

    Inspite of the antishake, a steady hand is still good. Also, did you try to take photos lesser than its minimum focussing distance? No way the camera can focus properly under this circumstance. To test this, mount the lens on a tripod and take a picture on remote timer.
    BTW, is your focal point set correctly? If you set it off centre and forget to set it back, that can cause the camera to focus on the wrong object. Generally, lenses tend to be least sharp at the wide open end. Try moving down a stop or 2.
    Last edited by airconvent; 10th January 2010 at 03:55 PM.
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  3. #3
    Member banana0ne's Avatar
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    Default Re: pentax 50mm 1.4 faulty? help needed.

    why don't you post some sample pictures.
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  4. #4

    Default Re: pentax 50mm 1.4 faulty? help needed.


  5. #5

    Default Re: pentax 50mm 1.4 faulty? help needed.

    yup. I've set my focal point correctly, taken with a tripod etc. however, the"blur" effect is still there. I've realised that i can adjust the aperture via two ways, one is turning the aperture ring, another is to set the ring to automatic and adjust the aperture via the dial on the camera, will any of these affect the quality of the picture?

  6. #6

    Default Re: pentax 50mm 1.4 faulty? help needed.

    The aperture should be set using the camera body control dial, with aperture ring at "A".

    If the aperture ring is used at other positions, pictures will be taken at maximum aperture if camera not in Manual mode.
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  7. #7

    Default Re: pentax 50mm 1.4 faulty? help needed.

    You may want to check if there is a BF/FF problem with your lens. I seem to recall there was a PDF posted that allows you to test the 50mm for that, but can't seem to find it anymore.
    But ya, do post a few pictures so we can see what the problem is. There are lots of different possible reasons for blur pictures.
    Don't forget to get a hood for the 50mm too, it really helps.
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  8. #8

    Default Re: pentax 50mm 1.4 faulty? help needed.



    this is the sample taken by the lens.

  9. #9
    Member zoom3's Avatar
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    Default Re: pentax 50mm 1.4 faulty? help needed.

    This lens is not easy to master. Pics are typically pretty soft wide open at 1.4. It is sharpest around f8. Take some pics of the same box between f5.6 and f8.0 and compare. They should be razor sharp. If not, then there is a problem....

  10. #10

    Default Re: pentax 50mm 1.4 faulty? help needed.

    Quote Originally Posted by doreymi View Post

    this is the sample taken by the lens.
    Looks out of focus to me.

  11. #11

    Default Re: pentax 50mm 1.4 faulty? help needed.

    It shouldn't be that soft. Try shooting 45degree down on a flat wordy thing like a newspaper or a wordy flyer to confirm your BF/FF suspicions.

  12. #12
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    Default Re: pentax 50mm 1.4 faulty? help needed.

    user is shooting at wide open f/1.4 and close focus distance, thin DOF have caused the pics to look unsharp.

  13. #13
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    Default Re: pentax 50mm 1.4 faulty? help needed.

    focus might be slightly off... but then again, u shoot at 1/25, maybe increase the iso to 800 and try again... also shoot at f4 and above...
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    Default Re: pentax 50mm 1.4 faulty? help needed.

    Since it was taken with a tripod, shutter speed shouldn't be an issue. Try shooting newspaper at an angle like hamustar suggested. The DOF at f1.4 and such short focusing distance is super thin, and even minor AF inconsistencies will show up.
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