Help me test my lens sharpness

Discussion in 'Photography Beginners' Forum' started by eric-holmes, Apr 28, 2010.

  1. eric-holmes

    eric-holmes No longer a newbie, moving up!

    Joined:
    Aug 8, 2009
    Messages:
    1,858
    Likes Received:
    48
    Location:
    Arkansas
    Can others edit my Photos:
    Photos OK to edit
    I took four different pictures with my 50 1.8 to find the sharpness. I used aperture mode and let the camera determine the shutter. No PP was done. These are SOOC JPEG quality.

    Tripod and remote release was used.

    f/8 s1/8
    [​IMG]

    f/6.3 s1/13
    [​IMG]

    f/4 s1/40
    [​IMG]

    f/2.8 s1/80
    [​IMG]
     
  2. D-B-J

    D-B-J Been spending a lot of time on here!

    Joined:
    Apr 13, 2010
    Messages:
    9,027
    Likes Received:
    2,171
    Can others edit my Photos:
    Photos OK to edit
    whatever your taking pics of.. it seems oof?
     
  3. D-B-J

    D-B-J Been spending a lot of time on here!

    Joined:
    Apr 13, 2010
    Messages:
    9,027
    Likes Received:
    2,171
    Can others edit my Photos:
    Photos OK to edit
    but if they are crops, the first one seems to be the sharpest.
     
  4. tsaraleksi

    tsaraleksi TPF Noob!

    Joined:
    Jun 12, 2007
    Messages:
    1,045
    Likes Received:
    0
    Location:
    Greencastle Indiana
    Can others edit my Photos:
    Photos NOT OK to edit
    What, exactly, are you trying to figure out?
     
  5. photonewbie86

    photonewbie86 TPF Noob!

    Joined:
    Oct 31, 2009
    Messages:
    241
    Likes Received:
    0
    Location:
    Canada
    Can others edit my Photos:
    Photos OK to edit
    What are you taking pictures of wood?
     
  6. chuckinsocal

    chuckinsocal TPF Noob!

    Joined:
    Apr 26, 2010
    Messages:
    5
    Likes Received:
    0
    Location:
    Carlsbad CA
    Can others edit my Photos:
    Photos OK to edit
    Since we have no idea of what your subject is supposed to look like, we have no idea if it's off or not.

    Try taking photos of something with high contrast with lines that we know are supposed to be sharp and straight. Perhaps a white box with black lettering from Office Depot or something like that.
     
  7. usayit

    usayit No longer a newbie, moving up!

    Joined:
    Nov 15, 2003
    Messages:
    9,523
    Likes Received:
    344
    Location:
    North New Jersey, United States of America
    Can others edit my Photos:
    Photos OK to edit
    Lay down measuring tape along the floor. Setup a tripod with the camera pointing down at a 45 (or less) angle focused on a number/mark on the measuring tape. Make sure you get focus confirmation and use a remote. You should have good light and use the lowest ISO setting. Take a photo.

    Examine the photo... is the number you are focused at the sharpest. Is it the number or marks behind or in front of the intended focused number/mark sharpest?
     
  8. Derrel

    Derrel Mr. Rain Cloud

    Joined:
    Jul 23, 2009
    Messages:
    35,456
    Likes Received:
    12,795
    Location:
    USA
    Can others edit my Photos:
    Photos OK to edit
    The 1/8 to 1/30 range your smaller-aperture shots are made at is kind of a dangerous zone for mirror slap and shutter vibration. On many lighter-weight camera bodies and lighter-duty tripod heads, there can,at times, be some vibration patterns that make exposures in the 1/8 to 1/30 second range prone to softness from the slap of the mirror going up, then the first shutter curtain racing across the film plane and exposing the film/sensor, and then the second shutter curtain closing to end the exposure.

    On a danger zone shutter speed, like say 1/8 second, the mirror creates slap as it swings up...then the first curtain thunks open...and so there are two (potential) vibration-causing effects, which are recorded in a brief exposure that takes as long to make as it takes for the vibrations to quell; longer exposures, like 4 to 6 seconds can actually appear sharper and less-affected by vibration than those in the 1/4 to 1/30 second range. One solution is to use a flash exposure to test sharpness...the flash duration is very,very brief, and guarantees there will not be sharpness lost due to camera vibration.

    That faded wood test target is not the best target....I'd rather see a page ripped from a magazine taped to a wall or something like that. The test target looks best in the first shot. Focusing accuracy is huge on these kinds of tests. I see that the shot done at f/6.3 and 1/13 second looks very slightly less-sharp than the one done at f/8 and 1/8 second; that could be due to any number of factors--mirror slap, slight camera vibration, or a very minute focusing error, or a bit of focus shift on the lens; many lenses will shift their point of focus a bit between wide-open and the shooting aperture.

    These kinds of tests demand really,really careful control if the tests are to be 100 percent trustworthy. Can you use your camera's Live View, to determine if there is some focus shift by focusing with the lens wide-open, and shooting a series of test shots at one specific aperture, and then doing another series of shots focusing with the lens stopped down to the shooting aperture? (Does your body even offer Live View?)
     
  9. ghpham

    ghpham TPF Noob!

    Joined:
    Dec 16, 2007
    Messages:
    535
    Likes Received:
    0
    Can others edit my Photos:
    Photos OK to edit
    I believe this is use to test...back focus? He just wanted to test lens sharpness?
     
  10. fokker

    fokker No longer a newbie, moving up!

    Joined:
    Jun 23, 2009
    Messages:
    2,830
    Likes Received:
    293
    Location:
    New Zealand
    Can others edit my Photos:
    Photos OK to edit
    Can't see why it wouldn't be a good way to test sharpness too...
     
  11. Johnboy2978

    Johnboy2978 No longer a newbie, moving up!

    Joined:
    Oct 21, 2004
    Messages:
    1,797
    Likes Received:
    30
    Location:
    Southwest Virginia
    Can others edit my Photos:
    Photos OK to edit
  12. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

    Joined:
    May 1, 2008
    Messages:
    23,090
    Likes Received:
    3,756
    Location:
    UK - England
    Can others edit my Photos:
    Photos OK to edit
    Another bonus that I have found when testing my own lenses is that shooting at an angle means that any accidental missfocusing does not affect ones ability to judge the sharpness - whilst shooting flat on one can sometimes wonder if the focus has been a tiny bit out - a very easy thing to do with large apertures (Eg f2.8) or in my case where I was testing macro lenses at high magnifications.
     

Share This Page

Search tags for this page

how can i tell if my lens is sharp

,
how to check if my lens is sharp
,
how to check if your lens is sharp
,
how to check lens sharpness
,
how to check sharpness of lens nikon focus
,
how to test a lens sharpness
,
how to test if a lens is sharp
,

how to test lens sharpness

,
lens sharpness test chart
,
testing sharpness of a lens