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45 1.8 sharpness wide open compared to 20 1.7

Discussion in 'Native Lenses' started by chilau2000, Oct 4, 2013.

  1. chilau2000

    chilau2000 New to Mu-43

    6
    Oct 1, 2013
    Hi

    Has anyone compared the wide open sharpness of the 45 1.8 to the 20 1.7
    I picked up a 45 1.8 a week ago and am finding it a bit soft wide open compared to the 20 which is razor sharp wide open.
    Its ok when I stop down to 2.8
     
  2. LowriderS10

    LowriderS10 Monkey with a camera.

    May 19, 2013
    Canada
    Hmm...either you have a bad copy or something is up with the way you're using it...the 45 is consistently rated by both reviewers who run it through test charts and everyday users as one of the sharpest lenses for this system.

    Can you post some samples (including 100% crops) and tell us a bit about your technique...that might help. :)
     
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  3. broody

    broody Mu-43 Veteran

    388
    Sep 8, 2013
    The Oly should be sharper at all apertures (mostly because of chromatic aberration on the pancake, other than that they are neck and neck), it should be the sharper lens of the two wide open.

    Maybe you got a lemon. Try to test it a bit more and return it if it doesn't perform as expected.
     
    • Like Like x 1
  4. boatman37210

    boatman37210 Mu-43 Regular

    103
    Jun 28, 2012
    Thailand
    From SLGear website:

    Sharpness
    The Olympus 45mm ƒ/1.8 m.Zuiko is a very sharp lens. Wide open at ƒ/1.8, the central region of the image is tack-sharp, with very light corner softness; there's not much difference in stopping down to ƒ/2, but by ƒ/2.8, the lens is as sharp as sharp gets. It's sharp all the way through to ƒ/16, where a slight hint of diffraction limiting is present, but it's still really sharp even at this aperture. At ƒ/22 there is only very slight softness across the frame.

    In short - this is really excellent performance for sharpness.
     
    • Like Like x 1
  5. timg

    timg Mu-43 Regular

    74
    Jun 13, 2012
    I have both and I find the 20 1.7 performs better wide open too... I think there's also an element of DOF to contend with too, as the 45 1.8 will have a thinner DOF than the Panny due to the longer focal length, so you have to be more careful with focussing... I usually stop my 45mm down a notch or two when I can to keep things sharp.
     
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  6. mh2000

    mh2000 Mu-43 Veteran

    254
    Jul 3, 2010
    I was going to point this out as well. Also, other than DoF, there is perception of rendering. The 20 is not only very sharp, but rather harsh whereas the 45 is much softer in its rendering. Another thing, is that the 45 is a bit prone to flare and at a minimum loses contrast when minor flaring occurs. The 20 seems to hold contrast better in this regard.

    I guess I'm kind of a weirdo in this regard, but I typically stop my 45 down to increase my DoF.

    Best!
     
    • Like Like x 1
  7. nuclearboy

    nuclearboy Mu-43 Top Veteran

    850
    Jan 28, 2011
    USA
    I have a poor mans lens testing chart in the basement and my findings are like the OP. The 45 is not as sharp wide open and generally not as sharp as the 20.

    I test lenses to see if there are any big issues and I do it in a controlled manner.

    Testing can get you all excited about small differences. At least for me, the 45 does not test as well as the best lenses in the system but it does produce excellent photos. I consider it a must have for the m4/3 shooter.
     
    • Like Like x 2
  8. mnhoj

    mnhoj There and back again

    Dec 3, 2011
    Los Angeles
    John M
    Two things that come to mind.

    Infinity focus can sometimes be tricky.
    Zoom confirmation with manual focus.

    Shutter shock and/or IBIS(depending on which body) can also be an issue.
    Tripod and/or safe shutter speeds to rule them out.
     
    • Like Like x 2
  9. LowriderS10

    LowriderS10 Monkey with a camera.

    May 19, 2013
    Canada
    Thanks for posting these...certainly a noticeable difference!

    Is it *TOO* soft? I'm not sure...I'm a bit busy right now, but in a couple of hours I'll do a comparison for you as well, so you can see how other 45s perform, maybe that can help you figure out whether it's your copy that's too soft or 45s in general! :)
     
    • Like Like x 1
  10. kevinparis

    kevinparis Cantankerous Scotsman

    Feb 12, 2010
    Gent, Belgium
    can I just point out that you have happened to compare 2 lenses that no doubt were optimised to work best in close to intimate situations, and found them lacking in sharpness at longer distances

    I have both lenses.. and they have never disappointed in the past... though recently I have favoured the 17 and the 75

    looking at your test shots I would worry less about sharpness and concentrate on taking interesting shots

    peacse

    K
     
    • Like Like x 1
  11. chilau2000

    chilau2000 New to Mu-43

    6
    Oct 1, 2013
    Hi

    Yes I do find that the 45 is sharper wide open at closer distances.
    The 20 seems to be sharp wide open at all distances.
    Seeing all the great reviews everywhere for the 45 I was wondering if I have a bad copy.
     
  12. kevinparis

    kevinparis Cantankerous Scotsman

    Feb 12, 2010
    Gent, Belgium
    I would bet on user error before bad lens every time..maybe you are a long and experienced photographer... but my spidey sense says no

    really dont fret on the sharpness thing... take interesting photos that engage you or your family/friends or any other audience you can find

    unless you work in forensics or archival stuff...whats in the image is much more important than how it was made

    K
     
    • Like Like x 1
  13. chilau2000

    chilau2000 New to Mu-43

    6
    Oct 1, 2013
    Hi Lowrider

    Did you get a chance to compare some other 45's to see if there was any difference in wide open sharpness.
     
  14. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    • Like Like x 1
  15. chilau2000

    chilau2000 New to Mu-43

    6
    Oct 1, 2013
  16. napilopez

    napilopez Contributing Editor

    826
    Feb 21, 2012
    NYC Area
    Napier Lopez
    Although I'm the last person to ever care about sharpness at general M4/3 levels of performance, I can unhesitantly say the 20mm f1.7 is easily the sharper lens. Also, as mentioned previously, the 45mm also just seems to be "softer" in its rendering. Strange because the oly has overall better contrast, yet at the 100% crop pixel level the 20mm always seems sharper to me. That's not to say the 45mm isn't incredibly sharp, just that the 20mm cuts like a knife. Conversely, the latter is also a bit more aberration prone, and sharpness fall off to the corners seems to be a little more noticeable (probably due to software distortion correction).

    Rogercicala from lensrentals.com measured the 20mm f1.7 as resolving an 870 Max, 720 avg. on MTF50 wide open, whereas the the 45mm "only" does 720 max and 615 avg. His results are consistent with my own, where the 20mm is the sharpest wide open, then 45mm, then the Panaleica 25mm. At f2.8, the 20mm resolves 1050/875 and the 45mm 900/790. Sources here:
    http://www.lensrentals.com/blog/2012/05/wide-angle-micro-43-imatest-results
    http://www.lensrentals.com/blog/2012/05/standard-range-micro-43-imatest-results

    For comparison, the 75mm f1.8 does 880/765 wide open, and 1020/925 at f2.8. The 20mm just barely loses, and primarily in the corners, which is again consistent with my own experience.

    EDIT: That said, I only just looked at your photos, and yes, you definitely have a bad lens.
     
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