Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 69,735   Posts: 1,515,428   Online: 1083
      
Results 1 to 8 of 8
  1. #1

    Join Date
    Feb 2012
    Location
    New York
    Shooter
    Large Format
    Posts
    305

    Apertures on RZ67 lenses

    Is there a chart that shows what lens apertures perform the best with RZ67 lenses? Just looking for sharpness and minimal diffraction. I have a 65, 110 and 140 so I'm just looking for those numbers, but all of them would be great. I've always shot around ƒ/8 and ƒ/16 and things look good so far.

  2. #2

    Join Date
    Oct 2010
    Location
    USA, Pac/NW
    Shooter
    Multi Format
    Posts
    368
    I think all three RZ lenses you mentioned are reviewed in the lens test below.
    Look at the lines of resolution in the third column vs the f:stop chosen, (center-middle & edge).

    http://www.hevanet.com/cperez/MF_testing.html

  3. #3
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,050
    Images
    12
    About f/8 or f/11 for most lenses. Most are great (especially the M-LA lenses and longer APOs) from f/5.6 but the DOF might be problematic and by f/16 you'll be seeing the beginnings of diffraction.

    While I like that people can measure concrete numbers and always advocate for quantifiable metrics, I don't really think the numbers posted in that link above are correct or at least, they don't match the performance of my lenses. Either I've got strange ones or they've got strange ones, but the sample count is far too small to draw any conclusions. Specifically, the link claims nearly aperture-independent performance from the 110/2.8 whereas in my experience, it is noticeably softer and with more coma at f/2.8, better by f/4 and reaching full sharpness by about f/8. A secondary effect is that performance varies with distance somewhat, and most lenses (except the 140) are not anywhere near flat-field so testing them against a flat target is inherently problematic.
    Last edited by polyglot; 04-09-2013 at 06:57 PM. Click to view previous post history.

  4. #4

    Join Date
    Feb 2012
    Location
    New York
    Shooter
    Large Format
    Posts
    305
    Thanks for the responses! My 110 is average, but the 65 MLA is tack sharp, I was never pleased with the 180, so I sold it and bought the 140 which I'm embarrassed to say haven't used yet even though I've had it for 4 months. I usually shoot a few stops down from open, but I'm really looking for a good SHARP wide angle like a 50 (or my 65) that I can use fully stopped down for maximum DOF.

  5. #5
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,050
    Images
    12
    There is no RZ67 wideangle sharper than your 65 M-LA; if you want better then you need to save up for a Mamiya 7. The 50 ULD is pretty close or on-par though and is of course wider. Once you reach f/11, they're all (except non-floating wides closer than a couple metres) basically the same in performance; stopping down makes even the poorest lenses look decent. If you stop down to f/22 or lower, it doesn't matter what lens you're using because you will be diffraction-limited and that is a function only of the aperture. Though shooting at f/32 will give you lots of DOF, the results will be visibly soft with any lens.

  6. #6
    Alan Klein's Avatar
    Join Date
    Feb 2011
    Location
    New Jersey, formerly NYC.
    Shooter
    Multi Format
    Posts
    414
    On landscape pictures where I want front to rear focus as much as possible, I'd opt for stopping down and not worrying about diffraction. I figure that sharper pictures with less DOF is worse than deeper DOF with some diffraction.

    What are others opinions on this issue?

  7. #7
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,050
    Images
    12
    Quote Originally Posted by Alan Klein View Post
    On landscape pictures where I want front to rear focus as much as possible, I'd opt for stopping down and not worrying about diffraction. I figure that sharper pictures with less DOF is worse than deeper DOF with some diffraction.

    What are others opinions on this issue?
    Hyperfocus is the optimum tradeoff between DOF and diffraction, assuming you know how much DOF you want.

  8. #8
    Alan Klein's Avatar
    Join Date
    Feb 2011
    Location
    New Jersey, formerly NYC.
    Shooter
    Multi Format
    Posts
    414
    Quote Originally Posted by polyglot View Post
    Hyperfocus is the optimum tradeoff between DOF and diffraction, assuming you know how much DOF you want.
    I estimate the closest object and then check the hyperfocal distance to infinity (or furthest object) and set the focus at hyperfocal distance if infinity is wanted or focus about a third in if furhtest distance is less than infinity. I set the aperture according to the lens I'm using (or from the lens tables) but usually stop down one more stop for good measure.

    That extra stop down might be overdoing it and getting me more into diffraction. What do you think?



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin