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Thread: SK 40 XL or Rodi 47 HR

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    SK 40 XL or Rodi 47 HR

    Hi all,

    First of all, sorry for my English.
    I just bought a RM3d and I hesitate between two optical. I'd like your advice. For the moment, Arca lent me SK 47 XL. I find it interesting thanks to its large image circle of 113 mm. For cons, I find it a little soft with the P65 + back. Do you agree with this sentiment? I hesitate with 40 HR Rodi, what do you think of this optical?

    Thanks

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    Re: SK 40 XL or Rodi 47 HR

    I've not tried the 47XL but when I purchased my Rm3di I tested both the SK43XL and RS40HR and found sharpness to be equal with the better contrast going to the Schneider.

    The SK is excellent in the centre at f8 with better edges at f11. At f5.6 you notice a drop in sharpness. The RS is very good to excellent from wide open to f11.

    The SK has a larger IC but due to large amounts of field curvature the usable IC of both lenses is about equal. The RS is good virtually up to the edge of its IC.

    Lens cast is less on the RS but fall off is very similar. Fall off on the SK can be improved a lot by use of the centre filter.

    The RS suffers very badly from flare and a lens hood even in situations you think will be ok is a necessity. The SK is very good with flare for a lens with such a large IC.

    The SK, even with centre filter is a very compact lens and the click stop aperture setting is very nice to use. The RS is big and heavy.

    I settled on the SK43XL because of its better contrast and the flare issue on the RS just turned me completely off that lens.

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    Re: SK 40 XL or Rodi 47 HR

    Quote Originally Posted by Diaphiris View Post
    Hi all,

    First of all, sorry for my English.
    I just bought a RM3d and I hesitate between two optical. I'd like your advice. For the moment, Arca lent me SK 47 XL. I find it interesting thanks to its large image circle of 113 mm. For cons, I find it a little soft with the P65 + back. Do you agree with this sentiment? I hesitate with 40 HR Rodi, what do you think of this optical?

    Thanks
    Did you calibrate the lens to your back? For optimal performance and comparison I would think this would be critical.
    Best,
    Bob

  4. #4
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    Re: SK 40 XL or Rodi 47 HR

    The SK 47 is obviously soft with 60 and 80 MP backs. (I assume you have your HR and XL mixed up in the thread title). The 43XL and and 40HR are both excellent performers. You will find the usable image circles similar as the 43XL starts to throw excessive lenscast at about the same point that the 40 hits its limits. I tested both and chose to buy the 40HR but you should do your own testing as we all have different ideas of what is acceptable. If you think there is even a small chance you will upgrade to a 80MP back during the service life of this lens, it would be a strong reason to lean towards the 40HR due to the much better performance re lens cast.
    Published image circles don't mean much as different sensors behave differently as they move away from the centre of the image circle and the angle of incidence of light striking the sensor gets more acute. This is a significant issue with the 60MP Dalsa sensor and an even bigger one with the 80MP. In the case of many of the large image circle wides, the useable image circle is smaller than the lens maker suggests.
    Siebel
    "In the end, it's all about the pictures"
    www.bryansiebel.com

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