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Thread: Rod 40/4 limitations, distortion and correction

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    Rod 40/4 limitations, distortion and correction

    So I've been taking my Cambo WRS 1250/IQ 380 out every other day (it's all very exciting to me) but one of the issues I keep on finding myself with is the distortion of the Rod 40/4. I tend to find that (with regard to framing) getting it right in camera tends to put my shifts between 12-16mm on the X-axis. However, when I bring it into C1, apply the LCC, etc etc.. the lines start to bend towards the top - and it's hugely problematic because the things I'm shooting are essentially lines from one edge to the other - so it *really* stands out.

    So what I'd like to know is.. what's the furthest I can safely shift with this lens (vs simply what said image circle will allow for) and, if I can take it to the very edge - how the hell do I correct for it after the fact?

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    Re: Rod 40/4 limitations, distortion and correction

    Have you entered the amount of movent in the lens movement panel in C1?
    I'm interested to see what you're talking about as I'm hoping to pick this lens up soon. Any chance you could post a sample?

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    Re: Rod 40/4 limitations, distortion and correction

    To get an indication you can look in the datasheets from Rodenstock:

    40 mm /4 HR Digaron-W

    there one can see that the 40 has some moustache distortion, a little bit less than the 32HR but not so much less. The longer lenses doesn't have that and may be a bit easier to correct.

    The issues with distortion is an unavoidable side-effect of making a lens retrofocus, which the wide angle Digarons are. Traditoinal symmetrical designs like in the Schneider Apo-Digitar series don't have this issue, but then they don't work that well with the current sensors...

    ALPA has lens distortion correction software which may work for you if you don't get it to work in C1:
    ALPA Lens Corrector

    (Note that I'm myself an old-school guy that uses the traditional distortion-free lenses and compatible sensor so I haven't worked with distortion correction in post myself so I don't really know what C1 can do and not...)

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    Senior Member Jamgolf's Avatar
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    Re: Rod 40/4 limitations, distortion and correction

    You might find this thread useful. It is about lens corrections in Capture One.

    It would probably be helpful to see an example of what you are referring to.
    IQ3 100 Cambo 1600 Rodenstock 23,32,50,90 Zeiss 350SA
    UnTroubled Land

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    Re: Rod 40/4 limitations, distortion and correction

    As Torger has stated the 40 Rody has a fair amount of distortion and is the main reason I stay away from it. I have stayed with my Schneider 35XL which is virtually distortion free - one of its claims to fame. I can shift a clean 7mm with my IQ 100 which may not seem like much but its enough for me. If needed I find that rotating around the Nodal is a better solution to shifting the wides.

    Victor

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    Senior Member dchew's Avatar
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    Re: Rod 40/4 limitations, distortion and correction

    I really wish the 43xl could tilt on an Alpa. I never would have given that lens up for the 40hr.

    Dave
    How glorious a greeting the sun gives the mountains! - John Muir

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    Re: Rod 40/4 limitations, distortion and correction

    Quote Originally Posted by vjbelle View Post
    As Torger has stated the 40 Rody has a fair amount of distortion and is the main reason I stay away from it. I have stayed with my Schneider 35XL which is virtually distortion free
    same for me... when i bought my 35xl, i had to choose between the 35XL and the 40HR...
    i went with the 35 because at the time i didn't have the 28, and because of distortion.
    But to be honest, i don't use the 35xl a lot because of the small amount of mvts available.

    I had the chance to try the 40, and i really enjoy this focal length and sharpness... but sometimes distortion is really visible, and the 40 is prone to flare... i've bought an apo sironar digital 45, good flare resistance, small amount of distortion, but not the best in term of sharpness.

    So, for art reproduction, i'm really happy with my distortion free 35xl... but for architecture, the IC is the limiting factor.

    if i was in your shoes, i will try the Alpa software !

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    Re: Rod 40/4 limitations, distortion and correction

    To state the obvious, it's a shame that Schneider have pulled out of the tech camera lens game...

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    Re: Rod 40/4 limitations, distortion and correction

    They left large format at the same time which also is a bit unfortunate. Unique lenses like the Fine Art XXL 550 / 1100 for Ultra-Large-Format can no longer be ordered.

    I was hoping that niche lenses could survive on a made-to-order basis, and that a large company like Schneider could stay in large format just to serve the photographic community, like some film manufacturers still make film despite limited profitability. I have no idea about the costs behind lens manufacturing though... if they pulled out because they were losing huge amounts of money, or if they pulled out just because the profits where not big enough.

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    Re: Rod 40/4 limitations, distortion and correction

    Quote Originally Posted by torger View Post
    I have no idea about the costs behind lens manufacturing though... if they pulled out because they were losing huge amounts of money, or if they pulled out just because the profits where not big enough.
    I wonder if someone did some math and decided they could make more money selling their inventory of copal shutters vs selling lenses with those shutters mounted in them.


    Dave
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    davechewphotography.com

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