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Thread: Leica S2 with Contax lens : focal lenghts ?

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    Leica S2 with Contax lens : focal lenghts ?

    Hi there..

    What are the comparable focal lenghts of Contax 645 lens ?

    So Leica is shipping the cool adapter for Contax lens... but... Contax uses a 6x45 format.. which is not the used by Leica S2.

    From what I've read, that makes the Contax 35mm ... a 43mm in Leica S2 terms, converted to 35mm fov ?

    43mm aint that wide.. if wide at all.. that means , comparing 35mm FOV :

    Leica 70mm Summarit = roughly 50mm
    Contax 35mm with S adapter = roughly 44mm ?

    Is this correct ? There goes my hipyeeee for a cheap wide angle for my S2.

    On the other hand, the Contax 350mm turns out a Contax 430mm .. thats even before the 1.4x converter is added, correct ? This could be fun..
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    Re: Leica S2 with Contax lens : focal lenghts ?

    A Contax 35 mm will give the same FOV as a native S 35 mm. Roughly 28 mm in so called FF terms. The image circle of the Contax lenses is wider than the S lenses.

    Edit: This also came up in the other adapter thread, I believe on page I and page II.

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    Re: Leica S2 with Contax lens : focal lenghts ?

    Quote Originally Posted by peterv View Post
    A Contax 35 mm will give the same FOV as a native S 35 mm. Roughly 28 mm in so called FF terms. The image circle of the Contax lenses is wider than the S lenses.

    Edit: This also came up in the other adapter thread, I believe on page I and page II.
    are you sure ? this doesnt make ANY sense.

    Contax 645 sensor is much bigger than S2 sensor.

    eg, Hasselblad 28mm vs Leica S2 30mm , both on S2 body... S30mm is wider...

    That said, that contax 35mm will equate to which "35mm focal lenght" ?
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    Re: Leica S2 with Contax lens : focal lenghts ?

    Last edited by Pics2; 16th June 2013 at 10:46.

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    Re: Leica S2 with Contax lens : focal lenghts ?

    Focal length is focal length. It does not make a difference if the lens has an image circle larger than the sensor/film in question or the same size. If the circle is smaller than the sensor or film in question, it's like cropping the final image with a narrower FOV.
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    Re: Leica S2 with Contax lens : focal lenghts ?

    exactly like emr says.

    proenca, yes I'm quite sure. Did you read the other thread?

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    Re: Leica S2 with Contax lens : focal lenghts ?

    Edited, I didn't understand the question.
    Last edited by Pics2; 16th June 2013 at 11:23.

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    Re: Leica S2 with Contax lens : focal lenghts ?

    The focal length remains the same but the F.O.V changes.. the Contax 35mm will not give a 35mm F.O.V on the S2.. it will be cropped..

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    Re: Leica S2 with Contax lens : focal lenghts ?

    sorry guys, my bad.

    i meant field of view. the 35mm contax will have which f-o-v on the S2 since the sensor size differences, ie, will be cropped.. therefore the factor will be ?
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    Re: Leica S2 with Contax lens : focal lenghts ?

    Quote Originally Posted by proenca View Post
    sorry guys, my bad.

    i meant field of view. the 35mm contax will have which f-o-v on the S2 since the sensor size differences, ie, will be cropped.. therefore the factor will be ?
    I think it's 43mm...

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    Re: Leica S2 with Contax lens : focal lenghts ?

    I don't think proenca and RVB quite understand.

    The 35mm Contax will have the same FOV as the Leica 35mm. 28mm equiv in FF terms, as peterv said.

    Whether or not the lens is designed for a bigger format has absolutely no affect on the field of view nor equivalent focal length on the S2.

    ANY lens you mount on an S2 that has sufficient image circle will have a 0.8x factor to get the 24x36mm full frame equivalent.

    S lens
    35mm x 0.8 = 28mm
    70mm x 0.8 = 56mm

    Contax lens
    35mm x 0.8 = 28mm
    45mm x 0.8 = 36mm

    etc etc

    If you are asking what the equivalent lens on the Contax 645 will be to the effective FOV you get on the S that is a little more complex.
    645 = 56x41.5mm = diagonal of 69.7mm
    S = 30x45mm = diagonal 54.08mm
    So the inverse crop would be 1.29x making the 35mm lens on the S look like a 45mm lens on the Contax 645 with a film back.
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    Re: Leica S2 with Contax lens : focal lenghts ?

    Quote Originally Posted by thrice View Post
    (...)
    So the inverse crop would be 1.29x making the 35mm lens on the S look like a 45mm lens on the Contax 645 with a film back.
    That was exactly the answer I was looking for.

    This means a Leica 70mm and a Contax 35mm via adaptor are very very close related in terms of effective FOV ( 56mm vs 45mm )

    thanks !
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    Re: Leica S2 with Contax lens : focal lenghts ?

    70mm 645 medium format lens (be it Leica or Contax or Hasselblad) is, like Thrice stated, 56mm equiv in FF terms. 70mm medium format lens is 70x1.29= 90mm (thanks Thrice for calculating the crop factor here)equiv in S 30x45mm terms.

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    Re: Leica S2 with Contax lens : focal lenghts ?

    Quote Originally Posted by Pics2 View Post
    70mm 645 medium format lens (be it Leica or Contax or Hasselblad) is, like Thrice stated, 56mm equiv in FF terms. 70mm medium format lens is 70x1.29= 90mm (thanks Thrice for calculating the crop factor here)equiv in S 30x45mm terms.
    70mm F.O.V equivalent on a 645 sensor is 0.62075x70 = 43.45 ,35mm is equal to 21mm FF ...

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    Re: Leica S2 with Contax lens : focal lenghts ?

    proenca and Pic2,

    I'm sorry to say you guys still don't get it. I suggest you re-read the answers here, and in the other adapter thread. Good luck!

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    Re: Leica S2 with Contax lens : focal lenghts ?

    Any lens with a certain focal length has on a specific sensor size the same fov.

    This means (like stated before), for example both the Leica S 35mm and the Contax 35mm lenses have the same field of view on a Leica S camera.

    I made a summery fov sheet for all Leica S and Contax S lenses if used on the Leica S. The nice thing is that many Contax lenses fill up the missing focal lengths in the current Leica S lens range.

    I added the focal lengths of a corresponding 36x24 camera system with equivalent fovs.

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    Re: Leica S2 with Contax lens : focal lenghts ?

    You are right guys. I mixed up the things. I wanted to say what happens if you put Contax lens on S2 via an adapter. Sorry for making confusion here.

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    Re: Leica S2 with Contax lens : focal lenghts ?

    Quote Originally Posted by proenca View Post
    That was exactly the answer I was looking for.

    This means a Leica 70mm and a Contax 35mm via adaptor are very very close related in terms of effective FOV ( 56mm vs 45mm )

    thanks !
    No, it doesn't.

    The Leica 70mm is a 56mm equiv on the S
    The Contax 35mm is a 28mm equiv on the S

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