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Thread: Using the Zeiss Touit 12mm on a Sony A7r.

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    Using the Zeiss Touit 12mm on a Sony A7r.

    The lens I've been using on my infrared converted NEX 7 for the past year has been the Zeiss Touit 12mm which in turn gives me about 18mm in full frame. I wondered yesterday what that same lens would produce on the Sony A7r.

    First some comparisons. My NEX 7, IR produces files that are 6000x4000 (350 ppi 16 bit RGB, 137.40 MB). Likewise my A7r (using a 35mm 2.8 or 55mm 1.8) produces files that are 7360x4912 (360 ppi, 16 bit, RGB, 206.90 MB). So what happens when I use the 12mm on the Sony A7r?

    The Sony A7r has the ability to automatically switch between APS-C and full frame lenses ( menu, second from top left looks like a wheel then over to the 5th screen and second down to APS-C Size Capture which offers the choice of On-Auto and Off my camera is normally set to auto). What this does is offer the choice of shooting an APS-C lens like the Zeiss Touit 12mm either in a cropped mode or full size. The full size will of course produce vignetting which can then be cropped out; but is it worth it...


    12mm APS-C Size Capture "Off"


    Crop of the file above


    APS-C Size Capture "Auto"

    I resized each file to better fit the web to 9x6 at 100 ppi. Both files were shot at f/2.8 1/100 ISO 400 handheld.

    This was just a fast test last night to answer my own question of how well the Zeiss Touit 12mm would play with my Sony A7r and if it was worth the added effort of shooting with the APS-C Size Capture turned off. My short answer is yes it plays well and no I'd just as soon keep the APC-S capture on auto.

    Forgot to add the aspect ratio was set at 3:2. Questions?
    Don Libby
    Iron Creek Photography
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    Tucson AZ
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    Re: Using the Zeiss Touit 12mm on a Sony A7r.

    There's a baffle in the touit lens, I wonder what happens if it was removed.

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    Re: Using the Zeiss Touit 12mm on a Sony A7r.

    I also want to know

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    Re: Using the Zeiss Touit 12mm on a Sony A7r.

    How many megapixels are you left with?
    I am not a painter, nor an artist. Therefore I can see straight, and that may be my undoing. - Alfred Stieglitz

    Website: http://www.timelessjewishart.com

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    Re: Using the Zeiss Touit 12mm on a Sony A7r.

    Quote Originally Posted by ken_vs_ryu View Post
    There's a baffle in the touit lens, I wonder what happens if it was removed.
    Interesting concept and a potentially expensive one. Since this lens normally lives on my NEX 7 IR body I'm unwilling to open it up.
    Don Libby
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    Re: Using the Zeiss Touit 12mm on a Sony A7r.

    Quote Originally Posted by Ben Rubinstein View Post
    How many megapixels are you left with?
    Ben, as near as I can tell you're down to 10 megapixels. I look at this as being much the same as if I need to shoot sensor-plus with my IQ160. Reduction of resolution in order to capture an image. With a full 36 I can print just about any size I want however down to 10 I don't want to go much ( if at all ) beyond 11x14.

    Don

    The baffel idea has merit only I'm too chicken to open up a perfect lens to find out
    Don Libby
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    Re: Using the Zeiss Touit 12mm on a Sony A7r.

    Quote Originally Posted by Don Libby View Post
    Ben, as near as I can tell you're down to 10 megapixels.
    That doesn't seem right, if your camera is an a7R. The manual says you get 15mps in APS-C mode, so your in-between setting should be more than that.
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    Re: Using the Zeiss Touit 12mm on a Sony A7r.

    Went back to the same images and Mike is correct.

    35mm (Sony Sonnar T* FE 35mm f/2.8 ZA Lens) produces a 7360x4912 file or 36.15 megapixel

    Using the Zeiss Touit 12mm f/2.8 the files are...

    APS-C on auto - 4800x3200 or 15.36 megapixels

    APS-C off - 7360x4912 or 36.15 megapixel but how much of it is usable?

    Cropping the above image to a usable file gives a file 5352x3360 or 17.98 megapixel.

    Your mileage may vary...


    Don
    Don Libby
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    Re: Using the Zeiss Touit 12mm on a Sony A7r.

    18 megapixels is not half bad!
    I am not a painter, nor an artist. Therefore I can see straight, and that may be my undoing. - Alfred Stieglitz

    Website: http://www.timelessjewishart.com
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