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Thread: Cosmicar 1.4/12.5: so whats the kb equiv after cropping?

  1. #1
    JanJordan
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    Cosmicar 1.4/12.5: so whats the kb equiv after cropping?

    Bought a Cosmicar TV lens with f1.4 12.5mm. I did expect it to vignette quite a bit but i figured that i would still get a useable wide angle lens after cropping, maybe equivalent to 35mm on 35mm film. After modifying it to fit into my c-mount adapter (had to file down quite a bit) i decided to compare it to my G1 kit lens at wide angle. I remember that the effective focal length of such a lens has been discussed here already without any real conclusion.

    standard cat lens coverage test. This is an uncropped image, as you can see cat disaproves:



    This is the kit lens at 14mm:



    This is a 4:3 crop of the cosmicar image at roughly f5. The kit lens is sharper, but i am not sure if i reached infinity focus completely either. This is shot is mostly to see how much softer the lens gets wide open:



    This is the cosmicar at wide open (f1.4) There is more darkening in the corner and it is quite soft, but i still like the result and its good enough for screen or small prints:



    The effective focal length is only slightly larger then that of the kit lens, so depending on the aspect of the crop i would say it you get a lens equivalent to 28-30mm for 35mm film.

    So here some other shots i did with it afterwards. It is quite good for moody pictures imho and should enable quite some nice low light shots (which i fancy currently). Even the cat approves now:





    Jan

  2. #2
    Super Duper
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    Re: Cosmicar 1.4/12.5: so whats the kb equiv after cropping?

    I always compose with mine for the central square, making a 9Mbyte image. That's about a 55x55 degree Field of View, minus a little bit of corner vignetting.

    It's a cool little lens and makes nice photos. I like the fact of its very short focal length and very large aperture ... gives a lot of options. Here's one of my favorite photos with it from last year:


    Somewhere I have an FoV demonstration with three frames, one with it, the 20 and the Konica 40. If I can find it, I'll post it.

  3. #3
    JanJordan
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    Re: Cosmicar 1.4/12.5: so whats the kb equiv after cropping?

    yes, i am very happy with it. Composition is imho possibly the biggest drawback, i have yet to find a good strategy here. And i need to find the time to take it on a field trip ;-)
    Jan

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    focal length - fov example

    Found it... same position, pointing the camera at similar scenes, the full frame for all three:


    The 12.5mm is nicely wide even when cropped to the central square. :-)

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    Senior Member apicius9's Avatar
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    Re: Cosmicar 1.4/12.5: so whats the kb equiv after cropping?

    This one looks really nice, much sharper toward the corners than some of the other ones I have seen.

    Stefan

  6. #6
    JanJordan
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    Re: Cosmicar 1.4/12.5: so whats the kb equiv after cropping?

    Stefan: i am fairly happy with it. Especially since the lens at first was was making clackering noises when i shook it. The front element was not correctly screwed in.

    Godfrey: it is surprising how narrow the fov of the 40mm suddenly looks and even the 20mm...

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    Re: Cosmicar 1.4/12.5: so whats the kb equiv after cropping?

    Quote Originally Posted by JanJordan View Post
    ... it is surprising how narrow the fov of the 40mm suddenly looks and even the 20mm...
    Oh yes: once your eye gets into the 12.5mm world, the 40 seems a very long lens. I only rarely use longer than that anymore: 70mm is a very long view on FourThirds to me nowadays.

  8. #8
    Member kai.e.g.'s Avatar
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    Re: Cosmicar 1.4/12.5: so whats the kb equiv after cropping?

    Until I was given the 9-18mm Olympus, the Cosmicar 12.5mm was the widest lens I owned for my E-P1 (well, I do have an Elgeet f/1.2 12.0mm, but it's pretty mushy 'round the edges of its image circle, to put it mildly). I like the Cosmicar. I mostly used it in square mode, but with certain images, it was possible to work with perspective distortions to create portrait-shaped images. Here's an example; first the original file, then the final file after messing with it.




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    Re: Cosmicar 1.4/12.5: so whats the kb equiv after cropping?

    Looks good! A creative and useful way to use warping tools. :-)

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