Cosmicar 4.8mm f/1.8 C-Mount lens.

Started Jan 4, 2012 | Discussions thread
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Tesselator Senior Member • Posts: 1,031
Cosmicar 4.8mm f/1.8 C-Mount lens.

This is a fun little toy. I got it from one of those anti-theft cameras that were in use in the 80's - you know the kind that are shaped like a flat rectangular whiskey flask? Using the 2x digital zoom on the GH1 I get perfect coverage with it. It's very sharp in the center wide open at f/1.8 and I do mean ONLY the very center! The smeary blurs proceed to get worse linearly as we go out toward the edges of the frame from there. Luckily by the time it's dialed down to f/5.6 or f/6.3 all of that is gone but for only the extreme edges - and by f/8 even those are cleared up. The lens has no focus ring at all. To get it to seat perfectly on the c-mount adapter at exactly the optimal registration distance I needed to create a gasket exactly the thickness of 1 piece of notebook paper - easily done and all that practice cutting folded paper in the 1st grade really paid off here! Here's an entire set shot with this lens set at f/5.6. A few of these are two exposure tone-mapped images where the DR was too great for my little GH1. The AOV is very close to 180˚ and I had kind of a hard time keeping my shoes out of the frame on most of these - especially the ones taken in portrait orientation. All of them were shot in fine JPeg with the digital zoom set to 2x - just so I didn't have to hand crop them even though all such images can be cropped all at once with just a mouse drag and a click.

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!-Enjoy

Panasonic Lumix DMC-GH1
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