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View Full Version : Sigma 4.5mm 2.8?



Craig
09-05-2012, 07:35 AM
Does anyone have any experience/thoughts on the sigma 4.5?
I wondered whether the bmcc crop would fit the circular fisheye and make this a useable but well distorted ultra wide?

Craig

Jason M.
09-05-2012, 09:54 AM
I'm pretty sure that the image circle on the Sigma is 12.3mm in diameter, which means it won't cover the sensor, which is ~15.6mm wide. Black curved bars on either side, though if you can find a way to make it work, it might look really interesting.

Craig
09-05-2012, 10:34 AM
I wonder if that difference falls within the difference between 2.5k raw frame and 1080? If you get me?..could crop without loss in resolution. Would be nice, also with such a wacky lens the circle would look cool for all sorts of purposes like docs n music vids.

Jason M.
09-05-2012, 10:54 AM
Well, it looks like it'll still come up a bit short even if you took a center 1080p crop from the 2.4K raw frame. Would be some pretty serious vignetting. Also, remember with the way a Bayer pattern sensor works, you'd still be losing effective resolution by taking a sensor crop.

Still, if you have a copy of the lens, or know anyone who does, you can always pop it on the BMCC and shoot some to see what it's like. Worst thing that happens is it doesn't really work well, and you know in future what to expect from that lens.

Craig
09-05-2012, 01:50 PM
Thanks Jason.