Micro-Four Thirds Blackmagic Cinema Camera - Shipping December

Barry_Green said:
it opens up the possibility that you could use the 17.5/f0.95 Voigtlander, which is nearly four stops faster than the ZF 18/3.5 lens, so -- when you want fast & wide, the m43 version provides a path to get it, that the EF version will likely never offer.
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That's a very good point. Also makes purchasing a m4/3 lens of that type more legitimate as I'm either going to be GH3 or BMC here in the future.
 
I used to reverse the 20/1.7 for macro shooting... the iris stays where you set it (on that lens, at least)


Barry_Green said:
-- when you want fast & wide, the m43 version provides a path to get it, that the EF version will likely never offer.
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Also the (rumored) Voigtlander 12/0.95, SLR magic 12/T1.6, the series of Navitar 1" and 4/3" C-mount primes in f2 and f0.95, and mostly the wide array of fast, wide C and PL 16 and S16 glass that 'almost' covers the sensor on m43, and would do just a little better on the BMCC (for instance, the Kern/Switar 16/1.8)...

I have no practical reason whatsoever to get one, but it was a very very smart move to offer a different mount.
 
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Barry_Green said:
Yep, focus is a big no-go. On a dumb mount, you will not be able to focus a Lumix or Olympus lens. You can zoom, and you can carry the iris over from another body, but you can't focus or change iris when the lens is mounted on a dumb mount.
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The Lumix 7-14 might still be a (expensive for the practical utility) option... set iris somewhat small and set focus for ~1m, then roll away with nearly infinite focus
 
Just tried it. According to the DOF calculator, at f/4 and 7mm, you get DOF from 1.3 feet to infinity.

Zoomed to 14mm, not so much... you only get about 1.5 feet of DOF. But as a hyper-wide-angle fixed-focus, fixed-iris 7mm f/4 lens, it does work...
 
I don't know how that DoF calculator that you used is programmed, but I know mine (http://www.similaar.com/foto/dof/dof.php?f_x=2.3&f_r=1.77&f_mm=7&f_f=4&f_d=1.3) would not be accurate. The most common formulas for DoF calculation (http://en.wikipedia.org/wiki/Depth_of_field#DOF_formulas) are linear approximations that become inaccurate at low focal lentghs, short focusing distance, etc.

But you can actually test it: put your lens at maximum aperture, switch to 10x focus-aid magnification (I guess Panasonic must have something like that too), focus at 1.5m, and start closing down aperture until you're happy with focus at infinity.
 
When I experimented with C-mount lenses on the GH1, I think the widest lens I could use without vignetting was a 26mm lens. With the BM camera having a slightly smaller sensor than MFT, I wonder how much wider lenses could be before vignetting?
 
TrueIndigo said:
When I experimented with C-mount lenses on the GH1, I think the widest lens I could use without vignetting was a 26mm lens. With the BM camera having a slightly smaller sensor than MFT, I wonder how much wider lenses could be before vignetting?
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Have a look at the test shots of the noctor 12mm f/1.6 at the link:

http://www.photozone.de/olympus--four-thirds-lens-tests/685-slrmagic_12_16?start=1

Vignetting on the BM should be pretty much gone, at least should have much improved. If I did the maths right, a 12mm lens on the BM should be equivalent to 28mm so that still would be a nice wide angel lens.
 
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Thanks for the link, Joe, interesting. I was wondering about C-mount image circle coverage on the BM sensor.
 
TrueIndigo said:
Thanks for the link, Joe, interesting. I was wondering about C-mount image circle coverage on the BM sensor.
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C-mount lenses are specified for different sensor sizes from 1/3" up to 4/3". Models designed for 1" and 4/3" format sensors will cover the BMC.
 
Thank you. The C-mount lenses I have date from the 16mm and Super-16mm movie era. I've always kept them in the hope of using them again some day!
 
Thanks for that comparison graphic, Joe -- 12.52 x 7.41 mm for Super 16mm versus 15.6 x 8.8 mm for the BM camera. Might be a good fit for Super 16mm lenses (if you crop for CinemaScope that would probably lose any slight corner vignetting).
 
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