Hi, guys—Kendo from TeamRokit, Intl. / RiceRokit, here.
Been asked by our esteemed UK colleague and bredren Saxon Rix, to repost my recent, Kinefinity Cinema Cameras, Facebook group ‘rantings of a madman,’ here in the forum—also regarding KineMINI 4K sensor size, and crop-factor:
As many of you might already know, crop-factor is actually calculated by dividing the DIAGONAL measurement of a 35 mm-based, full-frame sensor (1x crop-factor—43.3 mm diagonal on the Canon 5Dm3), by the diagonal measurement of the lesser camera.
* Now, since the diagonal of a rectangle is calculated by taking the square root of: the sum of the height squared, plus the width squared—I quickly jotted down the figures from some of the sensors in question:
• Canon APS-C sensor diagonal measurement is generally 26.82 mm—if you do the math and divide the full-frame 43.3 mm diagonal by this, you’ll get roughly the 1.6x crop-factor that’s advertised.
• Micro four thirds sensor diagonal measurement is 21.64 mm—comes out to about that 2x crop-factor that Vincent mentioned previously.
And lastly, * again, JUST ASSUMING the (22 mm x 12 mm) sensor specs Kinefinity emailed me are true:
• KineMINI sensor diagonal measurement is 25.06 mm—so that would be about a 1.7x crop-factor, which is pretty much comparable to the generally advertised ‘Super 35’ size sensors, in the market…
*** LAST POINT that I think must be remembered when testing this crop-factor in the real world—close attention probably should be given to comparing differences in BOTH HEIGHT and WIDTH of images, as APECT RATIOS of sensor imaging areas, of course differ!
The KineMINI’s sensor imaging area is cropped a bit ‘wider’ (as in, narrower aspect ratio) than an APS-C sized sensor’s imaging area, so while things may be cropped out on the top or bottom, we may be able to get more image near the sides of the frame.