adamroberts wrote:Erik Swan wrote:If I did my math correct, would give an ~10.4mm equivalent on APS-C DSLR's, even wider than the Tokina 11-16 at its widest (5.5mm * 3.02 = 16.61mm Full Frame equivalent / 1.6 = 10.38mm APS-C equivalent).
I believe you are doing the math wrong.
Focal length is a mathematical standard. It has nothing to do with the sensor size.
5.5mm C-mount would be 5.5mm on a Full Frame DSLR. It would however not cover the sensor as it's designed for a much smaller sensor.
Putting that 5.5mm on an ASP-C or Super35 camera would give you the equivalent field of view as if you were using about an 8.8mm on a Full Frame DSLR. (1.6x Crop Factor)
Putting that lens on a Super16mm camera would give you the equivalent field of view as if you were using about a 16.5mm on a Full Frame DSLR. (3x Crop Factor)
So that lens on the BMPC would be like shooting with a 16mm on a Full Frame and 25mm in a Super35mm.
Actually, I think I'm doing the math right. We've both got the same result for a Full Frame - putting the 5.5 millimeter on a super 16-sized sensor gives the equivalent field of view as if using a 16.5mm lens on a Full Frame DSLR. However, I believe you're wrong when you say it would be equivalent to a 25mm lens on Super35/APS-C. This would mean that the Super35 format is
larger than a Full Frame DSLR, which it's not.
The correct calculation is 5.5mm * 3x crop factor = 16.5mm equivalent field of view on full frame. Then assuming we have a 16.5mm lens on a full frame DLSR (same FOV as the 5.5mm on Super16), what lens do we need to get the same FOV on APS-C/Super35? Well, those are 1.6x crop factor, so
divide by 1.6 x, and you get:
16.5mm / 1.6x crop factor = 10.3mm equivalent field of view on APS-C. This can be confirmed by using
Abelcine's FOV tool, which shows a 2x crop factor from APS-C to Super-16 (so, 2 * 5.5mm = 11mm, close to what we calculated).
So, a 5.5mm lens on Super-16 is equivalent to a 10.3mm/11mm lens on an APS-C DSLR like the T3/4/5i or 7D. However, Julian brought up a good point that that 5.5mm sensor I was looking at may have been designed for a smaller sensor, not 1", so it might not cover the pocket cinema camera's sensor.
This means our next best option (actually, pretty much only modern option) would likely be the
Panasonic 7-14mm micro 4/3. Unfortunately it's f/4.0. This would give an equivalent FOV of:
7mm * 3x = 21mm for Full Frame
7mm * (3x/1.6x) = 13.1mm equivalent for APS-C
Not bad I guess, that's wide enough for me for pretty much everything. Would be nice to find something faster than f/4 though.