I've recently started to get interested in C mount (CCTV) lens, for they are fast, wide, and cheap. So I wondered, is there any CCTV lens that I could use as a Fisheye (and get the same effect as the Panasonic 8mm f3.5, but faster) ? Here's a few lens I've found looking on the internet :

• Rainbow 3.5mm 1.6

• Tamron 4-12mm 1.2

• Pentax 6mm 1.2 (+ wide conversion lens x0.45)

Wanted effect :

The GH2 exact m4/3 sensor crop is x1.86.

So I would like to get the same widness as the Panasonic 8mm or any 8mm Fisheye (Samyang, Peleng, Rokinon...) :

Panasonic 8mm : 8 x 1.86 = 14.88mm equivalent (no need for ETC mode)

Rainbow 3.5mm : 3.5 x 1.86 = 6.51 -> 6.51 x 2 = 13mm equivalent

Pentax 6mm : 6 x 1.86 = 11.16 -> 11.6 x 2 = 23.2mm equivalent -> 23.2 x 0.45 = 10.44mm equivalent

x 1.86 : GH2 Sensor Crop

x 2 : ETC tele conversion mode crop (to cover vignetting)

x 0.45 : Wide convversion lens

Does that mean we could use any CCTV c mount lens instead of the Panasonic lens to get the wide fisheye effect ?

A few videos :

Lenses :

• http://www.ebay.fr/itm/Varifocal-Manual-Iris-CCTV-Lens-4-10mm-C-Mount-2-Mega-Pixel-VF-MI-4-10-C-2MP-/121077583241?pt=UK_CCTV&hash=item1c30c94d89

• http://tinyurl.com/qx3utvp

• http://www.ebay.com/itm/DV3-4X3-8SA-1-LENS-1-2-3-8-13MM-VARIFOCAL-MANUAL-IRIS-/150585299071?

C mount lens (1/2") work well on the GH2, but I heard that the CS mount lens (1/3") would still have really heavy vignetting because even with the ETC mode it would not cover entirely the GH2 sensor. Is that true ?

Interesting CS mount lens, but 1/3 inch : http://www.ebay.fr/itm/TAMRON-Manual-Iris-CCTV-Lens-3-0-8mm-1-1-0-ASPHERICAL-C-Mount-3-Mega-Pixel-/261248954560?pt=UK_CCTV&hash=item3cd3a6b0c0

I would use the fisheye to film Skateboarding.

Thank you.