Wide angles?

[Mark]

I bought a second hand Inon 100 WA lens. I have had some nice results, I will be playing with my new strobe with it soon too. When I see reference to a fisheye 10.5, I have no idea what that means in relation to field of view. My Inon 100 has a 100 degree field of vision underwater.

Inon also make a dome port to increase the 100 degree to 131 degrees. Would this be a worthwhile upgrade? (CU £350, an expensive upgrade)

[johnny boy]

Your Inon 100 degree w/a equates to a 20mm lens i beleive. The nikon 10.5mm gives the user 15mm fisheye. The 131 degree add on lens for your existing 100 degree would give you even more wide angle, but more difficult to light with a single strobe.

[TimIngmire]

Mark the 10.5 gives 180 degrees coverage corner to corner which is pretty damned wide - it's taking some getting used to to be honest.

[Mike W]

I'm a bit sceptical about the claims for 100 deg underwater. These converters are all about 0.56x, almost halving the focal length of the lens to which they are attached. I think your Fuji is a 32mm, Mark, so effective focal length after the converter is added is 18mm, very wide, but underwater refraction adds a third, so you end up with a 24mm lens, wide but not superwide.

Adding the dome restores the full wide angle effect and will give you the 18mm equivalent. To see the effect take a pair of shots above water, one with and one without the converter. The effect undewater will be about halfway between the two.

I'd second Tim's comment about the fisheye taking some getting used to, the problem is the apparent curvature of the subject and just how much of those 180degrees is near the edge or corner.