Wide converter for Fuji F10

[Mark]

Mike W has pointed me in the direction of the INON website, where they advertise an AD adaptor to fit a Fuji F10 underwater housing. I have just had a long conversation about the AD adaptors, as INON states that you cannot use a standard tray, only the INON tray if you use their adaptor. It was recommended that I went for something that had a 67mm thread on it, although there is nothing available for the F10 housing.

Has anyone had experience of using the INON AD adpator on any other tray? Do they fit/can they be made to fit?

Has anyone found some sort of adjustable base that will allow a 67mm threaded adaptor to be moved so that it would fit any camera? That would save a lot of people a lot of money. Or an adaptor that looks like it could be easily modified to fit other camera housings?

[Mark]

Not going to go the way of the AD adaptor, I'm going to change to an Ikelite housing and then get a 67mm adaptor for that.

New question, it might sound silly to you, but I have no idea.

What is the difference between the lenses used above water and the lenses used underwater?

[TimIngmire]

Hi Mark,

I have an Inon 100 WAL with a 67mm Thread for sale if you want it. I also have a lens dock (with two sides) to take the wal and a macro lens when you don't want them attached to the housing.

PM me if you're interested.

Tim

[KenByrne]

Originally Posted by Mark

What is the difference between the lenses used above water and the lenses used underwater?

Not sure I understand the question but here goes.

Lenses work by refracting the light at the interface between the glass and the air or water. Refraction depends on the refractive index of the material. Water has a refractive index much closer to glass than air does. This means that there is less refraction at the water glass interface than there is at a water air interface. On the Nik V I had a wide angle lens that would not focus in air because it was designed for use in water only. The Nikon 35mm lens that came as standard would focus in air. It managed this by having the actual front element of the lens behind a flat glass port. This meant that the lens was actually focusing in air. I'm not sure of the construction of the Inon lens. It may be a lens behind a dome port or a lens designed for focusing in water. When you use lenses behind ports you either use a flat port, in housed cameras this is usually used for macro as it gives a narrow field of view and brings the apparent image about 1/3 closer, just like a mask. For wide angle lenses a dome port is used to maintain the field of view. This creates a lens effect which results in infinity being about 12 inches or so. This is why for wide angle with housed cameras you need to use a diopter or a very close focusing lens.

[Mike W]

Wide converters work by reducing the focal length of the lens to which they're attached.

The Inon has a conversion factor of 0.56x, so the 32mm lens on your Fuji becomes about 18mm, which is very wide indeed. But, as Ken pointed out, the refractive index of water is much greater than air, so underwater the effective focal length will be about a third more, 24mm, which is still pretty wide.

Inon also sell a dome that can be attached to the front of their lens so, again as Ken said, you can retain the full 18mm effective focal length. Nobody else but Inon offers domes for converter lenses as far as I'm aware.

(Note: Focal lengths are 35mm equivalents!)

[Mark]

Thanks Ken and Mike, thats explained it, as I have said before I am not a photographer, just a diver that takes photos.

Tim pm sent.

[Cussy]

I've got an Epoque wet WA lens and this reduces the 28 mm so much that I get a lot of vignetting:


My understanding is that with the dome on the Inon, you wouldn't get this. But I quite like the effect anyway
Rob