Newbie with wide angle question

[rab9361]

I am relatively new to underwater photography, but have really enjoyed the experience so far. I want to experiment with a wide angle lens on a Fantasea housing with a 46mm thread. I have seen numerous wide angle lenses with a variety of prices. My question is : Is it necessary to use a lens specifically designed for underwater use or would a "standard" lens do the same job as long as there were provisions to allow water inside the lens?

Roger

 

[Nemrod]

No---you cannot attach a standard surface use lens to a camera housing and go underwater with it. Is this a serious question?

Nto

 

[rab9361]

Yes. Sorry, but it was a real question. I mentioned I was new to this, so I am unaware of the diffrences. I assume it must have something to do with the refractive properties of water as discussed in the open water & advanced classes?

 

[butchpalmer]

No it has to do with damage to the lens itself. You need a lens that is for underwater use if it goes on the outside of your housing. These lens are sealed against water getting inside of them.

Butch

 

[Nemrod]

Well, why bother with an underwater lens, why bother with a housing or underwater camera, just go buy a camera and jump in with it and watch it flood with water. A camera lens is designed for surface use only and would be seriously damaged beyond repair by jumping into saltwater as would be the camera it is attached to. No, no, you cannot take a Canon or Nikon camera, stick a lens on it and jump in the ocean, both the camera and the lens would be flooded with water and would be ruined forever beyond repair.

There are some special made "wet" lenses. These are made by Inon among others and require adpaters or threaded ports depending upon the specific camera and housing unit. There is no way to mount a Nikon or Canon slr lens to the outside of any "point and shoot" or slr housing. A slr housing will accept the lenses on the INSIDE of the housing attached to the camera where they belong, protected from several atmospheres of saltwater, sand and other hazards.

N

 

[rab9361]

Obviously I can't ask any stupider question than the first one. So... Can the other sizes (52mm - 67mm thread) "underwater" lenses produced by other manufacturers be used with an adapter on the 46mm threads on the outside of the Fantasea housing or will the adapter cause problems with focusing?

 

[Nemrod]

Obviously I can't ask any stupider question than the first one. So... Can the other sizes (52mm - 67mm thread) "underwater" lenses produced by other manufacturers be used with an adapter on the 46mm threads on the outside of the Fantasea housing or will the adapter cause problems with focusing?

No, but there may be step up rings available. Fantasea is not very supportive of wet lenses. They may have their own brand, check their web page.

N

 

[Larry C]

You can use a step adapter to install a larger lens. You might need two. On my housing, also 46mm, I adapted a Sea & Sea 16mm lens designed for a Nikonos V. I needed a 46-58 step ring. It's not the greatest set-up, as I have to zoom a bit to avoid vignetting (a rounded frame on the corners of the picture). It also doesn't focus as close as some of the dedicated lenses such as those Inon makes. For about $100 on E-Bay though, it has been quite acceptable and I've taken some decent pictures with it. You didn't mention which camera you were using, but if you do you'll probably get more specific help with lenses.
You were correct, by the way about water's refractive qualities. Besides being designed to withstand the pressure of diving to depths of up to 100+ feet, wet lenses have air space inside, where most of the work is done. I think this applies more to macro lenses than wide angles, but the refractive index of water affects both.

 

[Nemrod]

Yeah and in addition to a conventioanl lens flooding and being ruined and many other issues even if it were possible the lens would cease to function correctly. The refractive index of the lens glass and air are different and thus the lenses are able to bend light ultimately into focus upon the film or sensor. If the lens were flooded water would be on both sides of the lens elements, water has a similar defractive index to glass and therefore the light would no longer be bent or focused as designed by the optical engineers. Wet lenses are sealed thus preserving the defractive difference between the lens elements and the interior gas or liquid.

It was not that the question was stupid, well, why do you think people spend thousands on special housings and lenses for their terrestrial cameras if all you really had to do was jump in the water and snap away. President Bush probably new and it was a conspiracy all along to defraud scuba divers of billions of dollars.

Good luck, hope you get it all figured out to a useful conclusion.

N

 

[JackConnick]

Hi;

There are no stupid questions. We all were new to this sport and hobby at one time and it is complicated in many aspects.

So to your question. The Fantasea WAL-02 lens is what you need for your housing. It sells for $225 and is quite good quality, as good as the similar Inon lens, almost identical, and yes I've used both of them. The Inon won't fit anyway. Other solutions that require an adapter may vignette (or cut off the corners slightly), not really a big deal as you can zoom in slightly.

It can be taken on/off underwater. There is a holder for it if you have a strobe arm or a leash if not.