Elcan Underwater Lens

[pgk]

Advertisement (gone after registration)

If you look at leica.overgaard.dk - Thorsten Overgaard's Leica Pages - The Leica History - Page 2 you will see details of an underwater M housing with a 90 degree f/2.8 lens fitted into it. I am curious about this lens as it is described as a 28mm f/2.8 lens on the page but this does not correlate with it being a 28mm as it would require a 20mm lens to give a 90 degree field of view (on land). Does anyone have any further information on this or any other Elcan underwater lenses by any chance?

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[giordano]

Maybe it's based on a standard 28mm Elmarit with additional elements in front that work like the wide angle converters made for various fixed lens cameras and videocams. Thanks to the different refractive indexes of air and water, lenses in general give a narrower angle of view underwater - though AIUI to a lesser extent when a lens is specifically computed for underwater use with its front element exposed to the water.

 

Nikon made a couple of underwater-only lenses. The 15mm UW-Nikkor was stated to have a 94 degree angle of view versus 78 degrees for the 20mm.

[pgk]

Thanks John

 

You've made me realise that if it is actually a 90 degree FOV then the effective focal length (in water where it would have to be measured) is probably more like 15 or 16mm, similar in fact to the Nikonos 15mm (which is a 15mm focal length lens underwater AFAIAA, but actually gives a field of view nearer to a 20mm lens on land as you point out). I'm intrigued because I doubt that its a modified lens or one with increased elements as this would be a compromise and I'm doubtful that Leica would have made such a compromise? Elcan are supposed to be one of the few manufacturers to have designed true underwater lenses.

[luigi bertolotti]

I think that maybe there is simply a not precise statement in the text : the 28mm focal length appears nowhere on the lens in itself... from the pictures, it looks simply engraved "90°/ f 2,8" and with one of the typical s/n of Elcan lenses (totally unrelated to the classic Leitz numbering of lenses). So could be it is NOT a 28mm, but a focal around 20mm.... maybe even a design related to the first Elmarit 21, which, if I remember correctly, was still a Canadian design.

Edited March 17, 2011 by luigi bertolotti

[giordano]

I'm intrigued because I doubt that its a modified lens or one with increased elements as this would be a compromise and I'm doubtful that Leica would have made such a compromise?

 

Also, the front element looks too small to be an extreme wide angle converter on a moderate wide angle lens. I made that suggestion just in an attempt to "save" the suggestion on the web page that it was a 28mm lens. If we ditch that I agree that it needs to be 16mm or thereabouts.

 

Even then, however, it's possible that the design incorporates the back half of an existing design (e.g. 21/2.8) with a new front half computed to give the same angle of view in water.

[Martin K]

In a Color Foto magazine (German) of many years ago - unfortunately I kept only the article and not the date of publication - a picture of three ELCAN lenses for underwater photography was shown. They are a 28.64mm, a 13.25mm and a 6.64mm lens - very precise these numbers! The 90 degree lens could therefore be the 13.25mm. No other information was given in the text, other than a note that these lenses had to be used with a spherical dome to deliver their full potential.

Kind regards, Martin

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[Martin K]

Advertisement (gone after registration)

I have found some additional information in the article I mentioned in the previous post. The auther says that ELCAN had the following underwater lenses for 35mm film:

1:4/21mm, underwater angle 76 degrees

1:2.8/15,3mm, underwater angle 90 degrees focussing down to 10cm

They also had lenses for 6x6 film, namley:

1:2.8/45mm, underwater angle 67 degrees

1:4/30mm, underwater angle 90 degrees focussing down to 23cm

 

The picture (previous post) shows something else though, and these may be special lenses for 16mm film cameras which ELCAN also manufactured.

Kind regards, Martin

[luigi bertolotti]

Thanks Martin, very interesting and intriguing infos. I agree that the picture you posted probably shows lenses that are not for 35 mm format : indeed the proportions don't fit well, and a 6,64mm, to cover 35mm, ought to be a sort of microphotography lens (like the Leitz Photars) . On the contrary, it could be well reasonable that the lens shown onto the Leica M underwater housing in Dennersten' site is the 15,3mm f 2,8 you quote.

 

The focal lengths of the lenses you depicted ar really "strange"... even translated to inches there's nothing round... but maybe, if they are really for 16mm as you suggest, they can be related to some "standards" for 16mm cine...

Edited March 18, 2011 by luigi bertolotti

[Martin K]

Luigi,

The article in Color Foto was all about how lenses behave under water, i.e. plane glass versus glass domes to protect the lenses, Ivanoff ports, Nikonos and Sea & Sea lenses, etc.. The picture caption very specifically mentioned that these three ELCAN lenses are for underwater use. Maybe the “funny” focal lengths has something to do with the refractive index of water which is approximately 1,33 as against 1,00 of air. ELCAN manufactured lenses for military customers for 16mm underwater film cameras, and these in the picture could very well be such ones rather than for civilian use. This could also explain the very precise markings.

Kind regards, Martin

[pgk]

Thanks Martin

 

Very useful information. I'm intrigued to hear that the lenses needed to be used behind a spherical dome port (the Nikonos 15mm includes a spherical dome incorporated as part of its design). And thanks for posting the images. I'll keep looking for more info though having seen this.