Underwater Photography

Contents a web magazine Dec/Jan 2003/4 e mail [email protected]

21 Digital Galapagos 30 Ligpo nudibranchs 40 Moment of truth

by John Belchamber by Muchael Aw

26 Digital reality

with Nonoy Tan

34 Scorpionfish with Alex Mustard

by Mark Webster by John Belchamber

43 Back to basics by Peter Rowlands

46 Book reviews by Peter Rowlands

Cover shot by Amos Nachoum

Editorial

Nikon D70

The imminent arrival of the Nikon D70 digital SLR is a significant event in the world of underwater photography. Its sub $1000 price tag will offer an attractive proposition for Nikon SLR film users who are considering a move into the digital world.

Nikon SLR cameras are the most widely used housed cameras underwater. This is due mainly to the TTL flash compatibility with Nikonos strobes which many underwater photograpers already had in their armoury.

For those Nikon film users, the new D70 can use their existing lenses albeit with a 50% increase in focal length to produce image quality which is knocking on the door of a direct replacement for film.

The long term savings on film and processing will pay for itself after just a few trips abroad and the pure enjoyment of digital simlicity and immediacy of results is very exciting indeed.

I feel sure that cameras like the D70 will open up digital photography underwater to a much wider audience and this can only be good for underwater photography.

Rugby World Cup

I know this has got nothing whatsoever to do with underwater photography but I prey your indulgence because it does explain, in part, why this issue of UwP is a bit late.

Firstly, to all our Australian readers, thanks to your great country for hosting such a fantastic Rugby World Cup and secondly commiserations on the outcome. No one likes to lose (especially to the Poms, I guess) but the finale of the tournament was as exciting a game as we are likely to see for a long time. Two great teams locked head to head for 100 minutes divided by one last minute moment of elation for the English and despair for the Australians.

The other reason for mentioning the Rugby World Cup is that it explains why this issue of UwP is a tad late. Add a trip to Manado around the time when UwP 16 should have been finalised and you have both of my excuses.

I promise it won't happen again for another four years!

Peter Rowlands

Underv/^ter Photography is published by PR Productions 13 Langley Avenue, Surbiton, Surrey KT6 6QN Tel & fax 00 44 (0)208 399 5709 e mail [email protected]

What links these sites?

London's premier watersports centre 11 - 14 Northumberland Avenue, London, WC2N 5AQ Tel: 020 7930 5050 Fax: 020 7930 3032 email: [email protected] www.oceanleisure.co.uk

UK Aquatica woe

I read the test of the new Aquatica S2 housing in issue 14 with interest. As a Mechanical Design Engineer working in the opto-electronics industry, I have long admired the quality of Aquatica's aluminium housings and the design philosophy built into sealing the controls, ports, etc,. I have owned an Aquatica 80 for some few years and built up a sizeable portfolio of images from various locations, at home and overseas.

I wonder, however, how many of your U.K. readers and potential Aquatica owners are aware that Aquatica are not represented in this country. When I purchased my housings and ancillary ports, strobes, arms etc., from The Image Centre in London, spares were easily available, usually off the shelf. However, since Aquatica were acquired by Nikon USA, spares for Aquatica housings in the U.K. have become extremely hard to come by. The nearest retail outlet for spares is now Spain. Cameras Underwater Ltd in Devon will place orders for spares with the Spanish agent but even a small order such as an o-ring service kit will take a few months to arrive.

If this letter prompts Nikon U.K. to address this matter to the obvious benefit of Aquatica owners, then something will have been achieved. In the meantime, if anyone is

Readers Lives contemplating the purchase of an Aquatica housing, beware - sooner or later you are going to need spares, if only just an o-ring, and these will take months to arrive!

Robin Nash [email protected]

Focal length v Angle of view

In your Back to Basics article you seem to have confused the term focal-length with angle-of-view.

The focal length is the distance between the rear node of the lens and the point of focus when the lens is focussed on infinity. Focal length is often used as a guide to angle of view but this can be misleading. For example, digital cameras with chips smaller than the normal film-size frame appear to give a certain telephoto effect.

The angle-of-view depends on the image-circle produced, the magnification and the medium in which it is used (normally air.)

I have a 165mm Super Angulon lens

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with a wider angle of view on my Sinar than the 20mm Nikkor lens on my Nikon behind a dome port.

How can this be? The image circle of the 165mm lens has a diameter sufficient to cover a 10x8 inch sheet of film (and allow a range of technical camera movements too). The 20mm lens on my Nikon behind the dome port covers only a 35mm frame. Of course, would it be possible to fit the 165mm wide-angle lens to the Nikon it would only use an area of the film the same as any other 165mm lens and not give a wide-angle effect. However, on the Sinar it is certainly a lot wider.

So the reason that Nikon give the focal lens of its Nikonos lenses in the form that it does, is because that is exactly what they are. For an accurate angle-of-view check the spec. for exactly that - not the focal-length.

I hope that is the explanation that has evaded you.

Best wishes, John Bantin [email protected]

Many thanks for your explanation John and I must say I have been sleeping a lot better ever since. I have just checked my article and noted that I wrote "the angle of coverage is the most important factor in evaluating lens performance".

Regards Ed

for Canon 10D and Nikon D100 Digital Cameras

r

Jonah Housings

Digital Camera and Digital Photography

Digital Camera and Digital Photography

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