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Let the AP team answer your photographic queries

Do you have a photographic question that you would like answered?

Be it about modern technology, vintage equipment, photographic science or help with technique-here at APwe have the team that can help you. Simply send your questions to: [email protected] or by post to: AP Answers, Amateur Photographer Magazine, IPC Media, Blue Fin Building, 110 Southwark Street, London SE10SU.

Lens coatings

Danny Madure asks I enjoyed your lens supplement (free with AP 25 April), and in particular Geoffrey Crawley's article on lens coatings. Could Geoffrey comment on the effect, or otherwise, of single lens coatings and/or uncoated lenses in monochrome film photography, where lenses with such coatings from the 1950s are sought after due to their properties in recording better shadow detail and tonal range. Is that myth, magic or fact?

There is presumably something in it when Cosina Voigtlander offers the option of single coating or multi-coating on some of its rangefinder lenses. Also, what are the implications for digital capture?

Geoffrey Crawley replies This sounds like one of those ideas that surface on the internet via the US, but in fact there is a technical basis for the preference. A multi-coated lens will pass more light than a single-coated one. so it would be expected to give better shadow penetration. In fact, it raises contrast that is especially noticeable in the highlight brightness. A single-coated lens transmits a little less light and the higher level of inter-surface reflections creates more stray light in the camera dark chamber. This has the

effect of reducing contrast by spreading light from the highlights into the shadows. At the same time, this level of non-image-forming light selectively overcomes the inertia of the emulsion in the barely exposed shadow areas, actually increasing the film's sensitivity there. The effect is to record further shadow detail. This process is known as latensification and, in days long gone, press photographers learned to pre-flash their plates and sheet film to benefit poor light performance. A movie cameraman once told me that a tiny 'peanut' bulb in the camera was once used to introduce stray light to reduce contrast and latensify film sensitivity. The effect was held responsible for some of the 'speed' of the Canon 50mm f/0.95 lens.

The procedure is best suited to black & white film since desaturation would result when using colour. There is no reason for it not to work in a digital camera as a sensor also has inertia, so there's room to experiment

Have camera, will travel

Angus Crockett asks I am travelling to Ladakh in northern India in the summer to assist in building a dormitory school with the Lotus Flower Trust. I would like to take a camera as I am keen to take some good-quality pictures, but I'm concerned about the weight of the camera. I currently own a Nikon D70, which is great, but it is heavy and bulky. I may also have problems recharging batteries as there is no constant electric supply. Should I consider a film camera that relies less on batteries?

Zenit: recycled tanks?

Trevor Pointing asks I enjoyed reading the £50 Challenge in your second-hand issue (AP 9 May), particularly Richard Sibley's tale of the £5 Zenit TTL camera. I found the comment about it being 'built like a Soviet tank' very interesting, as I have heard a rumour that they were built from the recycled metal of Soviet tanks. Is this true?

Ivor Matanle replies All Zenit cameras are substantially built, but I think you can rely on their having been conventionally manufactured from normal raw materials. All Zenit (and Zorki) cameras were made by Krasnogorski Mekhanischevski Zavod, usually known as KMZ, in Moscow. During the Second World War, the factory made optical devices for the Soviet Army, then concentrated more on consumer goods such as cameras in the postwar period. Similarly, Kiev cameras are produced in the Arsenal Factory in Kiev, Ukraine, which was founded in 1764 as a munitions and repair factory for the Russian army. During the Cold War they developed optical items for the military and space programs. It is probably from these facts that the tales of Russian cameras being built from tanks arise.

The earliest Zenit SLRs were adapted from the Zorki rangefinder (Laca lookalike) camera. The earliest Zenits even used the same baseplate as their contemporary Zorkis. A Zenit that is /^m regularly serviced could be a very reliable, ■■<> ? ^^ if rudimentary, SLR. The problem was r ' w . that in western Europe they were I Wi _ ^ - —

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that in western Europe they were heavily subsidised and cheap to buy, and nobody would pay for proper servicing of a cheap camera. Therefore, virtually all have declined into non-serviceability.

Richard Sibley replies In terms of power supply, you may wish to buy a battery charger, such as the FreeLoader Pro solar-powered battery charger, which is reviewed on page 49 of this issue. It should allow you to recharge your battery every day, provided it is left in sunlight for between six and nine hours at a time.

If size and weight are a major concern, I would recommend the Canon PowerShot G10. It received an impressive 76% when reviewed it in AP 22 November 2008. With a raw shooting mode and full manual exposure control, you should be able to capture some excellent pictures. As for size, it is large for a compact camera, but its

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