Mirror lenses Too many people criticize mirror lenses. There is really nothing wrong with most of them. They are relatively cheap. Someone new to wildlife photography will not have made an expensive mistake if they decide not to continue. They are compact and light in comparison. My Sigma 600mm mirror lens could be carried around on an all day hike. In good sunshine, they can produce excellent shots.

Two 500mm f8 lenses compared: Tamron's SP mirror (lower) and Carl Zeiss's Tele-Tessar refracting. Both have lens hoods. The mirror lens weighs 0.575kg and is 87mm long, the refracting lens 2.1kg and is 316mm long. It focusses down to 5.8m without extension tubes, and stops down to f64 for depth of field with flash or slow speeds. The Tamron, by contrast, has a fixed wide open aperture, focuses down to under 2 metres, and is one tenth the cost!

Advantages of the mirror design	Disadvantages compared with refracting lenses
Light weight Low cost Compact dimensions Shallow depth of field Rapid and close focus Normally high contrast and flare free	Slow speed Distracting out-of-focus circles Shallow depth of field for aperture Light weight (leading to image jitter) No aperture adjustment Commonly uneven exposure, with central "hotspot"

Fast lenses

Generally , I think they are a waste of money. Consider a 300mm f4 costing $3500 new, compared to a 300mm f2.8 from the same maker costing $10500. That’s $7000 for 1 extra stop! A well known Australian bird photographer used a 400mm f6.8 for all of his stalking shots. Another photographer used the same lens to produce incredibly sharp images of certain birds using up to 2 second exposures. That was in the 1970’s when the only high quality slide film available had a slow ASA speed. Except for specific needs, the fast lenses are not necessary.

Slow lenses give good results in bright light or with static subjects. This spoonbill was frozen in action by a 300mm f4.5 lens with a 1.4x teleconverter fitted, making a 420mm f6.3 combo, yet the morning sun allowed 1/250th of a second with 64 ISO Kodachrome. [Ecopix lcs34-2]

Autofocus

Autofocus lenses have their shortcomings. I know of several photographers who switch it off most of the time. While photographing fast moving wrens on Spinifex, I could get a shot using my old manual focus Novoflex outfit, while my friend’s autofocus lens continually hunted between Spinifex stalks. Autofocus lenses have driven down the prices of secondhand manual lenses. A Leica 400mm f6.8 lens was purchased for $1200 recently. My Novoflex 400mm f5.6 outfit cost $500. The quality of these lenses are excellent. As an added bonus, if ever I change cameras, the Novoflex is designed to be used on any system. Manual lenses do not use battery power, make no noises, and have no electrical components which could fail.

Tripods

Too many people neglect to use a tripod. No-one can hand hold a long lens as steady as a tripod. I admit that grabbing a shot here and there is necessary when something unusual comes along, but some people routinely avoid tripods. The quality of their images do not compare favourably at all.

Text copyright Carl Moller, table and pictures copyright Wayne Lawler. Available for publication, pease enquire.