Click to Enlarge | Yes, all three shots were taken with a handheld 500mm f/8! | |
| Balancing my elbows on an outdoor picnic table, I photographed the lilac-breasted roller in Kenya at 1/60 sec using a 500mm f/8 MTO lens on a Nikkormat FT with Kodachrome-X. | |
| Same equipment but at 1/30 sec for the Kenyan lion shot at 13 feet from car window, hands braced on sill. | |
| Halfway up the Toledo, Spain, bullring seats, I was able to catch famous matador El Cordobes at about 1/125 sec, same equipment and film, with no bracing. Do I approve of bullfights? No. | |
Major camera and lensmakers went back to producing larger, bulkier, all-glass transmitting lenses. What happened? Probably one or all of the following reasons:
1. Donuts went out of fashion. The secondary mirrors, located centrally in each CAT lens, produced round, black centers in out-of-focus highlight circles At first hailed as a nice artistic touch, photographers grew tired of donuts, and picture editors began to look on them with disfavor. What I think: I still find that donuts add interest to pictures, but if you don’t like ’em, avoid out-of-focus highlights. See my photographs.
2. Many 500mm f/8 mirror lenses turned out to have less light transmission and more focal length than marked. The MTO, for instance, was closer to a 550mm T/9.5 (T being the true light transmission), thanks to the secondary mirror, which not only produced donuts but also held back some of the transmitted light rays. What I think: With ISO 800 and 400 film what does a loss of f/8 to T/9.5 amount to anyway? Only a half stop.
3. Mirror lenses only have a single, smallish aperture that many pros and amateurs found objectionable, especially when using relatively slow film. Others wanted even smaller apertures to cut down on transmitted light. Attaching ND filters is the inconvenient way to do this, but ND filters do not increase depth of field as a smaller aperture would on an all-glass lens. What I think: F/8 (or T/9.5) is a good shooting aperture. I have a set of such ND filters for my CAT lens, and I’ve never used them.
4. Some mirror lenses produce considerable light falloff at the picture edges. What I think: Unless you’re shooting a natural-light subject, such as a blue sky, chances are you won’t notice the falloff. The wide exposure latitude of print film may also hide the falloff completely.
5. Mirror lens manufacturing requires high-precision components and assembly. Many lenses, particularly those made by small factories for off-brand labeling, are not of high enough quality. What I think: Try before you buy. Make sure you can exchange lenses or get a refund if your mirror lens is a dog. But remember: Don’t be too surprised if the macro settings yield poor results.
6. With the advent of autofocus SLRs, AF-mirror lenses weren’t available (except one, as we shall see). Manually focusing an f/8 mirror lens on an autofocus SLR viewing screen requires great care. Older SLRs often have split-image rangefinders, but with a 500mm f/8 they are usually unusable since one of the rangefinder semicircles goes black. What I think: If I can focus manually on SLR groundglass screens, so can you.
Print
Stumble It 
Comments
Be the first to comment!