Has anyone had any experience with this lens or know of anyone that uses it? I am assuming it is based on the same principle as a cassegrain telescope in which case I would expect very sharp image results. I have been searching the web for image examples but have not been successfull.
I am debating on this lens, which goes for around $300 and then possible a good macro lens in the $300 range or one Sigma 50-500 lens that cost around $700.
Any help appreciated.
Can't speak for this lens in particular. In general Mirror lenses are compact and provide sharp images BUT
1/As you have seen, maximum aperture is not usually large: f8 is fairly common. Minimum aperture may not be too far away from this: to allow some degree of exposure control, some make it easy to insert neutral density filters instead of stopping down. You REQUIRE an exposure of 1/600 second or less if handheld, and even with a tripod you probably want a fairly short shutter speed, which won't mix too well with a maximum aperture of f8.
2/Out of focus light sources appear as characteristic doughnut-shaped highlights, which can be distracting. Sometimes you will see this used as a special effect.
(Hence when you see sports photographers etc. they don't use mirror lenses, but monster telephotos that cost about 10 times as much).
quote:
Originally posted by mcdowella
Can't speak for this lens in particular. In general Mirror lenses are compact and provide sharp images BUT
1/As you have seen, maximum aperture is not usually large: f8 is fairly common. Minimum aperture may not be too far away from this: to allow some degree of exposure control, some make it easy to insert neutral density filters instead of stopping down. You REQUIRE an exposure of 1/600 second or less if handheld, and even with a tripod you probably want a fairly short shutter speed, which won't mix too well with a maximum aperture of f8.
2/Out of focus light sources appear as characteristic doughnut-shaped highlights, which can be distracting. Sometimes you will see this used as a special effect.
(Hence when you see sports photographers etc. they don't use mirror lenses, but monster telephotos that cost about 10 times as much).