Pentax has a combo (PF-80ED spotting scope + PF-CA35 adapter) that makes a light 1000mm lens. The Pentax PF-80ED is seen as the reference spotting scope from what I've read. APO glass.> I've been looking around lately for telephoto lenses 500mm or longer. Withsome modern computer design, glasses, and coatings, I was hoping to at least find decent but small aperture fixed lenses pretty cheap. Will I find that all the truly long telephotos either cost $5000, are mirror lenses, or are> turkeys?
With the PF-CA35 adapter (highly corrected, 6 elements in 4 groups), it makes a 1000mm f12.5 lens that weights 1850g with a min. focus dist of 5.8m. The 1000mm f/11 mirror weights 2300g and has a min. f. d. of 8m (and exhibits "donuts" highlights) ; the 1200mm f/8 ED weights 8500g and has the same min. f. d. (and costs an arm and a leg).
The combo can be had new for 925 US $ around here (625 for the scope and 300 for the adapter), which is lower than in USA. I am tempted to replace my SMCT 1000mm with this. It is one and a third stop slower but also three times lighter and must have little chromatic aberrations.
Andre
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