> I am looking at buying a 1000mm for important
> but occasional use. The Nikon 1000mm catadioptric
> is a bit expensive and the 1 review I have found
> rates it as optically so-so.
I've been running around this question for over a
year now, and haven't really found anything that's
as good as I want, that doesn't cost more than I
want to pay right now.
The Reflex Nikkors are plenty sharp. They lack
contrast, they have uneven illumination, and their
bokeh is abysmal (that's not a Nikon problem, those
are just the basic properties of cats), but they're
sharp.
If you want a cat, the reflex Nikkor's are as good
as most.
I've got an old (5-element version) 500mm/f8. It's
not close to a 500mm/f4, but it's a lot sharper than
an AF300mm/f4 on a TC201 (and it's cheaper than a
TC301, which I ought to be using with that lens).
> There are two Russian 1000mm cats which are one
> tenth(!) the price.
Never seen 'em, but at that price it sounds like
they would be worth a try. I doubt that they'd
match the Nikkor, but you never know.
> I have also had someone in the know recommend a
> Celestron 5" telescope which is supposedly
> diffraction limited and still cheaper than the
> Nikon.
One of the lenses I've considered was a 1250mm
Mead Schmidt-Makarov. But the telescope types are
hard to focus, and that one won't mount on a normal
tripod head. Besides, they still have cross-eyed
bokeh, and I suspect that they all have illumination
problems -- a cat's a cat, after all.
> The AFS 500/4 and TC20E would be nice, but I value
> my marriage higher :-)
Aw, c'mon -- everybody's got a wife, but how many
people on your block can take a close-up picture
of the inside of the queen's nostrils without having
to risk being thumped by a bobby?
All seriousness aside, what features are most important
for your use? Just sharpness? -- then get the best cat
that fits your budget. Is even illumination or good
bokeh important, or the ability to control depth of field?
If so you can forget all of the cats.
Let me know if you find a good compromise out there, I
haven't. I've pretty much decided that, despite the cost
of the long EDIF's, when you factor in ease of use and
overall picture quality they're just about the only
things in that focal length that are really worth what
they cost.
And, if I can just explain to the bank that I need to
skip the next 16 mortgage payments, that 800mm should
fit my budget just fine.
-Don
