David Wright:
>For what it's worth, there was an article in a special "bird photography"
>issue of Birding a few years ago in which the author claimed you can get
>much-better-than-average-scope-quality pictures with the kowa tsn-1/3 (by
>virtue of its fluorite objective). The pictures in the article looked
>OK. The kowa photo adapter makes it 800mm, f11, as I recall (also a
>1200, ?f16). Has anyone in tweeteria tried photography with a fluorite
>kowa? How do the results compare with, say, a 3rd party 400mm + 3rd
>party 2x teleconverter?

Such scopes are apochromatic in design, just like top-quality
telephotos. It isn't necessary to use calcium fluorite
elements to achieve such a design, but it's easier. Other designs
use special-dispersion glass and can be identified by code words
like "ED" (Nikon), "UD" (Canon, when fluorite elements aren't
used), "APO" (Sigma, others) etc.). It is the use of a calcium
fluorite element that gives Canon's 300/2.8 the reputation of
being the sharpest big telephoto out there, period.

(Apochramatic means that the three primary colors are resolved at
the same point, in rough terms, whereas an Anachromat only resolves
two of the three, leading to color fringing and reduced sharpness).

So - the Kowa should do pretty well but is slow, f11, and expensive.
Not a problem if you own one for birding, but I've always questioned
if the extra quality is really very noticable in the field for
viewing, and our informal testing at the tweeter's picnic didn't
answer the question, in my opinion.

I would expect a good-quality 400/5.6 (like the new Sigma) to
outperform the Kowa. But Dave's question is a very good one - how
about when you stick a doubler on the 400? I'm intrigued by
the question. You end up with an 800/11 in either case.

My first comment is that you're stuck with fast film, such as
ASA 400 print film. This gives you a shutter speed of 1/800
in good light, which means you drop down quickly to the 1/60-1/200th
range PDQ in our part of the country where "good light" means
"it just stopped raining" much of the year!

These films have improved drastically in just the past few years,
so you can make pretty decent 8x10 prints with these films.

Thus my original comments: "fast film and low expectations". You
won't be able to take a publishable shot on slow (50 or 100 speed)
slide film, or something that will look good printed out huge,
like a 16x20. You mustn't expect to get eye-poppingly
sharp results on fine-grained film, but that doesn't mean you
can't have a lot of fun and get some OK results.

In either case (Kowa or 400/5.6 with doubler and fast film)
you can get good documentary shots in reasonable light (or you
can use extra-fast film like Fuji 800 or Kodak Extapress 1600 in
worse light). This would give you the kind of grainy but reasonably
sharp shots you see in your daily newspaper's coverage of indoor
sports like basketball, for instance - check out some such photos
to get an idea of the limitations and possibilities.

Sadly, high-speed slide film has not kept pace with improvements
in high-speed negative film (which is important to the modern
photojournalism market which switched from B&W about 10 years
ago) or low-speed slide film (still the standard for most
publication work). Higher-speed slide films have been left
out in the cold. You can buy 400 speed slide film, but results
will be somewhat worse than the possibilities with print film.

But results will still be good enough for documentary photos.

Also - such scope adaptors are (relatively) cheap. If you've invested in
an extremely good scope, it would be a good way to learn the
basics of bird photography. Remember, a grainy, slightly-soft
photo which is well-composed, exposed, and fills the frame is
going to beat the pants off a razor-sharp micro-dot-bird taken
by someone who hasn't learned the basic skills!

Even if you outgrow such a setup as your skills accumulate, there's
no way one could consider this wasted money.

Oh, a last comment. You have no adjustable aperture with a
spotting scope, but f/11 is so slow you'll never miss it.

Just another donb diatribe...

- Don Baccus, Portland OR <donb at rational.com>
Nature photos, on-line guides, more at http://www.xxxpdx.com/~dhogaza