[joefru]

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If you are interested in manual focus lens there are many alternatives that are easily googled and fished on the bay (ebay).
Novoflex 400mm
Enna 400mm
Tair 3s (300mm)(was used by KGB to photograph people entering our embassies, quite heavy)

Most of the 400mm and 500mm preset lens on ebay, often dismissed as junk have an optical formula leading to very good to excellent performance as rated by Modern Photog in the 80s. This includes the preset Spiratone 400 and the current Opteka 500
Russians invented mirror lens and the current Rubinar 500mm is well regarded

Another interesting option is Tamrons adaptall telephotos mated to their custom matching teleconverter, see the following link.
TAMRON 160-420mm MACRO MC SUPER-ZOOM lens: PENTAX K - eBay (item 320257071101 end time Jun-03-08 18:06:31 PDT)

And remember if you dont like a lens just toss it back in the bay.

Holy crap! I count 16 aperture blades on that Tair 3s!

[barondla]

Have a Celestron C5 (1250mm F10) that is great. It isn't as contrasty as my Pentax A400 but has zero chromatic aberation. Putting even 2x on A400 means it gets beat by the C5. C5 is much better than the C90 mak design. More sharpness, more contrast. One of my favorite shots of all time was taken with this lens.
thanks
barondla
Enter POINT & SHOOT CONTEST #7 in P&S forum. Any camera type except slr. Any brand. Any subject. Less than a week left!

[Ben_Edict]

I have a large collection of old long lenses. I can also recommend the Novoflex rapid focus lenses in 400 or even 600mm focal length. Especially the 400 f5.6 (go for the later 3-lens-elements design, not the old 2-lens-elements version - The newer ones are called "T-Novlexar").

There is simply no better lens for that small money on the market. The T-Novlexars are very sharp and focusing is nearly as fast as AF, sometime even better. Also, the integrated shoulder pod allows for very long shutter times without the need for a tripod. Combined with the K10's SR I got completely sharp images at 400mm and 1/40s (ofcourse not all shots in a series, but some). Sharpnerss compares favourable with my Pentax A 400 f5.6, but contrast is somewhat lower - but that's a slight problem.

If you find the Novoflex too big or are afraid of problems with security poeple (it looks like a rocket thrower), some mirror lenses are quite fine. I can also recommend the Tokina 500 f8 and if you need something even longer the Russian 1000mm f11 lenses (the MTO 1000) can be fine (but buy from a dealer, which allows for exchange, as the sample variations can be very big).

The Tokina can be handheld if light is bright and you chose a higher ISO setting, the Russian is a pure tripod lens.

be aware, that most any mirror lenses have light transmission effectively 1 f-stop lower, than the f-number tells you. The Tokina 500 f8 is effectively an f11 lens (as are all the others with a central secondary mirror). The central mirror is the culprit and tales away a full f-stop. Only some rare to get by offset mirror lenses (pure mirrors then, not the catadioptrics we are talking about here) would be really as "fast" as their denomination tells...

The old Pentax K 300 f4 is a good lens, which can be combined with a 1.4x tc (a good one, of course, like the Pentax 1.4x-S or the Kenko 1.5 DG). Contrast is not quite up to modern standards (but still better as with many cheap zoom lenses) and there is some purple fringing around high contrast edges - but all the shortcomings are manageable in post-processing.

Ben

[Zewrak]

Im found of my S-M-C Takumar 300mm f/4. Its cheap, you can probably get one for like 100$. The Tamron SP 300mm f/5.6 is outstanding too.


Here are some shots with the S-M-C Takumar that I took for testing it.
Unprocessed:
5401614 - a set on Flickr

Might be postprocessed in different ways (but not necessarily):
Linked shots - a set on Flickr

[Steinback]

I just recently picked up an M42 mount Soligor 400mm f6.3 for $35 and the image quality is pretty good. I believe that Vivitar and possibly several other companies sold versions of the same lens in the '70s and they are cheap because they are off brand and you need an adaptor to use them. The built in tripod mount is a nice touch, and in decent light the lens is still light enough to hand hold.