I have the SMC 500/4.5 "K mount" version of the SMC Takumar 500/4.5, and I'm very happy with it. AFIK, it is exactly the same as the Tak version, and since it has a manual aperture (not controlled by the body), it makes little difference which you get. I use my SMC 500/4.5 "straight up", and with the Rear Converter-A 2X-S, 2X-L and 1.4X-L teleconverters. The images are excellent. I don't have experience with APO/ED big glass lenses, but those who do rate the 500/4.5 very highly, see:
http://home.att.net/~alnem/html/equipment_review.html http://www.concentric.net/~smhalpin/ SPLOSdb (at www.jcolwell.ca) has three prices from $500 [E] to $790 [M] for the SMCT 500/4.5 over the past six months, and the SMC 500/4.5 is selling for $560 [E] to $890 [M], and you can still get it new for $2314.95 at B&H. The lens does not have apochromatic glass (i.e. usually called ED or APO) which means that different wavelengths don't focus at the same plane (the film). One consequence is that an intense and small white light in the image can become partially separated into its constituent colours, and show a 'rainbow' effect. The only time that I have ever seen this is when I tested the 500/4.5 with extension tubes to see how close I could get it to focus; normal Dmin = 10m, you can get it down to about Dmin = 2.6m with 107mm of tube. When the tubes get longer than about 50mm, you start to see the light fractionation - it gets kind of bizarre (and really cool) with 107mm of tubes (it has a magnification greater than 1 - a superduper macro). It is not a problem for me. At f/4.5, the finder image is bright and easy to focus on LX, SuperProgram, MZ-5N and MZ-7 bodies. I have not used it with a *istD, but would be happy to if you send one to me. You have to remember to focus wide open and then 'stop-down' (if required) to take the pic, but this should not be a problem - you have to be deliberate with a lens this big - no P&S snapshots (well, I've done a few ...). I normally use mine on a Manfrotto 055GS tripod with a Manfrotto 3421 "heavy lens support" gimbal head, and the big 3272 quick release plate (BTW the picture of this head at B&H is wrong, the internal swing-frame should be down, inside the fixed external frame). It works really well, but you have to take care to level the tripod if you want to pan. Try it a few times on a ball head (with caution) and you'll see why a different support solution is required. The only drawback with the moving rear element focus is if you use a camera support as well as the lens tripod mount. I sometimes use the Manfrotto 3252 long lens support, with a quick release on the micro ball, for additional support when using one or two teleconverters - you have to loosen the strut when focusing. BTW, you have to be careful with the 'basket mount' filter holder, lest your camera or worse hits the ground (see the MZ-5N on my site). This lens is a great way to get into super telephotos. This type of lens has many more uses than simply 'things that move' (which it can do). The narrow angle of view image compression and shallow DOF are fascinating. Jim www.jcolwell.ca