I loved and still love my Olympus 2020. I have shot way over 20000 images with it. I then upgraded to a Dimage 7. Well, upgrade... I never really got warm with it. Yes, it was better in every way than my 2020, but it did not "click" inside of me. Almost by accident, I bought an Olympus 4040 on ebay with a bid I never thought would win. Now, the 4040 is a nice camera for sure, but when I was on a photo-walk with one of my analog M42 SLRs, I always admired the viewfinder and the way how you take pictures with an SLR.
Left: Revueflex 5005 = Chinon Memotron CEII
Center: Pentax ES (Electro Spotmatic)
Right: Revueflex = Zenith 3M
I already had "thrown an eye on" the *ist DS, because its smallness, backwards compatibility and use of AA cells appealed to me. One day two colleagues and me were walking around town, browsing digital cameras for one of them. So, we entered the shop where I had bought my Olympus 2020 some seven years ago!
My friend was looking around in the Leica section and as the sales person had no customer, I asked whether I could "hold" the *ist DS. I could and, well, it made "click". I asked whether I could return next week and try it with my old lenses. He agreed but warned that they get the *ist DS only in small quantities and it might be sold soon. He was right, so the next time I left my phone number with the sales person.
Less than a week later he called me and told me that they just got one kit and one body. The kit had already been sold but the body was waiting for me. So, two days later I finished work early and packed an SD card, my old Revuenon 55mm 1.2 lens, my M42 Cosina 20mm 3.8, the M42->PK adapter that had just arrived via ebay and went to the shop. Well, what can I say, the *ist DS handled nicely and I was able to teach the sales staff how to use the DS with a manual M42 lens in aperture priority mode ;) (thanks to the dpreview forum!) So, it was pretty much clear that I would _have_ to buy this camera - and so I did.
I bought the body only, with the option to purchase the kit lens later. At first, I only have manual lenses, only one of them is a PK, the rest is M42. I think I'll stay with M42 (for manual focus at least) as I can use these on my M42 bodies.
I now have a small collection of PK-A (manual focus) and PK-AF (auto focus) lenses, but still use the M42 lenses when I feel like it. I never bought the kit lens, but instead opted for the Sigma 18-125 zoom.
My Revueflex 5005 and my Pentax *ist DS, both with a M42 55mm 1.4 "standard" lens.
So, how do my old lenses perform on the digital body? First thing to remember: The CCD sensor is smaller than the 24x36mm "35mm" film. So, a 100mm lens on the *ist DS will provide the same field of view as a 150mm lens on my M42 bodies. This means that tele is easy with old lenses and I like portraits with my fast 50mm or 55mm lenses, as they act like "classic" portrait focal lengths of 75mm or 82.5mm due to the crop factor (also often incorrectly called "focal length multiplier"). You can see some of my M42 work here.
But extreme rectilinear wide angle is almost impossible. Now (2008) the field of "digial only" super wide lenses is rather full. Still, the widest FOV is still available for 24x36, but for most uses, the APS-C offerings are wide enough. Although I had a Tamron 17mm, my 20mm Cosina is the widest M42 lens I regularly use. It is small and good and I was lucky to bought one of the last "new in box" ones for a low price. Generally, the performance of these old primes on APS-C is a mixed bag. You can see a comparison of several wide and superwides for film with an APS-C lazy-zoom here
Three camera generations, three lens generations
Left: M42 Auto Aperture
Centre: M42 SMC, aperture information is transmitted for open-aperture metering
Right: Russian M39, which is like M42 manual
The properties of a CCD are different from film, so for best results, "Digital Lenses" are advertised by the manufacturers. There are certain characteristics that make this a good suggestion, but some of the old glass simply gives beautiful results. Please read here, how I converted an adapter to fully use auto-aperture M42 lenses with the Pentax *ist DS!
There are many pages on my site more or less concerned with the Pentax *ist DS, but among the more useful are:
Pentax *ist DS IR sensitivity
Flash photography (with the Pentax *ist DS)
A DS converted for Infrared (IR) use