I tried a step up ring on the FA35/2 (49mm to 52mm), but using a step up ring and the lens hood is a real pain. Because the hood will not fit over the ring, the hood has to be in place first. Trying to fit the CP filter with the hood in place for someone like me with arthritic fingers is not really practical, so I've abandoned this idea. Have decided now to bite the bullet and get a 67mm CP filter for the 16-45.

Alan[/quote]

I used circular polarizers quite regularly with film, but when I'm out and about with the K10D I tend to have the DA16-45 (67mm filter size, don't have it!) and the DA50-200 (52mm filter size) I will make some more tests with the DA50-200 when the atmospheric conditions are more appropriate. As for filters in general, I don't keep them on these lenses - they have good lenshoods to protect the front element. I would only get a cp filter for the 16-45 if I thought it would be useful - a top quality 67mm cp filter costs a few bucks!

Alan

Don't have an answer, just my experience. I tried a Hoya circular polarizer with the DA50-200 and found vignetting quite noticeable at 50mm, but not at longer focal lengths. I not sure of the benefits of these filters with DSLRs since you can do so much pp. I too would be interested in others experiences here.

Alan

I have both of these lenses. The 18-55 came with the K10D just before Christmas, and I obtained the 16-45 about a month ago because of the limitations of the kit lens. In good light and straightforward situations the kit lens will produce excellent pictures, as good as the 16-45. Difficulties arise however in low light, with the lens wide open at wide angle, when images can suffer in contrast and definition. I've also had problems with flare. The 16-45 in its construction is in a different league and is an excellent partner to the K10D. I've also found that the extra 2mm at wideangle is extremely useful, like comparing 24mm to 28mm in 35mm film. This lens is pinsharp throughout its range, and an excellent
performer wide open.

Alan

i have only one M lens, the SMC 135/3.5, and I have had a limited play with it on the K10D. Stop-down metering I have found to be reasonably accurate, but I have not tried it wide-open or fully stopped down. I would not expect to get accurate exposure fully stopped down because of the very limited amount of light hitting the meter. I think that if I were using these lenses consistently I would very quickly know whether the indicated exposure was correct and compensate if it wasn't. However, there seems to me to be a wider issue here - I really didn't spend a large sum of money on a state-of-the-art digital camera to use 30 year-old manual lenses and fiddle about trying to get the correct exposure. If I want to take pictures at 135mm I stick the DA50-200 on the camera and fire away. I cannot see any practical use for the 135/3.5 and will certainly not be looking for any other M lenses. 'A' lenses are of course a different matter, and I use my 50/1.7 regularly with no exposure problems - it is one very sharp lens.

Alan

Be very wary of the Pentax A 70-200 - it is not SMC and was sold in the mid-80's when Pentax decided they needed a dirt-cheap tele zoom, so rebranded the old Takuma. The A 70-210 f4 is an entirely different prospect - very sharp throughout and the f4 at 210 is very useful. It is however, very heavy at 680g and difficult to hand-hold. I tend to only use it when I've got a huge bag of kit and plenty of time to set up. THe DA50-200 is what I always carry with me, with the DA16-45 on the camera when I need to travel light. I don't think you can beat this combination with older zooms.

Alan