Have a chance to play with my friend's new DFA 100 Macro WR lens in the weekend, my brief first impressions about the lens are as follows (let's see how the new DFA version is compared against the old):-
1. Mechanically, I would say this is a refurbished old DFA 100 Macro with a FA 31 (Black) Limited design and look!
2. The lens barrel is all metal, it feels really cold but I don't like the fact that fingerprints and moisture will leave on the naked and bare barrel just so easily!
3. The MF damping now goes completely Limited, which means silky smooth manual focusing with more damping but yet even slower Auto Focusing! (Sightly, the old one is not that fast, already!)
4. The weather-sealing rubber ring at the lens mount is now in sharp Red colour, which I don't like subjectively! Why? Only Sony lenses look like that!
5. I don't like the comparatively thin double lines of hard-carved MF ring against the thick and wide rubberised MF ring of the old version DFA, which practically is easier to hold and turn! (Applies also to the Quick-Shift Focusing..)
6. The Aperture Ring is now omitted and so does the "Focus Clamp" as well, which both you can find in the old version. So, this new DFA 100 has the least practical function against all its predecessors, except it is weather-sealed. However, I don't think it's logical enough to design a Limited-style focus scale window for a weather-sealed lens anyway, as water will be trapped inside eventually (although the water should not be able to go inside the lens). (Well, btw, I just wish to ask: WHO will do Macro works Under the Rain??)
7. Optically, I don't find any big difference for the old and new versions. The glass elements look the same, the coating and colour look the same and more importantly, the image rendition seems to be the same! (This is nothing scientific and systematic, though - just my brief impression.)
So, would I recommend the new 100 WR? Honestly speaking, I actually prefer the old version if I had the choice and if I had to choose, as I prefer the FA version over the original DFA, too! I like the optical performance and colour response of the old FA 100 Macro more and it does have a Focus (Range) Limiter, which is much useful, practically! In fact, the Focus Limiter is practically the real utility for one to use the AF function of Pentax AFSLRs for doing macro works!
Besides, the old DFA has aperture ring which is a practical and useful feature, especially you have a film camera that need it. In fact, even when I use my DFA 100 on my Canon 5D, the operation is really superb as I can control the aperture using my left hand whilst my right hand is holding the shutter release - similar to the design concept and operation of the MZ-S. The best thing when it is put on my 5D is that I can see the DoF and focus in real-time, thanks to the stopped down metering. I have to do MF, though (and of course).
Last but not least, the wide/thick rubberised MF ring of the old DFA is practically more useful than the thin but might be better looking one of the new DFA. For macro shootings, MF is very important IMHO especially for Pentax system which has slow AF which is particularly even more slow with Macro lenses. Frankly, I am quite disappointed for this new version of the Macro 100 doesn't have an Ultrasonic AF motor, nor the re-introduction of the Focus Limiter.
My final words? It seems that now Pentax/Hoya put more weight on aesthetics than on practical usability when they introduce new lenses. If you need a 100 macro right now, I highly recommend that you should get the last stock of the old version DFA 100, as it has been discontinued already. The old version is just (much) cheaper, practically more usable and optically the same! Well, if you need to shoot flowers or insects outdoor under the rain(!?), just do it and get the new DFA! :=o ;-D