And I thought it was the 55mm F1.8 instead! LOL

Still, I am getting one of these 50mm F1.7 lenses, along with a couple of zooms. Cost? A bottle of red wine! (I can feel the envy already!)

mdc. I have never seen a K-mount Helios 44 series lens. They must be really rare.
Still the M42 one is great.

The Zenitar-K2 is something I must look out for. I might get one to have fun with.

I am not from Norfolk, but use a non-Pentax MF (Bronica). I have friends who do have Pentax MF, especially the 67, but they live a little closer to Norfolk than me (Yorkshire)

Having said that - Hi, and welcome.

So, for all you who have and use M42 screw mount lenses on your DSLR, which is your favourite(s)

For me, it is tough. But having said that my Takumars are probably my favourites. However I do have some others which would be considered just as good.

So, the Taks
SMC-Takumar 35mm F3.5 - This is just wonderful! sharp contrasty and lacks CA. More to do with the coating that has that radiation treatment. It is possibly the best 35mm That Pentax ever made.
Super-Takumar 55mm F1.8. What more can you say about the "pixie-dust". a beautiful lens and fast too. colour, CA control, contrast and sharpness are just wonderful. The 55mm is a must for any pentaxian.

The non-taks
Carl Zeiss Jena 50mm F2.8 - A lens that came with my Praktica many many years ago. Build is okay, focus ring has always been sticky. But, the results are fantastic! But in the end it is a Tessar, hence why it is so good. CA? what CA?
Mamiya-Sekor 55mm F1.4 - A recent purchase. Not quite as good as the Tak, but faster, beautiful bokeh and good contrast. Perfect for portraits. If you can live without AF and WR. Get one of these instead of the DA*55. Honestly it is that good.
Helios 58mm f2 44-2. This is supposed to be the lower resolution model of the 44 series. In the real world, can you tell? Not on my K-5 I can't! It is a rarity amongst Russian lenses. Not on how many are around - there are loads!, but it is a wonderful lens to use and the results are excellent. The is really a peanuts lens. Forget a couple of pints on a Friday, and go onto the auction sites and buy one instead.

Oh there are others too. If you get the M42 adapter, get hold of things like the Carl Zeiss Jena 50mm F2.8 Tessar, the Helios 58mm F2 (made for russian zenits), even the wonderful but dead cheap Mamiya-Sekor 55mm F1.4. All can be found for more or less peanuts, and all are wonderful to a point that they can match the Takumars.

Good thread. So why use old lenses?
Well I have a mix of M42 screw mount and K-mount manual prime lenses.
Reasons?

Colour rendition
Contrast or even lack of it on certain ones.
Sharpness!
tactile delight in using them
cheap
the sheer pleasure of using them
each lens have their own personality whereby they render the image slightly differently
did i mention sharpness? and price?

Get yourself an M42 to K-mount adapter, buy yourself some Takumars and then you will understand the sheer delight on using old lenses.

Oh, the first manual prime to buy is the 55mm F1.8. does not matter which "flavour" (Super-tak, SMC-Tak, auto-tak etc) the lens is the stuff of legend in the Pentax world. It is a wonderful cheap lens. You can even get it with a K-mount too. I have two.....

Some "troll" put on DPR (the main place for trolls as it happens....) said why show the patena of the brass on the top as the camera is not like a classic film cameras which last for years?
Well I have a Fuji S5000 that still works and is 10 years old, but then the MX-1 will have brass showing and should still work at that age.
At least Pentax have thought about that, and cameras of a certain age that have brass top plates (Leica, Pentax ES, Nikon etc) do have a certain style with the brass showing.

Anyway why not rub some of the paint off in the first place?

I think this may be Pentax meet. I have done a few studio sessions, and my current favourite studio is just outside of Chesterfield, which is about an hour up the M1 from Leicester. I also have a purestorm account so have the ability to book models for TFP or paid.
The studio itself has several rooms including an infinity room, and will cope with 6 togs, 8 at most. Last time it cost me £60 to cover studio and models.

What do you think all? Pentax studio meet?

Guys, you have sold me. I think this will be top of the list come Feb!

I agree, why?
I have used my LX-5 with both a flash (my FGZ360 as it happens) and wireless trigger in the studio, and get stunning results. I can imagine if you do the same with the Q you will get excellent results.

Anyway I digress, I still want an MX-1 in spite of the lack of hotshoe.