Thanks, I might order one.

Generally Yashica's are sharp especially wide open and very well made. Yashica owned Tominon/Tomioka. Their f/1.2's go for £300+

The f/1.7 can't be put back together if you modify the pin with a piece of insulation, so it's either glue it or get an adapter with a flange.

First I've got to get it back together. It's a bit like a Rubik's Cube

Some good info there on the buktus site. Looks like it will
need the Pentax/Practica mount.

The ebay link is the same supplier I linked to. I didn't think of looking
if they had others for sale.

That looks to be the correct mount, but it might need a bit of work
doing on it to hold the pin in if the lens hasn't got a manual
switch. Possibly glue it in or put a piece of cable insulation
on it from behind.

Edit: Gareth did you ever get that M42 adapter with the
flange and if so does it work? I could do with one for
a Yashica 50mm f/1.7

The YS was actually Sigma's interchangeable mount system. Try saving a search on ebay for YS Pentax mount also YS M42 one might come up.

One sold here

I just tried putting MA EE.22 into Google and I got:

http://www.myspace.com/maeekroft

Not exactly Camera Mounts

Is this why some carefully focussed shots at f/8 - f/16 don't come out as sharp as you expected them to.

Sorry for using a Nikoone lens (looks an excellent one as well) it was the only one I could find using the latest test method from f/1.4 to f/8

Link

Go to the focus chart (bottom of page)and mouseover f/1.4 the focus is at 100mm move the mouse to f/8 and the focus has moved back to 85mm.... sort of makes focusing a bit of a joke.

And this is on a very good lens look at the example shot at f/8 of the tree post in the shed (2nd down left column) you can read the lettering in pencil.

This is the Praktica 50mm f/2.4 Standard Lens.
The Mighty Pentacon Prakticar MC f/2.4

I wonder if that's where Pentax got
the idea for an f/2.4 Standard from

I like the first one amazing DOF

Why should it be... 50mm was the standard lens for FF. 35mm is the standard lens for APS-C so they need to release a 35mm f/1.7 with a proper distance scale and DOF scale. 50mm is the equivalent of a 75mm telephoto on APS-C.

There's no point in discussing a lens that's only available in Japan
I'm certainly not emigrating

Canon have a cheap £250 ish f/2.0 and a £1,000 ish L 35mm f/1.4

Might be a Minolta MC see here halfway down the page.