To be honest I'd be very disappointed if they didn't test them thoroughly.

I have to throw my hat in the ring and confess I'm an antfan too

I want a Ruby! I'm green with envy...

I've got a 2 door 900 Turbo 16v in Ultramarine Blue (daily driver), a 2 door 900i 16v in Malachite Green (show car) and a 4 door 900i 8v in Embassy Blue (on long term loan to a mate). I find them addictive...

I could probably find space to squeeze a Ruby onto the driveway though, love that colour.

Gotta love the prancing moose!

Both the 645 and 67 lenses are designed to cover a larger film area than 35mm so the effect that you'll see is similar to using lenses designed for 35mm on digital cameras - in other words you'll be using the central "sweet spot" of the lens (a good thing!) with the drawback being that the lens is larger and heavier than one designed specifically for 35mm.

Pentax themselves make converters for 67 and 645 lenses to be mounted on K-mount cameras but they are both as rare as hen's teeth and relatively dear (you'd probably have to get them on special order and think £100+ each). It would probably be worth asking SRB again if they could make one for you as there's no reason it shouldn't be relatively straightforward (and probably a lot cheaper).

The advantages of sticking with Pentax lenses are (a) the adapter doesn't require a glass element to retain infinity focus, (b) the focus and aperture rings will turn the same direction as your 35mm Pentax lenses (Canon lenses go the other way so it can be a bit disconcerting swapping between the two), and (c) the Pentax 67/645 lenses have the same SMC coatings as your Pentax K lenses so you'll get matching colour reproduction.

I'd only consider using the Canon lens if it was being offered to you very cheap in my opinion.

Pentax made a 400mm f/4 for the 67 system that usually turns up at reasonable prices (Ffordes have one now for £449).

All you'd need then is a 67>K-mount converter which is glass free.

I was sure this was next weekend!

I normally enjoy Hobble On The Cobbles - can't believe I got my dates wrong.

Nice shots though.

I think she's quoting the advert

Clarky beats me to it once again! At least we said the same thing

No, unfortunately not.

You can get adapters that go the other way (Pentax lens > Canon body) but not what you're after. The Canon bayonet is too wide to go in a Pentax mount and the shorter registration distance means you'd have to mount the lens so far back it would foul the mirror in order to achieve infinity focus.

The only thing you could possibly use a Canon lens for on a Pentax would be for macro work - either reversed using the filter ring or on a set of bellows (with a Pentax bayonet at one end and a Canon mount on the other).

Shame as I picked up a couple of nice Canon lenses with a job lot of other optics just yesterday and I can't use them for anything worthwhile either.

Glad it all worked out in the end