The thing is when the 1.4x first came out it worked fine with Sigma lenses then Pentax released a firmware update for all bodies under the guise of "compatibility issues" with some SDM lenses and from then on it never worked properly again.

Guess Pentax wanted to cripple the competition.

Original K-3 was a great camera, K-3 II was a fairly minor upgrade, K-3 III is a major jump over the II

Used K-3 about £350 for a decent one, £500 for a II and very unlikely you will find a used III but if you do (MBP) then they are around £1500 which is what they were selling for new a few months ago.

If you are thinking III then wait a couple of months for Black Friday.

Maybe look at the KP instead? or if you have the lenses then the K-1 is the way to go for what you are looking to shoot (IMO)

Sold ... thanks for looking

If the 18-35mm is HSM then you will probably have problems as the Pentax 1.4x doesn't usually play nicely with Sigmas version of SDM. (having tried on the 70-200mm HSM, 85mm HSM, 24-70mm HSM and 50-500mm HSM)

Saying that when I tried it was all on a newer body so I can't be sure it would be the same

I saw the ffordes one as well last night but thought the rear of it looked a bit rough so didn't bother posting it here.

Coming soon at SRS ..... not sure why Chris hasn't posted it on the forum but anyway .....

LINK

Personally I think a gun metal grey one would look better.

I had the A* ... very good lens, also works well with the 1.7x adapter.

4. Some of us are at work.
5. A 300mm AF f/2.8 is as rare as rocking horse doodah ... Infact I can only think of the FA* 300mm and Sigma DG EX 300mm. Even the manual focus lenses are very rare.

If you have the budget and want the best IQ then you won't do better than the 150-450mm I have for sale.

Honestly, I have been through them all and for Pentax that lens is the best option.

It's really only meant for the lenses I used it with plus the 70-200mm f/2.8 and a couple of long primes.(if I remember correctly I think it may fit the 70mm macro as well).