They are selling a cord for Pentax, so I assume it must work on Pentaxes. What camera is the person you know using? It would be interesting to compare the shutter lag on that camera to the K5's. I would be ordering it for delivery in the USA.

I do have a PK/A adapter, I just thought of having one on each lens, though I can swap them round. I hardly use the 90mm, anyway, there's no bugs, plants or much else in the macro world here, save what's in our small garden. The ide of using the converter is very attractive, I would probably sell my Tokina 80-400 if I bought the Tamron. Any ideas about price (assuming you want to sell)?

Am I right in thinking this lens would also work with the matched 2X converter I have for my
Adaptall 2 SP 90mm f2.5 macro lens?

Just been reading some reviews on this lens, sounds like it's just what I am looking for....though would have preferred a zoom lens starting with a slightly shorter focal length.
Do you want to make me an offer I can't refuse, Mike?
Also, would it come with a PK/A adaptor?

I am looking for a fast (constant f2.8 ) manual focus zoom, and am wondering if anyone has any recommendations? Is there anything available somewhere around the range of say the DA* 50-135? It has to be f2.8, I have an SMC Pentax-A 35-105mm F3.5, which is a fantastic lens, but I would like an extra stop, which could be the difference between shooting at 6400 or 3200 ISO. The reason I want a manual zoom is I want to be able to manually focus at infinity in very weak light, where AF won't work, and I have found my AF lenses are not very good at this, with infinity seeming to vary slightly at different focal lengths. Plus, being an eternal optimist, I don't want to buy any more DA lenses until I see if Pentax are going to bring out a full-frame model later this year.

Thanks for the replies. The company that makes these claims they work on any camera with a shutter lag of less than 120 milliseconds. The K5's shutter lag is 92ms. It seems a bit of a risk spending all that money and then finding it doesn't work, but I may try it. Bulb is not an option, I want to shhot lightning from an aircraft.

I have had limited success using exposures of 3 to 5 seconds handheld, as long as there is no moon (the clouds end up blurred) and only one lightning flash, which acts like a flashgun. Some taken on my K5 can be seen here . I only have about a 1% success rate using this method though.

I totally agree The WB looks a bit out, too, the sky is a decidedly odd colour.

The second is much better but could do with some more shadow detail.

Thanks for all the comments!

The images were taken enroute from Doha to Osaka, from 33000 feet.

I have to say I find the K5's built in HDR function little more than a gimmick, and a pretty poor one at that. Far better to bracket shots and do it yourself, you can also do it from one image at a push.