It would be interesting to compare this lens with the Sigma 150-500 which is now less than a third of the price.

I hadn't bothered changing the clock in the car all winter so I was looking forward to it being right again for a change - except it went in for a software upgrade (yes, really!) on the Friday when the good souls at BMW reset the clock to winter time. For one day - what were they thinking?

Since starting this thread I have actually read the flashgun operating manual, so I have finally twigged the answer to my original question (I think). Like all kids with new toys I got it out the box and set the flash up with a rudimentary scan of the instructions; I am on a steep learning curve with digital SLR so all you wizened semi-pros out there please stifle your sniggers! It turns out that although both the off-camera flashgun and the built-in flash appear to go off simultaneously it doesn't happen at the same time, and something very clever is happening: in a series of flashes by each unit they are communicating to each other all the information to enable TTL metering. Once done the shutter is released at the same time as the final flash from the off-camera unit; the built-in flash doesn't flash at that point unless contrast control is activated. I gasp in admiration at the clever bods at Pentax who came up with this and made it work.

I did consider a smart cable link which might still be an option in the situation McGregNi describes but not at Pentax prices! Cable £69, hotshoe mounts £32 each totals around £133 whereas I have seen all-in-one connectors for less than £20.00 allegedly doing the same thing.

PS re. Fletcher8's last comment, I was searching for a tripod mount for flash when I discovered that whilst the flash shoe is a standard fit across all manufacturers (apart from the contacts configuration), Sony is an exception with it's own size.

Thanks very much folks for your considered replies; I did see a feature on youtube: www.youtube.com/watch?v=EFchyocdQRI in which the presenter shows you can disable the built-in flash on the K5Ii in the camera menu. I tried this but it didn't work on the K50. As you rightly point out, the 'wireless' function is light-activated.

One other thing - the SRS Microsystems website says it can be used in the rain, but the manual says that it "is designed to be water-proof and dust-proof. However do not use the flash unit where it may be directly exposed to rain, water etc". In other words, it is designed to be waterproof but that doesn't mean it is. How does that stand with the Trade Descriptions Act?

I have just bought a AF360FGZII flash to use with a K50 and it all seems to be working ok EXCEPT I can't find how to trigger the flash when disconnected from the camera without using the built-in flash. The K50 manual says I must use the built-in flash or multiple units for wireless operation. Any ideas?

I used to live nearby years ago, always wondered why the road was so much higher than the pub. I remember as a callow youth getting so plastered at a stag do in the Queen's Head that I had to crawl up the drive to my parents' house on hands and knees and spent five minutes trying to put the key in the door. I thought I was being quiet and discreet but apparently woke the whole house with my stumbling around! I must have had all of two pints.

Thanks. Damn, no more excuses!

My mouse was hovering over a 100 macro (do I really need one?) but a thought came up - what happens if I fancy a full frame some time? Taking stock, I have 3 APS-C compatible lenses plus an old 35 mm film era zoom and a sigma 150-500 zoom which is full-frame compatible. Would a better strategy be to wait until a new full frame macro comes out even if I decide not to upgrade for a while, or ever? I know the APS-C lenses will work on the full-frame but only on part of the sensor which would render the change pointless. Does anyone else have these misgivings?

Don't worry you are not alone! Just ordered a flash. Not used one since the days of the one-shot disposable bulb and a clever fold-out reflector but you never know, it could come in handy one day. It will be fun finding out how it works.

£199 for the HD 55-300! Now I am spitting feathers