I have the 150-500, purchased a few months ago from SRS. It has rendered my old Sigma 600mm mirror lens redundant. I've managed to capture lots of good images of birds as well as one or two other interesting shots. It is a heavy old beast, but the OS systems (lens OS AND K5 SR working in tandem , as well as, of course, my rock-steady hand :wink produce some remarkably sharp images right up to 500mm.

How it compares with the 120-400, I cant say but have a look at the bird shots in my gallery for sample shots.

B.

A few times over the past few weeks, I've been happily shooting away with my K-5 and various lenses when, for no apparent reason, the camera refuses to focus and lock. It just kinda dies.

If I change the auto-focus from AFS to C it works fine, but I have to switch off the camera and back on again before normal service is resumed.

Anyone else experienced this?

B.

I have the OS version and I find having the image stabilised in the view-finder strangely reassuring.

Also, as Blythman says, it has the panning setting which I've used to some effect.

B.

^ Wot Giorgio said x 2.

B.

I have bought twice through this forum, and have nothing but praise for the other parties in both transactions. (Thanks again guys)

One sale however was almost scuppered by the ridiculous charges which both my bank and the vendor's bank attempted to levy on our transaction, and me being a typical tight Jockanese type person hated being ripped-off. Where there's a will, however ... and I'm the proud and happy owner of a pre-owned Sigma 10-20mm zoom and Pentax battery grip.

A wee bit off-topic, but can I also put in a good word for SRS for new purchases. A superb and easy on-line shopping experience every time so far.

I am now the proud and happy (and lucky) owner of a new Sigma 150-500 zoom with Optical Stabilisation. I'm having fun getting to know this lens and have had some reasonable results.

The instructions with the lens say that I should de-activate the shake reduction function in the camera (K-5) and switch on the OS in the lens. I have so far dutifully complied.

I'm not quite 100% certain how each of these aids work, but I would have thought that since they worked independently of each other, if both systems were switched on, the lens would produce a stable image, and the in-camera system would further stabilise the image. This is clearly too good to be true, but can anyone explain why?

What would happen if both systems were left switched on?

The usual copious drams of malt whisky for the correct answer.

I cant speak for the lenses you mention, but I bought a Sigma 10-20 f4 - 5.6 from a fellow forum member a few months ago (thanks Eddie)and I love it. Image quality is superb throughout the zoom range.

They seem to be changing hands for around £250 these days however new ones are reducing all the time too. It might be worth holding out to see if second hand prices drop.

I'm beginning to think along those lines.

[quote:3496ace15f="DaveHolmes"]UBER-BLING

]http://www.ebay.co.uk/itm/Rare-PENTAX-LX-w-50mm-f-1-2-special-gold-edition-limit...

I like that. I like that a lot. (But not at that price)

I think Timothy W meant a £1,400 price difference between the two.

I've captured a few half decent sport & wildlife shots with my kit 50-200 zoom, and my 600mm Sigma mirror lens has the reach, it's just far too slow at f8.

It's all a bit "pie in the sky" at the moment but if things go to plan over the next few months, I might be able to treat myself. Fingers crossed!