A couple of years ago a Sigma executive was asked why so few Sigma lenses were available with K-mount : http://www.imaging-resource.com/news/2014/04/02/sigma-qa-part-i-ceo-kazuto-yamak...
To summarise, a mount with a mechanically operated aperture needs a separate production run due to the special construction of the lens as opposed to an electronic operation which can be incorporated when the mounts are fitted. Unless sufficient numbers are required it is difficult to justify switching production. That being the case, I wonder whether more Sigma lenses will become available with the K4 mount?

London Camera Exchange didn't charge me, maybe an oversight but if you have one nearby you give them a call.

You certainly made the best of this opportunity! If pushed I would say I like the last one best, it resonates a degree of solitude as if all life had been wiped off the planet but they are all excellent.

Thanks kingalew, funny how the same faces have different names! And the same appearance on different websites! Looks like your research has just saved us from being scammed.

Has anyone had dealings with this company? Based in Cheshire they seem to have some amazing deals on lenses.

Thanks for the interest and comments. The lens is the new 28-105mm ED WC WR zoom on a K-1, but as the light was very dull and flat the contrast and clarity were boosted in Lightroom. I tried sharpening the second image but preferred it left; it would have been better if I had framed the shot properly as this is a crop of a landscape image. I used an ISO of 1250 due to the gloom and had to take a bit of background noise out in Lightroom; to be honest it's the first time I have asked a stranger if they minded me taking their photo in this manner so it was a bit rushed. The penny arcade was spot focused on a machine but the aperture of 5.6 and ISO 200 could have been changed to improve the depth of field.

The Ricoh rep at The Photographic Show told me this is incorrect; Tamron make lenses for Pentax to their specification using glass supplied by Pentax. That plus the weather sealing would explain some difference, but also perhaps that Tamron have access to a much larger market with other mounts so the economy of scale factors in.

Here are a few from our village fair today:










Comments welcome

No. 3 gives me an idea - get an insect to land on sticky tape and you can focus at your leisure! Maybe the low-tack sort to be kind.

I suppose there is a limit to how much progress can be made in electronic systems in order to stay competitive, and at the same time fully retain compatibility with older models. It is a bit disingenuous however to incorporate compatibility with say the KS-1 without flagging up this impending development at that camera's launch. We have just seen a tranche of new FF compatible lenses so if this is a real improvement why isn't it in those lenses? Or is it just to introduce everyday lenses that are smaller and lighter but not intended for the higher quality ones? This seems to be a trend with Pentax introducing the smallest DSLRs on the market to attract the mirrorless crowd, with compact lightweight lenses to suit.