Jonathan-Mac (above) said.......and if I were you I'd take it back.

My feelings also.
If you don't already have one I'd get an 18-135 instead. It may not be as fast or quite as wide but it has a longer zoom which I've found very useful and also good for pseudo macros. I got mine as the kit lens with my K50 and have used it extensively. It had bad reviews when first released but mine has never let me down and whilst perhaps not quite as sharp as the 17-50 Sigma and similar Pentax lenses I've found my copy quite sharp.

Good luck
Peter

Like cbrog I'm a bit surprised by those images.

I notice they were taken at Llyn Cwmystradllyn - I was there recently with my K50 and DA18-135 so here, for comaprison, is a shot I took, at 24mm, the other side of that fence :-
Peter

Here are the results of my initial trials of using the Green Button to set shutter speed. The lens this time is a Chinon 50mm f/1.7, similar to the M50 used at Portmeirion. I took 2 shots at f/8 and 2 at f/4.
These are the camera jpegs with NO PP adjustments except to reduce width to 1000pixels, so whilst quality may not be the best it gives an indication of how the green button does set the shutter speed (and also how f stop affects DoF !)

So many thanks again to Peter and David and here are the 4 shots, first 2 at f/8 and second 2 at f/4:-

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I'm now converted !
Thanks again
Peter

Well, Andrew, you certainly got me thinking. So as a challenge I took my M50 f/1.7 to Portmeirion recently and set myself the task of only using that instead of my usual zooms.
It was a fascinating experience and I learned a lot, both then and also from other members after posting the results in another thread on this Forum.
I checked today and there are still plenty of old M50 and A50 lenses on offer on the usual Auction site.
Thanks for asking the question and do give it a try!

Best regards
Peter

Many thanks Peter. That’s much clearer now so I’ll give it a try.

I looked again in the K70 Manual but it does not even mention the Green Button except in the illustration ! That’s why I need people like you!

Thanks again
Peter

Many thanks, David.
I was hoping that you would reply as I know you are a Master of Old Glass and would know 'the ropes'.
I did set the C menu to permit aperture rings but as the Manual just said 'the camera will now operate in Av mode I left it at that assuming it would use the preset aperture ?
I will now try your method of using the Green Button
One question though - do I need to keep holding the green button whilst pressing the shutter release ?

Thanks again
Peter

Many thanks for all the comments and also the helpful tips on using the M series lens.
I tried to get help from the K70 Manual but found that rather limited ? I'll try some of your suggestions and take some local shots to experiment.
Re the aperture settings I must admit that I normally take most shots at f/5.6 or f/8 as most lenses seem to perform best around there ? However, as this was an opportunity to use a 'faster' (f/1.7) lens (as oppposed to most of my zooms which open to f/3.5 or smaller) I thought I'd put it through it's paces. For my next tests I'll stop this lens down as well.

Re the Portmeirion pottery we did examine the origins of many of the the items on sale there and whilst many of the newer designs were marked made in China most of the traditional designs were marked made in England, so don't give up !

Thanks again for all the comments
Peter

Having previously taken many photos of Portmeirion using a range of zoom lenses I set myself a challenge of using a 50mm Prime instead, relying on PoV composure instead of resorting to changing the focal length by zooming. The following shots were taken on my K70 using a Pentax M50 1.7. For some of the shots I set the camera to use Av but for others (the night shots in particular) I used full Manual mode so I could select both shutter speed and ISO rating. Obviously, this being an 'M' lens I had to preset the aperture and tried to use f/2 or f/2.8 as much as possible to put the lens (and myself) to the test.
Over a few days I took around 200 shots which I shortlisted to around 50. Here is a selection from those, including some from the village and the woods and shore in daylight and some at night.
NOTE: These are all full uncropped images so you can see the actual image 'as shot', but the sizes have been reduced for posting
I'm not sure about the lens but I concluded that the photographer still has much to learn about how to get the best from this lens !
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All comments welcomed
Peter

Like you I tend to travel light with either my Sigma 18-250 (the earlier version of your lens) or the Pentax 18-135 which came with my K50.
Reviewing my exif data I find that a large number of my landscape and travel shots were taken at 18mm with others at various focal lengths between 18 and 60mm.
Going for a single prime I would therefore ask whether (on an APSC camera) a 28mm lens would be more useful ?

Whilst the larger aperture (e.g. around f/2 to f/2. might indicate a better quality lens (?), for landscape use I would doubt that the narrower DoF at wide apertures would seem a benefit so most shots would be taken at f/5.6 or f/8 ? A good quality zoom starting at f/3.5 or f/4.5 would then fit the bill ? So back to the old 'kit lens' 18-55 (which came with my Kr) then ? Perhaps not in my case as I found a s/h Sigma Epsilon 28-70 gave me better results (much to other people's surprise). I also got a used Pentax F 35-70 which is a very good sharp lens. (Both of these cost me under £20 on the auction site !)

It really is a case of what suits YOU and your requirements !
In my case it is those first mentioned lenses which get 99% of my use but of the two I would say that the Pentax 18-135 is the sharper (despite a bad 'Press' when it was first released !)

Good luck - you'll need it !
Peter

Surely you are well aware, John, that the shutter has to be planed in the focal !

Peter