[chrism_scotland]

Hi folks,
I've gone on a bit of a rationalisation exercise and stripped my current lens lineup to a Sigma 10-20 f4-56 and a Pentax DA 40mm which replaced my Sigma 17-70.
I've been trying to cut down bulk and have found my K20D with the 40mm a much nicer walkabout combination than the heavier Sigma.

However I am now considering whether to replace my Sigma 10-20 with a prime also, the most likely candidate would seem to be the 15mm from the Pentax Lens lineup as it would sit in the middle of the focal range, also I don't believe there is a wider Pentax fit prime or am I mistaken?

Just looking for some advice on what other people are using at the wide end.

[Nick Siebers]

There is a DA14mm f/2.8 as well. It is quite a bit bigger than the DA15.

For my "ultra-wide" I use a Pentax-A 16mm fisheye. There are also 17mm takumar and SMC "K" fisheye lenses that could work, and the Zenitar 16mm too. These allow you to take somewhat fishy shots, but you can eliminate most or all of that distortion in post processing, giving a very wide angle shot. Obviously the older lenses require manual focus and other compromises.

[elho_cid]

DA14 is a great lens. I love it. It features better built quality than 10-20 Sigma (In fact also bettern than ANY sigma). It is also reasonably fast for a wide lens, but do not expect it to be small.
DA10-17 is fun and it is not too big (about the size of kit lens)

[SpecialK]

I would not say don't get a 15, but I would say don't give up the 10-20 (or any other similar range). I don't think you can go too wide. I have a 15 and 21, but I'm not giving up the 12-24. If you have no use for really wide, then yep, maybe sell off the Sigma.

[axl]

As suggested above, if you use your 10-20 mainly close to 10mm then 14/15 won't be enough.

To original question. The only SMC available new at the moment are:
14/2.8 - most owners really like it. It's the widest pentax prime at the moment and fastest below 30mm lens by Pentax at the moment.
15/4ltd - 9.5 out of 10 owners adore it. Apparently has great flare resistance and very good IQ. It's quite small I'd say around 35mm or old nifty fifty size. It's the slowes wide(ish) Pentax offering.
21/3.2ltd - most owners like it but some say it's not much better than your 10-20 at 20mm (from shots I've seen and as previous 10-20 owner I'd disagree). It's the smallest Pentax wide(ish) lens.

Unfortunately there the list of new lenses ends. If you are willing to dig through used market, you may get reward in form of FA20/2.8 or A20/2.8. If you don't mind fully manual, there is rare 18/3.5. And if you don't mind defishing then suggedted Tak 17/4 K17/4 A16/4 or Zenitar 16 would be options. Also there is Tokina 17/3.5. There are some sigmas but they are mostly big as a brick. And lastly if you consider 24 wide enough (you were asking for wide-ish) then there are great FA*24 (prone to dud copies) K and A24/2.8 great little lenses and Sigma 24/2.8 AF or MF version (these are quite small for Sigma lenses).

Good luck choosing.

[paperbag846]

For a general purpose wide the 15 is great but it's only marginally *ultra wide* so if you like crazy wide angles it might frustrate.

The really great thing about the 15 is that it's super sharp, so going the OTHER way (towards 20mm) is really not a huge deal as long as your camera has over 12 megapixels and you aren't printing wall-sized photos. It takes to cropping really, really well (even wide open). I end up doing this quite often, while never wishing it was wider. It's just not *that* extreme of a focal length, but it's plenty wide.

[GeneV]

Given all the OP's criteria, including reducing bulk, I'd have to say the DA15 is his best bet. Otherwise, I'd stick with the 10-20.

[chrism_scotland]

Thanks for the advice guys I'm going to keep the Siggy for now.