[MrTea]

After about 14 months, and 2 major trips with the K100D, with only the 18-55 kit lens and the Tamron 70-300, I have reached the point at which I feel it is time to consider replacing the Kit. Not because I don't think it delivers good enough IQ for my purposes; but because I need a little more range.

Last year, I found myself frustrated at the fact that I had a gap of 15mm in focal lengths from the end of one, and the start of the other lens that I have; and not that many of my shots were wider than about 24mm. The Sigma 17-70 would have been the ideal replacement. (Actually, I think the Pentax 24-90 looks like a pretty good range, since I don't shoot long that often; but these are rare as hen's teeth.)

This year, different holiday, different scenery, and I found myself constantly wishing I had a bit more than 18mm at the wide end. I never used the 70-300 at all, and the 55mm long end of the kit lens was not a limitation. Enter the 16-45.

OK, the Sigma gives me an extra 1mm at the wide end over what I have now; but the 16-45 give me 1mm over that. How significant is that extra 1mm? Is it worth sacrificing a focal length gap of 25mm in the short telephoto range, for an extra 1mm at the wide end?

So this is my dilemma now. What would you do?

The other thing the 16-45 has going for it, is that it is smaller in diameter than the Sigma, so filters (if I get any) will be cheaper, but more importantly, it might fit better in my small Lowepro TLZ1 bag. I don't want to buy a new bag, if I can help it, as well as a new lens!

[iwhizz]

im vote for DA 16-45mm, a very good lense to replace ur 18-55mm kit lense

[ll_coffee_lP]

Although I've never used either of those lenses, the word on the street around here is that both are exceptional.

Picking one over the other is going to be a decision that you have to make though.

c[_]

[whitedogone]

I too am in need of a replacement for my kit. Although it has very good IQ, it does have limitations. The range of the 16-45 really lets something to be desired in my mind. 1mm on the wide end means close to nothing. 25mm on the long end means a great deal. After all, that’s one reason I mount a zoom in the first place. The more range I can get without sacrificing IQ the better. Another plus in the sigma’s favor is that it's a 2.8 @ the wide end. WDO

[rparmar]

OK, the Sigma gives me an extra 1mm at the wide end over what I have now; but the 16-45 give me 1mm over that. How significant is that extra 1mm? Is it worth sacrificing a focal length gap of 25mm in the short telephoto range, for an extra 1mm at the wide end?

I know what you want to do, and I know what I did. All you need is a little push!

Get the DA 16-45mm. I have recommended it often on this forum. You won't find better IQ in a wide zoom. I prefer the 1mm wide to the 25mm tele, mostly because I prefer a much faster lens for portrait/mid-tele purposes, like, say the FA77 Limited. The fact the DA 16-45mm is so inexpensive is just a bonus.

There are example shots in my millennium thread and on my Flickr pages.

[whitedogone]

P.S. The semi-Macro of the sig is pulling me that way as well. WDO

[flyer]

I have the Sigma 17-70. This is the lens I use most. It is very sharp and covers most situations. I don't use the macro that much on that lens, but it comes useful once in a while when I'm traveling light. If you want to see the difference the 1mm might make, just try your lens at aprox. 19mm, than go back to 18mm, that will give you an idea of what you can expect.

[creampuff]

First off, that 1mm difference on the wide end is noticeable.
The Sigma is very sharp in the center but less so on the edges. The Pentax is more even in center and edge performance. I find I use the wide end of the Pentax more but the Sigma has the edge on the long end. I don't particularly like variable aperture zooms nor Sigma's colour rendition so I'd recommend the Pentax. Of course the coming DA 17-70 would be one I'd choose.

[Mike.P®]

I went for the 16-45mm in the end after a lot of thought.
It also helped that someone on here was selling a mint one for $260 delivered to Spain.
Very nice lens but still not sure if I did the right thing
It does focus fairly close though.

[song_hm]

Notice you never mentioned the 55 mm of your kit lens as too short, but lamented the 18mm is too narrow. Given that, the choice is very clear (at least to me), you need to get the wider lens of the two option. Both are excellent lens to begin with, so the only consideration left is your shooting style, the 1mm difference on the wide end is going to be more significant than 25mm on the tele side.

[rparmar]

The Sigma is very sharp in the center but less so on the edges. The Pentax is more even in center and edge performance.

That's the clincher. There's no point using a wide lens for things like landscapes if the edges are no good.

Of course the coming DA 17-70 would be one I'd choose.

Only if it's much better than the DA16-45mm in terms of sharpness and rendering, since it means giving up the 1mm on the wide end, it's slightly bigger and heavier (not significant) and it costs twice as much.

[roentarre]

And Da 16-45 fringes and renders chalky bokeh being charged more expensive for it.

[thirdofthree]

Notice you never mentioned the 55 mm of your kit lens as too short

Actually, the OP did, just in a less direct way:

Last year, I found myself frustrated at the fact that I had a gap of 15mm in focal lengths from the end of one, and the start of the other lens that I have

Personally, I wouldn't find the extra 1mm on the wide end worth the 25mm gap, but then on vacation I find I don't always have the option to zoom-by-foot to make up the gap.

At any rate, I don't think the info provided by the OP suggests strongly the 17-70 or 16-45, so it's very much a personal decision at this point. Good luck in your decision!

[heatherslightbox]

Have you given any thought to the DA17-70? The main reason I mention this one is that it's filter thread is smaller--67mm vs. the Sigma's 72mm.
PENTAX

Having the Sigma 17-70 myself, I usually find that the wide end is wide enough for most situations.

A couple more lenses you might consider...
DA *16-50 (a good copy)--77mm filter size
Tamron 17-50/2.8--67mm filter size

Anyway you look at it, you're going to have to move up to a bigger filter size if you want to upgrade the kit lens Don't sweat the filter prices though, as The Filter Connection has name brand filters at great prices (Camera Filters The Filter Connection 2filter.com for Hoya HD filters, Hoya Pro 1, Tiffen HT, Tiffen 4x4 Camera Filters, B+W filters and Canon Inks) with very reasonable shipping rates.
A good example of the difference in price is on the Hoya Pro 1 digital UV filters-- TFC has the 72mm for $43.91 while B&H has it for $73.50. I checked TFC's website and they do offer international shipping, so it wouldn't hurt to check them out.

If you decide to get other filters like polarizing, ND, etc., you might be better off going with the Cokin (or similar)-type system, as you only need to buy one filter holder and rings for each size diameter of the lenses you have.

HTH,
Heather

[Lowell Goudge]

I think as you shoot more you will be wanting more than 16mm.

You have now had a taste of it, and neither 16 or 17mm will be wie enough.

Depending on priority, you will also want to replace the kit lens, and the real difference between the pentax 16-50 and sigma 17-70 is at the long end, depending on what your next high quality fst lens will be.

If you are leaning to the pentax 50-135 or sigma 50-150,, then the pentax 16-50 may be for you. If you are thinking more like a new sigma or tamron 70-200 F2.8 you will still be bothered by the 20mm gap, then you should consider the sigma 17-70, or for that matter sigmas 24-60, 24-70 or tamron's 28-75

Any of them will do what you want, but you will still need an ultra wide.

Ultimately you will need to work out how to best go from 10-12 mm at the wide end to 150-200mm at the long end.