Replacement for Sigma 17-70 ?

I'm currently considering upgrading my Sigma 17-70 and considering options...

the Pentax equivalent isn't really an upgrade, at least not IQ/distortion wise

the 16-50 also seems to suffer from heavy distortion at the W/A, although the MTF figures look good

I've also come across the Sigma 17-35 EX and wondered if anyone had any experience of this?

thanks

simon

Well, as landscape is your main business why don't you go the "Prime" route.
That way you will see a real upgrade ( at least against any other zoom on the market.)
And with landscapes you have the time to fiddle around and zoom with your feet, anyhow.
It will cost you more, but at the end it seems you want the ultimate quality. Otherwise.....why seeking for a upgrade??

Martin.

A similar amount to the Sigma 17-70 according to Photozone.de. All zooms of this sort of range suffer from significant distortion at the wide end.

Also good for the Tamron 17-50mm F2.8.

If you want a distortion free wide angle zoom then the SMC Pentax-DA 12-24mm is a cracking lens.

thanks everyone..I already own the Sigma 10-20 which is a great lens, I'm really looking at the range covered by the 17-70, although as I own the 55-300 too the Tamron 17-50 looks a pretty good choice, how do users find it ?

Whist I'm quite pleased with the Sigma 17-70 I do prefer the colours/contrast produced by the Pentax lenses

thanks

simon

Sharp and contrasty, minimal CA. I had inconsistent AF with it on K10D but not on k20D. Colour is slightly warmer than Pentax's. Tends to under-expose (though that's easy to compensate for). Solid reliable build quality.

thanks,

i've owned a Tamron 70-300 in the past but found the colours very "muddy" and shots often lacked contrast, I guess the 17-50 is quite different?

Lacking contrast: definitely not; au contraire.

Yes it's quite different from the 70-300. That's a cheap budget lens; the 17-50 is an "SP" (Super Performance) model.

I'll post a couple examples from mine later. Meanwhile see

http://images.google.co.uk/images?hl=en&q=tamron%2017-50mm&um=1&ie=UTF-8&sa=N&ta...

and http://www.pbase.com/cameras/tamron/sp_af17_50_28_xr_di_ii_ld_aspherical_if

I love the colours in this one:
http://gallery.photo.net/photo/6412508-lg.jpg
...If that's muddy, I like muddy! What a beautiful picture.

Vancouver + K10D + Tamron 17-50 + Silkypix =

18mm f8:[IMG]http://i493.photobucket.com/albums/rr298/lime501/IMGP8509.jpg[/IMG]

100% crop (strange "painting-like" appearance to this, but still you can see the amount of detail captured):[IMG]http://i493.photobucket.com/albums/rr298/lime501/IMGP8509crop.jpg[/IMG]

100% crop, extreme left:
[IMG]http://i493.photobucket.com/albums/rr298/lime501/IMGP8509crop2.jpg[/IMG]

50mm f3.2:
[IMG]http://i493.photobucket.com/albums/rr298/lime501/IMGP8713-1.jpg[/IMG]

20mm f11:[IMG]http://i493.photobucket.com/albums/rr298/lime501/IMGP8287.jpg[/IMG]

17mm f8:[IMG]http://i493.photobucket.com/albums/rr298/lime501/IMGP8754.jpg[/IMG]

100% crop:
[IMG]http://i493.photobucket.com/albums/rr298/lime501/IMGP8754crop.jpg[/IMG]

K10D + Tamron 17-50 @ 50mm f2.8 ISO 400:
[IMG]http://i493.photobucket.com/albums/rr298/lime501/IMGP7135-1.jpg[/IMG]

100%:
[IMG]http://i493.photobucket.com/albums/rr298/lime501/IMGP7135-2.jpg[/IMG]

K20D + Tamron 17-50 @ 50mm f2.8 ISO 6400, no flash:
[IMG]http://i493.photobucket.com/albums/rr298/lime501/20D01407.jpg[/IMG]

100%:
[IMG]http://i493.photobucket.com/albums/rr298/lime501/20D01407-2.jpg[/IMG]

100%:
[IMG]http://i493.photobucket.com/albums/rr298/lime501/20D01407-1.jpg[/IMG]

K10D + Tamron 17-50 @ 28mm f4:
[IMG]http://i493.photobucket.com/albums/rr298/lime501/IMGP6997.jpg[/IMG]

Thanks for posting the photos, definitely nice colour and decent contrast....

my only thought now is whether the Tamron is enough of an upgrade on the Sigma to spend the extra cash !!

simon

I believe the Tamron is a bit sharper than the Sigma at some lengths/apertures, and obviously it's faster, but otherwise it wouldn't really provide anything different from what you have already, apart from loosing 50-70mm!

I'd say it comes down to the speed - not something needed for classical landscapes.

I got mine for the speed, otherwise I would have got a Sigma 17-70, and I came very close to deciding on that.

In your shoes I would start looking into primes to see if there are any that are MUCH better than either of these zooms.

Good advice I'm sure, the added bonus with primes is that they're easily carried around too so if they don't quite work for the shot I'm trying to take the Sigma will always be available too

I'll definitely have a look at what's available

thanks

simon