[Toonahfish]

Which one should I get? This lens is to serve as a replacement to my DA 18-55mm which was stolen. i'm thinking more the 18-50mm. Note the 18-50mm macro is the newer version and has improved optics over the older one without macro, as well as a closer min. focusing distance and a larger filter diamter. Otherwise they are the same.

[RBellavance]

These lenses are in two different classes. The 18-50mm is an EX lens, which is Sigma's high-end line. It is a constant f/2.8 and is generally a better lens in all aspects. It covers a smaller focal range, however, and is more expensive than the 17-70mm

The 17-70mm is a great lens for the price, but if you don't need the 50-70mm range and can afford the 18-50mm, the latter is the better choice.

[barbosas]

I'm also considering this two lenses, if someone who owns any of them give their opinion would be good.

thanks

[JeffScottSF]

Just checked the price at Sigma4Less, and the 18-50mm f/2.8 DC EX macro IF lens (581602) is currently selling for $399.95, which isn't pocket change for someone like me, but I'd be inclined to go for the EX, because I've had very good luck with this Sigma type for several macro lenses. It also has the inner focus system, if that makes a difference to Toonahfish.

[slip]

I'm also considering this two lenses, if someone who owns any of them give their opinion would be good.

thanks

I own the 17-70 and like it a lot. the only thing I would change would be to make it 2.8 through out the range, but then again that would push the price up considerably.
the bohken (sp?) is smooth but not buttery smooth like my pentax smc m 50 1.4.
the 17-70 is very sharp, almost too sharp for certain portrait shots (that doesn't bother me though as I PP with photoshop anyways)
The macro is really good for a non dedicated macro lens and the only thing that stops you from getting closer to the subject is usually the shadow from the lens.
The lens is a bit big, comparing it to a prime lens.

I would say if you really need the 2.8 throughout, then go for the 18-50mm (and can spare the extra price)
If not, I would go with the 17-70mm (remember from 17-50mm the range is between 2.8 and 3.5, not a huge difference from the 18-50mm)

I think you would be happy either way...
let us know how you make out

good luck

cheers

randy

[dantuyhoa]

I have the older 18-50 version ( NO Macro ) which is very sharp , IMHO . You can get it new for 299.95 :

Amazon.com: Sigma 18-50mm F/2.8 EX DC Lens for Pentax Digital SLR Cameras: Electronics


You can check out the photos

Flickr: Photos from dantuyhoa

Good luck

[RBellavance]

(remember from 17-50mm the range is between 2.8 and 3.5, not a huge difference from the 18-50mm)

That's a very good point, and one I had overlooked in my comparison. Thanks Randy.

[Toonahfish]

Me too. I was pretty set on the 18-50 but that fact has swung me in the other direction...

[Kguru]

Would someone please explain what materially the EX in 18-50 provides when compared to the non-EX 17-70; is it better glass/coating, better build quality, better something, or a combination of these? Thanks.

[Rodelion]

Would someone please explain what materially the EX in 18-50 provides when compared to the non-EX 17-70; is it better glass/coating, better build quality, better something, or a combination of these? Thanks.

BUILD QUALITY - 18-50 wins. It's got only one extending barrel, whereas the 17-70 has two. It's clear which one can handle a three feet drop better. Also the 18-50 has a more solid feel when zooming. REMARK: but the 17-70 feels WAY better then the Canon, Sony and Nikon kitlens, like a real lens.

OPTICALLY the 18-50 is a tad better, but I think their sharpness is the same to the untrained eye.

MACRO - 17-70 wins with 1:2 instead of 1:3.

Reason to buy the 18-50 for me: it's a LOT better lens for portraiture! I love blurry backgrounds instead of half-sharp ones when doing portraiture (f2.8 vs f4.5 is a LOT of DOF-difference). If you've got a 50/1.4 for your portraits (better yet!), the 17-70 may be a good alternative for allround use. Just my views. Good luck.

[Kingsofronin]

If your kit lens got lost/stolen, then just get what you can afford!

If you can afford the 18-50, do it now.
But if not, the 18-70 will do for a little while.

[egordon99]

Changing your tune? Did we convert you? yay!
(not sure what 18-70 you're talking about though....Did I stumble into Nikon territory by accident?)

If your kit lens got lost/stolen, then just get what you can afford!

If you can afford the 18-50, do it now.
But if not, the 18-70 will do for a little while.

[offertonhatter]

I think I would go for the 18-50 f2.8 Lens.

I am considering it myself as my prime lens, unless the pentax DA* 16-50 sdm lens appears first (if ever!)

[barbosas]

Changing your tune? Did we convert you? yay!
(not sure what 18-70 you're talking about though....Did I stumble into Nikon territory by accident?)

I think he ment to say 17-70 instead of 18-70

[Kguru]

BUILD QUALITY - 18-50 wins. It's got only one extending barrel, whereas the 17-70 has two. It's clear which one can handle a three feet drop better. Also the 18-50 has a more solid feel when zooming. REMARK: but the 17-70 feels WAY better then the Canon, Sony and Nikon kitlens, like a real lens.

OPTICALLY the 18-50 is a tad better, but I think their sharpness is the same to the untrained eye.

Thanks for your explanation.
I guess the gut of my question is why do they stamp EX on one and not the other when the differences are so minute. It kind of does a disservice to any specialty Sigma imply to attach to their EX designation, don't you think?