….image quality?

Let me explain:
The first lens I bought years ago was a Sigma 17-70 f2.8. It’s great. Sharp as a tack and fast.
A year or two ago I bought another Sigma , 18-250 f3.5 with IS. and whilst the zoom is great, I just don’t like it. Don’t get on with it. It can’t take the crisp pics my 17-70 can and I get too many blurred images. Most of this I put down to the big range – it’s always gonna be a compromise, right?
So I’m thinking of selling it and replacing the now rather battered 17-70 with either the newer version or maybe the 18-125, both of which have IS these days.
But do I really need it? I’ve got it at the back of my mind that IS itself isn’t going to improve the actual image quality and might even make it worse in some ways: panning shots, close ups etc.
Yeah, I know you can turn it off, but just by being there, does the lens suffer in any other way?

Just an idle question really. 🙂

Does anyone have the Sigma 18-125 by the way? Any good?

Oops. Might be wrong about the 18-125 Sigma. Can’t find it now…. Hmmmmm
And I’ve just worked out why the 17-70 is better than the 18-250. It’s a fair bit more expensive!

IS is really handy, especially at the longer end of the zoom range on the 18-125. Also good for doing stuff with a slow shutter speed for effect (water, moving cars etc) without having to use a tripod.

Can’t see how it would negatively impact image quality unless there’s something wrong with it.

I have a canon 400mm lens without IS and it’s fine in good light with a reasonable shutter speed, in winter in poorer light and slower shutter speed getting a good image in more challenging. You could try using a tripod and seeing if the pictures are better.

IS makes a massive improvement for long exposures. This is not debatable.

IS does harm image quality slightly if it’s on when your camera is very well supported ie on a tripod.

18-250 f3.5 with IS. and whilst the zoom is great, I just don’t like it. Don’t get on with it. It can’t take the crisp pics my 17-70

Wide range zooms are always a compromise, and I’d expect one with that kind of range (18-250) to be significantly worse than a 17-70. In addition, your 18-250 could have a fault, or just be a bitch to focus like my 30mm f1.4 is. Fantastic images, when it feels like it.

The 18-250 is what gets called a “superzoom”. Super because it covers a very large range of focal lengths, not because it’s actually any good.

This review suggests it’s pretty soft http://www.dpreview.com/lensreviews/sigma-18-250mm-3p5-6p3-os-hsm-macro/5

This is because it’s trying to do a lot while staying small and cheap. Either pick a lens that covers a small range of focal lengths or spend a lot more money.

In my experience.
1) IS isn’t bad. It doesn’t take anything away on the lenses I’ve tried (mostly Canon to be fair though) as long as you turn it off when you’re not using it.
2) Not all copies of Sigma/Tamron lenses are equal. I’ve had to send a couple back and had better versions of the same lens through. I used online reviews to compare with my own findings.
3) The 17-70 had a good reputation as a budget lens and the version I tested was pretty good (although I went with a Tamron 17-50 instead in the end).
4) The 17-70 IS is probably going to be better than the 18-125 IS – as there is nothing for free in lenses – it’s more expensive and has a shorter zoom range.

I’m pretty happy either swapping lenses, or accepting the compromises of whatever lens is on the camera, so I will always choose quality over zoom range, but I can understand the appeal.

Personally, on a limited budget, I went with the best ‘standard’ zoom I could afford (£250 for the Tamron), bought the 50mm Canon f1.8 for image quality and wide aperture when really needed (sometimes it stays on my camera for weeks), then added a cheap-as-chips Sigma 70-300 telephoto for the rare occasions when I fancy it.

ymmv

IS makes a massive improvement for long exposures. This is not debatable.

IS does harm image quality slightly if it’s on when your camera is very well supported ie on a tripod.

This.

What molgrips said.

Also, IS can effect quality if you’re moving, ie, shooting from a vehicle or even panning with a subject.

Cheap super zooms are also crap.

IS makes a massive improvement for long exposures. This is not debatable.

Never do that so it’s no use to me there. 🙂

I might just flog the 18-250 and not bother, just keep the battered 17-70 I’ve got. I just don’t think I need the IS…
I’ve crashed on it (strapped to my cheat) and thrown it down the road (taking pics facing backwards at ankle height, kicked it out of my hand…) and it just carries on…!

Cheap super zooms are also crap.

I had a dirt cheap Tamron 55-200, it was literally about £60 on eBay. It was slow, cheap feeling and noisy but get it right and it took some ace pics. Better quality than the Sigma at 5 times the price I reckon…. Might get another of those

The first lens I bought years ago was a Sigma 17-70 f2.8. It’s great. Sharp as a tack and fast.
A year or two ago I bought another Sigma , 18-250 f3.5 with IS

17-70 is a small range, so easier to make a good telephoto over that range. I have a 17-50 Tamron, which cost $200 and takes very sharp photos.

18-250 is a big range for a lens (with or without IS); so it is going to take a hell of a lot more elements to get the same quality (if at all possible), which either bumps the cost up massively or keep the price low and have much lower quality images.

The big boys eg Nikon, tend to keep to smaller ranges for their pro kit eg 70-200. Going wider still just erodes image quality or puts the price way too high.

This is how many elements it takes to make a good quality 70-200 zoom, for which you pay about £1600!