[Kombisaurus]

Hi all,

I bought myself the Canon 17-85mm f/4-5.6 USM IS lens a couple of weeks ago, and thought I'd share my experiences with you.

I was shopping for a take-everywhere, do-everything lens to replace the kit lens. I already have a 70-200mm f/4 L lens, so I didn't need a big tele zoom but simply wanted something to take me out to around 70mm. I also have a 50mm f/1.8 prime to use as a fast lens (although not a zoom).

After much deliberation, the choice came down to the Canon EF-S 17-85 f/4-5.6 USM IS or the Sigma AF 18-50mm f/2.8 EX DC lens.

The pros of the Canon are:
* Longer zoom range
* Image Stabilisation

The pros of the Sigma are:
* Faster lens (f/2.8 instead of f/4-5.6)
* Better image quality

The Canon 17-85 has received mixed reviews, with the general opinion being that the image quality is a definate step up from the kit lens, but not fantastic and should be better considering the price of the lens. Most of the reviews I read about the Sigma were very positive about the image quality, but it wasn't as flexible as the Canon lens.

The fact that both lenses are designed for non-full frame cameras (ie DSLRs only) wasn't a big consideration for me as I don't really intend to use them on film cameras, and I believe the 1.6x crop factor (or thereabouts) is here to stay.

After looking at the type of shots I used my kit lens for (landscapes, architectural, etc) I concluded that although I would have loved to have an f/2.8 zoom, the fact is that I often use a tighter aperture than f/2.8 anyway... And although I realise the image stabilisation of the Canon lens does nothing to prevent moving subjects from blurring, it would be more useful to me because it is useful at any aperture, so not only will it let me get many (but not all) low-light shots like the f/2.8 would, but it will let me get handheld shots at f/8 or f/11 when I normally couldn't. I don't intend to use this lens for wildlife or sports, so moving subjects weren't a huge concern to me.
I have a 50mm f/1.8 prime for times when I really want a shallow DOF or to capture moving subjects in low light, and I intend to get one or two other primes to use for such situations where I need a really fast lens.
Plus there have been many many times when I found the kit lens a bit too short at 55mm... and as my "proper" tele lens is a 70-200, I had nothing to fill the gap. I wanted a true general purpose lens. Something to replace my kit lens that would give me better images and more flexibility. There was no doubt the Sigma would give me better images (and some more flexibility with f/2.8), but it wouldn't give me the flexibility in focal lengths I was after, or give me any more flexibility if I wanted a wide DOF.
So the Canon was my choice.

So... how have I found it?

Well... I've found the image quality pretty much as the reviews I'd read stated. Definately better than the kit lens, but not fantastic considering it wasn't much cheaper than my 70-200 f/4 L lens.
In the centre of the frame it isn't much better than the kit lens, but it holds together noticably better at the edges where the kit lens gets really fuzzy-wuzzy.
CA and flaring also seems better than the kit lens.
But... At 17mm this thing has *heaps* of barrel distortion and vignettes badly with a (normal thickness) polariser fitted.
Fortunately both the distortion and vignetting can be corrected easily in PS, but they shouldn't have to be! I haven't checked, but I suspect it actually distorts more than the kit lens at the shortest focal lengths.

So the image quality is nothing to write home about... but does that mean I'm not happy with the lens? Well, no.. actually I'm pretty happy with it.

Despite the lacklustre image quality, it is a definate step up from the kit lens... but that's not why I like it. It's because it really is a really useful, convenient and flexible bit of gear. If I'm walking around town with my camera and I can only take one lens with me, the focal length and functions of this lens make it amazingly useful. 17mm at the wide end is plenty wide enough for most shots, and 85mm at the tele end is very useful as well... and the IS makes a big difference.
It is the swiss-army knife of lenses..... Not always the best tool for the job, but one of the more flexible ones that can at least *do* the job.

I think this lens should really either produce better images or be a bit cheaper... but unfortunately there seems to be little else available to compete with it as far as usefulness goes... Its not bad, but not great either.
I'd give it a 6.5/10... and would recommend it with some reservation, mainly due to a lack of suitable alternatives.

...my 2c anyway..
all opinions based on my own copies of the lenses, seen through my own eyeballs and processed by my brain. I reserve the right to be wrong

[slejhamer]

Good writeup Kombi.

I really liked the 28-135 IS, and got some amazingly sharp pics from it in bright light but it wasn't a great performer in dim light even with the IS. It performed best between 50 and 100mm, f/8 or smaller. That made it a surprisingly good portrait lens with studio flash and a tripod (IS off.)

If your optical construction is similar, I'd guess that you'll get the best performance from your lens between 30-70mm, f/8-11. Just a guess.

[shuttertalk]

Thanks for the writeup Kombi... I wonder what decision I'd make in the same situation? I guess you would be trading off the fast aperture vs IS + slightly longer zoom.

Hm... would IS have much of an effect at such short focal lengths? IS on a 70-200 zoom I definitely wouldn't argue against, but...

[Kombisaurus]

Well ST, in answer to you question simply ask yourself if a tripod or monopod is useful at short focal lengths? Certainly for me the answer is that it is extremely useful. I can stick a polariser on the front of this lens and basically walk around and forget it is there as long as I'm not shooting anything that's moving. I can shoot low light dawns and sunsets without a tripod.

Here's one of the first photos I took with the lens - handheld at dawn.



Admittedly it was 35mm, 1/60th sec @ f/11 so wasn't really pushing the IS hard, but I wouldn't have had the confidence to try that shot with the kit lens. It handled it with ease here, and every shot I took came out sharp.

But this next shot on the other hand was handheld at 85mm, 1/13th second at f/5.6... so it was a very slow shutter speed for an 85mm focal length, yet the statue's face is very sharp (with quite a shallow DOF for f/5.6).



There's no question that IS is more of a necessity on a long lens than a short one, but that doesn't make it in any way superfluous at wide angles. It just means I can shoot at even slower shutter speeds.
The way the IS seems to work doesn't guarantee you sharp shots, but it dramatically improves your odds of getting a sharp shot and can make some shots seem impossibly sharp.
If I am steady I can get perfectly usable results with about 50% of shots handheld with shutter speeds as low as 1/4 second at 17mm.. and have no problem shooting at 1/10th to 1/15th second at 85mm...

And while I'm showing sample pics from this lens, here is a worst-case-scenario of the barrel distortion I mentioned. Admittedly the distortion soon disappears around 20mm, but this next photo was taken @17mm and it is shocking.



Cheers
Adrian

[EnglishBob]

Great Review, thanks for sharing the information.

[shuttertalk]

Awesome... you've convinced me!

[slejhamer]

That door is going to have some trouble sliding open ...

That's some big-time distortion. Well, just don't get too close when shooting portraits and you'll be okay.

[Kombisaurus]

Follow up:

I recently bought a Canon 430EX speedlite, and it has changed my opinion on this lens somewhat.

In my initial review I wasn't all that enthusiastic about the image quality of this lens, and when shooting only with available light I still agree with that.
But.. for some reason when using it with the 430EX flash, this lens just seems to come alive! It appears to get much sharper, and just seems to give a much nicer "look".
Of course using any flash will give a different look to all photos from all lenses, but it seems to work much better with this lens than the others in my arsenal (kit lens, 50mm prime, etc). These two just seem to have been made for each other.

Whether it is because the IS might introduce slight movements and therefore softness in all but the fastest of shutter speeds (and a flash is so brief that it is like using a very fast shutter speed)... Or maybe it is the AF-assist lamp that provides more accurate focusing... Or maybe something else (E-TTL II magic pixie dust?).. Or maybe I'm just imagining things.. I don't know...

But I do know that I love having this lens on my camera when the flash is on there!

Here's a sample pic of Rocket with the 430EX used as a fill-in flash:


And here's a 100% crop of part of that image:


Unfortunately it doesn't magically correct the other little annoyances I have with the lens (CA near the edges and distortion at short focal lengths), but overall I am really impressed with its performance in combination with this flash.