Is the 17-40 L worth the upgrade of 50D kit lens?

...had some serious softness issues with it when I first got it, but after a few trips to Canon, it is tack sharp, corner-to-corner, wide open, at any focal length. LOVE the lens. And, when I go full-frame, it will become my ultra-wide.

You can save some money and buy Tamron 17-50 or you can save some money to buy 17-55. Both are (much) better than 17-40 in IQ, speed and reach. 17-55 also has stabilization. 17-40 is an UWA lens for full frame and never was intended for use as standard zoom for APS-C. People had no choice before those crop lenses were introduced but you have those wonderful lenses that you can choose from now. You’re wasting you money, not to mention getting less, if you buy the full frame lens instead.

I would actually trade 28-135 for 18-55IS/55-250IS combo. It's a much more versatile kit with better IQ but does not cost much more than 28-135.

Sam Shapiro said:

The 17-40 is a beautiful lens, mainly in terms of its construction, and has good resistance to flare and CA. However, ultimately getting the picture is the most important thing, so I would not recommend it to anybody as their only lens, as the zoom range is too short for general use.

The 28-135 is a reasonable lens (a bit soft in the corners at wide angle, but tolerable) and gives a very useful focal length range. You can supplement it with 18-55 IS for wide angle, which is cheaply built but at least as sharp as the 17-40 at the wide end (though contrast and flare resistance are not quite as good).

Click to expand...

At f/4, the Tamron is slightly sharper, but even there the difference is not huge, and by f/5.6 the difference is trivial, so most people would say it is an exaggeration to say that the Tamron is "much" better.

Against the Tamron's slight optical advantage, you have a noisy and slower focussing motor, which may also be a bit less accurate. The "mechanical/physical" advantage of the Canon is huge compared to the Tamron, which has a slight optical advantage.

Here is what SLRgear.com wrote about it, and that matches my experience:

"The Canon 17-40mm f/4 L is a high quality lens with a full-frame image circle that showed really exceptional performance on the EOS-20D we used to test it with. (The EOS-20D has a nominally APS-C size sensor, so corner sharpness and distortion will be better than if the lens is used on a camera with a full-frame sensor.) Sharpness at maximum aperture is excellent across the board (just a slight decrease in sharpness around 30 mm), and the "sweet spot" for sharpness is unusually broad, with truly excellent results from f/5.6 to f/8 at all focal lengths."

carlk said:

You can save some money and buy Tamron 17-50 or you can save some money to buy 17-55. Both are (much) better than 17-40 in IQ, speed and reach.

Click to expand...

and yet when i went on a hike with both, in the field, the tamron had more pics with better focus and later when I dropped it the plastic mount snap was a $5 repair if the L fell it would've been at least $200 and maybe much more to fix so build can work against you too

when i was making my decision which to keep, i finally went out on that hike after all the charts and tests (where the tamron seemed to do a little bitter, similar in the center sharpness a little better in the corners, a little worse contrast in teh center a little better at the edges), and the tamron delivered better and had the f/2.8 option and was smaller and lighter and used less expensive filters and had an extra 10mm on the long end (which is noticeable).

anyway i sold the L (and my first copy of the L was not as good the second that was tested against the tamron; although some complain about bad tamron copies as well, so far i have been lucky with them)

i couldn't see paying more for the L considering it seems to deliver a little bit less.

on FF the L does worse and yet there there is no other real competition so if you need an ultrawide zoom it makes sense IMO to get it on FF and is the lens to get in that case (although if you can go prime the 17mm,24mm TS-E or straight primes deliver better, radically better near edges and corners, granted at much higher cost)

Sam Shapiro said:

At f/4, the Tamron is slightly sharper, but even there the difference is not huge, and by f/5.6 the difference is trivial, so most people would say it is an exaggeration to say that the Tamron is "much" better.

Against the Tamron's slight optical advantage, you have a noisy and slower focussing motor, which may also be a bit less accurate. The "mechanical/physical" advantage of the Canon is huge compared to the Tamron, which has a slight optical advantage.

Here is what SLRgear.com wrote about it, and that matches my experience:

"The Canon 17-40mm f/4 L is a high quality lens with a full-frame image circle that showed really exceptional performance on the EOS-20D we used to test it with. (The EOS-20D has a nominally APS-C size sensor, so corner sharpness and distortion will be better than if the lens is used on a camera with a full-frame sensor.) Sharpness at maximum aperture is excellent across the board (just a slight decrease in sharpness around 30 mm), and the "sweet spot" for sharpness is unusually broad, with truly excellent results from f/5.6 to f/8 at all focal lengths."

carlk said:

You can save some money and buy Tamron 17-50 or you can save some money to buy 17-55. Both are (much) better than 17-40 in IQ, speed and reach.

Click to expand...

Click to expand...

That lens is a work of art that delivers excellent IQ, reliable focusing and first rate build quality.The only negatives I can see are 2.8 and stopping at 40mm, but the fabulous color and contrast make up for that. Once you shoot with the 17-40L, putting on an EFS or non-L lens feels weird.....

That's what I always been saying you want to look at the lens or you want to look at the pictures? I have to admit those L lenses are really good to look at and nothing beats the red strip in front of it. Somehow all these don't matter to me anymore when I looked at the pictures.

Montana500 said:

That lens is a work of art

Click to expand...

The 17-40 is a great FF UWA for the money, but on crop you're wasting money with it.

The 17-55 is better optically, stabilized and has a much nicer range (yes, 15mm and 1 stop matter a lot, try shooting portraits at f 4 and 40mm and then at 55mm and f 2.8 and you will see what I mean, the difference in subject isolation is significant, plus 40mm on crop is really not much of a portrait distance anyway).

If you want the best for crop, that's it, and the price difference with the 17-40 is not that big.

carlk said:

You can save some money and buy Tamron 17-50 or you can save some money to buy 17-55. Both are (much) better than 17-40 in IQ, speed and reach. 17-55 also has stabilization. 17-40 is an UWA lens for full frame and never was intended for use as standard zoom for APS-C. People had no choice before those crop lenses were introduced but you have those wonderful lenses that you can choose from now. You’re wasting you money, not to mention getting less, if you buy the full frame lens instead.

Click to expand...

--
http://www.flickr.com/photos/bogdanmoisuc/

agreed and after i used them both (L and tamron) in the field, I actually sold my 17-40L (and I had really wanted to like the L better). Extra 10mm on long, f/2.8, AF that actually did better overall in the real world, less CA on the long end, lighter, smaller, only thing it gave up was a little bit of contrast in the center.

i have little doubt that I'd have liked the 17-55 IS better too (and maybe overall better than the tamron) but at the time I couldnt see paying that much more for what appeared to be mostly IS and a little less CA on the wide side (since the tamron does clean up fairly smoothly in ACR), but with unlimited money i'd probably go for the 17-55 IS on a crop.

and i'm not saying it as an anti-L guy either, I did go for the 70-200L over sigma/tamron

and I do have a few other L's

carlk said:

That's what I always been saying you want to look at the lens or you want to look at the pictures? I have to admit those L lenses are really good to look at and nothing beats the red strip in front of it. Somehow all these don't matter to me anymore when I looked at the pictures.

Montana500 said:

That lens is a work of art

Click to expand...

Click to expand...

My copy of the 28-135mm is very good. I take it on photo shoots along with a 10-22mm for landscapes and a 100-400mm L for wildlife. I have the 17-40mm L lens as well. It gives good IQ but is neither long enough nor short enough. I use it for family shots.
--
C Sidney