I am looking for a wide angle zoom that is not too expensive, but extremely sharp. I have been using the 17-40L--it struggles a bit for me in the corners full frame, and also at the wide end things in the corner tend to distort. Ditto for the Sigma 15-30 which I have also used. Has anyone used this Tamron 20-40? Judging by the MTF charts it seems like it would definitely be sharp. But of course, there is more to consider than just charts, so I was wondering if anyone had used it and could give me an evaluation. I am expecting it would probably be sharp in the center, but how is IQ in general, and at the wide end would it give me better corners than the 17-40L or Sigma 15-30?
From my experience, it is an excellent lens that is overlooked. These are from my Kodak SLR/n, which is very picky with lenses, but loved the Tamron 20-40/2.7-3.5.
I've used the 17-40L for many years, and I find it is plenty sharp to the corners when you stop down to f/8 or f/11. I expect that the 20-40SP is probably a very solid performer, but I doubt that a 20-40SP is better than the 17-40L for any meaningful aspect of IQ. I've used many Tamron SP lenses of about the same vintage as the 20-40SP, and they are generally very good, but modern L equivalent lenses are generally better. The user reviews at PhotoZone support this point of view: the 17-40L has an average IQ of 87, and the 20-40SP is 78. The Sigma 15-30mm has considerably lower ratings than both the 17-40L and 20-40SP at PZ. The Tokina 20-35/2.8 AT-X Pro has much higher user satisfaction scores than the 20-40SP. Of course, if you want excellent IQ with high sharpness to the corners and low distortion from an ultrawide angle lens, then you need a prime or a much more expensive zoom, like the Nikkor 14-24/2.8 G ED.
I note that your profile says you take photographs to document your research activities for art history - if that means you're shooting a lot of 2D subjects like paintings and manuscripts, then maybe you're encountering curvature of the focal plane. That's not particularly important for landscape work, where you're stopped down and focused at or near to infinity, but it might creep in for close focus distances. For this type of work, I think you'll be better served by a set of two or three small primes - choose your poison.
The Tamron 20-40 is much better than the canon 17-40 for B and C zone sharpness, color, and the 3D look. The corners also sharpen up much sooner, and it is faster across the zoom range. The lens originally sold for about $800US, but can now be had for cheap. My copy is the updated version with the new outer style. If you plan to buy, look for the later model. It is very well built and has great feeling manual controls.
What's the use in comparing one Tamron to another? Like any brand of lens, each model may perform completely different. Heck, even a specific model, has sample variation. The Canon 17-40 being a strong case in point. BTW, I have also tried the Tokina 20-35 in both the /2.8 and /3.5-4.5 varieties. They are no match for the 20-40.
At 20mm the Tamron is better than all of the 20-21mm primes I have tried, except the very best. It is better than a all four copies of the 21/3.5, my excellent copy of the Nikon 20/4, and for most parts even the Zuiko 21/2's I've had. Only the Nikon 12-24 does better. I'm sure the Zeiss 21/2.8 would be better as well, but I don't know of any other. In fact, seeing the results from this lens led me to sell my Nikon 12-24. It's that good
Thanks for the comments on my pics. They were taken with a Kodak SLR/n (14MP full frame, with no AA filter) in RAW, very little PP on all. The last was converted in BW in PP. All show the full frame.
I have and use both versions of the Tamron SP 20-40 f/2.7-3.5 lenses. They are very good and very sharp. Actually sharper than some primes in this range. Both versions are identical optically. The second version is only different cosmetically and outer build. Both are very good.
Following up, since I am the one who started this thread--I went to look at one I found on Craig's List. I brought my Canon 17-40L so I would have something to compare it to, on my 5d ii. The Tamron 20-40 is a decent lens I suppose, but honestly I took a handful of shots with each and in comparing them it was pretty obvious that the Tamron was decidedly inferior. Personally I saw no zone in which it outperformed the Canon. So obviously I decided to keep the money and not buy it. That sounds pretty glum regarding the Tamron 20-40, but as always there is potential sample variation, and definitely it was not the newer version pictured in this thread. So it could well be that there are superior versions of the lens out there, but the one I looked at was not one of them.
Sorry it didn't work out for you, but like any wide angle lens I recommend buying New or Mint condition as most wide angle zooms are easily knocked out of calibration. Do you have any pictures to share from your test?
Sorry, I didn't save the pictures on the card--I was in the living room of the guy who was selling it, I just took some quick snaps of stuff on his table and some rocks. But it was just obvious as soon as you zoomed in on the details: the 17-40 was better both in the center and the corners. Actually, the Tamron may have picked up just as much detail for all I know, but the color and contrast on the Canon were better and that at least gave the perception of greater resolution.
The center of mine is prime lens sharp, so there must have been some issue with your lens or the test.
One thing you won't see from an indoor test is CA. The Tamron 20-40 has much less than the Canon 17-40. And how can you judge color on and indoor test? I think my outdoor color shot with the blue sky and white snow show excellent color, with more pop and 3d than I ever got with a Canon 17-40.
I took delivery of this lens on Wednesday and tried a basic test today. I dont think the composition lends itself well to this purpose but my goal was more of a real world test and not so much a brick wall. I am curious what you think (here goes my first try at posting on FM)
tamron 20-40 at 20mm f2.8: (sorry kinda big)
at 20mm f8:
Here is the canon 17-40 F4L (I shot the 17-40 about an hour after the other two lenses)
at 20mm f4:
Honestly, I really can't tell much difference in those photos, perhaps because they are small, and of course it's grass so it's hard to make out fine detail in a small imge. Maybe you could post some crops as well to assess resolution? A closer look at the at the foreground corners might help show some differences. The Canon lens seems to be darker, but you noted that it was an hour later, and it looks overcast so maybe that's why. I think though that the Canon lens is not really set to 20mm, or at least not to what the other lenses read as 20, because in the other photos I can see a patch of dead grass in the front, but not in the Canon. I have noticed that the millimeter lengths of Canon's lenses in particular seems pretty approximate--well, of course in this case it's zoom, so it's a matter of setting it properly, so this is just a total tangent I am going off on here. But it's something I have noticed with modern lenses in general--they just call it 24, or 28, or 50 or whatever millimeters to fit into the standard size categories, but it could be a couple off either way. The older lenses often had non-standard sizes--the 58mm Biotar or Rokkor, or the 21mm and 25mm Distagon, etc. But I think they were just giving you the exact, real size. Nowadays a 24mm lens might very well be 25, but they just call it 24 to make it seem more standard.
, but it is f/2.7-3.5
