When stop down, both defination and color is good and consider an average performance but far away from impressive.

Personally, I will prefer Canon excellent EF20 f2.8 USM and will have no worries with future EOS bodies.

Conclusion : It is buyable.

With 24mm, need about f8 to have similar results.

I somehow do not like the distortion at both 17mm and 20mm. IMO, all focal length and all aperture give excellent color but not excellent edge definitions. For this reason, I will against it.

However, given the fact that color re-production and mid-range color detail are slightly better than Canon non-L primes, it is still worth considering. And if you are in press works, this is most probably the most useful lens.

Conclusion: RECOMMENDED for those who need ultra wide zoom.

Wide open defination is slightly soft. However, due to its good flare control, the overall pictures are still acceptable. Stop down to f8 primarily increase the defination which are better for enlargements.

Optically speaking, I find it is pretty good. But I have no confident that if it will not give any troubles in long term means.

Personally, I will prefer this lens than using either EF17-35 L or EF20-35 L because of the excellent optical performance. Many people that I know use this lens with thier EF28-70 L.

Conclusion: I HIGHLY RECOMMEND this lens. IMO, it is a great combo with EF28-70 L which give professional results at all aperture and all focal length.

Distortion control are pretty good.

Color are warm and similar to older L lenses like EF80-200 L.

Conclusion: I RECOMMEND this lens. Buying it used is a smarter choice than getting a new EF20-35 USM non-L IMO. Reason given is the good distortion control.

Distortion control is of excellent mean. I had taken pictures where my subjects are about 1 meter or less from the lens and I still cannot notice any distortion.

Edge defination at wide open are comparable to 17-35 L at f8. For your information, the price of EF24 f2.8 in Malaysia had just been doubled from RM880 to RM1700!

Further more, it is better sealed as more expensive 'L' lenses, as a result, for those whose places are humid, it is much more resistance to fungus. From my experience, fungus will only grow outside the elements where you can wipe it off easily.

Another interesting things that I want to share with you is that I can hardly find any negative comments against it from the net. After several dozen of pictures, I agree with them where the performance is hard to complain.

Conclusion: I HIGHLY RECOMMEND this lens. Excellent distortion control.

At 50mm, wide open results looked like out-of-focus. With others words, lousily soft. Color saturation is terrible at wide open.

Stop down to f5.6, contrast and overall sharpness increased. However, it is still lousy IMO. At f8, contrast and sharpness further increased. But results are still no good.With my pictures shot, solid green became pale green, both Red and Yellow response are jokes to me. Flare control are lousy also.

Generally speaking, optical performance which mean both color saturation and contrast is better at the shorter focal length.

Conclusion: Avoid it. It is nothing but a sub-average lens.

However, it suffer some flare problem towards strong lighting. Lens Hood is a must! You can't save the money IMO.

Conclusion: I HIGHLY RECOMMEND this lens except if you already own EF28-70 USM L.

IMO, EF28-70 L will give you professional quality, edge to edge defination, perfect distortion control starting from f2.8! All focal length and all aperture used will give you first class quality images.

With all the excellent results, it is so hard to believe that I am actually shooting with ZOOM lens.

Conclusion: I HIGHLY RECOMMEND this lens if you can afford. One of the best lenses that I had tried.

Well, at the time I am writing this review, there is still no lenses can beat Canon EF28-70 L but this lens is near. Just use this lens stop down to f5.6 and below, and the difference will be even nearer.

Personally, I think it is a good alternative for Canon EF28-70 L for those who can't afford the L. I myself is looking forward in the used market.

The only worry is the compatibility with future Canon EOS bodies.

Wide open defination is good. Overall defination is better than Tamron 24-70. Stop down to f8 slightly increase the defination further. Overall defination is about the same as EF28-105 USM. It should be able to give satisfied 8" x 12" prints.

Conclusion: To buy or not to buy? I am not sure... but it is worth considering.

So does it mean it is excellent in optical mean? NEVER! In my own subjective ranking, the most I can rank this lens is GOOD. That's all. It is indeed better than many consumer lenses but it doesn't mean it deliver professional results. With other words, don't expect so much.

Distortion control is pretty acceptable across the focal length. However, group pictures taken at 28mm is very disturbing at the edges.

Mechanically, it is good (not excellent). Focusing with USM is smooth and silence. Auto-focusing is much faster from 28mm to 70mm compared to focal length after that.

Conclusion: Don't expect too much from a consumer zoom. Buy it if you are thinking of shooting with one lens and you don't mind slight distortion. By the way, it is one of Canon best consumer zooms.

Defination are also jokes at the longer ends. After seeing all the so-so and poor performances, I wonder how this lens can win so many awards? Can someone explain to me?

Anyway, I THINK, and MAYBE... the optical quality is still acceptable for someone who need the convenient of super zoom range.

Conclusion: To buy or not to buy? Don't ask me but personally I will avoid it.

Conclusion: Disappointed and avoid it.

On the negative side, it is not well sealed as my EF24 f.2.8 or more expensive L lenses. For those who are in humid places, be careful and please do some prevention. Beside, since it is mostly built with plastic, it cannot stand free falling to concrete floor beyond 1 meter. What did I know? Well.... it is a long story (not a happy one). So, if you plan to use it professionally (abuse it), it is not the lens.

Conclusion: I love this lens and HIGHLY RECOMMEND it. I wish Canon can make more good lenses at this affordable price.

Conclusion: I HIGHLY RECOMMEND it. It is the one for those who need the top optic.

The one I used to have perform very good even at wide open. Stop down give slightly better results which are of near-excellent mean. Sharpness, contrast and color saturation are all very good but color rendition is not as good as Canon's L. As a result, some slight detail of light color/signal might be lost or washed off.

There are 2 major complains against this lens. First, the loose construction can auto-zoom to the longer end if you point it to the floor. Lousy construction, right? Second, the aperture is too small and one usually need larger aperture for telephoto lenses because they need higher shutter speed. For these reasons, I sold mine and got myself a EF80-200 L.

Conclusion: I still like this lens very much and HIGHLY RECOMMEND it. Try to seek it in the used market.

The ability to use Canon original TC is a BIG BIG PLUS.... Quality degradation when used with TC is negligible. One can never go wrong with this excellent zoom.

Conclusion: I love this lens and HIGHLY RECOMMEND it. Good Stuff!

As a result of superb contrast + superb sharpness + excellent flare control, pictures taken with this lens become much clearer and much more solid. In other words, if you compare pictures taken with several non-L lenses, you can notice there are much difference between them even in small prints (especially there are strong lighting). Optically, I love this lens. If I am not mistaken, its flare control is better than all of my non-L Canon lenses that I had used.

However, its slow auto-focusing motor as well as the name itself make me avoid it.

Conclusion: Forget about it, ok?

My main complaints against this lens is the poor contrast and flare problem when compare with EF70-210 USM.

For the same money, IMO going for a used EF70-210 USM is a much wiser choice.

For those who want to understand what is flare and poor contrast, try to shoot with this lens. This lens also enjoying itself hunting and hunting. I guess sometime manual focusing is faster than its autofocusing when used on my EOS A2.

Conclusion: Nothing but a stupid lens which cause me lots of problems.

Its color rendition is better than EF70-210 USM IMO which the Sigma bring out lots of mid-range color detail. Color saturation also very good.

The biggest problem with this lens is only not-so-good flare control. Stop down decreased the flare but still clearly visible. Disappointed, right?

Well, after some experiences with this lens, I like it. The Macro capability at 300mm is also very useful. But... it is a Sigma....

From 80mm to 135mm, wide open performance is of very good. Stop down to f5.6 and above, you get crazy sharpness (more than excellent? I call it superb sharpness). Just be sure to mount it on a stable tripod and you can do as large enlargement as you wanted.

At 200mm, color are very good. However, wide open definitions are only good. Stop down and the results become very good (not excellent). If you have this lens, try to shoot a bit less than 200mm (something like 180mm), and you can get even better definitions.

Color balance is more to warm. Contrast is very good (natural to eyes) and sharpness is undoubtedly excellent. Both color rendition and color saturation are very good (even better than some non-L prime lenses). For these reason, I love it for taking portrait. Many had mentioned that its color is better than the newer EF70-200 L but I am not sure.

Complaints? It is a bit too heavy and it need really good tripod. My combination with this lens on my cheap Silk 8000 was shaking even I use the mirror lock. As a result, I got myself 2 rolls of blurred films.

Conclusion: I love this lens and HIGHLY RECOMMEND it. Good Stuff!

Optically, it is next to EF70/80-200 L. There are still some minor optical quality difference between pictures taken with L lenses and this lens especially if you pay attention to the color rendition. But I doubt how many people can tell which pictures are taken with which lens.

Conclusion: RECOMMEND only if you cannot find any used 80-200 L lenses.

Contrast is nothing but JOKES. Wide open contrast is lousy. When stop down to f8, contrast slightly increase but doesn't help much. With other words, still terrible.

Defination at wide open is slightly soft. I think my EF50 f1.8 II at f1.8 is sharper than its wide open at the center. Stop down to f8, defination increased and is enough for 8" x 12" prints.

Conclusion: 2 words, Avoid It!

Distortion? I cannot detect any.

For comparison, Canon EF100 Macro, at wide open and f4, with 4 extreme corners, color are not well solidly focused. Stop down to f5.6 and below, all results become perfect to my eyes.

On the other hand, Tamron SP90 Macro, staring from wide open to f8, all give me excellent defination at 4 extreme corners. All aperture results are excellent. Construction is good but not as solid as Canon or Sigma EX. Auto-focusing also hardly hunt in my case when compare with Sigma EX. Filter size is 55mm but it is not a problem. Always use a step up ring to the standard 58mm and the current 55mm Tamron lens cap will fit perfectly.

However, after I got myself a EF80-200 L, I hardly use this lens. Should I sell it? I don't know... Well, I still use it once a year.

Conclusion: One of the best lens for MACRO and I HIGHLY RECOMMEND it.

For comparison, Tamron SP90 Macro, staring from wide open to f8, all give me excellent defination at 4 extreme corners. All aperture results are excellent. Construction is good but not as solid as Canon or Sigma EX. Auto-focusing also hardly hunt in my case when compare with Sigma EX. Filter size is 55mm but it is not a problem. Always use a step up ring to the standard 58mm and the current 55mm Tamron lens cap will fit perfectly.

It is a very good lens and you have no worries about the compatibility with future EOS. However, I don't like the price tags.

Conclusion : I do recommend this lens. Who can go wrong with Canon original lenses, right?

Defination at 300mm are slightly softer than EF70-210 USM at 210mm. Well, it is still useable IMO.

Conclusion: I HIGHLY RECOMMEND it. Great combination with EF28-105 USM.

At the wider aperture and when compared with both Canon excellent EF70-200 L and EF80-200 L, the minor difference is only due to vignetting where the EF 135 f2 L suffer a bit wide open and became perfect staring from f2.8!  While on the other hand, both L zooms suffer more vignetting at f2.8 if compared with EF135 f2 L at f2. EF80-200 L's vigneting at wide open is even more serious relatively.

When stop down to f5.6 and below, the 3 lenses are perfect IMO and I cannot detect any difference at all means except the EF80-200 L color is slightly more to warm.

The comparison between this 3 lenses produced the least difference compared to all my previous tests conducted. The differences are really too minor and take many people to see the pictures and opinions to confirm it.

Just remember to use the lens hood to reducer flare.

Conclusion: PERFECT in every sense. HIGHLY RECOMMENDED! Another lens for those who must have the best.

Both color rendition and contrast are excellent as expected. On the plus side, the 72mm filter size is also good for Nikon soft IMO.

A fine portrait lens which help one to narrow down the background. I love both the perspective and color produced.

Personally, I am not sure if it is worth the money to cover my EF80-200 L's minor weakness (weaker defination and vigneting) at 200mm. Should I get it?

Conclusion: HIGHLY RECOMMENDED!