There really isn't a ton of information available specifically comparing the two best 3rd party 70-200 2.8 offerings. Without a doubt the Canon Mk2 lens is the holy grail of 70-200s. Even Chuck Norris cannot contain it's awesomeness. I haven't had the opportunity to compare any of these lenses directly to the MK2 but for some of us "Hobbyists" the price could be a bit out of reach leaving slower F4 lenses or the 3rd party Tamron/Sigma offerings as our only choice. With that being said I've had the luxury of owning several models of the 70-200 specifically the Canon 70-200 F4 non-IS, Canon 70-200 F4 IS, Sigma 70-200 2.8 OS & now I currently own the Tamron 70-200 2.8 VC. I have seen many topics about these two specific lenses which tells me there is a market for a budget offering so I figured I would take the time and take some sample shots of both of these lenses while I have both in my possession and post my findings and show everyone the real world sample shots. Let's get started:
DISCLAIMER: I am not a pro, I'm a dad. In the quest of a controlled variables there could be some flaws in my testing, however, I did my best to make sure that focusing, mirror lockup, tripod, everything that I could think of was utilized to make sure the results were as accurate as possible. Too add to this, I will not be posting any more samples beyond this review comparing the two as I simply struggle with free time having 4 kids and working 60+hrs a week. On to my comparison...
Note: Everything will have Tamron first and Sigma second, all comparison photos will have Tamron on left and Sigma on right
There are many websites available showing the technical specs (weight, size, etc) of these lenses. I recommend The-Digital-Picture.com to see this data. In my first hand experience they are very similar in size and weight. The Tamron hood is noticeably smaller than the Sigma but overall they are almost equal in size
STREET PRICE (at time of review 8/30/13 comparing the big 3 adorama, amazon, BHPhoto)
Tamron - $1499 (Cheapest price is via cameraland for 1299)
Sigma - $1250 (Cheapest price is via Buydig for 1199)
Sales happen. I got my Tamron for 1199 after rebate. Recently the Sigma went on sale new at Adorama I think for 999. There seems to be a consistent 200-300 more for the Tamron so long as you shop around. This is my findings based on US models from places that are reputable. Used markets can be all over the place. I've seen the Sigma sell for 850-1100 used. Average price is right at $950 although you can find better deals and higher prices. The Tamron used I've seen mostly for $1200. There isn't much available thus far which just could be because it's a rather new lens
The Tamron has weather sealing, very nice construction the grip material is a nice soft rubber and there is a texture to the exterior which is close to the texture exterior of the Canon lenses. The Sigma does not have weather sealing the rubber on the zoom rings is denser than the Tamron and the finish is smooth. A very clean look. Overall I feel the Tamron has a more solid construction than the Sigma but not to omit that the Sigma is well constructed either. I think the Tamron does its best to come as close as possible to the Canons that I have owned.
I actually do not like the Tamron collar. It's indeed built well but I like to have mine facing up when not using a black rapid strap attached to it and the hinge sticks out and rubs the palm the wrong way. The screw on it takes about 3-4 turns to loosen up. This sigma on the other hand uses a 1/2 turn knob and I like it's design because you turn it about 1/4 way and you can turn the lens and quickly lock it back down. For some this could mean accidental opening so I suppose the Tamron design would win on that but I have never had any issues with the Sigma collar opening up prematurely.
Both lenses have very good VC/OS units. This is my first Tamron with VC and it works very well. I can say this however that when you half press shutter and it engages then when you release for a half second to reframe and then half press again to refocus it does have a tendency to jump back into place. If you engage/disengage it in this fashion this it will do this quite regularly. The Sigma on the other hand engages and works and it actually locks the viewfinder down a bit better than the Tamron. I would almost say that Sigma has a 1/2 stop advantage, not much but I think it does work a bit better. Sound wise the Tamron wins hands down. The Tamron engages/disengages quietly and is not audible at all when your eye is to the viewfinder. The Sigma has a clunk sound when it turns on/off similar to the Canon F4 IS I owned and is also very slightly audible with a higher pitch sound. Neither Tamron/Sigma sound gets picked up by the internal mic like the way the Canon F4 IS did. It's quiet during video so that might help some. Also note that I've had to have my OS unit in the Sigma replaced once before and have friends who own the same lens and also the 120-300 and have had consistent failures. It's an known issue. Tamron VC at this moment I cannot comment on longevity.
As mentioned earlier they are both similar in design, both are petal type. The Tamron feels thicker and has a harder engagement than the sigma meaning it holds tighter. The Sigma has never came off by its own will before but just commenting that the Tamron has a snugger fit. I also feel the hood thickness at the mount is thicker than the Sigma but I didn't measure it with a mic to be for sure. This is based on feel.
Please take a look at this "Youtube" video here:
Sigma 70-200 OS VS Tamron 70-200 VC
It's easy to see who the clear winner is. The Tamron AF speed from MFD to Infinity is substantially quicker. The Tamron AF noise is quiet but is louder than the Sigma which is a nice smooth sound. One thing to note the Sigma sound doesn't change at all no matter what focal setting you are on where the Tamron has a bit of a different sound at different focal lengths, almost louder at 200mm than at 70mm. The AF speed is very noticeable when looking through the viewfinder and focusing on something that is 8' away to something that is 40' away... the Tamron is instant while the sigma has a slight delay.
ONE SHOT MODE KEEPER RATE: Tamron: 97% - Sigma: 85%
SERVO MODE KEEPER RATE: Tamron 85% - Sigma 80%
The Tamron has a slight edge however based on the 6D this is my results testing both of these lenses. I really feel I haven't had enough time with the 6D to justify this test as I don't think my 6D is as accurate at tracking when compared to the 7D I had. I would love to borrow my friends 5D3 and really test this out to rule out any body errors at all. I did not move to the 6D to for servo mode as my photography has moved more toward portraits/family. ALSO, in one shot mode I feel the Tamron has an edge because of its key strength... Sharpness/IQ. I mostly shoot F2.8-4 and although the keeper rate seems lower on the Sigma it could be because it appears to be less sharp than the Tamron. Which leads me into the last category:
The Tamron wins. Plain and simple every photo I have taken with the Tamron has far exceeded my expectations. No longer do I need to shoot at 3.2 or 3.5 for optimum sharpness that I had to do for the Sigma. I shoot the Tamron wide open with no regrets. Tack sharp at all focal ranges. 100% crops look stunning. Simply amazing for the price level of this lens. The Sigma also has excellent sharpness when stopped down to 3.5-F4. The biggest key factor where the Tamron wins is the midrange and corners. WOW is what you will say. I don't know if it's due to the Sigma having some sort of curvature on its focal plane or if it is truly softer in corners than the Tarmon. The bokeh on the Tarmon is smoother/creamier and is less "Busy" than the Sigma as well. The Tamron also produces a warmer color which works out great for me for portraits. In the samples below you can definitely tell when you look at the brick on the house and compare the color to the Sigma. You will have to look at my samples to be the judge.
All of these images where taken in manual focus in live view with 10x mode being used on a tripod with a 2 second delay using mirror lockup and using my Canon infrared remote. They were imported straight into Lightroom 4.3 and exported with no modifications. There may be some slight differences in exposure but not much. I shot wide open, stopped down to 3.2 and at 4.5 so you can get a good idea at each setting. If there are issues with my testing... shoot me, I'm a dad not a pro :P
My 100% crops posted below are only at 2.8, feel free to download the full size JPG at the various settings to compare for yourself. Here are the full size images:
Sigma 70mm 2.8 full size JPG
Sigma 70mm 3.2 full size JPG
Sigma 70mm 4.5 full size JPG
Tamron 70mm 2.8 full size JPG
Tamron 70mm 3.2 full size JPG
Tamron 70mm 4.5 full size JPG
Sigma 200mm 2.8 full size JPG
Sigma 200mm 3.2 full size JPG
Sigma 200mm 4.5 full size JPG
Tamron 200mm 2.8 full size JPG
Tamron 200mm 3.5 full size JPG
Tamron 200mm 4.5 full size JPG
70MM F2.8 100% CROPS (remember Tamron is on left, Sigma is on right)