My friend recently told me that he was planning to sell his Sigma 70-200 F2.8 EX DG HSM II lens, and I saw an opportunity to borrow it to make a comparison review before he sold it off. And thus, a long and arduous task of trying to keep everything comparable begun.
The lenses: 
Sigma 70-200 F2.8 EX DG HSM II - Link to PF's user reviews/specifications (Not to be confused with the most recent Sigma 70-200 iteration) Tamron 70-200 F2.8 - Link to PF's user reviews/specifications My full album of sample shots and comparisons. Includes full size image links shot on the k-3 (24MP) Physical comparisons
The Tamron 70-200 F2.8 is surprisingly longer than the Sigma 70-200 F2.8 HSM II. I always thought the Tamron was the smallest of the bunch, compared to Sigma, Canon, Nikon, and even Pentax. That being said, the Tamron comes in at 200g less than the Sigma (and that weight can be seen in the girth).
The Sigma has the older crinkle finish. It felt quite solid, and the zoom and focus rings were smooth. The focus ring was especially nice to use in comparison to the Tamron, which has a AF/MF clutch by shifting the focus ring forwards and backwards. In addition, the manual focus of the Tamron had a little more friction and was not as enjoyable. The Tamron has a deeper/longer/more substantial hood, and I believe that it is a better hood. It certainly gives the lens a better look when compared side to side:
Both lenses have 77mm front elements that are non-rotating or extending. The lenses are (as typical of lenses in this class) internal focus and internal zoom. They both mounted nice and tight on my k-3, and I felt no wobble in any way on either lens. Both lenses have the classic positioning of zoom ring closer to the body, and focus ring closer to the front. This was changed in the most recent iteration of the Sigma, where the focus ring and the zoom rings swapped (I assume for faster autofocus).
On both lenses, the hoods are reversible and help with storing the lens. There aren't any discernible differences between the tripod feet. Both tripod feet rings have markings to indicate 90 degree positions, and the knobs are easy to use and tighten. I had no issues mounting either lens onto my tripod, and the feet stayed on nicely even when shifting the lens around.
I will comment that both Tamron and Sigma makes some really terribly difficult to use rear caps. Tamron's requires you to align the correct dot before turning. Sigma's turns the other way. Pentax's rear caps are significantly easier to use and I would go get myself a bunch of those just to replace the OEM ones from Sigma and Tamron.
Since the Tamron is my lens, I can comment on durability. I have used the lens since 2011 and it has continued to chug along. I had one scary spell when the lens had some issues autofocusing (I took it on a flight to Malaysia), and I couldn't solve the reason. After a month, the issue went away and the lens performance never changed. I've dinged it many times and the body is extremely resilient. It is super susceptible to dust, so there's quite a lot inside - but I never noticed any optical issues caused by the dust. So now that it is late 2014, the only problem I have is that the hood quick-connect mechanism is a bit loose and the lens hood does not stay on as tightly. I assume it's loosened on the hood itself and not on the lens hood-ring.
Autofocus performance:
Well, here is where people would assume that Tamron would lose out to the Sigma. From my experience with both lenses, I would disagree. I didn't do much of an AF test as I don't have the tools to make a consistent and repeatable test, so this section is just my opinion.
My first camera was the Pentax k-x, and I used my Tamron 70-200 on that camera until this year when I got a k-3. On the k-x, it was somewhat slow to focus - a person walking towards me would be a difficult shot to get. On everything else, the lens focused well (with a little adjustment).
Fast forward to now, and on my k-3 the Tamron is fantastic. I can track people walking towards me, birds flying towards and perpendicular to me, and I can lock onto a target very quick. It's noisier than the Sigma of course (microadjustments is quiet, but racking from near to far and vice versa is loud enough to disturb animals), but it is by no means slow. And on the k-3, it barely hunts. I've shot in bright and dim conditions, and the Tamron is a new beast with the k-3.
The Sigma is no slouch on the k-3 either. Everyone knows of how the Sigma HSM is better than Pentax's SDM (or at least, that's the note I gather from this forum) - and I will admit, my Sigma 50 F1.4 HSM was faster focusing and had less hunting than my DA*55 F1.4. The Sigma was quick to focus and very silent. I sometimes wouldn't know if it actually performed the microadjustment, because there was no sound. When it hunts, it hunts very quickly (the image just goes in and out of focus so fast). It is fast enough for tracking a person walking towards me, and the limitation is mostly the k-3.
So for both lenses, I would say the AF is mostly equal in speed and consistency, with the edge going to the Sigma for quietness.
Bokeh!All my photos were edited for brightness and white balance only - I tried to get the white balance similar so that it doesn't bias anyone when dealing with sharpness. No sharpening was added to the images - but I did increase the clarity a little (on par with what I do for all my photos). All shots were processed in Lightroom 5.0.
So I am going to start with bokeh first, because the lens resolution section is long and arduous, and anyone who finishes through it is going to be too tired to look at anything else.
My impression after having looked at both lenses is that the Tamron has a marginally better bokeh overall, but the two of them create very smooth backgrounds that it doesn't really make a difference which lens to use. Their effect on specular highlights is not unpleasing, and at 200mm they make the background melt into a blur. This may be surprising as the Tamron is highly touted for bokeh, but the Sigma isn't often mentioned. I know that my DA*55 F1.4 had better bokeh than my Sigma 50 F1.4, but in the 70-200 - the bokeh is lovely and I don't really have any issues with it.
Tamron: 
Sigma: 
Full size link:
https://farm4.staticflickr.com/3865/15264094812_cb54ae826f_o.jpg Please see the album linked in the beginning for more bokeh samples. Flare performance:
I tried to get the flare performance test to be the same framing for both lenses, but the Sigma (I think) changes the frame a little because it is slightly shorter than the Tamron. As such, the flare performance test is shorter and less comprehensive compared to the rest.
My opinion from the test is that the Tamron performs remarkably better on flare. In all scenarios, the Tamron either had less flare, or less distracting flare. I attribute it partly to the hood and to the better coatings perhaps.
Tamron (first) and Sigma (second) at 70mm F2.8:
Tamron (first) and Sigma (second) at 200mm F2.8:
Please see the album linked in the beginning for more flare samples. Image Quality
And now we come to the section that most people (or at least, in my head) care about. Now to preface this section, I did this just for fun and I do not have all the tools to make perfect comparisons between the lenses. For one, the Tamron focuses closer than the Sigma, and for another, the Sigma has a tendency to frame a little more at the same camera distance. So I did my best to keep everything as similar as possible, and I know I made one or two focus mistakes in the whole set. Also, I didn't bother doing corner/edge performance because I don't have a subject flat enough to do that.
When doing this test, while there are some differences between the lenses wide open, they pretty much evened up by F4 at any aperture/focal length. By F5.6, they were pretty much equal and I would say both lenses are extremely sharp. I know that my Tamron 70-200 is sharp enough to resolve pores on half body portraits, so it's definitely sharp enough for my use. For a professional environment, I find both lenses sharp enough to get the job done (unless you want to compare it to a prime, but that's a different animal).
At F2.8 and their sharpest focal lengths, I would say that both lenses resolve as much detail as my DA*55 F1.4 when stopped down to F2. They are definitely not lacking in detail.
I will break down the comparisons into three parts. In each part, I will show the test image and a link to the full size image for perusal, because I can't link full size images to PF. The test image is a side by side comparison of center 100% crops. The full images are on my flickr in the album as linked at the beginning of this post. Each image has a full size link in the comments, so I am presenting everything up to scrutiny (including how dusty my area is).
Close focus (minimum FD for Sigma, close to minimum FD for Tamron)
At 70mm-135mm, I find the Tamron to have an edge over the Sigma at F2.8. They even out around F5.6. The difference is noticeable, but the Sigma isn't bad. At 200mm, the Tamron's performance drops significantly, introducing a lot of bloom. I attribute bloom to lack of contrast, and the hood not being size for 200mm (otherwise it'll vignette). As far as sharpness goes, the Sigma will win this round, but they both equalize around F4, and become very sharp at F5.6.
This test is also where I think I got the Tamron 200mm F2.8 focus slightly off, which can make a big difference. On the other hand, at minimum focal distance - the Tamron was always a little weak in my experience.
https://farm4.staticflickr.com/3836/15264095392_a9ef9014a1_o.jpg 
https://farm6.staticflickr.com/5586/15077915917_623b71c6ec_o.jpg 
https://farm6.staticflickr.com/5572/15264486505_9f400e0816_o.jpg 
https://farm4.staticflickr.com/3887/15077915667_d99a46151c_o.jpg Medium focus distance (About 12', or good for portraits)
At the medium focus distance, the IQ of the lenses followed a similar pattern to the close focus shots. From 70-135mm at F2.8, the Tamron is sharper at the center than the Sigma. At 70mm, the Sigma gets an edge at F4, but then they both tie up at F5.6. From 100-135mm, the Sigma ties up at F4. At 200mm F2.8, the Tamron and Sigma look about equal in performance. The Sigma shows a bit more contrast, but I don't think it's resolving more. By F4, they are both very sharp. I would say that at 200mm, the Sigma has an edge overall from F2.8-F8, while the Tamron wins out similarly at 135mm.
https://farm6.staticflickr.com/5565/15077782140_b11be2a045_o.jpg 
https://farm4.staticflickr.com/3866/15077917077_a665f5fe4f_o.jpg 
https://farm6.staticflickr.com/5558/15264096262_9b889b5ea0_o.jpg 
https://farm4.staticflickr.com/3852/15261389501_dea802a07f_o.jpg Semi-far focus distance (About 22-24', or where I take pictures of animals and stuff)
In the semi-far distance test, I found the Tamron to start outperforming the Sigma wide open at all focal lengths. i skipped the 100mm focal length in this test, but I could see a clear difference between the Tamron and the Sigma at F2.8 in the 70mm, 135mm, and 200mm range. The Sigma ties up around F4, but I would give the general edge to the Tamron at 70mm and 200mm, and the Sigma wins a little at 135mm.
https://farm4.staticflickr.com/3901/15241474896_8cefb225d7_o.jpg 
https://farm6.staticflickr.com/5553/15264487095_2c24aaa0b2_o.jpg 
https://farm4.staticflickr.com/3909/15264486785_f05a34106e_o.jpg Infinity focus distance (About infinity, or where I take pictures of far away things)
I didn't take this test. I didn't really have a location where I could set up and do a consistent test in this range. I apologize for my laziness, but I think the above tests give a good indication of what the lenses can do. In addition, I've shot infinity shots with my Tamron before, and I find that the atmospheric aberrations and the heat effects do way more to the image than the lens will. Also, people don't tend to take infinity shots with these lenses at F2.8, so it may be a moot point anyways.
REMEMBER, EACH SAMPLE SHOT IS FOLLOWED BY A FULL SIZE LINK. THE SAMPLE SHOTS WERE SCALED DOWN TO BE POSTED ON PF. Chromatic Aberrations/Coma/Vignetting
I must apologize that I do not have a way to test for CA/coma easily. Neither lens showed much CA in my testing, with the exception of LoCA in the OOF areas. As far as vignetting goes, I have not been bothered by either lens. Cycling between the photos in my Flickr album will give an example of how the vignetting shows up, but I didn't have a large flat white wall to do the test with.
Conclusion (i.e. which one is better?)
Well, I don't know. The Tamron is priced at $769 at B&H right now, and used is typically $450-500. The Sigma isn't even on B&H anymore for Pentax, and was replaced with a newer APO EX DG version that is also not available in stores for Pentax. The newer version is said to be sharper than the HSM II, and the retail price was around $1199 when I last saw it. The HSM II version was probably that price before it got replaced, and I see it used at around $800 now. So IQ/value wise, the Tamron definitely wins. Its sharpness practically the same (wins some, loses some) to the Sigma, but at $300-500 less it is a bargain. It's also the cheapest of the 70-200s, and from everything I've read on this forum, it and the Sigma are amongst the top performing.
I've used the Tamron for 3 years now and I always enjoy using it. It has a nice solid body, it has fast AF on my k-3, it hasn't let me down yet, and Tamron gives a nice 6 year warranty (I think Sigma is 2 years for non-EX, and 4 years for EX lenses). The Sigma's good points are the silent autofocus and the smoother focus/zoom rings. If I had the money to spend, I would go with the Sigma for the silent autofocus. Or even for the newer version, which is supposed to be sharper. If I were on a budget, or I didn't care about silent autofocus, the Tamron would be a sure buy for me.
Of course, there's also the DA*50-135, DA*60-250, the Tokina 80-200 F2.8 ATX, the Pentax FA*80-200 F2.8, and the Sigma 50-150 F2.8 EX DG HSM. There is a Pentax official review of the FA*, the newer Sigma (APO EX DG), and the Tamron
at this link, but it doesn't provide much info on the image quality. To me, I think all these lenses will have similar sharpness and the overall difference is the features and handling.
Let me know if there are any questions and I will try to answer them to the best of my ability. I am limited by the fact that I had returned the Sigma to my friend for him to sell.
Also for convenience, so you don't need to scroll all the way back up, the link to the album is:
https://www.flickr.com/photos/jindesu/sets/72157647685646442/ 
Originally posted by VisualDarkness 
Post #1 by JinDesu
Similar Threads 
