The 105mm f/2.8 EX DG OS HSM Macro Lens is Sigma's first macro lens to feature OS (Optical Stabilization) and replaces the Sigma 105mm f/2.8 EX DG Macro Lens. The Sigma 105 OS Macro lens has been in my kit for just over two years and has seen intermittently regular use. I have been quite pleased with the results the lens has delivered for me.
Why Use a Macro Lens?
The primary reason to use a macro lens is for the high, 1:1, 1x reproduction ability macro lenses possess. The Sigma 105mm f/2.8 EX DG OS HSM Macro Lens and similar true (in my opinion) macro lenses can reproduce the subject at life size on the camera's imaging sensor. Since your camera's imaging sensor is tiny compared to your monitor or your print, subjects reproduced at life-size on the imaging sensor can appear MUCH larger than life-size. For most macro lenses, the high reproduction ratio is completely a bonus over an equivalent non-macro lens, because the macro lens also has a standard lens' capabilities (more on this to come).
One of the biggest reasons to use a macro lens is because doing so is very fun.
Why are Macro Lenses so Fun?
A primary reason that macro lenses are so fun is because there is an endless supply of bright and interesting subjects available for them. Also fun is that these typically-small subjects are not generally seen so-enlarged, with a seldom-seen level of detail showing. There are few subjects that a macro lens cannot be used for and the results you can get from a macro lens are only limited by your imagination. Your location and available space is not a limitation nor is the time of day (if using artificial lighting).
There are many other reasons that macro lenses are fun, including making holidays such as Valentine's Day become just a little more exciting:
Speaking to the guys here ... If you buy a macro lens, you will want to get your wife flowers. If you get your wife flowers, she will be happy. And if your lens makes your wife happy, she will want you to buy more lenses. You can see the perfect win-win circle forming here.
OK, maybe that paragraph is a stretch, but flowers are of course a great subject for a macro lens and the colors of this subject can deliver an image that really pops. Flowers are readily found year round and are seldom far away. If not in your own flower beds, these greatly diverse and colorful subjects are available in local stores/shops. With permission, your local greenhouse can provide endless hours of entertainment.
Insects and little critters of all kinds are also great macro subjects. Everyone has these available locally. Fortunately, my daughter enjoys raising moths and butterflies which provide ideal subjects – perfect wings and no desire to fly for an adequate period of time for some good captures.
While the Polyphemus moth image above was captured outdoors in late day sunlight, the tulip tree moth image below was captured in my studio. This particular tree stump was rather large and required some effort to get indoors, but macro lenses and small subjects can mean small space requirements for shot setup. Even high end macro shooting setups can be relatively compact – even a small apartment has adequate space for a pro-grade macro photo setup that includes flash or other light sources. A small table/counter/desk can be very adequate for macro photography. Lights, backgrounds and other accessories can all be micro-sized as well.
Good medicine. The medicine cup (shown below) was in the cupboard. The good medicine that was in the form of tiny candy balls (cookie toppers) and was purchased for a few dollars at a craft store. It entertained me for hours and stretching the analogy, a macro lens is indeed good medicine for the photographer.
Let's take a look at the DOF (Depth of Field) the apertures available on the Sigma 105mm OS Lens deliver at close distances.
Those tiny little balls of candy look sweet and savory, but they sure left a bad taste in my mouth – but not after eating them. I had the *great* idea to load them into a narrow funnel held by a Delta 1 Grip-It Single Arm with 1" Clamp and then shoot a motion-blurred shot of them dropping onto and bouncing off of the black back-painted glass desktop. The idea included use of a hot light along with a flash set to second-curtain sync to get a bright little ball at the end of each ball bounce streak.
I lined the desktop with multiple layers of gaffer tape to catch the balls, causing them to stick to the tape instead of hitting the floor. A small test showed that this tactic was going to work fine. Because I would not have many chances for the shot, I setup two cameras, triggering both simultaneously with a Canon RC-6 wireless remote. I filled the funnel and went live.
That is when I gained a new respect for those little balls. Hundreds of the tiny rock-hard balls managed to leap over the tape fence. Upon hitting my epoxy-covered concrete studio floor, they of course then bounced much higher and farther. I spent over an hour cleaning them up and will probably never get all of them. Yes, I got the shots, but unfortunately they were not as exciting as I visualized. The images will not likely make it out of my archives and they were definitely not worth the cleanup that was required.
Lessons are valuable – I try to learn as many as possible every day. But learning lessons from others' mistakes is much more fun than making the mistakes yourself.
Macro lenses come in a range of focal lengths. In general, the longer the focal length, the more working space the lens has at 1:1 magnification (I'll talk more about this later in the review). Other differences include the amount of background present in the image (due to the angle of view) and the amount of magnification the details in that background are given. In general, I find longer macro focal lengths to be my preference over shorter ones.
Most big lens manufacturers have an entry in the 90-105mm macro lens class, which is the mid focal length range in the overall macro lens field. I typically recommend a 90-105mm lens macro lens as the ideal choice for general purpose macro work with an ASP-C/1.6x FOVCF sensor format DSLR. On those cameras, the 105mm focal length has an angle of view similar to a 168mm lens on a full frame format DSLR.
The 105mm focal length is of course very useful on the larger sensor cameras as well. All of the images included in this review were captured with a full frame Canon EOS 5D Mark III.
The Macro Capabilities are a Bonus
As I mentioned before, in addition to being macro-capable, the Sigma 105mm f/2.8 EX DG OS HSM Macro Lens functions as a standard short telephoto lens. You can use this lens just like most other lenses in your kit. The 105mm focal length is great for various uses including portraits and the wide aperture combined with OS make this lens a good option for low-light, hand-held photography.
Note that, as with all macro lenses, the effective aperture becomes narrower as very close macro focus distances come into use. The camera's auto exposure system will automatically compensate for this loss of light, but manual exposure settings will need to be adjusted to compensate for this.
As I said in the review introduction, this is Sigma's first macro lens to include OS. However, I can't say that this is my favorite Sigma OS implementation to date. The first thing you notice when OS activates is a mild but easily audible noise and the same noise is heard again when OS turns off. I've been struggling for a good description of the sound, but ... it is clicking/buzz-like noise. Some deeper-pitched clunking sounds and some whirring can be heard while IS is active, especially when the lens is moved.
Mirroring the OS startup and shutdown sounds is a usually-minor viewfinder image jumping that occurs with both events. While active, OS does its job and makes subject framing much easier, but the viewfinder image wonders around slightly. I didn't notice this at first, but I perceived that I didn't care for the image that this OS provided in the viewfinder as much as some other lens. With more careful testing, I determined that the subject framing actually moves around a small amount while OS is active. This anomaly is especially noticeable when handholding the camera in a very stable position. While the amount of movement is small, it is annoying nonetheless.
The 105 OS Macro OS requires a second to activate, but you will know when this has occurred – the viewfinder image will settle and the startup noise will complete.
Sigma rates this lens for 4 stops of shake reduction. Though not confirmed to me, the 4 stop rating is probably not applicable at the closest focusing distances this lens is capable of. The Canon EF 100mm f/2.8 L IS USM Macro Lens, with its macro-ready Hybrid IS, is rated for only half of its normal 4-stops of shake reduction when used at 1.00x magnification.
Testing the shake reduction with this lens caused me some confusion. In the first round of testing, I was getting no sharp results (nearly 100% were blurred) even at 1/60 sec with OS enabled. There is some play in the OS mode switch and I'm guessing that the switch may have been slightly out of position – just enough to prevent OS from working on that occasion. I have not come up with any better excuse.
Round two went much better. OS allowed reasonably-sharp-image hit rates with the lens handheld down to 1/10 sec. About 73% of my images were usably sharp and about 50% were very sharp at this shutter speed. This equates to about 3 1/3 stops of assistance for me. A high percentage of the results captured at longer exposure times were motion blurred.
The comparison example below, featuring a 100% crop pencil drawing courtesy of my daughter, was captured at 1/8 second.
The owner's manual for this lens instructs that the OS switch should be in the off position when mounting/dismounting the lens. I do not remove a stabilized lens while OS is active (I make it a rule to never do this with any lens).
The owner's manual also instructs that OS be turned off when using the lens on a tripod. I usually follow this instruction with all lenses (except Canon's big white super telephoto lenses).
OS cannot stop an in-motion subject, but the mode 2 setting provides stabilization in one direction only, to allow panning with a subject. While this mode will not likely see much use in macro photography, it has value for other uses.
The Sigma 105mm f/2.8 EX DG OS HSM Macro Lens has very good image sharpness when used with a wide open aperture. As is often the case with wide open aperture image quality, corner sharpness trails the center of the image circle sharpness – but only slightly in this case. A nice improvement is seen, especially in the corners, at f/4 and by f/5.6, images are razor sharp across the frame.
I've been using this lens intermittently for over two years and have been very satisfied with the image quality it has given me. When shooting at macro focus distances, I'm using narrow apertures most of the time and this lens delivers excellently at these. When I'm using a wide aperture at macro focus distances, I'm usually looking for a mostly-strongly-blurred image. And in this case, any lesser image sharpness at f/2.8 (there isn't much) is going to be hard to detect in the extremely shallow DOF (Depth of Field).
Typical for lenses in general is a noticeable reduction in vignetting when narrowing the aperture. This lens shows a modest, just-over-2-stops of peripheral shading in full frame corners with a wide open f/2.8 aperture. Vignetting is reduced to a barely-visible 1 stop at f/4 and by f/5.6, vignetting is reduced to an extremely low .2 stops. Within the APS-C angle of view, vignetting at f/2.8 is just under 1 stop – an amount that goes unnoticed in many images.
Like many prime lenses, the Sigma 105 OS controls CA (Chromatic Aberration) very well, but I occasionally see a small amount in full frame corners in extreme scenarios such as backlit tree branches.
Put a bright light in the frame and the Sigma 105 OS Macro will show some flare. This is not unusual for a short telephoto lens. With the sun in the corner of the frame, the amount of flare is medium until the aperture narrows to about f/11. At f/11 and narrower, significant amounts of flare show in the frame.
As is normal for macro-capable prime lenses, the Sigma 105 OS is essentially distortion free.
Bokeh (the quality of the foreground and background blur) appears to be normal for this this lens. Often more important is that this lens, with the ability to focus so closely, can create a very strong background blur.
Featuring Sigma's HSM (Hypersonic Motor), the Sigma 105mm OS Lens focuses with decent speed in good light. Low light focusing is quite slow and I noted some focus hunting issues when initially evaluating the lens; however, focus hunting does not appear to be a problem as I work hands-on with the lens right now. A fast series of quiet lens element movements can be heard as the lens adjusts for the requested focus distance.
A focus limiter switch allows restriction of focus distances to within ranges including: 1.02 - 1.48', 1.48' - 8 and 1.02' - 8 (full range) (.312 - .45m, .45m - 8 and .312m - 8). Narrowing the autofocus distance range can decrease focus hunting which increases overall focus speed.
Sigma 105mm OS Macro Lens subjects change size significantly as they go into and out of focus.
Key to an autofocus system is focus accuracy and this lens has performed very well in this regard. I did not stress test AI Servo AF with this lens, but One Shot AF has been consistently accurate.
This is an internally focusing lens with non-rotating front filter threads that facilitate easy use of circular polarizer filters.
The Sigma 105mm f/2.8 EX DG OS HSM Macro Lens' adequately-sized focus ring is smooth with no play and the right amount of dampening. The ring is nicely sized with 146° degrees of rotation. While this is a good amount of rotation for lenses in general and the rate of focusing is very nice at macro focus distances, manual focus adjustments seem quick/touchy at longer focus distances. The Canon EF 100mm L IS has a not-much-longer 157° focus ring rotation, but the Nikon 105mm VR Lens has 254° degrees of focus ring rotation and the Zeiss 100 Makro Lens has 350° of focus ring rotation (and does not focus nearly as close). Depth of field markings are not provided, but magnification ratios are included in the focus distance window.
It is a macro lens, so close focusing is this lens' specialty and a large MM (Maximum Magnification) is the big point of having a macro-capable lens. Since most macro lenses have a 1:1/1.00x reproduction ratio, showing a comparison chart of all of them doesn't make as much sense. However, I wanted to see if the MFD (Minimum Focus Distance) specs reflected the focal length across the various macro lenses I've used. So, I made the chart. And the answer is yes, the MFD closely follows the focal length with the exceptions being the non-1.00x lenses – those lenses with MFD specs that I've shown in bold.
|Canon EF 24-70mm f/4 L IS USM Lens||7.9"||(200mm)||0.70x|
|Nikon 40mm f/2.8G AF-S DX Micro Lens||6.4"||(163mm)||1.00x|
|Canon EF 50mm f/2.5 Macro Lens||9.1"||(230mm)||0.50x|
|Sigma 50mm f/2.8 EX DG Macro Lens||7.5"||(190mm)||1.00x|
|Zeiss 50mm f/2.0 Makro-Planar T* ZE Lens||9.4"||(240mm)||0.50x|
|Canon EF-S 60mm f/2.8 Macro USM Lens||7.9"||(200mm)||1.00x|
|Nikon 60mm f/2.8D AF Micro Lens||8.6"||(219mm)||1.00x|
|Nikon 60mm f/2.8G AF-S ED Micro Lens||7.2"||(183mm)||1.00x|
|Tamron 60mm f/2.0 Di II Macro Lens||9.1"||(231mm)||1.00x|
|Canon MP-E 65mm Macro Lens||9.4"||(240mm)||5.00x|
|Nikon 85mm f/3.5G AF-S DX VR Micro Lens||10.8"||(274mm)||1.00x|
|Tamron 90mm f/2.8 Di Macro Lens||11.4"||(290mm)||1.00x|
|Canon EF 100mm f/2.8 L IS USM Macro Lens||11.8"||(300mm)||1.00x|
|Canon EF 100mm f/2.8 USM Macro Lens||12.2"||(310mm)||1.00x|
|Zeiss 100mm f/2 Makro-Planar T* ZE Lens||17.3"||(440mm)||0.50x|
|Nikon 105mm f/2.8G AF-S VR Micro Lens||12.0"||(305mm)||1.00x|
|Sigma 105mm f/2.8 EX DG OS HSM Macro Lens||12.3"||(312mm)||1.00x|
|Sigma 105mm f/2.8 EX DG Macro Lens||12.3"||(312mm)||1.00x|
|Sigma 150mm f/2.8 EX DG OS HSM Macro Lens||15.0"||(380mm)||1.00x|
|Sigma 150mm f/2.8 EX DG HSM Macro Lens||15.0"||(380mm)||1.00x|
|Canon EF 180mm f/3.5 L USM Macro Lens||18.9"||(480mm)||1.00x|
|Tamron 180mm f/3.5 Di Macro Lens||18.5"||(470mm)||1.00x|
|Sigma 180mm f/2.8 EX DG OS HSM Macro Lens||18.5"||(470mm)||1.00x|
|Nikon 200mm f/4D AF Micro Lens||19.2"||(488mm)||1.00x|
Canon's 24-70 f/4 L IS USM Lens is the only zoom lens I've used that comes close to 1.00x MM, so I decided to include it in the chart. This lens' 0.70x MM is higher than some of the prime macro lenses included here.
The MFD spec is based on the distance from the subject to the imaging sensor. Although the longer focal length lenses are also physically longer, the longer focal lengths still give you more working space – and make it less likely that you will frighten your timid little insect away.
You can use this site's specs and measurements information to calculate the actual from-the-end-of-the-lens working distance for any lens in the database.
Using the referenced calculation shows that the Sigma 105 OS lens' working distance is about 5.6" (141.6mm). Install the hood and the minimal working distance goes down to 3.7" (93.6mm). For modestly closer focusing and higher magnification, mount an extension tube(s) behind the lens.
Need even more magnification? Add an extender. An advantage held by the Sigma 105mm f/2.8 EX DG OS HSM Macro Lens over many competing lenses with similar focal lengths is that it is compatible with extenders. Sigma's 1.4x and 2x DG extenders to be specific. With the 1.4x mounted, this lens becomes a 147mm f/4 OS lens and it becomes a 210mm f/5.6 OS lens with the 2x behind it.
The biggest downside to using extenders is that they negatively impact image quality. I suggest stopping the aperture of this lens down at least one stop to get decent results when using extenders.
Build Quality & Features
The Sigma 105mm f/2.8 EX DG OS HSM Macro Lens features an attractive-looking, clean design. The plastic lens barrel is smooth aside from an indent around the lens near the mount and a much more significantly bumped out switch bank. Though not always the case, the raised switch area does not detract from the comfort of using this lens. My hand does not naturally touch firmly this area when holding or focusing the lens.
The switches standing out make them susceptible to being inadvertently changed, but they are firm and crisp. I have not encountered an accidental change during my use. Three-position switches always require a little more precision to use and the OS mode switch does not lock into place as crisply as the other two switches.
The predecessor to this lens, the 105mm DG non-OS Macro Lens, utilized an extend-with-focus design that is more compact when focused at infinity but extends to longer than the OS lens when focused at MFD. I much prefer the fixed length of the new OS lens.
Overall build quality seems nice and this lens is solid. This is not a weather sealed lens, so take precautions when there is a moisture risk.
From a size and weight perspective, I'll tag this lens as a "medium". Here again is the large table of macro lenses with their manufacturer size and weight specs included.
|Model||Weight||Dimensions w/o Hood||Filter||Year|
|Canon EF 24-70mm f/4 L IS USM Lens||21.2 oz||(600g)||3.3 x 3.7"||(83.4 x 93mm)||77mm||2012|
|Nikon 40mm f/2.8G AF-S DX Micro Lens||8.3 oz||(235g)||2.7 x 2.5"||(68.5 x 64.5mm)||52mm||2011|
|Sigma 50mm f/2.8 EX DG Macro Lens||11.1 oz||(315g)||2.8 x 2.5"||(72 x 64mm)||55mm||1998|
|Canon EF 50mm f/2.5 Macro Lens||9.9 oz||(280g)||2.7 x 2.5"||(68 x 63mm)||52mm||1987|
|Zeiss 50mm f/2.0 Makro-Planar T* ZE Lens||18.7 oz||(530g)||2.8 x 3.5"||(72 x 88mm)||67mm||2010|
|Nikon 60mm f/2.8D AF Micro Lens||15.5 oz||(440g)||2.8 x 2.9"||(70 x 74.5mm)||62mm||2003|
|Nikon 60mm f/2.8G AF-S ED Micro Lens||15.0 oz||(425g)||2.9 x 3.5"||(73 x 89mm)||62mm||2008|
|Canon EF-S 60mm f/2.8 Macro USM Lens||11.8 oz||(335g)||2.9 x 2.8"||(73 x 70mm)||52mm||2006|
|Tamron 60mm f/2.0 Di II Macro Lens||14.1 oz||(400g)||2.9 x 3.1"||(73 x 80mm)||55mm||2010|
|Canon MP-E 65mm Macro Lens||25.8 oz||(730g)||3.2 x 3.9"||(81 x 98mm)||58mm||1999|
|Nikon 85mm f/3.5G AF-S DX VR Micro Lens||12.5 oz||(355g)||2.9 x 3.9"||(73 x 98mm)||52mm||2009|
|Tamron 90mm f/2.8 Di Macro Lens||14.3 oz||(405g)||2.8 x 3.8"||(72 x 97mm)||55mm|
|Canon EF 100mm f/2.8 L IS USM Macro Lens||22.1 oz||(625g)||3.1 x 4.8"||(77.7 x 123mm)||67mm||2009|
|Canon EF 100mm f/2.8 USM Macro Lens||21.2 oz||(600g)||3.1 x 4.7"||(79 x 119mm)||58mm||2000|
|Zeiss 100mm f/2 Makro-Planar T* ZE Lens||24.0 oz||(680g)||3.0 x 4.4"||(76 x 113mm)||67mm||2010|
|Nikon 105mm f/2.8G AF-S VR Micro Lens||27.9 oz||(790g)||3.3 x 4.6"||(83 x 116mm)||62mm||2006|
|Sigma 105mm f/2.8 EX DG OS HSM Macro Lens||25.6 oz||(726g)||3.1 x 5.0"||(78.3 x 126.4mm)||62mm||2011|
|Sigma 105mm f/2.8 EX DG Macro Lens||15.9 oz||(450g)||2.9 x 3.7"||(74 x 95mm)||58mm|
|Sigma 150mm f/2.8 EX DG OS HSM Macro Lens||40.6 oz||(1150g)||3.1 x 5.9"||(79.6 x 150mm)||72mm||2012|
|Sigma 150mm f/2.8 EX DG HSM Macro Lens||31.6 oz||(895g)||3.1 x 5.4"||(79.6 x 137mm)||72mm||2006|
|Canon EF 180mm f/3.5 L USM Macro Lens||38.5 oz||(1090g)||3.3 x 7.4"||(83 x 187mm)||72mm||1996|
|Tamron 180mm f/3.5 Di Macro Lens||32.5 oz||(920g)||3.3 x 6.5"||(85 x 166mm)||72mm|
|Sigma 180mm f/2.8 EX DG OS HSM Macro Lens||57.9 oz||(1640g)||3.7 x 8.0"||(95 x 203.9mm)||86mm||2012|
|Nikon 200mm f/4D AF Micro Lens||41.8 oz||(1185g)||3.0 x 7.6"||(76 x 193mm)||62mm||1993|
For many more comparisons, review the complete Sigma 105mm f/2.8 EX DG OS HSM Macro Lens Specifications using the site's Lens Spec tool.
As a generalization, the size and weight increases down the increasing-focal-length list. The Sigma 105 OS is not going to beat you up and wear you down even with extended use.
As is typical with Sigma lenses, the hood is included. This is a narrow hood that provides good front element protection and remains very compact when installed in reverse orientation for storage. Not shown in the images on this page is the APS-C hood extension that is also included. The extension better-shades the narrower angle of view utilized by the APS-C sensors.
The Sigma 105mm OS Macro has a 62mm filter size. While not large (which generally means not pricy), no Canon lens shares this size. A handful of Nikon lenses are 62mm-threaded and a few Sigma and Tamron lenses can also share 62mm filters. You can use a step up adapter ring to use a larger filter size on this lens (such as a Canon-common 67mm size), but due to the larger filter width, use of the hood may be forfeited.
A tripod ring is not provided or available for this lens. The Sigma 105 OS Macro comes with a nice zippered, padded nylon case. However, the case is quite large. The APS-C lens hood extension does not reverse on the lens, which means that that case must be long enough to house the longer length. There are two large cushions on the bottom of the case. One is removed when the hood extension is being used.
Here is a closer look at the review-time-current Sigma macro lenses:
Positioned above from left to right in their fully retracted positions are the following lenses:
The same lenses are shown below in their fully extended states with their lens hoods in place.
Those comparison pictures show a lot – especially that the 50 is small when retracted and that the 180 is a big lens. Here is a comparison of the Sigma with the very popular Canon and Nikon 100mm/105mm macro lenses.
Positioned above from left to right in their fully retracted positions are the following lenses:
The same lenses are shown below with their lens hoods in place.
The story here is that you are probably not going to make your 100mm-ish macro lens decision based on size.
Macro lenses are a lot of fun to use and to see/share the results from. I recommend that every kit contain at least one of these lenses. Obviously from the tables above, there are a lot of options to choose from. I maintain a list of recommended Canon macro lenses and Nikon of course has their strong contenders. I'll address a couple of more comparisons in a moment.
To match its medium size and weight, the Sigma 105mm f/2.8 EX DG OS HSM Macro Lens has a medium high price tag – unless there happens to be a very significant rebate available. And in that case, it is a bargain.
At regular price, the Sigma is priced less than $100.00 USD lower than the Canon EF 100mm f/2.8 L IS USM Macro Lens and at those prices, I recommend the Canon over the Sigma. As I write this review, both of these lenses have rebates available for them. However, the Sigma rebate is significantly higher than the Canon rebate, placing it into a different price class and making it a very good bargain.
The Canon L lens is a better-polished product overall, but the Sigma challenges the Canon for image quality. You might see some Canon sharpness advantages in specific comparisons (such as at f/4), but overall, these two lenses are very similar. The Sigma has slightly less CA in full frame corners, the Canon has arguably less flare at narrow apertures and the Canon has very-slightly-better-corrected distortion. Canon L has a better (Hybrid) IS system, has a better AF system, is slightly lighter, is weather sealed and has a tripod ring optionally available for it.
The Canon EF 100mm f/2.8 USM Macro Lens is regularly priced at about the significantly-rebated Sigma price. It is a bargain every day. This Canon lens does not have image stabilization, but equals the Sigma in image quality and is slightly lighter.
That the Sigma accepts extenders is an advantage it holds over the other lenses specifically compared here.
The Sigma 105mm f/2.8 EX DG OS HSM Macro Lens is available in Canon (reviewed), Nikon, Sony/Minolta and Sigma mounts. My standard disclaimer: There are potential issues with third party lenses. Since Sigma reverse engineers (vs. licenses) manufacturer AF algorithms, there is always the possibility that a DSLR body might not support a (likely older) third party lens. Sometimes a lens can be made compatible by the manufacturer, sometimes it cannot be made compatible. There is also the risk of a problem that results in the lens and body manufacturers directing blame at each other. Sigma USA's 3-year warranty is superior to Canon's standard 1 year warranty (Sigma's North and South America warranty is also 1 year).
The reviewed lens was purchased online.
As I said earlier, I've had the Sigma 105 OS macro lens in my kit for over two years and have used it with some frequency. Some of the product images you have been seeing in the recent reviews have been captured with this lens and I have used it for many other needs. While this lens has a little room for improvement (especially with the IS system), the image quality it has reliably delivered has been excellent. I'm comfortable using the Sigma 105mm f/2.8 EX DG OS HSM Macro Lens for important macro projects that come my way.
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