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120-300mm F2.8 EX DG OS HSM features:

  • Designed for use with full frame digital SLR cameras. May also be used with smaller APS-c size sensors.
  • Offers Sigma’s OS System (Optical Stabilization) allowing handheld photography even in low-light situation.
  • HSM (Hyper-Sonic Motor) ensures a quiet & high-speed auto focus.
  • FLD glass elements with performance equal to fluorite glass for compensate for color aberration.

By Robert O’Toole

On specifications alone the Sigma 120-300mm F2.8 EX DG OS APO HSM is one of those lenses that most photographers would love to have in their camera bag. What makes this lens so attractive and unique is that it offers the speed and reach of a fast 300mm F2.8 lens with the additional flexibility of it’s wide 120-300mm zoom range. Of course the factors that really matter to a wildlife nature photographer such as autofocus speed, tracking ability, and sharpness are not the kind of things you can get from a specifications list. Thanks to Sigma I was able to spend some of time in the field with the lens in Alaska in all kinds of shooting conditions to see how this lens performs in the field.


The 120-300mm F2.8 EX DG OS APO HSM is big and solid with all metal construction. The internal focus lens design means that the length of the lens remains constant regardless of zoom or focus ring position. Both of these controls are very smooth without any play. The large 2.8 maximum aperture made it possible for me to photograph action even in very low light situations. At close to 6 1/2 pounds I did not have a problem handholding this lens it but it might be better suited to tripod use or short periods of handheld photography for most people.

Zoom range

The focal range is very popular with wildlife and nature photographers especially for birds in flight. Looking back at my very favorite images over the past couple of years in Alaska working with eagles the 270-280mm range is just about optimal for me so this lens has me covered. On a full frame body this lens is already 120-300 and with a 1.3x factor body it is equivalent to a 156-390mm or 180-450/192-480mm on 1.5x/1.6x factor bodies. For even more flexibility the 120-300mm F2.8 EX with a 1.4x attached extends the available reach to 168-420mm F2.8 on a full frame body.

Zoom lenses always have the advantage for birds in flight, a 300mm fixed lens would have clipped both wings. 120-300mm @ 200mm, 1/2000 sec, f/4, Mode: Manual, ISO: 320

Full frame eagle portrait made at 120mm against sky reflections in water. 120-300mm @ 120mm, 1/500 sec, f/8, Mode: Manual, ISO: 500

Close up portrait made from the same position as the above image at 300mm. 120-300mm @ 300mm, 1/500 sec, f/8, Mode: Manual, ISO: 500

Image quality

This is the most popular question I am asked about this lens. What kind of image quality can this lens deliver? I found the 120-300mm F2.8 EX DG OS APO HSM lens sharp at all zoom settings. Fine feather detail was crisp and very well defined and sharpness even with the Sigma 1.4x was very surprising. The new generation OS made handholding a pleasure and good results were very easy to obtain.  Bokeh is nice and smooth, color and bokeh fringing were very well controlled.

This portrait was made handheld with a Sigma 1.4x. At this small size you cannot really appreciate all the detail the lens can resolve. Look at the crop below to get a better idea of the sharpness of this lens even with a 1.4x. 120-300mm + 1.4x @ 420mm, 1/500 sec, f/8, Mode: Manual, ISO: 400, Handheld

This is the same image above only at 100% crop.

OS performance

This lens was the first Sigma lens that I have used with the second generation Sigma OS and it worked amazingly well in the field. Sigma OS really makes a huge difference especially when handholding or using off of a tripod with a bean bag or other support. This new OS performance really gives you an extra degree of support you need to deliver consistent sharpness even at low shutter speeds.

This screaming eagle portrait was made handheld with OS mode 1 120-300mm + 1.4x @ 420mm, 1/500 sec, f/8, Mode: Manual, ISO: 640

AF performance

The combination of internal focus and HSM means that the AF is quick, silent and precise. This lens had no problem keeping up with eagles in flight even in low light or low contrast situations. Focus acquisition was quick and HSM worked very well tracking eagles in flight. I had good results with multi point, single point and area AF.
As with any telephoto lens I would recommend that you test your body and lens AF calibration and adjust if needed for maximum sharpness.

The 120-300 AF allowed me to track the eagle handheld and capture this image just before touch down. 120-300mm + 1.4x @ 420mm, 1/2000 sec, f/4, Mode: Manual, ISO: 640

Even against detailed backgrounds the 120-300 performed very well. 120-300mm @ 210mm, 1/2000 sec, f/4, Mode: Manual, ISO: 320

The 120-300 focus tracking made sharp full frame eagle images like this easy. 120-300mm @ 300mm, 1/6400 sec, f/2.8, Mode: Manual, ISO: 400

Performance with teleconverters

With a Sigma 1.4x teleconverter attached to the 120-300mm F2.8 AF was fast enough track eagles in flight without a problem. With the added magnification of the 2.4x the new OS system really worked well for consistently sharp handheld images.
With the Sigma 2x I was able to make clean sharp images with a limited amount of time I spent with the combination. This is not a combination I use very often but given enough light you can make sharp images.

120-300mm @ 120mm, 1/8000 sec, f/2.8, Mode: Manual, ISO: 200

120-300mm @ 300mm, 1/8000 sec, f/2.8, Mode: Manual, ISO: 200

120-300mm with 1.4X @ 420mm, 1/4000 sec, f/4.0, Mode: Manual, ISO: 200

120-300mm with 2x @ 600mm, 1/1000 sec, f/8.0, Mode: Manual, ISO: 200


Judging by the amount of email I receive with questions about this lens it is very popular and for good reason. The price of this lens is about half of other manufacturers 300mm F2.8 prime lenses and not to much more than the competitions 70-200mm F2.8 lenses. But specs alone do not always translate into success in the field. The Sigma 120-300mm F2.8 EX DG OS APO HSM is very solid and well made and most importantly it is a very good performer even with the Sigma 1.4x teleconverter attached. The real strength of this lens is its cost vs performance value since compared to most 300mm f/2.8 lenses on the market today it is really seems almost too good to be true.


SIGMA 120-300mm F2.8 EX DG OS HSM

Lens Construction 23 Elements in 18 Groups
Angle of View 20.4-8.2 degrees
Number of Diaphragm Blades 9
Mininum Aperture f22
Minimum Focusing Distance 150-250cm cm / 59.1-98.4in in
Filter Size (mm) 105mm
Maximum Magnifications 1:8.1 (at 200mm focal length)
(Diameter x Length)
114.4mm x 289.2mm mm/4.5in. x 11.4in. in
Weight 2950g / 104oz.
Corresponding Mounts
Sigma OS, HSM, APO, EX, DG
Nikon OS, HSM, APO, EX, DG
Canon OS, HSM, APO, EX, DG
OS – Optical Stabilizer Function
HSM – Hyper-Sonic Motor
APO – Apochromatic
EX – EX Lens
DG – DG for Digital* The appearance, specifications, and the like of the product are subject to change for improvement without notice.


120-300mm F2.8 EX DG OS HSM: lens construction

MTF Chart

@ 120mm

@ 300mm

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  1. is the lens compatible with Nikon 2x TCs ?

  2. […] read.The lens is fast,too.I shot the Sigma 50-500mm now and at 500mm 6.3 it needs alot of light. LENS EXPLORATION: 120-300mm F2.8 EX DG OS HSM, Part II | SIGMA Blog This is my dream lens now,lol. If you don't know where to start,Go back to the beginning. […]

  3. Same question as Anoop said, only for Canon. Are the Canon 1.4x and 2.0x teleconverters (both are version II) compatible with the Sigma 120-300? I know both of them have a lens element that sticks out into the lens body, so not sure how much clearance there is in the Sigma body.

  4. I’ve been using your 120-300mm 2.8 lens for nearly 9 years now out at the Hawaii lava flows and that lens has produced excellent images. Great for video too. It takes a beating and keeps on going. It would be great to give the DP2 and new DP3 a try out there.