Sigma 17-50mm F2.8 EX DC OS HSM features the brand new FLD glass. FLD glass has an optical characteristic similar to fluorite glass. Such glass elements, Sigma 17-50mm F2.8 EX DC OS HSM can be used to compensate optical aberrations more efficiently than conventional “special” elements such as Sigma’s more commonly used SLD glass. Sigma 17-50mm F2.8 EX DC OS HSM build quality is good. It’s made of tightly assembled combination of metal and high quality parts so there’s nothing wrong here. Like its predecessor, Sigma 17-50mm F2.8 EX DC OS HSM uses a mono-cam system to extend the lens when zooming towards the tele setting.
You can compare this great lens with Canon EF 50mm f1.4. Canon EF 50mm f1.4 may actually seem bigger than the others in order to fit in an autofocus motor system. Canon EF 50mm has an autofocus system called micro-type ultrasonic motor that makes it fast and unbelievably quiet. But still you have to remember that focus speed and accuracy can also be affected by some factors like the subject contrast and light levels. Canon EF 50mm f1.4 is compatible with all the DSLR cameras of Canon in any case of the sensor format. You can easily change the lens because it comes up with a 6mm wide moulded plastic grip. You can actually get an accurate manual focus because its 11mm wide focus ring can be rotated by 200 degrees clockwise. But the focus ring cannot be rotated during the autofocus. Canon EF 50mm f1.4 has 50mm focal length; fast F1.4 maximum aperture and Micro-type USM autofocus with full-time manual override which serve as the main highlights of its features. Canon EF 50mm f1.4 is included in Canon’s mid range of primes which is made with a good quality. Canon EF 50mm f1.4′s lens is made up of metal while the barrel is made up of plastic. Click here to get this exciting features of Canon EF 50mm f1.4.
The Sigma 17-50mm F2.8 EX DC OS HSM zoom ring has a smooth, pleasant action whereas the focus ring has basically no friction in manual mode. The focus ring is coupled to the AF mechanism so it rotates during focus operations. Sigma 17-50mm F2.8 EX DC OS HSM is fast and nearly silent but full-time manual (FTM) override is not possible in one-shot AF mode. The Sigma 17-50mm F2.8 EX DC OS HSM AF speed via in contrast AF (Live-View) is on the slow side. Sigma 17-50mm F2.8 EX DC OS HSM manual focusing is delicate due to the extremely short focus path. Click here for more of Sigma 17-50mm F2.8 EX DC OS HSM.
Here is a summary of Sigma 17-50mm F2.8 EX DC OS HSM review from a satisfied customer:
After spending an hour with the Tamron and Canon competitors…
So I’ve been bouncing back and forth between the big three competitors. If you’re looking at this lens, you’ve probably weighed Tamron’s 2.8 17-50 VC and Canon’s more expensive but much beloved 2.8 18-55 IS that’s been out for a few years. I finally broke down and went into a store to wrap my hands around all three, shoot some comparative video with the various IS/VC/OS, futz with the focus rings and zoom, etc. I did not run a full professional test on the image quality, but those reviews can be easily found online. In most fields the Sigma beats the Tamron, like Bokeh and low distortion. The Tamron is ever so slightly sharper at 2.8. At 2.8, I do get some easily visible circular distortion in the corners with the Sigma when pointing the camera at a window or bright source. I basically determined that image quality between the lenses was a draw.
A major new feature of Sigma 17-50mm F2.8 EX DC OS HSM is the OS (“Optical Stabilizer”). Sigma 17-50mm F2.8 EX DC OS HSM is impressively efficient and as good as the corresponding genuine manufacturer implementations. Sigma claims a gain of 4-stops which seems to fit here based on our field impressions. When you need to stand ready for any photo opportunity you need a fast aperture so you can shoot in low existing light or at maximum range with a flash. This Sigma lens is perfect.
Sigma 17-50mm F2.8 EX DC OS HSM has the following features and specifications:
- For use with smaller chip APS-c or 4/3 digital cameras only
- Offers Sigma’s OS System (Optical Stabilization)
- HSM (Hyper-Sonic Motor)
- FLD glass elements with performance equal to fluorite glass
- Ultra compact with overall length of just 3.6″
Sigma 17-50mm F2.8 EX DC OS HSM has the following Pros and cons:
- Fast auto focus
- Quiet auto focus
- Image stabilization
- Good center sharpness
- Solid construction
- Good sharpness and contrast
- Ultrasonic autofocus
- Big and heavy
- Small zoom range
Sigma 17-50mm F2.8 EX DC OS HSM anti shake feature offers the use of shutter speeds approximately 4 stops slower than would otherwise bepossible. The Sigma 17-50mm F2.8 EX DC OS HSM feature allows Sony and Pentax users the option of viewing a stabilized image in the viewfinder, a feature offered only by Sigma. HSM provides fast and quiet AF. Sigma’s own FLD glass elements, which have performance equal to fluorite along with two glass mold and one hybrid aspherical lens, provide excellent correction for all types of aberrations. Click here to get the exciting features of Sigma 17-50mm F2.8 EX DC OS HSM.