Canon EF-S 55-250mm f/4-5.6 IS STM (latest version) The EF-S 55250mm f/4-5.6 IS STM is the most recent generation of this distance and completely updated with Canon’s latest technologies: STM AF system, for smooth and silent Movie AF Servo; an all internal, back focusing mechanism that doesn’t rotate the front element; and a better optical design for improved performance. Let’s evaluate its performance? Nice reading! BUILD QUALITY Canon EF-S 55-250mm f/4-5.6 IS STM At 375g of 7x11cm the EF-S 55-25mm f/4-5.6 IS STM is lighter than any of the previous EF-S 55-250mm and absolutely better built. It is made of two plastic barrels that expand using a gigantic zoom ring. Practically the whole lens body is a zoom ring and it can even be hard to mount it on the camera because there’s no room left for your fingers to grip; be careful. But its movement is very smooth and a pleasure to use, with zero wobbling when completely extended at 250mm. There are distance markings near the mount but no distance window for the focus. The MFD is 85cm, great for short DoF wide open and the “bokeh effect” that blurs the background. At the front the manual focusing ring is fly-by-wire, meaning it is not mechanically connected to the inner pieces. An electronic signal tells the STM motor to move whats inside (like other STM lenses). That makes the MF ring too loose and require power from the camera to operate; AND it’s not “ON” all the time. You have to half press the camera to start it to send electricity to the lens, making the full time manual not that “full time” at all. At least the front element doesn’t rotate like previous 55-250mm and it accepts ø58mm filters at the front, like polarisers. At the back the extenders EF 1.4X and EF 2X are not compatible, as with no other EF-S lens. There are just two switches at the back, one for the AF/MF and other for the ON/OFF of the image stabiliser. The AF/MF can be set permanently at AF because of the full time manual. If the camera fails to lock focus, you can help it with the ring; but that never happened during my tests. By the way the focus performance was great with the EOS 60D, and I have no OOF pictures with this lens. The same can be said about blurry shots and the excellent three and a half stops “IS” implementation. Canon’s IS are always discreet and efficient. Just leave it on at all times. The EF-S 55-250mm f/4-5.6 IS STM shows Canon’s commitment with the APS-C market. It’s very nice to use and offers the same reach as much longer EF lenses, for a fraction of the cost (and weight). It is definitely not the same as an EF 100-400mm f/4.5-5.6L IS USM: it won’t cover the 135 format; the plastic build is no match for the all metal L lens; but its newer IS, shorter size and overall better user experience raises the question if you really need a bigger lens. Let’s see if the updated optical formula delivers performance close to the full frame offerings. Canon is known for its great telephoto lenses. Since the 80’s introduction of the EF mount and its high performance AF zooms, this manufacturer got famous for taking care of most professionals needs: great telephoto IQ, fast AF and reliable IS. And the EF-S 55-250mm f/4-5.6 IS STM keeps that tradition matching all these qualities on a budget equipment.