07-07-2013 09:41 AM
I have the Rebel XTi and am ready to upgrade - looks like the T4i and T5i are comparable, and I know that I need to get STM lens for video performance. My question is in choosing which kit lens 18-55 or 18-135 (both IS STM)? I already have a Canon 50-250mm telephoto lens (and 50mm fixed focal length lens). Is it worth paying more for the 18-135, are there any quality differences in normal shooting , or would I be fine with the 18-55 since I already have telephoto lens (and I don't think I will need to shoot video with the extra zoom)? I also wasn't sure about the extra length of the 18-135 and if it was a bit long and bulky for an every day carry around lens. Thx
07-10-2013 12:38 AM
The "STM" versions of the lenses have "inner focusing" which means the end of the lens does not physically rotate as the lens focuses. This was also true of the 18-135 non-STM version... but the 18-55 non-STM actually rotates as you focus. If you have special effects filters or a polarizer, it means the filter would be rotating when the lens focuses and that can drive you nuts.
But as both 18-55 and 18-135 "STM" versions use inner-focusing, the only significant difference is the zoom range. 18-55 isn't a very substantial range... it's a mild wide-angle to a very mild zoom... whereas the 18-135 has a more useful everyday "walking around" zoom range. It's a fairly nice lens. It's not particularly large and it's fairly light.
The EF-S 17-55mm f/2.8 IS USM is a fantastic lens in terms of quality and it's ability to work in low light as well as it's ability to produce a nice shallow depth of field for more dramatic out-of-focus blur.... but it's NOT an "STM" lens (so it does not have the silent focus motors and they aren't stepper motors.) That means focus is fast and snappy and can't be slowed to a gradual speed (great if you're shooting action... but not as much control for video). Part of the value of STM lenses is that the motor can operate so silently that the internal mic cannot pickup the sound of the focus motor. Although... if you're REALLY into video, get an external mic -- the Rode VideoMics are _very_ popular. The primary value is that they have dramatically better audio quality, they're also substantially more directional (so the mic picks up the subject you're filming and not you or anyone else behind the camera)... but also since it's an external mic (even if it's mounted in the flash hot-shoe) it wont be able to pick up on the noise of the lens focus motor.
The EF-S 55-250 does not have inner-focusing... the end of the lens will rotate as you focus. If you use a polarizing filer (and for your camera it would need to be a "circular" polarizing filter) then the polarization tuning would change as you focus and you'd constantly be reaching forward to re-tune the filter polarization angle.