Discussion in 'Mirrorless Cameras' started by Jennifer2010, Jan 23, 2013.
Here you're comparing different sensor formats, which is quite misleading. The Micro Four Thirds (and Four Thirds, for that matter) cameras have slightly (some say significantly) smaller sensors than the Canon T4i's, thus images shot at the same focal length with each are somewhat more "cropped" with the Micro Four Thirds cameras.
The ratio between the two "crop factors," in this case, is 1.25x. So in essence, a shot taken at 135mm on the Canon T4i would look similar to a shot taken at 108mm on a Micro Four Thirds camera, as far as framing is concerned, when shooting from the exact same spot.
The bread-and-butter "fast" (f/2.8 or better) telephoto zoom lens for Micro Four Thirds is a rather recent addition—the Olympus 40-150mm f/2.8 lens, part of the company's PRO series of very high-grade optics and rugged designs. However, there is one huge flaw to that lens for users of cameras other than Olympus's own, or the Panasonic Lumix DMC-GX7: it does not have optical image stabilization, as it is designed mostly for Olympus camera bodies which have in-body image stabilization, which works by shifting the sensor in multiple axes. Of all Panasonic cameras, only the aforementioned GX7 has that (though reportedly inferior to Olympus's implementation). Image stabilization becomes very important—if not absolutely crucial/necessary—in such long focal lengths, especially if you intend to shoot videos handheld. If you plan on using a monopod/tripod, it isn't nearly as necessary.
The Panasonic 35-100mm f/2.8 does have image stabilization, making it more sensible and usable with camera bodies like the GH3. You will lose 'reach' significantly, though, as 50mm is nothing to scoff at.
You can use an adapter to mount the Sigma 50-150mm f/2.8, and while it may not be so practical in most cases, it might just be sensible in yours, at least if you use a monopod/tripod. With relatively cheap adapters, you'll almost certainly lose autofocus(!) and image stabilization, making the lens almost unusable for shooting any moving action, though with video it might not be a bad thing—many video shooters never use autofocus. I don't shoot video myself, so I can't really comment on that.
It is very likely that most expensive adapters will also disable autofocus and image stabilization. Those two functions require electronic communication between the lens and the camera body, while most adapters are simply mechanical bits that put a different lens mount on the camera, basically. More expensive adapters usually differ from cheap ones in the materials they're made of, which is actually a big consideration when heavy lenses are meant to be used. Some adapters, mostly those that convert Canon EF to other mounts, do have contacts that enable electronic-dependent features of the lens—you really have to look for them, but they exist. I think Metabones is one of the leaders in "smart" adapters.
If you just can't find a good solution, don't force yourself into the Micro Four Thirds system. Many others will give you great video quality and control, even if they're not up to the GH3's standard. The Canon EOS 70D, for example, is very highly regarded. Of course, you can use it with the Sigma 50-150mm f/2.8 and get autofocus and image stabilization.
This is quite an old thread--from 2013.
Oops! Thanks for the heads-up.
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