The Panasonic GH-1 is designed for Micro Four Thirds lenses but can also use all the Four Thirds lenses – although many of these latter are manual focus.
One of the main reasons for buying into the Micro Four Thirds system instead of using a more compact point and shoot camera is the combination of image quality and versatility, in particular, the ability to achieve shallow depth of field with a range of wide aperture lenses.
Some of my favorite wide aperture lenses for nice medium telephoto shallow depth of field effect are the Four Thirds lenses such as the Olympus ZD 50mm f/2.0 macro and 50-200mm f/2.8-3.5 SWD lenses.
Unfortunately, both of these will only manual focus on the GH-1, and the 50-200mm is a bit too big for it.
I thus thought I would try out my Canon EF 85mm f/1.8 lens. Whilst this lens designed for Canon EOS dSLRs, it must be used at a fixed aperture on the MFT cameras via an adapter (although you can change this aperture by setting it on a Canon body then holding in DOF preview button as you remove it).
In reality this is not such a big problem as my main reason for using it is to get the wide aperture in a relatively compact lens. To get this sort of focal length/aperture in Four Thirds, you would have to resort to the very expensive, 1.8kg ZD 35-100mm f/2.0 lens – not really a nice size for the GH-1!
Of course, if you have a Nikon or Carl Zeiss 85mm f/1.4 or f/1.8 lenses and you would have full aperture control, but alas I do not have them.
The Canon EF 85mm f/1.8 is quite a nice size for the GH-1 given that it gives you 170mm focal length reach at f/1.8 and it is quite a sharp lens even wide open but it does have one big problem – purple fringing at wide aperture – this is a common problem on legacy film lenses in particular when used on digital cameras at apertures wider than f/2.8, but it is correctable in post-processing.
Here are a few quick shots on a recent trip into the city to show what you can do with this combo at f/1.8 with no post processing (click on image to enlarge):
and now to demonstrate the purple fringing that occurs in high contrast junctions (click to see full image resized for web):
It’s a great lens if used carefully wide open. You can reduce purple fringing by using f/2.8 instead of f/1.8 but you also lose a bit of your nice shallow depth of field.
It is not as good a lens optically as a Canon 135mm f/2.0L lens or an Olympus ZD 50-200mm lens, but it is much more compact, and very usable.
I wouldn’t go out and buy it just to use on Micro Four Thirds cameras, but given that there are many Canon users buying into MFT for a more compact solution with true AF video capability, this does become a very useful option for them as long as manual focus and fixed aperture will fit their needs.