I was very excited to get my Panasonic Lumix GH2 DSLR for a couple reasons, the most important being the the extended tele converter zoom mode which adds a 2.4X zoom to the normal 4/3s sensor field of view by actually using 1920X 1080 pixels from the sensor without interpolating the resolution. This is also good in that it allows the use of traditional C-mount 16mm film lenses with the GH2 without using the digital zoom. So here are a series of test using various lenses with the GH2 in both the Extended Tele Converter zoom mode and in the normal zoom mode.
There are a couple things to note, while in the the Extended Tele Converter mode the camera does not output an HDMI signal, the new HDMI output does help with focusing this camera. All of these tests were shot at extremely low light levels (about 26 Lux) The camera is set to ISO 3200 and the shutter speed is set to 1/50 sec. and all the footage was shot 23.97 FPS at 1080P. I then edited all the footage on a 720P timeline in Final Cut Pro with minimal grading (only white matching). The C-mount lenses all were using the same Rainbow Imaging M4/3 to C-mount adapter. The 2/3′ broadcast lens used my custom fabricated M4/3 to B3 lens adapter. Also note ththis test was to test lenses with a less than 50mm full frame FOV.
I’ll lead off with the most pleasant surprise. The first lens is a no name Chinese C-mount 25mm F1.4 CCTV surveillance lens that I picked up on Ebay for approx. $20. This is a retro-focus lens, meaning that the focus adjustment is behind the iris. The shot was shot at F1.4 and is surprisingly clean over the entire FOV and I didn’t have to engage the ETC mode to achieve full sensor coverage. As long as you don’t have to pull focus during a shot, this is an excellent and cheap lens for low light 50mm equivalent shots.
The next lens is my sentimental favorite, this is a Angénieux retrofocus 9.5mm f2.2 lens. If you want that 60s Cinéma vérité look, this is your lens. Using the GH2′s ETC mode this lens is another 50mm equivalent lens, while slower than the Chinese lens, it has a nice clean center with a slight soft vignetting around the edges. I also shot with this lens without the ETC mode, which I’ll show in the wider angle shots.
The next lens is also a surprise in that I had written it of as a bad lens at one point because of it weird chromatic aberrations when zoomed in . (More on that later) but when set to wide open iris and zoom, the lens actually looked pretty good. This is another C-mount CCTV lens, but it is a Canon and it is both fast (f1.4) and wide (11-70mm zoom). Again this is another lens that ends up being a 50mm equivalent.
This next lens was a huge disappointment for me. Having used ENG cameras for many years, I was very excited when I adapted a 2/3″ Fujinon 9.5-133mm 12X broadcasts lens from my old Ikegami HL-95 camera to a M4/3 mount. For all the effort, I am heartbroken at the results. While the lens is really old, I can’t see any fungus when inspecing the lens, and after several careful back focuses, I have to admit, this lens looks terrible. Given the potential for this lens I just have to say I am disappointed.
So, there is no shortage of fast lens that will give you a 50mm full equivalent FOV. The hard part is finding an inexpensive lens that will give you a wider FOV.
The next test is where I took the 1080P vignetted footage from the Angénieux retrofocus 9.5mm f2.2 lens and dropped it into a 720P timeline at 100%. This is my favorite shot. The Angénieux has nice soft edges and a wide enough FOV (28mm equivalent FOV) for most wide angle close-ups. It’s a great “love scene” lens. If you can stand shooting a vignetted shot, knowing that you will crop it in post, this is a great lens.
Next up were the two common kit lens that come with the Lumix GH1 and GH2. Don’t misunderstand that these are inferior lenses,because they are not, Both are fine lenses in their own right. The only downside is that they are relatively slow. f4.0 for the 14-140mm and f3.5 for the 14-47mm. Both these lenses give you a approximately 28mm equivalent FOV and are quite clean from edge to edge. If you don’t need a long lens or Optical Image Stabilization that the 14-140mm offers, then the 14-47 is a good lightweight lens 9and cheap).
The final set of test are just to show the natural vignetting of the the C-mount and 2/3″ lens. They are quite interesting to note the edge differences.