Saturday, October 30, 2010

Panasonic GH2 Tele Conversion: Bagful of Primes?

Panasonic GH1 1080p Camera Test from Ted Fisher on Vimeo.

I have a hacked Panasonic GH1. It works great, and it's great to be able to work with a camera that's so small and light. The Panasonic GH2 is shipping soon, and it has a few key improvements -- it should be better for low light video, for example.

There's one advanced feature that's really intrigued me, though, that might end up a fantastic bonus for documentary shooters: the Tele Conversion feature.

The idea is that video on a DSLR is recorded at either 1920 pixels by 1080 pixels (1080p) or 1280 pixels by 720 pixels (720p) -- but the camera's sensor is really closer to 5000 pixels wide. So these type of cameras are reading the 5000 pixels and doing some number-crunching to downsize and output a frame 1920 wide or 1280 wide.

The Tele Conversion, however, seems to mean essentially cropping to a 1:1 ratio -- grabbing the center 1920 pixels by 1080 pixels rectangle -- and using that for the recorded frame. This results in a lens acting as if it were had a focal length 2.6 times longer (if you are recording 1080p) or 3.9 times longer (if you are recording 720p).

Well, this has been mentioned in the previews of the camera, and generally the reaction is "Great. That will provide amazing telephoto reach." That's true: the long end of the HD zoom is 140mm, and that would now act (in 1080p) as if it were a 364mm focal length. (The equivalent, on a fullframe 35mm camera would be a 728mm lens.) Or the Tele Conversion results in your 14-140mm now acting like a 546mm lens if you shoot at 720p/60 (typical for sports shooting), which is equivalent to a 35mm fullframe camera with a 1092mm lens. Hmm.

That's all well and good. But here's what I think is exciting:

You get your Panasonic GH2. Tiny, light, ready to travel. Now, buy the Panasonic LUMIX G 20mm f/1.7 Aspherical Pancake Lens and the Panasonic Lumix 14mm f/2.5 G Aspherical Lens for Micro Four Thirds Interchangeable Lens Cameras.

The 20mm goes for about $333 these days, the 14mm is about $400.

They are both tiny tiny tiny, light light light. The camera and these two lenses will fit in a very very small bag and will hardly weigh anything at all.

Here's what happens if you use the Tele Conversion feature, assuming it works well.

Put on the 14mm f/2.5 lens. This is great for wide shots -- equivalent to a 28mm lens on a 35mm camera. But if you turn on the Tele Conversion while you are shooting 1080p / 24, suddenly the lens acts like a 36.4 mm lens (72.8mm in 35mm equivalent).

Put on the 20mm f/1.7 lens. This is great for "standard" shots -- equivalent to a 40mm lens on a 35mm camera. But if you turn on the Tele Conversion while you are shooting 1080p / 24, suddenly the lens acts like a 52 mm lens (104mm 35mm equivalent).

So that means you could travel with a tiny camera and two pancake lenses, and have the equivalent of these prime lenses (considered in 35mm equivalent focal length).

  • 28mm f/2.5
  • 40mm f/1.7
  • 72.8mm f/2.5
  • 104 mm f/1.7
So: a bright wide, a very bright standard, a bright medium portrait, a very bright long portrait.

Check out Elliott Erwitt's Camera Case, Circa 1974 and you'll find out what he carried:
"Inside the case: two Canon F1s, a complete set of prime lenses (17mm, 24mm, 28mm, 35mm, 35mm tilt/shift, 50mm, 100mm, 135mm, 200mm and 300mm), a cable release, a Minolta light meter and an Eastman Kodak "Pocket Guide to Photography."
Hmm. Getting there, with just two tiny pancake lenses. (Erwitt's case must have weighed a ton, no?)

So add a Olympus 17mm f/2.8 Lens. These are going for about $260 right now, and again: tiny and light.

So the Olympus is 17mm, which acts on a Micro Four Thirds sensor about the same as a 34mm lens on a fullframe 35mm format camera. Hit the Tele Conversion button, and it acts 2.6 times longer, or as if it were a 88.4mm lens. This brings your range of primes to:
  • 28mm f/2.5
  • 34mm f/2.8
  • 40mm f/1.7
  • 72.8mm f/2.5
  • 88.4mm f/2.8
  • 104 mm f/1.7
So: with two Panasonic Lumix DMC-GH2's and three tiny pancake lenses -- all extremely small and lightweight -- you can get a broad range of focal lengths in bright, high-quality prime lenses.

Now, Erwitt's got some longer lenses there as well, but so consider adding Panny's new Panasonic Lumix 100-300mm f/4.0-5.6 G Vario Aspherical MEGA OIS Lens for Micro Four Thirds Interchangeable Lens Cameras. That provides a range, including a 100mm / f/4 end (the 35mm equivalent is 200mm) that Tele Converts to 260mm / f/4 (in 35mm equivalent, that's 520mm).

Now, remember: this Tele Conversion feature is brand new. No one has reported on the quality yet, though in theory there's no reason it might not actually be better than "regular" video recording. And that's the key factor: it works on video, not stills.

Still, it's fairly amazing to think of what a documentarian today could pack into a small case or backpack. And when the new Voigtlander 25mm / f0.95 ships....


Anonymous said...

Except the tiny little m4/3 primes will be easily outpaced by the 35mm primes from the 1970s on good small grained film in terms of optical resolution rendered in the final image.

Ted Fisher said...

Well, the comment is appreciated, but I don't plan on shooting film again.