Panasonic G2 Super High-Res Electronic Viewfinder

The Panasonic G2 has the same same high resolution, high performance electronic viewfinder found in the G1 and GH1. The keys to the Panasonic G2's exceptional EVF performance lie in two technologies. First, the active element of the display is an LCOS (liquid crystal on silicon) chip. This technology actually controls the state of the liquid crystals with electric fields projected through the silicon. This means that all the active circuitry can be on the back side of the chip, so the entire display surface is active: With no dead areas between pixels, light is reflected from the entire surface, so there are no distracting black areas surrounding each pixel.

Because the LCOS chip is reflective, you generate an image by bouncing light off its surface, rather than by passing light through it as in a conventional transmissive LCD. It turns out that LCOS chips can also change states very rapidly; fast enough that you can display the red, green, and blue color channels in very quick succession with no blurring or crosstalk between the color channels. Human persistence of vision blends these together into a single pixel displaying a full range of color. Looking into the Panasonic G2's EVF then, you don't see individual red, green, and blue stripes or dots -- there is no grid -- you just see a surface of continuous color, which looks more like an optical viewfinder. To be fair, this isn't a new innovation with Panasonic: The original Minolta A1 digicam used similar technology, but its EVF had much lower resolution, and considerably lower image quality overall. The concept has certainly been seen before, but the Panasonic G series' EVF takes the technology to another level.

Light for the G2's EVF comes from a trio of red, green, and blue LEDs: They strobe on and off in very quick succession (180 times a second, for a 60 frames/second overall refresh rate), as the LCOS chip displays the red, green, and blue image planes in lock-step. I expected to see some tearing of the display, or perhaps a rainbow effect if the subject moved rapidly, but actually saw very little evidence of this.

The second key technology in the Panasonic G2's EVF is a holographic diffraction grating that's curved above the LCOS chip. This optical element reflects the RGB light from the LED array onto the LCOS chip's surface, but lets the light reflected from the imaging chip pass through unobstructed, out the eyepiece and to the user's eye. Other technologies could be used to make a reflective imager work in a viewfinder, but the holographic grating allowed Panasonic's engineers to squeeze the whole assembly into an incredibly compact package.

As befits its heritage in the high-end broadcast TV field, the Panasonic G2's EVF has impressive specs. It has unusually high resolution for a camera EVF, displaying 800x600 (SVGA resolution) full-color pixels. (A total of 480,000 full-color pixels.) Panasonic equates this with 1.44 million dots in a conventional display, as most displays would need three separate dots for each full-color pixel. In practice, the effective perceptual equivalent of 480,000 full-color pixels is more like 960,000 RGB dots, but the fact remains that this is a very high-resolution, very smooth-looking display. As noted above, the G2's EVF also refreshes at 60 frames/second, so there's very little flicker or tearing with moving subjects.

Thanks to its LED illumination, the Panasonic G2's EVF also has a very wide color gamut, covering 100% of the NTSC color space, an unusually broad range for a camera display. As you'd expect, it also covers 100% of the field of view of the camera, since it's getting its image directly from the camera's image sensor. Finally the EVF's optics give an effective magnification of about 0.7x relative to a 50mm lens on a 35mm camera. This is about the same viewing magnification as is found on most higher-end SLRs. In practical terms, it means that with a 35mm lens attached (roughly equivalent to a 50mm lens on a 35mm camera), the image in the viewfinder will match what you're seeing through your other eye. This makes it easier to shoot with both eyes open, so the eye not looking through the viewfinder can give you much better peripheral vision of subjects about to come into the field of view, etc. The viewfinder also offers a generous diopter adjustment of -4 to +4, adjustable via a dial to the left. Infra-red sensors just to the right of the eyepiece are used to detect when an eye is moved close to the viewfinder, to automatically switch between the LCD monitor and viewfinder. An LVF/LCD button to the left of the eyepiece can also be used to switch manually.

 

Panasonic G2 Full-time Live View

By its nature, the Panasonic G2 is always in "Live View" mode: In that respect, it's like any point & shoot digicam with the combination of an electronic viewfinder and rear-panel LCD that works as a viewfinder as well. The differences with this camera are that it has interchangeable lenses, focuses a lot faster than the average digicam, and has a larger sensor to provide better low-light performance than typical pocket cameras.

To their credit, though, Panasonic seems to have made more of an effort in the Lumix G2 to have the viewfinder display accurately mimic what you'll see in the final image file once you've snapped the shutter. They seem to be trying to go the point & shoot market one better with their viewfinder display accuracy and simulations, and they seem to be succeeding.

The shots above show two options the camera gives you for viewing your subject in record mode. On the left, the subject fills a larger area of the display, but the exposure information is overlaid on the bottom of the image. This gives more image area, but potentially makes the exposure info a bit harder to read. As seen on the right, you can instead opt for a smaller view of the subject, putting a sharply contrasting black background behind the exposure readouts, making them easier to see. The shots above show the display on the rear-panel LCD; the information overlay on the EVF screen is considerably less extensive. (See the Operation tab of this review for illustrations and callouts describing the information shown on the various displays.)

The Panasonic G2 features a live histogram display with a nifty trick: you can select to have it displayed or not, and you position it pretty much anywhere on the display screen that you like. In the screen shots above, I've put it in the lower right corner. There are three grid options available as well: Grid (shown above right), Grid + Star, and one one that is customizable, allowing you position single horizontal and vertical lines anywhere in the frame you want.