The GH1 appeared to be the first fully compliant camera with the MFT system standard, which includes High Definition (HD) video capability.

This means that the GH1 14 megapixel sensor was capable of recording images in user selectable, native aspect ratios of 4:3, 3:2 and 16:9 with no cropping, and more importantly, the same angle of view and maximization of pixel count in any particular format.

The GH1 was also the first consumer-priced interchangeable lens camera to also offer continuous autofocus capability while shooting HD video.

Notably, since the introduction of the GH1, every other MFT system compliant camera, whether made by Olympus or Panasonic, has been capable of some type of AVCHD HD video.

However, only the GH1 and the successor GH2 have provided the wide range of manual control over HD video recording, garnering the attention of amateur film makers worldwide.

The user is also able to manually select shutter speed and aperture openings for more creative control over HD video recording.

In the United States, the HD video recording length is limited to the capacity of the memory card (or the battery life, unless the AC power adapter is used).

In Europe, however, the HD video recording length is limited to 30 minutes, due to EU regulatory and tax reasons.

[11] This dual CPU speeds up HD image processing and offers a number of other advantages, including improved image noise reduction performance, ability to display a live view direct from the sensor for either the fully articulated LCD display on the camera back or the high resolution electronic view finder, a very fast contrast detect auto focus system, and even the ability to output both images and sound via HDMI directly from the camera.

[11] At the time of introduction, the dual processor Venus Engine HD also allowed faster contrast detect autofocus ability at the time, in addition to the implementation of a live view electronic viewfinder with DSLR like functionality, but without the penalty of a complex and bulky mirror box and pentaprism.

Traditional digital single-lens reflex cameras (DSLRs), typified by Canon EOS or Nikon FX or DX offerings use Phase Detect Auto Focus (PDAF) systems.

When used in Live view mode, especially for video, traditional DSLR's must rely on direct output from the main image sensor in order to autofocus.

Relying strictly on the sensor output to autofocus is called Contrast Detect Auto Focus(CDAF).

As implemented in the GH1, the effect is 60 frame/s full-time live view with no visible pixels for an image as large or larger, and brighter than competing optical viewfinders using a mirror box and pentaprism than most prosumer DSLR's.

Unlike traditional optical viewfinders which may use a ground glass focusing screen, the GH1 EVF takes a small portion of the scene and magnifies it 10X.

[8] The effect is that the GH1 body is smaller in every critical dimension, especially depth, and is also lighter weight when compared to a typical DSLR.

This 20mm flange to image sensor distance prohibits the practical implementation of the traditional mirror box and pentaprism optical viewfinder of the typical DSLR.

With an electronic viewfinder, in addition to providing a clear brighter than DSLR view, the user can also select between a variety of image aspect ratios (4:3; 3:2; 16:9 and 1:1) with a 100% image area through the lens in live view, something impossible with the traditional DSLR optical viewfinder.

For example, flash setting, optical image stabilization mode (there are 3), drive mode (single, burst, bracket, timer), image aspect ratio, image quality (RAW, JPEG or both), exposure indicator, ISO speed, shutter speed, aperture, record mode, white balance, composition grid lines and exposure histogram are just some of the available pieces of information in the EVF, all without ever having to move the eye from the viewfinder.

The user can adjust shutter speed and aperture in manual mode and see the actual effect on the recorded exposure in the EVF.

This optical image stabilized (Panasonic brand name "MEGA O.I.S") is video unique because it is near silent in operation, designed with an internal direct-drive linear motor for fast and continuous accurate contrast detect auto focusing, and a silent, step-less (as opposed to the traditional stepped) circular (as opposed to the more traditional hexagonal) aperture diaphragm, ideal for smooth light control so important for video.

The micro four thirds sensor provides some advantages in allowing a smaller, lighter, more compact zoom lens design.

Panasonic has not endorsed PTool nor the 'patches', and certain versions of the firmware, notably 1.3, made the camera 'unhackable', that is, until about May 2011, when users developed a work around.