The G5 boasts a top equivalent ISO sensitivity of 160-12,800 and uses the same imaging sensor as the DMC-GH2.
Its new Venus Engine VII FHD image processing engine aims to deliver a higher signal-to-noise ratio and improved noise reduction.
Due out in August, priced around £599 body only, the G5 will sit above Panasonic's DMC-G3 which will continue in the range (the G3 features a maximum sensitivity of 6,400).
Features include a maximum burst rate of 20 frames per second (at 4MP); and 6fps at full resolution.
Meanwhile, Panasonic has announced that it will no longer call its Lumix G cameras ‘CSCs'.
Instead, it has introduced the name DSLM (Digital Single Lens Mirrorless), which the company says it will use worldwide.
Designed to be ‘more DSLR-like', in handling terms, the G3 is housed in an aluminium body which sports a larger mode dial and ‘easy-to-grip' chassis.
In a nod to the growing popularity of filters on smartphone applications such as Instagram, the G5 has 14 digital filter effects, like the Lumix DMC-GF5.
The G5 is capable of recording videos in Full HD at 1080 pixels (50fps) in AVCHD format and 1080p at 25fps in MP4.
The 3in, free-angle, LCD (920,000-dot) touchscreen allows photographers to select and touch a focus point, even when using the EVF.
The monitor has a built-in level gauge and the camera features a '300-shot' battery, according to Panasonic. Armoury also includes a silent shutter mode.
Camera functions such as exposure compensation can be assigned to a new Function Lever that also enables zoom control, for example.
In September, Panasonic is due to release a new Lumix G Vario 45-150mmm f/4 micro four thirds lens.
Priced £279.99, the 12-elements-in-nine-groups zoom contains two aspherical lenses.
And Panasonic has confirmed the upcoming launch of two other lenses: a 12-35mm f/2.8 and 35-100mm f/2.8.
In an interview with Amateur Photographer, Panasonic did not dismiss the possibility of a 20 or 24-million-pixel CSC at some future date.
For now, however, bosses say they are satisfied with the image quality and ‘sensitivity' of the firm's current 'DSLM' models.
The G5 will be available with a standard 14-42mm lens in a kit priced £699, and in an outfit that includes a 14-42mm X lens, priced £829.