Monday, August 10, 2015

Panasonic G7 Technical Review

The body of the Panasonic G7 is based on the classic SLR system design. Clearly defined edges create a retro look that is a little different than the curved and smoothed body of its forerunner, the  Panasonic G6.



The camera was tested with the kit lens, the G Vario 14-42mm f/3.5-5.6 II ASPH OIS. Combined with this lens, and even with larger lenses like the G VARIO 14-140mm f/3.5-5.6 ASPH. POWER O.I.S., the cameras is well balanced. A large grip on the right hand side offers slip-proof handling, while function elements and the two setup dials (one at the shutter release button, one at the backside of the top plate) are easily accessible.

The new G7 offers a high resolution EVF with 2.36 million RGB dots, which makes image control very comfortable. It offers all the electronic aids and utilities available with an electronic system like “focus magnifier” (including free choice of the magnified image area), “focus peaking” and more.



The Panasonic offers all standard exposure modes like P, S, A and M. Beside these standards it offers numerous (24) scene modes and additional image effects. The modes are chosen with the large mode dial on the right hand side at the top and is easily accessible, even when the photographer is composing images. The camera offers additional settings like a “panorama” mode and a special video mode that allows the user to make manual video settings.

A second dial on the left hand side of the camera's top plate offers modes like single and continuous shot modes and the self-timer function. A special setting is added to these shooting modes and marked by a small “4K” icon: in this mode the camera takes serial shots at 30 frames per second. These images are saved as an MP4 video file from which the best shot can be saved as a single JPEG file. The resolution of these images varies slightly but is basically 8MP. The actual resolution depends on the chosen aspect ratio; the Panasonic can record with an aspect ratio of 4:3, 3:2, 1:1 and 16:9 when recording in “4K Photo” mode.



Note: Basically, you can use all 4K video cameras for taking video sequences with up to 30 frames per second and using single frames of these videos as an 8MP still. However, the Panasonic G7 (and all other new Panasonic cameras, like the GX8 or the FZ300) offers a more convenient way to get these shots and allows for the use of photographic aspect ratios other than 16:9, which is used by all other cameras.

The “4K Photo” function offers different options as well. The camera is able to “pre-record” sequences in its image buffer consisting of the last second before pressing the shutter release button and the second after pressing it. Other “4K Photo” modes allow the user to record very long sequences, similar to recording video scenes.



The Panasonic G7 uses SD cards for storing image and video files. It worked well with all kinds of SD, SDHC and SDXC cards in our test. The card slot is located at the bottom of the camera (next to the tray for the battery), which can be a bit unhandy when trying to change the card while working on a tripod.



Comments on Image Quality

Color: The camera showed a tendency towards cooler colors with a very highly saturated reproduction of blue. The white balance system did a good job; only the brightest nuances of the gray pattern in our test chart showed a shift into the yellowish and green area. The reproduction of skin tones is good. The corresponding colors in the result chart showed only a minor shift. Characteristically for Panasonic cameras, the brighter skin tones showed a shift into the more magenta/pink area. This is also noticeable in our portrait test shot.



The overall color reproduction is very good. The camera offers a lot of additional color settings for changing the white balance characteristic or image parameters like saturation and contrast. This allows the user to change the magenta overlap into a more neutral or even warmer rendition, for example.

Sharpness: The camera achieved a very high resolution result by reproducing the ISO 12233 test chart with 3147 of 3348 lines per picture height. Nevertheless, the standard test box shot and the portrait shot have a slightly softer look than the images of most other (even Panasonic) cameras.

This is also a bit surprising because ImaTest showed a clipping warning for the images of the resolution chart. This is a result of a very intense sharpness filtering done by the “Venus Engine” processor and causes some exaggerated reproductions of hard contrast lines, like in the Siemens star of our test box image or line patterns in our ISO 12233 test chart. With more than 22 percent, the overshot effect is very high: most other cameras will create overshot effects of about 10 to 15 percent.



Noise: The Panasonic G7 showed very good results in our noise tests. The luminance noise level is a little higher than in images taken with full frame cameras, but nevertheless is on a low level. Color noise gets noticeable in images taken at ISO 1600, while images taken at ISO 200 to 800 have a very clean look. The color noise level is noticeable, but still acceptable in images taken at ISO 3200 and 6400. In images shot at ISO 12,800 the combination of color noise and anti noise filtering becomes visible and is annoying in images taken at ISO 25,600.



The camera showed a good performance in tests of its dynamic range. It achieved a maximum of 11.1 f-stops at ISO 200, although at higher ISO settings the dynamic range drops to 9-10 f-stops.


Video Format and Handling

The G7 offers numerous video modes and recording formats. It can use a standard AVCHD setting with Full HD recording of 1920 x 1080 pixels and high framing rates up to 50/60 full progressive frames per second. In this mode the highest data rate is 28 mbit/s, which is the maximum defined as AVCHD 2.0 standard.

The Panasonic also allows users to record in MP4 file format. In this mode it is able to record UHD movies (4K) with 3840 x 2160 pixels and 25/30 frames per second. In addition, it offers a “cinema” and Blu-ray compatible mode with 24 frames per second. In all of these MP4 modes it offers higher data rates up to 100 mbit/s. In addition, the camera can record 720p movies and videos with 640 x 480 pixels.

The camera uses a second shutter release button to start video recording, even when working in photo mode. But choosing the special video mode on the mode dial allows for the use of the standard shutter release button to start video recording as well as providing access to a lot more tasks and functions, including manual exposure modes for video recording. The camera can be used in P, S, A and M mode plus manual selection of ISO speed settings. In contrast to photo mode, the ISO speed settings are limited to a maximum of ISO 6400.

Using the electronic viewfinder helps with manual focusing in video mode; additional focusing modes and aids include “focus tracking” and “focus peaking” (colored and enhanced contrast lines which are in focus) plus a magnifier function.

The camera also offers manual sound control. “Level bars” are shown in the electronic viewfinder when working in video mode. To enhance sound quality, the camera offers a 3.5mm jack for an external microphone. A second jack for an earphone and for direct sound control is missing.

An integrated image stabilizer based on sensor shift technology is missing. But the camera can use the optical stabilizer systems of its G-lenses when recording video. This helps to create steady and smooth video shots.

Comments on Video Quality
The Panasonic showed a very good performance in our video tests. In Full HD mode it reproduced the ISO 12233 chart with 940 of 1080 lines per picture height. In 4K mode it showed up to 1525 of 2160 lines.

The color reproduction in video mode corresponds to color reproduction in photo mode. The white balance shows a shift of bright and white nuances into the yellow direction, while most other gray nuances will show a “neutral” behavior. Blue colors have high saturation, especially the clean cyan test pattern, which shows a big shift into the dark blue area resulting in a higher magenta rate.

Noise results are very good. The G7 shows only minor luminance noise effects in videos taken at ISO 200 to 800. At ISO 1600 and ISO 3200 we noticed some noise grain effects and at ISO 6400 very intense noise artifacts. We suggest that ISO 6400 should only be used when absolutely necessary. The dynamic range in video mode is good. The camera achieved a maximum of 11.2 f-stops, while dynamic range drops to 8-9 f-stops at higher ISO speed settings.



Pro
-very compact system camera
-good body design with numerous function buttons, plus more virtual function buttons on the touch screen
-innovative 4K photo modes combine 4K video function and continuous photo shooting with high burst rates
-very fast AF system
-WiFi system for remote control and transferring images to Smartphones and more
-swivel LCD offers comfortable image control
-high resolution EVF

Con
-missing NFC system (would have made WiFi function more convenient)
-MFT (Micro Four-Thirds) format means high lens crop factor of 1:2

Lab tests and comments by Betternet, edited by George Schaub, a member of TIPA’s Technical Committee. For more on TIPA visit www.tipa.com

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