After 2 years of using my first Ricoh GX100 and about 200,000 shots taken with it (most of them in the interval mode), I decided to purchase a second GX100, as a backup to the first one. This was a good opportunity to test the accuracy of the shutter mechanism of the first heavily used camera, comparing it to the new one. The test was simple - shooting simultaneous interval sequences, with both cameras set identically in the manual exposure mode (M), WB set to "cloudy", and AF set to "infinity". My expectation was that the older camera is going to show somewhat more flicker, namely at shorter exposures - due to irregularity of the exposure which I was expecting as a result of the "mechanical wear" of the shutter.
All the movies below are 5 minute sequences, taken at 5
second intervals; all of them are resized (to 640x480) only from the full
image size (F quality), and saved without any other processing as H.264 MOV
files at their best possible quality, to avoid any artificial flicker
resulting from the movie compression. The frame rate is 10 fps, which is
about optimal to show the flicker of the individual frames. All of these
files are about 4 to 4.5 MB large:
| GX100-1 (12/2007) 200,000 shots | GX100-2 (11/2009) new |
| 1/320 F9.1 | 1/320 F9.1 |
| 1/640 F6.5 | 1/640 F6.5 |
| 1/800 F5.7 | 1/800 F5.7 |
| 1/1000 F5.1 | 1/1000 F5.1 |
| 1/1250 F4.1 | 1/1250 F4.1 |
| 1/2000 F3.6 | 1/2000 F3.6 |
Both cameras do not show any flicker at the longer exposures (1/320 and 1/640), from 1/800 to 1/1250 they show about the same level of light flicker, and at 1/2000 the new GX100 shows even more flicker than the old one. This result is rather surprising: I was expecting the older camera to show more flicker, namely at the shorter exposures.
Added later: it was explained to me that in digital cameras there is no classic mechanical shutter like in the film cameras. The exposure time is set electronically, and the mechanical "shutter" closes the lens system during the readout of the CCD only. Thus, the only part in GX100 related to exposure which is set mechanically is the diaphragm. Therefore the flicker at the shortest exposures is probably related to certain inaccuracy of the exposure period, and has nothing to do with mechanical wear of the "shutter" system...
