"Picky Details" for the Nikon Coolpix 7900 digital camera
(Timing, Power, and Storage Info)
Timing
When you press the shutter release on a camera, there's usually a lag time or delay before the shutter actually fires. This corresponds to the time required for the autofocus and autoexposure mechanisms time to do their work, and can amount to a fairly long delay in some situations. Since this number is rarely reported on (and even more rarely reported accurately), and can significantly affect the picture taking experience, I routinely measure both shutter delay and shot to shot cycle times for all cameras I test, using a test system I designed and built for the purpose. (Crystal-controlled, with a resolution of 0.001 second.) Here are the numbers I collected for the Nikon Coolpix 7900:
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(secs) |
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| Power On -> First shot |
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LCD turns on and lens extends forward. On the slow side.
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| Shutdown |
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First time is time to retract lens, second time is worst-case buffer-clearing time. Slow.
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| Play to Record, first shot |
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Time until first shot is captured. Fairly fast.
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| Record to play |
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First time is that required to display a large/fine file immediately after capture, second time is that needed to display a large/fine file that has already been processed and stored on the memory card. Average.
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| Shutter lag, full autofocus |
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First time is at full wide-angle, second is full telephoto. Somewhat better than average. |
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Shutter lag, continuous autofocus |
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As usual, no benefit from continuous AF with stationary subjects.
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| Shutter lag, prefocus |
0.084
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Time to capture, after half-pressing shutter button. Very fast. |
| Cycle Time, max/min resolution |
3.67 / 3.3 |
First number is for large/fine files, second number is time for "TV" mode (640x480) images. Times are averages. In either mode, clears the buffer after each shot, and maintains this pace indefinitely. On the slow side of average. |
| Cycle Time, continuous mode, max/min resolution | 0.64 (1.56 fps) |
Times are averages. Shoots 19 frames at this rate in large/fine mode, then slows to about 4.4 seconds per shot. In TV mode, maintains this pace for more than 100 shots. Buffer clears in 82 seconds for large/fine images, 62 seconds for lowest resolution. Reasonably fast, very high buffer capacity. |
| Cycle Time, "5 shot buffer" mode, max/min resolution | 1.00 (1.00 fps) |
Times are averages. Shoots one frame per second at any resolution, and stores the last five frames before the shutter button is released. Buffer clears in 7 seconds for large/fine shots, in 2 seconds for "TV" sized images. Not terribly fast. |
| Cycle Time, continuous "Multi Shot 16" mode | 0.60 (1.67 fps) |
Camera captures 768 x 576 pixel images, stores them in 4x4 arrays inside normal 3072 x 2304 files. Shoots 16 shots 0.60 seconds apart, pauses about a second, then takes 16 more. Clears the buffer in 4 seconds. Oddly, only slightly faster than normal continuous mode. |
Slightly faster than average shutter response, average shot to shot cycle times. Apart from its blazing shutter response time when you "prefocus" it by half-pressing and holding down the shutter button before the shot itself, the Coolpix 7900 is only average in its timing performance. Shutter lag in full autofocus mode is a bit faster than average, particularly at the wide angle end of its zoom range, but shot to shot cycle times are on the slow side of average. Continuous-mode speed is also average, at about 1.6 frames/second.
Power
Very good battery life. The Nikon Coolpix 7900 uses a custom rechargeable LiIon battery for power, and has no external power terminal, so I couldn't conduct my normal battery-life tests. In a simple run-down test in record mode with the LCD illuminated (the camera's worst-case power mode), a freshly charged battery lasted 136 minutes. This quite good for a compact digital camera like the 7900, but I do recommend that you purchase a second battery if you plan any really extended excursions with it. (Particularly since the poor viewfinder accuracy means that you'll find yourself using the power-hungry LCD viewfinder more often than not.)
Storage Capacity
The Nikon Coolpix 7900 stores its photos on SD / MMC memory cards, or in approximately13.5 MB of internal memory. No memory card is included with the camera. (I strongly recommend buying at least a 64 MB card, preferably a 128 MB one, to give yourself extra space for extended outings.) The chart below shows how many images can be stored in the internal memory at each size/quality setting.
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Resolution/Quality 13.5 MB Memory Card |
Fine | Normal |
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| 3072
x 2304 |
Images (Avg size) |
3 3.6 MB |
7 1.8 MB |
14 931 KB |
| Approx. Compression |
6:1 | 12:1 | 23:1 | |
| 2592
x 1944 |
Images (Avg size) |
5 2.6 MB |
10 1.3 MB |
19 681 KB |
| Approx. Compression |
6:1 | 12:1 | 22:1 | |
| 2048
x 1536 |
Images (Avg size) |
8 1.6 MB |
16 831 KB |
31 432 KB |
| Approx. Compression |
6:1 | 11:1 | 22:1 | |
| 1024 x 768 | Images (Avg size) |
31 432 KB |
56 240 KB |
97
138 KB |
| Approx. Compression |
6:1 | 10:1 |
17:1
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Images (Avg size) |
68 196 KB |
115 117 KB |
76 KB |
| Approx. Compression |
5:1 | 8:1 |
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Download Speed
The Nikon Coolpix 7900 connects to a host computer via a USB interface. Downloading files to my Sony desktop running Windows XP (Pentium IV, 2.4 GHz), I clocked it at 734 KBytes/second, a respectable if not astonishing speed. (Cameras with slow USB interfaces run as low as 300 KB/s, cameras with fast v1.1 interfaces run as high as 600 KB/s. Cameras with USB v2.0 interfaces run as fast as several megabytes/second.)
7900 Test Images
7900 Specifications
7900 "Picky Details"
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