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Timing & Performance

Aside from a rather leisurely start-up time and extended shot-to-shot time in anti-red-eye flash mode, the Coolpix 7900 feels pretty responsive in use, and rarely keeps you waiting to perform any task. A look at the measurements below show the 7900 is pretty fast, though by no means the best performer in its class (in almost all aspects the Canon SD500, for example, is measurably quicker).

Timing Notes

All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 3072 x 2304 FINE JPEG image (approx. 2,078 KB per image). The media used for these tests was a 1.0GB SanDisk Extreme III SD card.

Action Details
Time, secs
Power: Off to Record   4.4*1
Power: Off to Play Image displayed 5.6 *2
Power: Record to Off Lens retracted and all activity ceased 2.2
Power: Play to Off When buffer is empty, lens already retracted ~0.9
Power: Play to Off When buffer is empty, lens extended ~2.7
Record Review Image displayed ~0.5
Mode: Record to Play   ~1.0
Mode: Play to Record Lens already extended 1.6
Mode: Play to Record Lens not extended 2.2
Play: Magnify To full magnification (10x) 3.0
Play: Image to Image Time to display each saved image (low res) ~0.2
Play: Image to Image Time to display full res image (allows zooming) 1.0
Play: Thumbnail view 2 x 2 thumbnails ~0.7 *3

Action Details
Time, seconds
Zoom from Wide to Tele 38 to 114 mm (3 x) 0.9
Half-press Lag (0->S1) Wide angle ~0.55
Half-press Lag (0->S1) Telephoto ~0.75
Half to Full-press Lag (S1->S2) LCD live view ~0.1
Half to Full-press Lag (S1->S2) Viewfinder < 0.1
Full-press Lag (0->S2) LCD live view, wide angle ~0.6 - 0.9
Off to Shot Taken LCD live view 4.8
Shot to Shot Flash off 2.0
Shot to Shot Flash on 2.4
Shot to Shot Flash on (red eye mode) 6.0
*1 Startup time can be reduced to around 2.1 seconds by disabling the startup animation
*2 The 7900 can be powered up directly into playback mode by holding the play button for around a second. This figure includes the delay before the camera turns on (designed to avoid accidental activation).
*3 You can also view 3x3 thumbnails by pressing the zoom button a second time. This adds around 0.9 seconds to the time taken.

Lag Timing Definitions

Half-press Lag (0->S1)
Many digital camera users prime the AF and AE systems on their camera by half-pressing the shutter release. This is the amount of time between a half-press of the shutter release and the camera indicating an auto focus & auto exposure lock on the LCD monitor / viewfinder (ready to shoot).
 

(Prime AF/AE)
Half to Full-press Lag (S1->S2)
The amount of time it takes from a full depression of the shutter release button (assuming you have already primed the camera with a half-press) to the image being taken.
 

(Take shot, AF/AE primed)
Full-press Lag (0->S2)
The amount of time it takes from a full depression of the shutter release button (without performing a half-press of the shutter release beforehand) to the image being taken. This is more representative of the use of the camera in a spur of the moment 'point and shoot' situation.
 

(Take shot, AF/AE not primed)

Continuous mode

The tables below show the results of our continuous shooting test, indicating the actual frame rate along with maximum number of frames and how long you would have to wait after taking the maximum number of frames before you could take another shot. Media used for these tests was a 1.0GB SanDisk Extreme III SD card. Shutter speed was kept above 1/100 sec during these tests.

A 5-shot buffer mode offers around 1 frame per second at the top (7MP Fine) setting, but only saves the last five frames captured (when you take your finger off the shutter button). There does not seem to be a limit to how long you can shoot for in this mode, though of course you'll still only get five shots. Finally, a 16-shot 'burst mode' captures 16 small images in a single 7 megapixel file (in a 4x4 grid) over a period of around 9 seconds.

Continuous drive mode

In burst mode the Coolpix 7900 shows a brief review image for each frame taken. Focus and exposure are fixed with the first frame.

Image Type
Mode
Avg. frames
per sec
Frames in a burst *1
After
burst
*2
3072 x 2304 JEPG Fine Continuous 1.54 fps 21 0.3 fps
3072 x 2304 JPEG Normal Continuous 1.55 fps 44 0.3 fps
3072 x 2304 JPEG Basic Continuous 1.54 fps 100 + n/a *3
2592 x 1944 JEPG Fine Continuous 1.57 fps 100 + n/a *3
1600 x 1200 JPEG Fine Continuous 1.6 fps 100 + n/a *3

*1 In a single "burst" (finger held down on shutter release) until the buffer is full.
*2 With the shutter release held down it is possible to continue shooting after the initial burst at around one frame every 4.4 seconds, though the camera re-focuses between each frame. The buffer takes around 100 seconds to completely clear if you want to shoot another full burst.
*3 With a fast card it is impossible to fill the buffer at the 7MP/Basic setting and below, meaning to all intents and purposes you can keep shooting until the card is full.

Not the fastest burst rate in the world, but one that shows the 7900 has a large, fast buffer, allowing you to keep shooting - even at 7 million pixels - for at least 21 frames (and until the card is full at most file size/quality settings).

File Write / Display and Sizes

Timings shown below are the time taken for the camera to process and "flush" the image out to the storage card, the timer was started as soon as the shutter release was pressed and stopped when activity indicator went out. This means the timings also include the camera's processing time and as such are more representative of the actual time to "complete the task". The media used for these tests was a 1.0GB SanDisk Extreme III SD card.

Image Type
Time to store
(secs)

Time to display
(secs)
*3

File size *1
(approx.)
Images on a *2
1.0 GB Card
3072 x 2304 JEPG Fine 2.4 ~0.2 2,080 KB 286
3072 x 2304 JPEG Normal 2.3 ~0.2 1,110 KB 568
3072 x 2304 JPEG Basic 2.0 ~0.2 615 KB 999
2592 x 1944 JEPG Fine 2.4 ~0.2 1,475 KB 399
1600 x 1200 JPEG Fine 2.3 ~0.2 918 KB 632

*1 All file sizes are an average of three files. As is the case with JPEG it's difficult to predict the size of an image because it will vary a fair amount depending on the content of the image (detail and noise).
*2 Camera estimation.
*3 The 7900 uses low res thumbnails to speed up playback of images. Scrolling through images is therefore almost instantaneous. If you want to do anything to a displayed image (crop, zoom etc), you need to wait around 0.9 seconds (all file size/quality settings) for the full resolution file to load.

Although the buffer is large enough for you to rarely experience any delay, the Coolpix 7900 is more pedestrian when it comes to writing the data to the SD memory card (2.4 secs for a 2,080 KB file equates to around 870 KB/s - hardly taxing the capabilities of our fast card).

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