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"Picky Details" for the Sony DSC-T7 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 Sony DSC-T7:

Sony DSC-T7 Timings
Operation
Time
(secs)
Notes
Power On -> First shot
1.3
LCD turns on. Very fast (no wait for lens to telescope out.)
Shutdown
0.4 - 16
First time is simple shutdown, second time is worst-case buffer-clearing time. Fairly fast, worst-case time corresponds to 9 large/fine shots clearing from the memory buffer.)
Play to Record, first shot
0.1
Time until first shot is captured. Extremely fast.
Record to play
3.1 / 0.2
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. First time is about average, second is very fast.
Shutter lag, full autofocus
0.38 / 0.35
First time is at full wide-angle, second is full telephoto. Very fast, the T7 is one of the fastest-shooting consumer cameras on the market, regardless of size.

Shutter lag, continuous autofocus

0.38
As usual, there's no advantage to continuous autofocus with stationary subjects.
Shutter lag, manual focus
0.213
A bit faster than average.
Shutter lag, prefocus
0.012
Time to capture, after half-pressing shutter button. Extremely fast.
Cycle Time, max/min resolution

1.26

Times are averages. Shoots at this pace regardless of resolution. In large/fine mode, shoots 18 shots this fast, then slows to 1.6 seconds per shot. Continues at this pace indefinitely in TV mode. Clears buffer after each shot in either mode. Quite fast, especially for a subcompact model. (Times are measured with a Memory Stick PRO Duo, non-PRO cards could be slower.)
Cycle Time, Flash exposures 4 Flash at maximum power output. Pretty fast, but then it's also a pretty underpowered flash.
Cycle Time, continuous "Burst" mode, max/min resolution 0.70 / 0.61
(1.43 / 1.64 fps)
First number is for large/fine files, second number is time for "TV" size images. Times are averages. Shoots a burst of 9 frames in large/fine mode before stopping to clear the buffer. Shoots 100 frames in TV mode before buffer fills. Buffer clears in 15 seconds for large/fine images, 14 seconds for lowest resolution. Times are measured with a Memory Stick PRO Duo, non-PRO cards could be slower. Surprisingly fast for a subcompact camera, and buffer capacity is also much larger than average.
Cycle Time, "Multi Burst" mode 0.03
(30 fps)
Camera captures 320 x 240 pixel images, stores them in 4x4 arrays inside normal 1280 x 960 pixel files. Frame rate can be set to 30, 15, or 7.5 fps. Buffer clears in only a second, and it's ready for another burst. Very fast, great for analyzing golf and tennis swings, etc.


Surprising speed for a consumer camera, very surprising in a subcompact model. More so than most digital camera makers, Sony seems to have really gotten a handle on autofocus speed. All of their current cameras focus quite quickly, and the T7 is really surprisingly fast, particularly for a subcompact model. Full-autofocus shutter lag ranged from 0.35 - 0.38 seconds depending on the zoom setting, and prefocus shutter lag was a blazing 12 milliseconds (0.012 seconds). (Big kudos to Sony for getting one of the most annoying digicam shortcomings under control.) The T7 was also quite fast from shot to shot, managing a shot every 1.26 seconds in single-shot mode, and capturing up to nine large/fine images at a time in burst mode, at a rate of 1.43 frames/second. All in all, very impressive, especially for a subcompact camera.

 

Power

The Sony DSC-T7 uses a custom rechargeable LiIon battery for power. Its custom power connector prevented me from conducting my usual direct power measurements, but Sony's InfoLithium battery technology is quite accurate in its run time estimates, so I report those below, for a fully charged battery.

Operating Mode
Battery Life
Still-image capture mode 74 minutes
Movie capture mode:
640 Fine
71 minutes
Movie capture mode:
640 Standard
58 minutes
Movie capture mode:
160
63 minutes
Playback mode
125 minutes

Short battery life, typical of subcompact cameras. With a worst-case run time of 74 minutes in record mode, and playback run time of 125 minutes, the Sony T7 has worse battery life than most full-sized digital cameras, but such short run times are unfortunately common subcompact models. Given the short battery life, my usual recommendation of buying a second battery right along with your camera applies doubly with the T7.

 

Storage Capacity

The Sony DSC-T7 stores its photos on Memory Stick Duo memory cards, and a 32 MB 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.) As noted elsewhere, be sure to get a PRO Duo Memory Stick too, to take maximum advantage of the T7's video capability. The chart below shows how many images can be stored on the included 32 MB card at each size/quality setting.

Image Capacity vs
Resolution/Quality
32 MB Memory Card
Fine Normal
2592 x 1944
Images
(Avg size)
12
2.5 MB
24
1.3 MB
Approx.
Compression
6:1 11:1
2048 x 1536
Images
(Avg size)
20
1.6 MB
37
859 KB
Approx.
Compression
6:1 11:1
1280 x 960
Images
(Avg size)
50
634 KB
94
340 KB
Approx.
Compression
6:1 11:1
640 x 480
Images
(Avg size)
197
162 KB
493
65 KB
Approx.
Compression
6:1 14:1

 

Download Speed

The Sony DSC-T7 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 3316 KBytes/second, a very fast rate. (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.)

T7 Review
T7 Test Images
T7 Specifications
T7 "Picky Details"
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