"Picky Details" for the Canon PowerShot A85 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 Canon PowerShot A85:
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(secs) |
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| Power On -> First shot | |
LCD turns
on and lens extends forward. |
| Shutdown | |
First time is time to retract
lens, second time is worst-case buffer-clearing time. |
| Play to Record, first shot | |
Time until
first shot is captured. |
| Record to play | |
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. |
| Shutter lag, full autofocus | |
First time is at full wide-angle, second is full telephoto. |
| Shutter lag, prefocus | |
Time to capture, after half-pressing
shutter button. |
| Cycle Time, max/min resolution | 2.06 / |
First number is for large/fine files, second number is time for "TV" mode (640x480) images. Times are averages. In large/fine mode, shoots 4 shots this fast, then slows to about 4.2 seconds apart, and clears the buffer in 11 seconds. In TV mode, maintains this rate for over 50 shots, and clears the buffer in 16 seconds. |
| Cycle Time, continuous mode, max/min resolution | 0.71 / 0.67 (1.4 / 1.5 fps) |
First number is for large/fine files, second number is time for "TV" size images. Times are averages. In large/fine mode, shoots 4 shots this fast, then slows to about 2.2 seconds apart, and clears the buffer in 13 seconds. In TV mode, shoots 71 shots this fast, then slows to about 1 second apart, and clears the buffer in 25 seconds. |
Power
The Canon PowerShot A85 uses four AA batteries for power.
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(@3.4 volts on the external power terminal) |
(four 1600 mA cells) |
| Capture Mode, w/LCD |
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| Capture Mode, no LCD |
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| Half-pressed shutter w/LCD |
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| Half-pressed w/o LCD |
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| Memory Write (transient) |
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| Flash Recharge (transient) |
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| Image Playback |
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Storage Capacity
The Canon PowerShot stores its photos on Compact Flash 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.) The chart below shows how many images can be stored on the included 32 MB card at each size/quality setting.
| Resolution/Quality 32 MB Memory Card |
Fine | Normal | |
|
| 2,272 x 1,704 | Images (Avg size) |
15 2.1 MB |
27 1.2 MB |
54 593 KB |
| Approx. Compression |
6:1 | 10:1 | 20:1 | |
| 1,600 x 1,200 | Images (Avg size) |
30 1.0 MB |
54 587 KB |
103 310 KB |
| Approx. Compression |
6:1 | 10:1 | 19:1 | |
| 1,024 x 768 | Images (Avg size) |
53 603 KB |
93 342 KB |
163
196 KB |
| Approx. Compression |
4:1 | 7:1 |
12:1 |
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Images (Avg size) |
115 277 KB |
178 179 KB |
114 KB |
| Approx. Compression |
3:1 | 5:1 | |
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Download Speed
The Canon PowerShot 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 484 KBytes/second. (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.)
A85 Test Images
A85 Imatest Results
A85 Specifications
A85 "Picky Details"
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