"Picky Details" for the Pentax Optio MX 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 Pentax Optio MX:
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(secs) |
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| Power On -> First shot |
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Hard to understand, there's no lens to telescope out, but this is a slow startup time by current standards.
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| Shutdown |
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First time is simple shutdown, second time is worst-case buffer-clearing time. Pretty fast.
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| Play to Record, first shot |
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Time until first shot is captured. Very 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. First time is average, second time is very fast.
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| Shutter lag, full autofocus |
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First time is at full wide-angle, second is full telephoto. Very slow, current "average" range is 0.8-1.0 second. (Which is still too slow, IMHO.) |
| Shutter lag, prefocus |
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Time to capture, after half-pressing shutter button. On the fast side of average.
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| Cycle Time, max/min resolution |
3.35 / |
First number is for large/fine files, second number is time for "TV" mode (640x480) images. Times are averages. In either mode, no buffering, writes to card with every shot. Slow by current standards. |
| Cycle Time, continuous low mode, max/min resolution | 1.93 / 1.87 (.52 / .54 fps) |
First number is for large/fine files, second number is time for "TV" mode images. Times are averages. In either mode, writes to card after every shot. Rather slow. |
| Cycle Time, continuous high mode, max/min resolution | 0.38 (2.67 fps) |
In either large/fine or "TV" mode, shoots a burst of 3 shots, then stops while buffer clears. This takes about 4.4 seconds for large/fine images, and 2.4 seconds for "TV" sized images. Quite speedy, albeit for only 3 shots. |
Shutter response is probably the Optio MX's most significant Achilles heel. Including autofocus delay, it's just slow by any measure, with a lag time of 1.33-1.40 seconds. (The current average range is 0.8-1.0, which is still too slow, IMHO. Shot to shot time is also somewhat leisurely, at a bit over three seconds, but at least there's no further delay after the buffer fills, because the camera doesn't appear to use a buffer in any but its "high speed" continuous mode. - Said high-speed mode actually is decently fast though, at roughly 2.7 frames/second, for three frames.
Power
The Pentax Optio MX uses a custom rechargeable LiIon battery for power.
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(@4.5 volts on the external power terminal) |
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| Capture Mode |
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| Half-pressed shutter |
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| Memory Write (transient) |
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| Flash Recharge (transient) |
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| Image Playback |
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With a worst-case run time of just under two hours, the Optio MX's battery life is better than average. As always though, I strongly recommend purchasing a second battery at the same time as the camera, to have a spare.
Storage Capacity
The Pentax stores its photos on SD/MMC memory cards, and a 16 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
16 MB card at each size/quality setting.
| Resolution/Quality 16 MB Memory Card |
Fine | Normal | |
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| 2,048 x 1,536 | Images (Avg size) |
7 2.0 MB |
14 1.1 MB |
21 754 KB |
| Approx. Compression |
5:1 | 9:1 | 13:1 | |
| 1,600 x 1,200 | Images (Avg size) |
13 1.2 MB |
22 704 KB |
31 508 KB |
| Approx. Compression |
5:1 | 8:1 | 11:1 | |
| 1,024 x 768 | Images (Avg size) |
28 557 KB |
51 311 KB |
65
245 KB |
| Approx. Compression |
4:1 | 8:1 |
10:1
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Images (Avg size) |
61 262 KB |
97 164 KB |
131 KB |
| Approx. Compression |
4:1 | 6:1 | |
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Download Speed
The Pentax 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 3468 KBytes/second. This is extremely fast. (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, so the Optio MX is about as fast as current cameras get.)
Optio MX Test Images
Optio MX Specifications
Optio MX "Picky Details"
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