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"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:

 

Pentax Optio MX Timings
Operation
Time
(secs)
Notes
Power On -> First shot
5.5
Hard to understand, there's no lens to telescope out, but this is a slow startup time by current standards.
Shutdown
1.2 - 5.2
First time is simple shutdown, second time is worst-case buffer-clearing time. Pretty fast.
Play to Record, first shot
0.8
Time until first shot is captured. Very fast.
Record to play
2.3 - 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 average, second time is very fast.
Shutter lag, full autofocus
1.40/1.34
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
0.18
Time to capture, after half-pressing shutter button. On the fast side of average.
Cycle Time, max/min resolution

3.35 /
3.24

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.

Operating Mode
Power
(@4.5 volts on the external power terminal)
Est. Minutes
Capture Mode
781 mA
114
Half-pressed shutter
812 mA
109
Memory Write (transient)
573 mA
n/a
Flash Recharge (transient)
1927 mA
n/a
Image Playback
479 mA
185

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.

 

Image Capacity vs
Resolution/Quality
16 MB Memory Card
Fine Normal
Basic
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
640 x 480
Images
(Avg size)
61
262 KB
97
164 KB
122
131 KB
Approx.
Compression
4:1 6:1
7:1

 



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 Review
Optio MX Test Images
Optio MX Specifications
Optio MX "Picky Details"
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