Timings & File Sizes

The HP 850 did feel more sluggish than the average four megapixel prosumer digital camera, that said it did perform better than the HP 812 before it. Startup times were of course the longest operation, because of the extending lens. Focusing times were slower than we would like but just about acceptable if you're used to a digital camera. One other area of disappointment were write times.

Timing Notes: All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 2272 x 1712 JPEG image (approx. 1.7 MB per image). The media used for these tests was a 256 MB SanDisk SD card.

Action	Details	Time, seconds
Power: Off to On	Lens extension	3.9
Power: On to Off	Lens extended	2.5
Mode: Play image	Image displayed	1.5
Play: Magnify	4x magnification	4.4

Action	Details	Time, seconds
Zoom from Wide to Tele	Full zoom from 37 mm to 300 mm (8 x)	2.2
Auto Focus LAG	Wide angle (37 mm)	0.7 - 1.3
Auto Focus LAG	Telephoto (300 mm)	0.7 - 1.7
Shutter Release LAG	Using Electronic Viewfinder *1	0.2
Shutter Release LAG	Using LCD Monitor *1	0.2
Total LAG	No pre-focus	0.9
Off to Shot Taken		4.7
Shot to Shot	Wide angle (37 mm)	2.0

Auto Focus LAG is (roughly) the amount of time it takes the camera to autofocus (a half-press and hold of the shutter release button), this timing is normally the most variable as its affected by the subject matter, current focus position, still or moving subject etc. This timing is an average.

Shutter Release LAG is the amount of time it takes to take the shot from the moment you fully depress the shutter release button, measured both as a time including auto focus and a time assuming you have already pre-focused by holding a half-press of the shutter release.

File Write / Display and Sizes

Timings shown below are the time taken for the camera to process and "flush" the image out to the SD card, the timer was started as soon as the shutter release was pressed (shutter click was heard) and stopped when activity indicator LED beside the SD compartment returned to green colour. This means the timings also include the cameras processing time and as such are more representative of the actual time to "complete the task". The media used for these tests was a 256 MB SanDisk SD card.

Image Type	Time to store (seconds) *1	Time to magnify (seconds) *2	File size *3 (approx.)	Frames on a *4 256 MB SD card
2272 x 1712	14.1	4.5	1,700 KB	120
2272 x 1712	12.3	3.1	900 KB	240
1136 x 848	12.0	2.4	800 KB	240
1136 x 848	11.2	1.7	430 KB	616

Although a considerable improvement over the lethargic HP 812 the 850 still isn't in the same league as other digital cameras when it comes to write times. For example the Minolta DiMAGE F100 (also an SD card digital camera) took just 3.1 seconds to process and store a 1.3 MB 2272 x 1704 JPEG image, approximately four times faster. This is one area HP really need to fix.

Battery life

We ran the camera through our new battery life test. This test is designed to be fair and comparative to each camera and battery type:

• Take 4 shots without flash
• Wait 2 minutes (50% of the time powering the camera off)
• Take 1 shot with flash
• Wait 1 minute
• Repeat

Batteries are fully discharged and recharged before the test and all cameras were reset to their factory default settings. Here are the results:

The 850 put in a solid three hour plus performance on our standard set of AA batteries, which is pretty impressive. It's amazing to thing how much better modern digital cameras are on standard NiMH AA's compared to just 18 months ago.