Timings & File Sizes

There are some functions of this camera which can feel almost normal, such as power up which although slow wasn't that much different to many other extending lens cameras. Off to shot taken and shot to shot times were average to below average. Where the HP really suffers is in its image processing and SD storage communication, both of which appear to be exceedingly slow. For example magnifying an image in play mode takes over five seconds, storing a full resolution average quality image in record mode takes over twelve seconds. Performance and responsiveness (the 'feel' of the camera) are both issues HP need to address.

Timing Notes: All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 2608 x 1952 JPEG image (approx. 2,300 KB per image). The media used for these tests was a 512 MB Viking SD card.

Action	Details	Time, seconds
Power: Off to Record	Lens extension	4.5
Power: Record to Off	Lens extended	3.7
Mode: Record to Play *1	Image displayed	1.2
Mode: Play to Record		0.5
Play: Magnify	To 4x magnification	5.3

Action	Details	Time, seconds
Zoom from Wide to Tele	Full zoom from 37 mm to 111 mm (3 x)	1.5
Auto Focus LAG	Wide angle	0.8 - 1.2
Auto Focus LAG	Telephoto	1.1 - 1.4
Shutter Release LAG	Using Viewfinder	0.1
Shutter Release LAG	Using LCD Monitor	0.2
Total LAG	Wide angle	1.1
Total LAG	Telephoto	1.1
Off to Shot Taken	Wide angle	4.6
Shot to Shot	Wide angle	2.3

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 CF card, the timer was started as soon as the shutter release was pressed and stopped when activity indicator LED above the SD compartment stopped blinking. 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 512 MB Viking SD card.

Image Type	Time to write (secs)	Time to display (secs)	File size *1 (approx.)	Images on a *2 512 MB SD
2608 x 1952 JPEG	14.5	<0.5	2,300 KB	196
2608 x 1952 JPEG	12.5	<0.5	1,100 KB	392
1296 x 976	12.2	<0.5	900 KB	392
1296 x 976	11.5	<0.5	500 KB	838

Pretty appalling really, no camera should take fourteen seconds to store a 2 MB JPEG. Looking down the figures you will note that the times change very little as the image dimensions and file size drop, this hints that the bottleneck is in HP's image processor rather than the actual SD interface. We repeated the above test with various SD cards of different capacities and from different manufacturers and got the same results +/-2%. Consider that Pentax's Optio 550 (not a quick camera by anyones standards) takes just five seconds to process and store a similarly sized file (to an SD card).

Low Light Auto Focus

This test is designed to measure the minimum amount of light under which the camera can still focus. The focus target is our lens distortion test chart (shown here on the right), camera is positioned exactly 2 m (6.6 ft) away.

Light levels are gradually dropped until the camera can no longer focus. This is carried out at both wide angle and telephoto zoom positions (as more light reaches the focusing systems with a larger aperture).

This test target is the optimum type of subject for most "contrast detect" AF systems (as it has a vertical line at its center), you should consider the results below the best you could expect to achieve.

Light intensity (Lux) = 2.5 x 2^EV (@ ISO 100), 10.76391 Lux = 1 foot-candle (fc)

Without an AF assist lamp the HP 935 struggled to focus without some moderate lighting, and indeed performed better zoomed in closer to the center of the AF target than at wide angle.

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:

Thanks to its aggressive power saving the HP 935 lasted over three hours on just two 1600 mAh AA batteries. This is a very good performance and goes a long way to supporting the relatively short LCD on time (just 60 seconds).