Minolta DiMAGE A1 Review

Timing & Performance

The DiMAGE A1 delivered good results in our timing and performance tests, thanks to its mechanically linked zoom lens (which doesn't need to extend) power on times were around two seconds, which is actually quite good. Other operations were also relatively quick, Auto Focus taking around three quarters of a second if the focus distance is similar to the last, up to a longest of two and a half seconds for a full AF scan at telephoto in medium light. The only disappointment would be the lag induced by the LCD / EVF which weighs the shutter release lag figures down to 0.2 seconds, compared to 0.1 seconds for most other prosumer cameras.

Timing Notes

All times calculated as an average of three operations (all cards were formatted before testings begun). Unless otherwise stated all timings were made on a Large/Fine (2560 x 1920) JPEG image (approx. 1,900 KB per image).

Media used for these tests:

• 512 MB SimpleTech Type I Compact Flash card
• 1 GB SanDisk Ultra II Type I Compact Flash card
• 1 GB IBM Microdrive Type II Compact Flash card

Action	Details	Time, secs (Simpletech)	Time, secs (SanDisk)	Time, secs (Microdrive)
Power: Off to Record		1.9	1.9	1.9
Power: Off to Play	Image displayed	2.6	3.1	6.3
Power: Record to Off	Includes one second hold *1	3.0	3.1	3.0
Power: Play to Off	Includes one second hold *1	2.5	2.5	2.5
Mode: Record to QV	Image displayed	1.3	1.3	3.0
Mode: Record to Play	Image displayed	1.3	1.3	3.0
Mode: Play to Record	Same for QV to Record	0.9	0.9	0.9
Play: Magnify	To initial 2.0x view *2	2.6	2.3	4.5
Play: Thumbnail view	3x3 thumbnails	0.9	0.9	0.9

Lag Timing Definitions

Half-press Lag (0->S1) Many digital camera users prime the AF and AE systems on their camera by half-pressing the shutter release. This is the amount of time between a half-press of the shutter release and the camera indicating an auto focus & auto exposure lock on the LCD monitor / viewfinder (ready to shoot).	(Prime AF/AE)
Half to Full-press Lag (S1->S2) The amount of time it takes from a full depression of the shutter release button (assuming you have already primed the camera with a half-press) to the image being taken.	(Take shot, AF/AE primed)
Full-press Lag (0->S2) The amount of time it takes from a full depression of the shutter release button (without performing a half-press of the shutter release beforehand) to the image being taken. This is more representative of the use of the camera in a spur of the moment 'point and shoot' situation.	(Take shot, AF/AE not primed)

Continuous mode

The tables below show the results of our continuous shooting test, indicating the actual frame rate along with maximum number of frames and how long you would have to wait after taking the maximum number of frames before you could take another shot. Media used for these tests was the 1 GB SanDisk Ultra II card.

Standard Continuous drive mode

Standard continuous drive mode is specified to shoot at two frames per second, however as you can see from our results below we found it to be closer to 1.7 frames per second. In RAW mode you can shoot a burst of five images (although you'll have to wait over 30 seconds before the next burst), in the JPEG modes you can shoot a maximum of only three images. The wait before next burst timing gets gradually longer after each sucessive burst (as buffer space becomes more reliant on CF speed).

High Speed Continuous drive mode

In high speed continuous drive mode the A1 shoots at 2.8 frames per second (the specs here matched our results), again a maximum of five images in RAW mode and three images in JPEG mode. Once more the wait before next burst timing gets gradually longer after the second burst.

Not a bad performance but nothing to write home about either, continuous shooting and the buffer size are probably the A1's weakest points, it would have been nice to see a camera which is so capable in so many other areas complemented with a better continuous shooting rate and a larger buffer.

File Write Time and Sizes

Timings shown below are the time taken for the camera to process and "flush" the image out to the storage card, the timer was started as soon as the shutter release was pressed and stopped when activity indicator LED beside the viewfinder 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".

Media used for these tests:

• 512 MB SimpleTech Type I Compact Flash card
• 1 GB SanDisk Ultra II Type I Compact Flash card
• 1 GB IBM Microdrive Type II Compact Flash card

The DiMAGE A1 appears to be around 33% faster than the DiMAGE 7Hi to process and write an image, that said the performance is still short of the fastest prosumer digital cameras and digital SLR's, peak write speed for even the fastest card is just under 900 KB/sec. Note that the DiMAGE A1's RAW files are around 2 MB smaller than the 7Hi, obviously Minolta has optimized the file format or added lossless compression.

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)

Despite not having an AF assist lamp the DiMAGE A1 manages to focus in extremely low light situations thanks to its high gain B&W live view mode which also appears to enhance auto focus. Our test results were very similar to those produced by the DiMAGE 7 series. The lower light AF at telephoto was a side-effect of our chart design, the AF target lines are larger at telephoto and therefore the camera has more to focus on.

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 DiMAGE 7 series didn't have a good reptuation for battery life, indeed a good deal of battery power appeared to be wasted through heat, the earlier cameras getting very hot under prolonged use. Minolta clearly decided to avoid any problems with battery life by fitting the DiMAGE A1 with the most powerful Lithium-Ion battery we've yet seen in a digital camera, the NP-400 has a huge capacity of 1500 mAh at its rated 7.4 V and that provided enough power to keep the DiMAGE A1 going just past the five hour mark in our battery test. A superb performance which is virtually twice the lasting power of the DiMAGE 7Hi. Kudos Minolta.