We've provided this printable version of our review for your convenience. Please remember that your shopping clicks support this site. If you think this camera is a good choice for you, please consider returning to the link below to check prices and make a purchase via our shopping links.

Also note that this is just one of the pages from this review. Full reviews have several pages with complete analysis of the many test shots we take with each camera. Feel free to download and print them out to see how the camera will perform for you.

Full Review at: http://www.imaging-resource.com/PRODS/AA900/AA900A.HTM

 

Sony A900 Performance


Timing and Performance

The A900's timing performance is about average for a semi-pro SLR.

Startup/Shutdown
Power on
to first shot
0.5 second
Time it takes for camera to turn on and take a shot.
Shutdown
0.5 second
How long it takes to turn off.
(Timings with SanDisk Extreme III Pro Duo Card)
Buffer clearing time
Large Extra Fine JPEG
28 seconds*
(after 11 LEF JPEGs)
Worst case buffer clearing time. -- This is the delay after a set of shots before you can remove the card. Some cameras won't shut down until the buffer is cleared.
Buffer clearing time
Small Basic JPEG
5 seconds*
(after 20 SB JPEGs)
Buffer clearing time
RAW
31 seconds*
(after 13 RAW frames)
Buffer clearing time
RAW + LF JPEG
35 seconds*
(after 11 RAW + LF JPEG frames)
*Note: Buffer clearing times measured with a SanDisk Extreme III Pro Duo Memory Stick card. Slower cards will produce correspondingly slower clearing times. Slow cards may also limit length of bursts in continuous mode. Settings such as ISO sensitivity can also affect cycle times and burst mode performance, with higher ISOs generally increasing JPEG cycle times and reducing burst performance.

Startup and shut-down times are quite fast, difficult to measure. Buffer clearing time depends on the image size and quality, burst length and the speed of memory card used.


Mode Switching
Play to Record,
first shot
0.3 second
Time until first shot is captured.
Record to Play
1.2 seconds
Time to display a large/extra fine file immediately after capture.
Display
recorded image
0.5 second
Time to display a large/extra fine file already on the memory card.

Mode switching is reasonably fast, except for Record to Play, which is notably slower than average. (Slow enough to be an annoyance; this bothered us a fair bit as we shot with our test sample.)


Shutter Response (Lag Time)
Full Autofocus
Optical Viewfinder
0.183 second
Time from fully pressing shutter button to image capture using optical viewfinder, with the lens already at the proper focal distance setting. (all AF timing done with Sigma 70mm f/2.8 Macro lens).
Prefocused
Optical Viewfinder
0.072 second
Time to capture, after half-pressing and holding shutter button.
Continuous AF
Optical Viewfinder
0.181 second
This mode usually shows no speed increase with our static subject; we have no way to measure performance with moving subjects.
Manual focus
Optical Viewfinder
0.153 second
For most cameras, shutter lag is less in manual focus than autofocus, but usually not as fast as when the camera is "prefocused".

In terms of the A900's ability to determine that it's properly focused when shooting the same target multiple times, its speed is about average for a semi-pro SLR. The A900 required about 0.183 second for full AF. Continuous autofocus mode lag time was about the same at 0.181 second, and manual focus was slightly faster at about 0.153 second. When prefocused, shutter lag dropped to 0.072 second. This is slightly faster than Sony's consumer SLRs, but slightly slower than some competing prosumer models.


Cycle Time (shot to shot)
Single Shot mode
Large Extra Fine JPEG
0.40 second
Time per shot, averaged over 20 shots, 27 seconds to clear.*
Single Shot mode
Small Basic JPEG
036 second
Time per shot, averaged over 20 shots, 1.5 seconds to clear.*
Single Shot mode
RAW
0.41 second
Time per shot, averaged over 15 shots, 30 seconds to clear.*
Single Shot mode
RAW + LF JPEG
0.34 second
Time per shot, averaged over 11 shots, 35 seconds to clear.*
Single Shot mode
APS-C Extra Fine JPEG
0.51 second
Time per shot, averaged over 20 shots, 12 seconds to clear.*
Single Shot mode
APS-C Small Basic JPEG
0.50 second
Time per shot, averaged over 20 shots, 1.5 seconds to clear.*
Single Shot mode
APS-C RAW
0.47 second
Time per shot, averaged over 20 shots, 14.5 seconds to clear.*
Single Shot mode
APS-C RAW + Fine JPEG
0.43 second
Time per shot, averaged over 13 shots, 18.5 seconds to clear.*
Early shutter
penalty?
No
Some cameras refuse to snap another shot if you release and press the shutter too quickly in Single Shot mode, making "No" the preferred answer.
Continuous mode
Large Extra Fine JPEG
0.20 second
(4.98 frames/sec);
11 frames total;
28 seconds to clear*
Time per shot, averaged over 11 shots. Then slows to about 0.43 seconds per frame or 2.33 fps.
Continuous mode
Small Basic JPEG
0.20 second
(4.99 frames/sec);
20+ frames total;
5 seconds to clear*
Time per shot, averaged over 20 shots, with no signs of slowing down.
Continuous mode
RAW
0.20 second
(5.00 frames/sec);
13 frames total;
31 seconds to clear*
Time per shot, averaged over 13 shots. Then slows to about 2.14 seconds or 0.47 fps.
Continuous mode
RAW+ LF JPEG
0.20 second
(5.00 frames/sec);
11 frames total;
35 seconds to clear*
Time per shot, averaged over 11 shots. Then slows to about 3.31 seconds or 0.30 fps.
Continuous mode
APS-C Extra Fine JPEG
0.20 second
(4.99 frames/sec);
20+ frames total;
18 seconds to clear*
Time per shot, averaged over 20 shots, with no signs of slowing down.
Continuous mode
APS-C Small Basic JPEG
0.20 second
(4.99 frames/sec);
20+ frames total;
3 seconds to clear*
Time per shot, averaged over 20 shots, with no signs of slowing down.
Continuous mode
APS-C RAW
0.20 second
(4.91 frames/sec);
14 frames total;
15 seconds to clear*
Time per shot, averaged over 14 shots. Then slows to about 1.03 seconds or 0.97 fps.
Continuous mode
APS-C RAW + Fine JPEG
0.20 second
(5.00 frames/sec);
11 frames total;
18 seconds to clear*
Time per shot, averaged over 11 shots. Then slows to about 1.70 seconds or 0.59 fps.
Flash recycling
n/a
(No built-in flash.)
*Note: Buffer clearing times measured with a SanDisk Extreme III Pro Duo Memory Stick card. Slower cards will produce correspondingly slower clearing times. Slow cards may also limit length of bursts in continuous mode. Settings such as ISO sensitivity can also affect cycle times and burst mode performance, with higher ISOs generally increasing JPEG cycle times and reducing burst performance.

Single-shot cycle time performance is also about average for a semi-pro SLR, at about 0.4 second between shots in large/extra fine JPEG quality or RAW mode. Buffer depth is quite good (particularly for a camera with such exceptional resolution) at over 20 frames for JPEGs and 15 frames for RAW. Continuous mode is also about average among high-end prosumer SLR models at 5 frames per second in all modes, with good buffer depth at 11 frames for large/extra fine JPEGs and 13 for RAW files. (Remember, though, that these are very large, 25-megapixel files, and our test target when doing timing is designed to be difficult to compress to deliver results from a worst-case scenario.)

Switching to APS-C crop mode did not improve cycle-time or burst rate, which implies the sensor interface is the bottleneck, but it did improve burst length and/or buffer clearing time.


Download Speed
Windows Computer, USB 2.0
12,928 KBytes/sec
Typical Values:
Less than 600=USB 1.1;
600-770=USB 2.0 Low;
More than 770=USB 2.0 High

Download speeds were extremely quick, fast enough that you probably won't feel the need for a separate card reader, even with the A900's huge files. (Note that this test was performed with a SanDisk Extreme III CF card: Slower cards would likely show slower transfer times.)

Bottom line, the Sony A900 is generally a very responsive camera, able to handle typical family shots as well as faster sports action. For a semi-pro SLR, performance is only average, but not at all surprising, considering the huge 25-megapixel files and full-frame format, which requires a larger (and therefore heavier and harder to move) mirror.

Battery and Storage Capacity

Battery

Good battery life for a full-frame DSLR.

Test Conditions
Number of Shots
Lithium-ion rechargeable battery,
(CIPA standard)
880

The Sony A900 uses a custom rechargeable lithium-ion battery pack for power, and comes with both a single battery and charger. The rated 880 shots per charge is above average for an SLR, but don't forget, the A900 does not have a built-in flash which is normally fired for 50% of the shots during CIPA standard testing. We recommend getting a second battery and/or the optional battery grip for extended outings.

The table above shows the number of shots the camera is capable of on fully-charged battery, based on CIPA battery-life and/or manufacturer standard test conditions.

(Interested readers can find an English translation of the CIPA DC-002 standards document here. (180K PDF document))

Storage

The Sony A900 stores its photos on CompactFlash or Memory Stick Duo memory cards, and no card is included with the camera. The chart below shows approximately how many images can be stored on a 2GB card at each size/quality setting.

Image Capacity vs
Resolution/Quality
2GB Memory Card
Extra Fine Fine Normal
RAW
RAW
+
LF JPEG
6,048 x 4,032
Images
(Avg size)
87
23.5 MB
201
10.2 MB
302
6.8 MB
54
37.9 MB
42
48.8 MB
Approx.
Comp.
3:1 7:1 11:1 1:1 -
4,400 x 2,936
Images
(Avg size)
157
13.0 MB
344
6.0 MB
491
4.2 MB
- -
Approx.
Comp.
3:1 7:1 9:1 - -
3,024 x 2,016
Images
(Avg size)
283
7.2 MB
599
3.4 MB
789
2.6 MB
- -
Approx.
Comp.
3:1 5:1 7:1 - -

We strongly recommend buying a fast, high-capacity CompactFlash or Memory Stick Pro Duo card. The A900's files are huge, so you should probably consider at least a 4GB card, if not an 8GB one, to give yourself extra space for extended outings, especially if you plan on doing a lot of RAW shooting. (Check the shopping link above, cards are cheap these days, so there's no reason to skimp -- But do consider faster cards for this camera, to reduce buffer clearing times.)