Timings & File Sizes

In use the A100 feels fast and always responds to user input, thanks to very fast media throughput (at 13 MB/sec, the fastest we've seen) you're never really aware of the actual image write process or any kind of delays due to buffering or in playback. As you can see from the first table below the A100 isn't that picky about CF cards either, as long as it's reasonably fast you can expect the kind of performance we measured. I suppose the only slight niggles could be that the power on time isn't absolutely instant as it is on some competitor cameras and the continuous shooting rate was slower than specified and a little inconsistent.

Timing Notes: All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 3872 x 2592 JPEG Fine (approx. 2,400 KB per image).

The media used for these tests were:

• 1 GB SanDisk Extreme III CF card
• 1 GB Lexar Pro 133x CF card
• 4 GB SanDisk Ultra II CF card

Continuous Drive mode

To test continuous mode the camera had the following settings: Manual Focus, Manual Exposure (1/320 sec, F5.6), ISO 200. Measurements were taken from audio recordings of the tests. Media used were the same as above.

We initially tested to see if any of the following factors slowed continuous shooting:

• Auto-Focus / Manual focus - no change
• Shutter speed - 1/50 sec or faster to achieve maximum frame rate (2.85 fps)
• Aperture - no change
• ISO sensitivity - no change
• Metering mode - no change
• DR mode - no change (although fewer shots buffered in Advanced mode)
• Super SteadyShot - no change

The tests carried out below measured the following results for JPEG and RAW:

• Frame rate - Initial frame rate, this was always 2.85 fps (+/- 0.15 fps)
• Number of frames - Number of frames in a burst
• Buffer full rate - Frame rate if shutter release held after burst (buffer full)
• Next burst - How soon after the burst it is fully written to the CF (indicator goes out)

Inconsistent frame rate

Our normal testing method means measuring the amount of time that the camera takes to shoot (at least) ten frames (in JPEG) and dividing that by the number of frames. On average this gave a rate of 2.8 frames per second, however in ten shots we had a fastest rate of 2.95 fps and a slowest of 2.62 fps. (Click here for a graph of 100 shots).

Burst of JPEG Large/Fine images

Burst of RAW images

The A100's (average) continuous shooting frame rate wasn't quite the 3.0 frames per second specified (or quoted elsewhere), we found it to be variable giving an average of 2.85 frames per second (not important to most but to anyone planning to produce flip animations or take timings from bursts should be aware of this slight inconsistency).

With a fast CF card you can indeed keep shooting in JPEG mode until the card is full, in RAW mode buffering was also good and thanks to very fast CF throughput (see below) you don't have to wait long after a full burst to start shooting again (not that I imagine many people shoot continuously in RAW mode).

File Flush Timing

Timings shown below are the time taken for the camera to process and "flush" the image out to the storage card. Timing was taken from the instant the shutter release was pressed to the time the storage card activity indicator beside the storage compartment went out. The activity indicator light comes on around a second after shutter release, hinting at the time taken to process an image. Writing continues 'in the background' and doesn't affect any camera function. Media used were the same as above.

At first glance these times appear slightly longer than we've seen from more recent digital SLR's, and in total they may be. However the first second or so of this is 'processing time', the time taken to actually write the image to the card is never much more than one or two seconds. We were interested to see the Lexar 133x card outperform the pretty much benchmark SanDisk Extreme III and also note the slightly slower write times of the larger 4 GB Ultra II card (FAT32).

The graphs below support the very short write times we calculated above, the A100 delivers the fastest Compact Flash write times we've ever measured at almost 9 MB/sec for JPEG and an amazing 13 MB/sec for RAW files, it becomes our new benchmark. This extremely high throughput helps to explain the A100's unlimited JPEG continuous shooting (with a reasonably fast card).

Card performance: JPEG Fine continuous burst write

Card	Sony DSLR-A100 write speed (JPEG Fine files)
1 GB SanDisk Extreme III	9,090 KB/sec
1 GB Lexar Pro 133x	9,345 KB/sec
4 GB SanDisk Ultra II	5,698 KB/sec

Card performance: RAW continuous burst write

Card	Sony DSLR-A100 write speed (RAW files)
1 GB SanDisk Extreme III	13,749 KB/sec
1 GB Lexar Pro 133x	13,178 KB/sec
4 GB SanDisk Ultra II	7,114 KB/sec

Cardbus 32-bit Adapter benchmark

Card	Cardbus 32-bit Adapter, write speed (RAW files)
1 GB SanDisk Extreme III	9,368 KB/sec
1 GB Lexar Pro 133x	9,043 KB/sec
4 GB SanDisk Ultra II	4,816 KB/sec

USB transfer speed

To test the A100's USB transfer speed we transferred approximately 128 MB of images (mixed RAW and JPEG) from a SanDisk Extreme III 1 GB CF card (the same card used in the other readers). The DSLR-A100 produced the fastest USB 2.0 transfer speeds we've yet measured with a very impressive 8.8 MB/sec (14 seconds for 128 MB), it also posted the slowest transfer rates we've seen when switched to PTP mode.

Battery life

The A100 utilizes a new 'NP-FM55H' Lithium-Ion battery, the user manual quite clearly states that the Info-Lithium NP-FM50 and NP-FM30 can not be used in the camera. The NP-FM55H provides 11.5 Wh (7.2V, 1600 mAh), the user manual states that this is sufficient for 750 images using the CIPA standard testing method. In use we almost never found ourselves needing to charge the battery even after two days of regular use.