Sony A850 Performance

Except for burst speed, the A850's timing performance is about average for a semi-pro SLR.

A850 startup and shut-down times are quite fast. Buffer clearing time depends on the image size and quality, burst length and the speed of memory card used.

A850 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.) We noticed this with the A900, the A850 shows the same behavior.

In terms of the A850'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, and very similar to the A900. The A850 required 0.184 second for full AF using the center AF point. (The A900 measured 0.183 second.) Multi-Area (Wide) AF mode was a little slower, at 0.205 second. Continuous autofocus mode lag time was a bit slower at 0.189 second (the A900 measured 0.181 second), and manual focus was slightly faster at 0.154 second (0.153 second for the A900). When prefocused, shutter lag dropped to 0.074 second (vs 0.072 second for the A900), which is quite fast.

Single-shot cycle time performance is good for a 25-megapixel SLR, at 0.40 second between shots in large/extra fine JPEG quality, increasing to 0.50 second in RAW mode and 0.46 second for RAW + large/fine JPEG. (The JPEG quality is fixed to large/fine in RAW+JPEG mode.) If we ignore the sometimes slower cycle times we found in RAW mode, that average falls to 0.44 second. Buffer depth is quite good (particularly for a camera with such exceptional resolution) at 23 frames for large/extra fine JPEG, 22 frames for RAW and 15 frames for RAW+JPEG.

Continuous mode is a bit slow among prosumer SLR models at 3 frames per second in all modes, but with good buffer depth at 23 frames for large/extra fine JPEGs, 16 for RAW and 10 for RAW+JPEG 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.)

We did not measure APS-C crop mode timing on the A850, but it didn't improve cycle times on the A900.

One note here, on a difference in behavior between the Sony A850 and A900 that may affect some users: In our prior review of it, we indicated that the A900 didn't penalize you for pressing the shutter too quickly again, after the previous shot was taken. (On some cameras, if you press and hold down the shutter button too quickly after a shot, the camera won't fire the shutter again unless you release and re-press the button.) That's because we really never noticed the problem on the A900. With the A850, this was a real problem when we were trying to measure the minimum single-shot cycle time: If we got our rhythm of pressing the shutter button wrong, things would slow down dramatically. Puzzled that we hadn't seen this with the A900, we went back and re-tested it, and discovered that it did in fact penalize early shutter presses, it's just that the "dead time" after a shot was so short that we never encountered it when we were using the camera in any normal sort of way. (To trigger it, we had to frantically mash the shutter button down continuously many times/second, in order for a button-press to happen to fall at just the wrong time to trigger the penalty.) So... If you anticipate needing to fire multiple shots in rapid succession in single-shot mode (as some sports shooters very well might), the A850 could be frustrating to use and the added cost of the A900 would be well worth it.

A850 download speeds were extremely quick, fast enough that you probably won't feel the need for a separate card reader.

Battery

Good battery life for a full-frame DSLR.

The Sony A850 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 A850 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 A850 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. (These numbers from A900, A850 files sizes appear to be identical.)

We strongly recommend buying a fast, high-capacity CompactFlash or Memory Stick Pro Duo card. The A850'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.)