Kodak DX7590 Review
Timing & Performance
Although the DX7950 is fairly speedy on paper, it can feel sluggish in use - particularly when attempting to shoot several pictures consecutively, when the very slow buffer clearing (see bottom the page) means you end up staring at a blue screen with the word 'processing' and a lovely little graphic of an egg-timer. Power-up also feels a bit leisurely at 3.3 seconds, meaning you need to leave the camera on if you want to avoid missing grabbed shots. Focus speed is fine unless you're shooting at the very long end of the lens in low light, when it can stretch to the best part of two seconds before focus is found. At the wide end of the zoom, and whenever there is plenty of light, focus speeds are acceptable, if hardly class-leading.
All times are calculated as an average of three operations. Unless otherwise stated all timings were made on a 2576 x 1932 Fine JPEG image (approx. 1,300 KB per image). The media used for these tests was a 512MB SanDisk Extreme (aka Ultra II) SD card.
|Power: Off to Record||3.3|
|Power: Off to Play||cannot power up directly into playback mode||n/a|
|Power: Record to Off||All activity ceased||2.7|
|Power: Play to Off||When buffer is empty, lens retracted||2.3|
|Record Review||Image displayed||~1.3|
|Mode: Record to Play||~0.75|
|Mode: Play to Record||Lens already extended||~0.7|
|Play: Magnify||To full magnification (8x)||1.6 *1|
|Play: Image to Image||Time to display each saved image||~0.2|
|Play: Thumbnail view||3 x 3 thumbnails||0.8|
|Zoom from Wide to Tele||38 to 380 mm (10 x)||2.2|
|Half-press Lag (0->S1)||Wide angle||~0.6|
|Half-press Lag (0->S1)||Telephoto||~1.0 - 1.8 *2|
|Half to Full-press Lag (S1->S2)||LCD live view||~0.15|
|Half to Full-press Lag (S1->S2)||Viewfinder||~0.1|
|Full-press Lag (0->S2)||LCD live view, wide angle||~0.7|
|Off to Shot Taken||LCD live view||~4.3|
|Shot to Shot||Flash off||2.1 *3|
|Shot to Shot||Flash on (with red eye reduction off)||2.3 *3|
|*1||This figure does not include the time taken for the DX7590 to load the full resolution JPEG (it uses screen res previews for fast scrolling). If this time is included the time increases to 2.3 seconds.|
|*2||Due to the wide variation in focus times at telephoto we have included a range, rather than an average figure. The average was 1.13 seconds|
|*3||This includes focus time and is an average of 25 shots. When focus is found quickly (using continuous AF helps here), the figure drops to around 1.75 seconds between shots. All this depends on the buffer not being full (which is around 4 or 5 5MP/fine quality shots). Once the buffer is nearly full the delay between shots stretches to many seconds.|
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. The media used for these tests was a 512MB SanDisk Extreme (aka Ultra II) SD card. Shutter speed was kept above 1/200 sec during these tests.
Continuous drive mode
The DX7590 has two 'burst' modes. The standard mode shoots up to 5 frames in a burst at around 2fps (in our tests 4 was the maximum on most occasions). The DX7590 does not show a preview image during bursts (it does, however, show a brief review image).
Frames in a burst *1
|2576 x 1932 JPEG Fine||Burst||2.0 fps||4 or 5||~20s delay *3|
|2576 x 1932 JPEG Standard||Burst||2.0 fps||4 or 5||~17s delay|
|2304 x 1728 JPEG Fine||Burst||2.0 fps||4 or 5||~25s delay|
|2048 x 1536 JPEG Fine||Burst||2.0 fps||4 or 5||~21s delay|
|*1||In a single "burst" (finger held down on shutter release).|
|*2||Once the buffer is full the DX7590 freezes for anything up to 25 seconds, displaying the word 'processing' as the images are saved to the SD card.|
|*3||This figure is similar when using the internal memory.|
Although 2 frames per second - albeit only for 4 or 5 shots - is fairly respectable for a budget 5MP camera, the unbelievably slow buffering makes this feature one you need to use with care. In most cases you're looking at a delay of at anything from ten to 25 seconds before you can take another shot, and it's a full 30 seconds before the buffer is completely emptied and you can take another burst. If you like to snap quickly you'll soon tire of the endless freezes and seemingly interminable 'processing' screen.
File Write / Display 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 went out. This means the timings also include the camera's processing time and as such are more representative of the actual time to "complete the task". The media used for these tests was a 512MB SanDisk Extreme (aka Ultra II) SD card.
Time to store
Time to display
File size *1
Images on a *2
|2576 x 1932 JPEG Fine||~8.4||~1.3||1298 KB||147|
|2576 x 1932 JPEG Standard||~7.5||~1.2||552 KB||316|
|2304 x 1728 JPEG Fine||~13||~1.3||907 KB||183|
|2048 x 1536 JPEG Fine||~12||~1.2||713 KB||229|
|*1||All file sizes are an average of three files. As is the case with JPEG it's difficult to predict the size of an image because it will vary a fair amount depending on the content of the image (detail and noise).|
Here we see the problem with the DX7950 - around eight and a half seconds to process and store a 1.3MB file gives a net write speed of just over 150KB/s... which is very slow indeed. There's no doubt that Kodak is doing some pretty heavy processing to the files as they are saved (including noise reduction), but in a camera that is otherwise very snappy, it's a real pity the performance falls so badly at the last hurdle. You won't notice this if you shoot at intervals of more than about 7 or 8 seconds, but if you're trying to keep up with the action and take a lot of pictures, this simply isn't the camera for you.
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