>My assumption is that the bottleneck that precludes me from >shooting more than 17 uncompressed FX 14bit NEFs at 8 frames a >second is the buffer size being too small for the CF card's >low speed. The buffer is of finite size and the CF card can >only be written to at a finite speed. I know the CF cards >speed at c.90MB/s, but I can't find a figure in the manual for >the buffer size.
While some CF cards have a maximum write speed of 90MN/sec. it doesnt mean that the camera can write to the card at 90MB/sec. In fact the maximum write speed of the D700 is about 32-33MB/sec. Raw with Sandisk Extreme Pro 90MB/sec. cards demending on capacity. Even the new Lexar Pro 1000X cards are limited to between 38.2 and 41.6MB/sec. Raw when used on the D700. In other words the maximum write speed is limited by the camera.
>Quite how the D700 goes about moving the frame to the CF card >and when is a moot point. If it did it immediately the frame >was taken, then the only limit for the number of frames for >the JPEG formats would be the CF card capacity. But it >doesn't.
Jpegs are written to the buffer a little slower than Raw files. The D700 writes jpegs to an Extreme Pro 90MB/sec. card at between 26.1 and 26.9MB/sec. and between 30.3 and 33.1MB/sec. with Lexar Pro 1000X cards.
>How big is the buffer then?? Simple sum probably, multiply the >buffer capacity by the file size for the various picture >formats? Nope! The results are all over the shop. The largest >requirement being 610MB (for large format TIFFs, 17 frames >@35.9MB each).
As stated above, various camera settings take additional space in the buffer and the buffer starts writing to the memory card as soon as the first image is captured. So there is no easy way to calculate the actual buffer size.
When I shoot at the Maximum FPS rate I usually shoot in bursts of between 4 and 8 frames depending on the subject. This statagy will allow you to capture the maximum number of composed images per unit time while minimising waiting for the buffer to clear enough space to allow capturing another image. Good Luck and Enjoy your Nikons!