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The
location of the buffer within the camera system is normally not
specified, but affects the number of images that can be shot in
burst mode. The buffer memory is located either before or after
the image processing.
After
Image Processing Buffer
With
this method the images are processed and turned into their final
output format before they are placed in the buffer. As a
consequence, the number of shots which can be taken in a burst can
be increased by reducing image file size (e.g. shoot in JPEG,
reduce JPEG quality, reduce resolution).
Before
Image Processing Buffer
In
this method no image processing is carried out and the RAW data
from the CCD is placed immediately in the buffer. In parallel to
other camera tasks, the RAW images are processed and written to
the storage card. In cameras with this type of buffer, the number
of frames which can be taken in burst mode cannot be increased by
reducing image file size. But the number of frames per second
(fps) is independent of the image processing speed (until the
buffer is full).
Smart
Buffering
The
"smart buffering" mentioned by Phil Askey in his Nikon
D70 review, combines elements from the above two buffering
methods. Just like in the "Before Image Processing
Buffer" the unprocessed image data are stored into the buffer
(1) allowing for a higher fps. They are then processed (2) and
converted into JPEG,
TIFF or RAW.
But instead of writing the processed images to the storage card
they are stored in the buffer (3). Therefore, the image processing
is not bottlenecked by the writing to the storage card, which
happens in parallel. Moreover, it constantly frees up buffer space
for new images since (3) takes up less space than (2), especially
in the case of JPEG. Just like in the "After Image Processing
Buffer", the output images are then written from the buffer
to the storage card (4). But an important difference is that here
the image processing happens in parallel with writing to the
storage card. So the image processing of new images can continue
while the other images are being written to the storage card. This
means that you do not necessarily have to wait for the entire
burst of frames to be written to the CF card before there is
enough space to take another full burst
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