V1.02
Thom Hogan’s Complete Guide to the Nikon D300
Page 133
Best Quality
fine - Optimal quality
fine
-
Size
priority
normal - Optimal quality
normal - Size priority
basic - Optimal quality
Worst Quality
basic - Size priority
Note: There is wide variance in the way JPEG compression levels
are presented in software user interfaces. Some programs
show you the approximate compression amount as a ratio
(e.g. 4:1), some use descriptions (e.g. “high,” “moderate,”
and “low” or Nikon’s “fine,” “normal,” and “basic”), and
still others use sliders and other controls to continuously
vary the amount of compression. The best programs show
you a preview of the resulting compression, letting you
visually determine how much compression to use.
One interesting side note about JPEG: the process that
converts the pixel values into equations ends up putting the
“average” pixel of each 8x8 block in the upper left corner of
that block prior to compression. Nikon doesn’t use this
average pixel directly (the D300 generates the image’s
thumbnail using other methods; some Coolpix models used
this pixel to generate the thumbnail).
Thus, if you want to create smaller images from the JPEGs that
the D300 produces (say for Web use), the highest quality will
be obtained if you reduce the size to 1/8 (e.g. 536 x 356 from
the
Large
JPEG size created by a D300). That’s because
you’ll force your image editing program to summarize the 8x8
blocks used in generating the JPEG, and minimize any
artifacts that might be otherwise produced.
Setting JPEG
The D300 allows you to create three sizes of JPEG images:
L
=
Large
= 4288 x 2848 pixels
M
=
Medium
= 3216 x 2136 pixels
S
=
Small
= 2144 x 1424 pixels