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Quality 131

As a file size comparison, I set my camera up on a tripod and took five
shots of a single scene, with Image Size set to “L:24M” and Aspect ratio set
to 3:2 and ISO set to 400 to produce an average amount of noise. (.jpg
images tend to take up more space the more noise they have). Then I
compared them all to the equivalent “JPG Quality” compression settings
used in Photoshop. Check out the table below for how they all compare.
This is the nature of .jpg’s; the file size is very much content-dependent.
(These numbers show relative sizes for a single image and make for good
ballpark comparisons.) Here are the different file sizes used by each:

Image Format File Size JPG Quality Equivalent
in Photoshop
Standard (.jpg) 4.0 MB Quality = 10+
Fine (.jpg) 6.2 MB Quality = 11+
Extra Fine (.jpg) 12.5 MB Quality = 12+
RAW (.arw) 24.2 MB
RAW + JPEG produces 2 files 24.2 MB (.arw) +
6.2 MB (.jpg)

TIP: These .jpg file sizes are larger than the equivalent versions for the original
A77. This means that there’s less compression going on, yielding even better
.jpg image quality!

Notice that when you shoot RAW+JPG, it writes a “Fine” quality .jpg to
the card. Why not store a better quality .jpg? The thinking probably was
that a person who shoots RAW+JPG probably wants the .jpgs just so they
can go through them quickly to find their “keepers” – after which they’ll
then open the corresponding RAW file for further adjustment. In that
scenario it makes sense to store something of medium quality.
The sizes of .jpgs can vary greatly. So if you try this experiment yourself,
don’t be surprised if your numbers differ by a factor of two or more. This is
why the “Images Remaining” counter shows you conservative numbers –
often you can fit more images on a card than what the camera shows you