Re: Compression in JPEG files in digital cameras

David J Taylor added these comments in the current discussion du
jour ...

I was pretty surprised that my Rebel XT can't save to TIFF
but only mildly miffed that it didn't have a 3rd,
higher-compression- thus-lower-quality image. I did my usualy
testing the first day at 2, 4, and 8 MP and both JPEG
settings, made an initial eval, then went and shot some real
cars at each, came home and looked at them.

Jerry,

TIFF doesn't really help if it's only 8-bit depth - as the
best quality JPEG has so little loss. RAW would be the next
step up in saved image quality, but it has the overhead of
requiring more processing which I think both you and I try and
minimise.

Both ordinary JPEG and TIFF are both 8-bit. I only mentioned
TIFF, either the uncompressed kind or LZW, as an alternative to
the OP or any lurkers who want a simpler lossless file system
than RAW,

Have you ever gone back and revisited the resolution and
quality settings? This is something I keep meaning to do as I
gain experience, but somehow I never get round to it! I
wonder if we would make the same choices a second time,
particularly on JPEG quality setting?

Yes, David, as recently as this spring as I was getting ready for
the summer car show season. It isn't that I dispute you at all,
you're much more skilled and knowledgeable than me, it is that MY
experience shows that the amount of work necessary to get an 8 MP
image down to my 1.5 MP finished size without introducing
aliasing and other undesirable non-compression artifacts just
isn't worth my time and effort.

I never revisited the lower quality, i.e., higher compression,
option on my Rebel because I could easily see JPEG compression
artifacts at a large enough percentage that I didn't want to risk
blowing otherwise good pictures. As you and others have so
correctly pointed out, memory is so cheap, that it really doesn't
matter if the image is 500KB or one meg.

Yes, we agree to disagree on shooting - I go for highest
resolution with "normal" JPEG quality. I leave any resampling
up to the display software - indeed I wrote my own simple
slide-show program so that I had control over the display
process.

http://www.david-taylor.myby.co.uk/software/imaging.html#Slid
eShow

What works best for you, is best for you, and I respect that.

Thanks for the link, David. And, I respect YOUR preferences.
People in this NG, like most Usenet NGs, get along a whole lot
better if they respect each other's rights and freedoms to do
things in alternate ways, and I think you and I have previously
agreed that there NEVER is one or even two "right" ways to do
anything. And, as you so eloquently say, "what works best for
you, is best for you", where "you" means anyone anywhere anytime
doing anything.

Have a great day!

--
HP, aka Jerry
.

Relevant Pages

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