Jpeg shooters, I have a question

jgredline · 08-25-2009, 01:59 PM

Hi Folks,
How many of you that shoot jpegs use the high setting? I shoot all jpegs (no raw for me) but just noticed there is a higher setting than the default. I tried it, but could not see a difference. Am I missing something?

Lowell Goudge · 08-25-2009, 02:04 PM

I shoot all the time on maximum quality, but to be honest I have not tried to evaluate the difference between maximum quality and one step down, but I do not ethe file size is cut in half, and that says something about loss of data.

jgredline · 08-25-2009, 03:02 PM

Originally Posted by Lowell Goudge

I shoot all the time on maximum quality, but to be honest I have not tried to evaluate the difference between maximum quality and one step down, but I do not ethe file size is cut in half, and that says something about loss of data.

Oh, so maximum quality means more data? I have not noticed image size, but will do so. Thanks

Arpe · 08-25-2009, 06:28 PM

IMAGE size is the same.
FILE size is different.

danielchtong · 08-25-2009, 07:43 PM

Originally Posted by jgredline

Oh, so maximum quality means more data?

I would rather say max quality means less compression . Data should be the same but with more compression it is more scrambled though.
That is the way how jpg works

Daniel

jgredline · 08-25-2009, 08:37 PM

Originally Posted by Arpe

IMAGE size is the same.
FILE size is different.

Yes, I know this. I should have been more clear

jgredline · 08-25-2009, 08:38 PM

Originally Posted by danielchtong

I would rather say max quality means less compression . Data should be the same but with more compression it is more scrambled though.
That is the way how jpg works

Daniel

Thanks Daniel, this makes sense. I shot a few pics like this today, but have not looked at them yet.

WheresWaldo · 08-25-2009, 10:49 PM

Originally Posted by danielchtong

I would rather say max quality means less compression . Data should be the same but with more compression it is more scrambled though.
That is the way how jpg works

Daniel

Not 100% accurate, without mentioning that the compression is lossy. In other words it is not like ZIP vs. RAR. The more you compress a JPEG the more information you simply throw away. JPEG images degrade with higher levels of compression. Compressed RAW files retain all the information that a non-compressed RAW file has.

egordon99 · 08-27-2009, 09:31 AM

Originally Posted by danielchtong

I would rather say max quality means less compression . Data should be the same but with more compression it is more scrambled though.
That is the way how jpg works

Daniel

Not when the compression is LOSSY

Two kinds of compression exist; LOSSLESS is like using WinZip to zip up a bunch of Word files. You're able to unzip the Word files and you have not lost ANY data.

LOSSY actually tosses out data that can NOT be retrieved. JPGs (generally) use LOSSY compression as does mp3 for audio files.

bdery · 08-27-2009, 12:56 PM

I tested it a bit...

If you post-process a LOT, you might find a gain by using the highest quality (I believe the ratio of compression is about 1:2, which means half the data of a RAW file). Second best is 1:4 again IIRC. For the record usually the values for P&S are 1:8 through 1:32... by default.

I have never seen the need for the highest setting, and many reviewers also think that way.

jgredline · 08-27-2009, 01:54 PM

Originally Posted by bdery

I tested it a bit...

If you post-process a LOT, you might find a gain by using the highest quality (I believe the ratio of compression is about 1:2, which means half the data of a RAW file). Second best is 1:4 again IIRC. For the record usually the values for P&S are 1:8 through 1:32... by default.

I have never seen the need for the highest setting, and many reviewers also think that way.

i to have been testing of late and have found the same thing as you have. Will know more in a few more days.