Image Size and Compression.
in [Digital Cameras]
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From: Peter on 30 Jul 2010 09:29 "bugbear" <bugbear(a)trim_papermule.co.uk_trim> wrote in message news:LridnROBwbkKVs_RnZ2dnUVZ8gKdnZ2d(a)brightview.co.uk... > Outing Trolls is FUN! wrote: >> On Fri, 30 Jul 2010 12:59:32 +0100, Martin Brown >> <|||newspam|||@nezumi.demon.co.uk> wrote: >> >>> For my money the higher resolution image using higher compression will >>> almost always beat the lower resolution less compressed image. There can >>> be exceptions and unless you are absolutely certain you will never need >>> the extra pixels or you are running out of media space there is little >>> or no advantage in decreasing image size in the camera. >>> >>> Regards, >>> Martin Brown >> >> Showing how little you know. >> >> If using higher ISO's with more noise, it can be advantageous to use >> in-camera downsampling. As this will average-out the noise from the RAW >> sensor data. > > It would be more "advantageous" to retain the original data > and use a superior noise reduction algorithm later. > > You can look up noise reduction algorithms on your own time > if you think averaging is a good one. > the only reason to answer it, is when, as above, it is spreading misinformation. You are correct. It is not stating that most NR, including averaging, works on a principle of blurring. Therefore details will be lost. -- Peter
From: ray on 30 Jul 2010 10:12 On Fri, 30 Jul 2010 01:25:37 -0700, bobwilliams wrote: > Let's assume I have a 10MP camera > My sensor is say, 3650 X 2740 pixels. But say I want to create an image > at 1825 x 1370 pixels. How does the camera actually reduce the 5.0MPs to > 2.5MPs Does it choose groups of 4 pixels and somehow average them out to > groups of 1 pixel each? > How does this process differ from compressing the 10MP image by a factor > of 4. > I know that in one case the image SIZE is reduced (as well as the file > size) whereas in the other case, the image SIZE remains the same but the > file size is reduced. > How exactly does each process affect the appearance of say an 8x10 > print. Bob Williams I would imagine you are talking about JPEG compression here. Suggest you experiment a little with your favourite photo manipulation software. You'll find that most images can be very highly compressed without any noticeable degredation. The same is not true for dropping resolution.
From: David J Taylor on 30 Jul 2010 10:17 "Martin Brown" <|||newspam|||@nezumi.demon.co.uk> wrote in message news:z8z4o.4989$F%7.1397(a)newsfe10.iad... [] > For my money the higher resolution image using higher compression will > almost always beat the lower resolution less compressed image. There can > be exceptions and unless you are absolutely certain you will never need > the extra pixels or you are running out of media space there is little > or no advantage in decreasing image size in the camera. > > Regards, > Martin Brown That reflects my own findings, Martin Cheers, David
From: David J Taylor on 30 Jul 2010 10:18 "Tim Conway" <tconway_113(a)comcast.net> wrote in message news:i2ulah$lpt$1(a)news.eternal-september.org... [] > And you don't have to be so damn rude. Better to kill-file it, not repeat it's lies, and not to feed it.
From: Ryan McGinnis on 30 Jul 2010 10:53
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 7/30/2010 8:50 AM, Tim Conway wrote: > And you don't have to be so damn rude. He's trying to troll. The art of Usenet trolling has fallen quite a bit in recent years, but then so has Usenet in general. Most of the talented trolls have fled to message boards. - -- - -Ryan McGinnis The BIG Storm Picture -- http://bigstormpicture.com Vortex-2 image licensing at http://vortex-2.com Getty: http://www.gettyimages.com/search/search.aspx?artist=Ryan+McGinnis -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJMUuddAAoJEIzODkDZ7B1bh90H/2nJxB9EMZWNtmCXlYzv9wvw TEweN+gSnQwopISzE0rp0/PP5XF+R1d6Vgvtl163Cm8WnFsQUGPf0fpGdPD7crhl u04iiiollwCHfGHqp+fIw4QjlY/lFHh7rZY2bjGobrNKht5+xAkplbnG3g1H2mf/ eJqodJDCir3XDVGdurvEYSjqmvduv7A1gmD3ybkBiaYRpUy+ViouvcCgtVmTTBA7 OP3BJ42BMPBqplRwRtnH5jZiSPXOfeJrcuYQyXSyk2TcheqWBS3WX0Wi3CPFJlqa 3ZfmUU49uHbYJLedlj5Vqfb4ZBSFQ+UF5vjY2mqDcqgfj6918JK6SwVQI5qBuMU= =yB/A -----END PGP SIGNATURE----- |