Convert from Canon CR2 raw to PNG?

Hi all.
I've had a canon EOS350D for about a year now, and up until a month ago
I always used high quality JPEGs for my images. I've recently gone the
way of the raw file and will never look back.
I use photoshop CS2 to convert my images to JPEG - normally not even
opening them into Photochop, just using the import plugin and saving to
JPEG.
I have been investigating the use of PNG files and think that I should
be using these instead of JPEGs to preserve detail in my photos.
Unfortunately to convert an image to png in photoshop, I either have to
export as a TIFF (45MB) and then batch convert to PNG or open into
photoshop and then save as a PNG. Both ways lose the EXIF data and are
slow (not to mention the TIFF way requires a temp folder of 5GB for the
contents of a 1GB card full of raw files).
Is PNG the way I should be going or is there a better format I should
use?
If PNG is the best way to go, is there some other way of converting
from CR2 to PNG? Bear in mind for 99% of my photos, all I adjust is the
exposure, brightness and white balance before I save them (and Gasp!
Delete the CR2)
Thanks
John

Johnburns007@gmail.com

Re: Convert from Canon CR2 raw to PNG?

Set your Canon 350d to save the same picture in raw AND jpg.
Save the raw file as your "negative", and use the jpg for low res. work.
AsleB, Oslo, Norway

Asle Bjerva

Re: Convert from Canon CR2 raw to PNG?

...
I'd be interested in what went into this decision. Do you have a specific
image that you believe does better starting from raw than high quality jpeg,
or were you persuaded by someone's discussion of the topic?
It's not clear that this is giving you an advantage over using jpeg from the
start.
Png is a lossless format, and there are situaitons - medical images for
example - where this is crucial. With few exceptions high quality jpeg is
adequate, though I would recommend against editing and resaving a chain of
jpegs.
This should give you an indication of how many other people use this
workflow: very few indeed.
Most people use PSD or TIFF files for lossless storage.
The CR2 is your digital negative, and I recommend that you keep it in
preference even to your edited files. Raw files are smaller than the
corresponding TIFF or PSD file, and since raw processing is an evolving art
you may be able to get a better image from your files in the future.
That said, there is nothing wrong with using high quality jpeg as your main
format. There is much more to getting good images than simply adjusting
exposure and color temp. I would also recommend that you delve more deeply
into editing your images with - what else - curves!
--
Mike Russell
www.curvemeister.com/forum/

Mike Russell

Re: Convert from Canon CR2 raw to PNG?

Ooops! Mixup between png and dng. Still, dng might be worth looking
at.
Colin D.
--
Posted via a free Usenet account from http://www.teranews.com

ColinD

Re: Convert from Canon CR2 raw to PNG?

You might like to try the DxO Optics program ( http://www.dxo.com ),
which will convert to jpg, tiff, or dng, 8 or 16-bit, as you wish; as
well it will correct exposure color from the exif data, and also correct
for lens distortion and chromatic aberration specific to the lens used -
again from exif - and does it all automatically. reads from one folder,
puts the corrected images into any other folder of your choice.
Colin D.
--
Posted via a free Usenet account from http://www.teranews.com

ColinD

Re: Convert from Canon CR2 raw to PNG?

Thanks for all your recommendations.
The initial reason for my inquiry is because I currently have about
8000 photos on a telehoused server all availabl over the net as
120x120, 600x600 and full res images.
Up until now I've kept a copy of this on two servers and a portable
hard drive but wanted to look at a lossless alternative while still
having them available on the net. I've since decided that this is not
the best way forward so will from now on keep the raw images and not
bother linking to a web available full res image - its simply not
required.
I agree that harddrive space is cheap and that at this point in time,
48 bit color is overkill. Does the original raw file even store the
data in 48bit?
I'm also interested from an earlier post how to get a 32 bit image..
unless its stored in CYMK I can't fathom how 32 is divisable by 3
unless its 10 bit colour with 2 bits wasted for ease of transportation
within 4 byte (32 bit) chunks.

Johnburns007@gmail.com

Re: Convert from Canon CR2 raw to PNG?

You really need to rethink the whole workflow issue.
Not to be disrespectful but you appear to need to spend more time reading
about the basics of how to use Photoshop, or watching video tutorials,
rather than posting to a newsgroup like this to find out the best solution
for a problem that should not exist.
The benefits of 48bit color are debatable. Regardless, if you hold the idea
of 48 bit color and jpeg in your head at the same time then you really are
not understanding the relevant issues with regard to image quality.
Storage is cheap so worrying about file size in terms of storage is like
worrying about the cost of air in your tires when gas sells for $5 a gallon.
File size is an issue not for storage but because Photoshop running on even
the fastest CPU with gigabytes of RAM will eventually start choking on file
sizes larger than 100mbs or after a session where many large files have been
processed. If you do not print larger than 8.5 x 11 then most of the data in
that immense file will be arbitrarily stripped out by the 8 bit printer
driver, but that is another issue. Also another issue is that you cannot see
48 bits of color data and no display or printing process can reproduce 48
bit color, but I digress.
You should be thinking about lossless image processing and storage: layers
and the PSD format. Label all your layers, save notes within the file, so
when you reopen the image you will know what you have already done to it.
Save your original raw image, as DNG if you like or whatever preserves the
exif data (IMHO the least important image info) and save your processed
image any way you like along with the PSD (this loses the "history" info but
that will not matter if you have labelled layers).

Bmoag

Re: Convert from Canon CR2 raw to PNG?

Are you discarding the original RAW images ? If not, I can't see why
you'd want to save as PNG. There's HARDLY (if any) any visual difference
between a PNG image and a JPEG using low compression. (I can't see any
difference) This applies to viewing on the monitor or printing. All you'd
be accomplishing is using more disk space.
(I know disk space is cheap, but I find the time involved in backing up
and maintaining images can become a chore when the gigabyte count gets
high enough)
If you're keeping the original RAW image, then you have the 'negative'
with all the information. If you have a real need for the highest quality
possible, then you can always go back to the RAW 'negative'.
If you aren't keeping the original RAW file then you should be saving your
images as 32 bit. Anything less and you are throwing away color detail.
If I never kept my RAW files, I'd be using 32 bit TIFF rather than PNG.
Of course I keep my RAW files so JPEG is just fine for archiving.
Of course you SHOULD be keeping the RAW files. They are the 'negative'
and contain ALL the information your camera captured.

Re: Convert from Canon CR2 raw to PNG?

Thanks for your reply,
Firstly: No, i don't throw out negatives, it must be just a different
attitude towards digital files since you can get fairly good prints
from the JPEGs.
I'm not actually opening the images in photoshop. In photoshop CS2,
you can go to file>open and select the raw files. Once the files are
selected a window appears where you can change some of the details of
the raw images such a white balance, brightness, exposure, etc. You
can then either open the files into photoshop for editing or save them
back as a file.
I am trying to save as png from this window rather than open all the
raw files into photoshop as child windows.
Any ideas?

Johnburns007@gmail.com

Re: Convert from Canon CR2 raw to PNG?

Johnburns007@gmail.com

Re: Convert from Canon CR2 raw to PNG?

Sounds like you are creating 48bit color files (16 bits per color
channel). 16bit files can only be saved in certain formats,
interestingly one is PNG (there goes this theory). There is a drop down
menu in the PS save dialog box to select your file types. If you are
saving as a 24 bit files there are quite a few choices but PNG is
there, much less in the 48 bit.
Do you throw out negatives too? I generally just keep the RAW files,
unless I'm using the file for something else (printing, publication).