[filmscanners] RE: Genuine fractals?????

["LAURIE SOLOMON" <laurie@advancenet.net>]

I beg to differ with you; but I am not going to get into a food fight with
you over it.  In the case of RAW, you are correct the dpi is somewhat
irrelevant in that raw files do not contain any reference to resolution per
se only to the size of the image X x Y pixels; however, if you save to a
standard non-RAW format, resolution does matter in that it is made part of
the file metadata which is used to instruct applications how to render the
image in the image file. However, in terms of the camera, there is not
specific settings that use the terminology or provide for options in ppi or
dpi terms per se.  The frequently set the effective resolutions in terms of
the maximum umber of pixels along the longest side that are captured but
assume that is will be divided by 300 dpi when written to the standard
non-raw file format.  This is what allows them to  point to print sizes that
can be produced at different quality levels depending on the quality
level/file format combination selected.

But more importantly, many if not all cameras do put resolution limitations
on what can be saved when it is being saved to standard non-RAW files.  The
two Nikon digital cameras and the Kodak pro 14/n that I own will not allow
one to save images to Jpeg file formats with resolutions certain maximum
effective resolution; wherein the TIFF format permits the highest ant the
JPEG format allows for lesser effective resolution depending on the
compreesion level selected.  To wit, capture an image at each of the
available quality and format combinations your camera allows (except RAW)
and open each image without any manipulation in Photoshop and check the
resolution of the opened image in the Photoshop Image/Image Size box in the
Resolution space.  I think you will find that they will have different
resolutions (dpi/ppi).  This is not after any resampling or after the image
has been through the printer and produced as a hard copy but as it is
rendered on the monitor display in ppi directly as imported from the camera
flash card.


-----Original Message-----
From: filmscanners_owner@halftone.co.uk
[mailto:filmscanners_owner@halftone.co.uk]On Behalf Of Jawed Ashraf
Sent: Thursday, November 25, 2004 12:16 PM
To: laurie@advancenet.net
Subject: [filmscanners] RE: Genuine fractals?????


The dpi setting of a digital camera file is utterly irrelevant here.
Different cameras output their files (no matter their format) at fixed dpi
settings.  Different manufacturers of digital cameras have different norms
for dpi, but it has no impact whatsoever on resolution or print size.

A 2560x1920 file at 72dpi or 300dpi is identical.  Choosing TIFF or RAW
solely based on dpi is an unfortunate misunderstanding of the key parameter
of digital camera files, pixel-dimensions.  The quality differences you may
observe between maximum resolution JPEG, TIFF and RAW files have absolutely
nothing to do with the "dpi" setting recorded in a digital camera file.

Jawed

> -----Original Message-----
> From: filmscanners_owner@halftone.co.uk
> [mailto:filmscanners_owner@halftone.co.uk] On Behalf Of LAURIE SOLOMON
> Sent: 25 November 2004 17:36
> To: Jawed@cupidity.force9.co.uk
> Subject: [filmscanners] RE: Genuine fractals?????
>
>
> Well, I do not own that camera and am not familiar with it;
> but I assume
> that if you look in the manual you will find that you can capture your
> images at around 300 dpi and save them to a tiff format; but
> capturing them
> at a high resolution around 300 dpi as a RAW file would also
> be good, as
> long as you have an OEM program or Adobe's RAW application to
> work with them
> prior to saving them as a TIFF.  After you save them as a
> TIFF (or PSD if
> you use Photoshop) format file, you can than manipulate and
> edit them image
> editing programs like Photoshop, including using
> interpolation if necessary.
> The last thing I would suggest if you are shooting serious
> pictures is to
> capture and save them as 72 dpi Jpeg files unless you are shooting
> exclusively for internet use or refrigerator door snapshot
> prints.  Even if
> those are some of the uses that the image might  be put to, I
> would shoot at
> maximum resolution and save without compression or if necessary with
> lossless comprssion so as to have the highest quality
> original possible;
> You can always convert that original into a compressed Jpeg
> for use on the
> internet and you can always downsample the image resolution
> to 72 dpi after
> the fact (both of which I would save as different working
> copies of the file
> so as to retain the original file.
>
> In your case, I would archive  the original RAW file and make
> a working TIFF
> copy for use in editing and printing or from which I would
> make any jpeg
> files.
>
> -----Original Message-----
> From: filmscanners_owner@halftone.co.uk
> [mailto:filmscanners_owner@halftone.co.uk]On Behalf Of Myles
> Sent: Thursday, November 25, 2004 10:18 AM
> To: laurie@advancenet.net
> Subject: [filmscanners] Re: Genuine fractals?????
>
>
> Date sent:            Sat, 20 Nov 2004 15:12:13 -0600
> Send reply to:        filmscanners@halftone.co.uk
> From:                 "Laurie Solomon" <Laurie@advancenet.net>
> To:                   dryden@mgt.gla.ac.uk
> Subject:              [filmscanners] RE: Genuine fractals?????
>
> > I use the program frequently; and find that for most
> upsampling within the
> > normal ranges, it is not all that much different from
> Photoshop's Bicubic
> > methods.  It is in the extreme ranges of upsampling that
> the difference
> may
> > begin to appe      arandGFmaybegintoshine.
> >
> > What I do not understand is, if you are concerned with
> quality, why are
> you
> > saving your digital camera captures to a Jpeg format which
> uses lossy
> > compression and which most digital cameras will not let you
> save captures
> at
> > resolutions in the 300 ppi range but tend to limit one to
> capturing at
> > resolutions less than 300 ppi.  If it were me, I would be saving the
> > captures to Tiff format files which most cameras allow to
> be saved at
> 300ppi
> > resolutions.
>
>
> My canon G2 digital  does not offer the tiff option but offers Raw
> format which I believe can be converted to tif.Would such a conversion
> give me the benefit you mention ?
>
>  Resolutions of 72 ppi are common for web use but not for
> > printing and especially not for large prints; and Jpeg
> format is used so
> > that the user can capture on one card more images (assuming
> that they will
> > only be used for viewing online or via monitors or will
> only be printed at
> 4
> > x 6 sizes at best).
> >
>
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