Why pixel peeping (usually) makes no sense

On Sat, 17 Nov 2007 09:22:19 +1300, frederick wrote in
1195244161.5116@ftpsrv1:

Scott W wrote:

Shoot, hit the wrong button and send a blank replay, sorry about that.

Once your message appears in Thunderbird, select it, right
click, select cancel message, and if you've been quick
enough you'll get the message deleted from the news server
before it propagates.

Not necessarily -- many (most?) newservers are configured to ignore
Cancels (thanks to abusive rogue canceling).

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

LOL. Run along.


"Scott W" wrote in message
...
John Navas wrote:
On Fri, 16 Nov 2007 19:13:37 GMT, "Ali" wrote in
:

Two points you didn't take into consideration is what about cropping
images post process and also it's very difficult stitch photos with
moving subjects.

True, although the best current stitching software may be better than
you think at removing ghosts. (I commented on cropping earlier in the
thread.)

This is certainly true, I use Smartblend which almost always takes care of
object that were moving.


In addition to this, stitching adds to post process time and if you want
a certain perspective in the photo (very wide angle/fisheye), stitching
won't work.

Actually it will -- the best stitching software easily produces multiple
different projections.

Very nice indeed.

And if we are talking about only stitching say 10 photos or less it takes
very little time to do so.

PS: From a commercial point of view, certain clients require photo's to
be a minimum of XYZ MB TIFF.

True, but I've not (yet) seen any that wouldn't accept what I can get
right out of camera for other than mural prints.

This would depend on the client and how they are going to use the photo.

Scott

On Fri, 16 Nov 2007 11:23:41 -1000, Scott W wrote
in :

John Navas wrote:

Assuming your Costco uses the Fuji Frontier on Crystal Archive paper
(or something comparable), and assuming it's properly adjusted, then
print quality at 300 DPI should be comparable to your inkjet printer
at any DPI.

The reason cheap inkjets need more DPI is that they don't do as good
a job of reproducing a given DPI.

(PPI pertains to screen, not printing.)

Costco, our's at least, use a Noritsu model 3111.
The paper is Fujifilm Crystal Archive.
The inkjet prints are far sharper, as I said the Costco prints might
have 200 ppi of detail.

So try a Fuji Frontier.

Try scanning a print at 300ppi and see how soft it looks, an inkjet
print might look noisy, a least a cheap one like mine, but it will be
very sharp when scanned at 300ppi.

That's a kind of pixel peeping.
I compare prints with normal viewing.

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

On Fri, 16 Nov 2007 21:23:31 GMT, "Ali" wrote in
:

Mmm. I'm not talking about ghosts. I am talking about shooting moving
subjects, whether it maybe a F1 car or people.

Super-wide shot of a moving F1 car? Really?
You're that close to the action?!

I also can't see how stitching software is able to create the same effect as
a fisheye lens with multiple images, without a lot of time spent in post
production.

I've easily done complete spherical panoramas.

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

On Sat, 17 Nov 2007 08:13:14 +1100, "cmyk" wrote in
:

For my 7.2MP Panasonic FZ8, 11x14 is "excellent" at about 216 DPI.

To produce an 11x14 print without interpolation from your FZ8, you can only print at 200ppi. Printing at 216dpi is only going to
degrade the image through interpolation. You can see what's optimum by dividing the print dimensions by the available number of
pixels. That gives an angular resolution of around 115 arc-seconds.

With all due respect, that's an essentially meaningless distinction.

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

You are confusing the two points that I made, which are two TOTALLY separate
scenarios. One is stitching super wide and fisheye. The other is stitching
moving subjects such as an F1 car or people.


"John Navas" wrote in message
...

Mmm. I'm not talking about ghosts. I am talking about shooting moving
subjects, whether it maybe a F1 car or people.


Super-wide shot of a moving F1 car? Really?
You're that close to the action?!

"John Navas" wrote in message ...
On Sat, 17 Nov 2007 08:13:14 +1100, "cmyk" wrote in
:

For my 7.2MP Panasonic FZ8, 11x14 is "excellent" at about 216 DPI.

To produce an 11x14 print without interpolation from your FZ8, you can only print at 200ppi. Printing at 216dpi is only going to
degrade the image through interpolation. You can see what's optimum by dividing the print dimensions by the available number of
pixels. That gives an angular resolution of around 115 arc-seconds.

With all due respect, that's an essentially meaningless distinction.

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

You would do well to take time to study this instead of peremptorily dismissing it. Your response betrays a certain lack of
understanding of some fairly basic issues.

cmyk

Try reading what I wrote a bit more carefully.

On Fri, 16 Nov 2007 22:04:37 GMT, "Ali" wrote in
:

You are confusing the two points that I made, which are two TOTALLY separate
scenarios. One is stitching super wide and fisheye. The other is stitching
moving subjects such as an F1 car or people.

"John Navas" wrote in message
.. .

Mmm. I'm not talking about ghosts. I am talking about shooting moving
subjects, whether it maybe a F1 car or people.

Super-wide shot of a moving F1 car? Really?
You're that close to the action?!

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

On Sat, 17 Nov 2007 09:10:43 +1100, "cmyk" wrote in
:

"John Navas" wrote in message ...
On Sat, 17 Nov 2007 08:13:14 +1100, "cmyk" wrote in
:

For my 7.2MP Panasonic FZ8, 11x14 is "excellent" at about 216 DPI.

To produce an 11x14 print without interpolation from your FZ8, you can only print at 200ppi. Printing at 216dpi is only going to
degrade the image through interpolation. You can see what's optimum by dividing the print dimensions by the available number of
pixels. That gives an angular resolution of around 115 arc-seconds.

With all due respect, that's an essentially meaningless distinction.

You would do well to take time to study this instead of peremptorily dismissing it.

Been there; done that.

Your response betrays a certain lack of
understanding of some fairly basic issues.

Insults only serve to diminish the credibility of your own argument.

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

You took most of the words out of my mouth, cmyk - well done..

Apart from a few comments below, I would also add that image content
has a marked effect on the 'required' resolution for a print - for
example, a very close-up portrait usually does not invite the viewer
to get up *really* close (unless you are fascinated with nose hair
detail and the like.. (O. However, a group shot of 40 people, or a
detailed land- or city-scape will generally draw the viewer in to see
how much *real* detail is there.

There is also the topic of black and white, and generally that
requires higher resolution. Imo, the acceptable range for resolution
in a print could be anything from 180 ppi through to over 400,
depending on all those factors.

So when a typical monitor only gets you up to about 100 ppi, then I
agree with cmyk that zoomed viewing is essential for anything other
than a rough look at what a print *might* look like.

On Nov 17, 6:56 am, "cmyk" wrote:
"John Navas" wrote in messagenews:0qerj3h8h3lnphrvi09kurvub5e7v3hucd@4ax .com...
There's a great difference between screen resolution (72-96 PPI) and
good printing, where rules of thumb for normal viewing distances are at
least 130 DPI for barely acceptable results, and up to 230 DPI for
excellent results.

I don't know what distance you're viewing the prints from, but 230dpi doesn't cut it for a anything smaller than a 22.5x15 print
viewed at *normal* viewing distances
Absolutely agree - for a print that contains fine detail, even 300 can
struggle. And then there's b&w... But it depends on what you regard
as acceptable. But 230 *can* look excellent - see comments about
image content above.

With current technology, anything more than 300 DPI
is pretty much wasted.
Again, if restricted to family snapshots and 'average' work, I would
agree. But what about for the really good stuff...?

Your assumption that print densities would remain the same regardless of print size is wrong unless you're one of those sods who
insists that everything has to be viewed from some arbitrary fixed distance.

Yes, but then the problem is that meaningful comparisons become even
more complex. And you are excluding the possibility that the vewer
might want to get close and personal, looking for that detail we are
discussing. Guess I am one of those sods.. but having said all
that...

For a:
. 4x6 print, you'd want about 360ppi
. 5x7 print, you'd want 300-360ppi
. 8x10 or 11x14 print, you'd want about 288ppi
. 16x20 print, you'd want about 240ppi
. 20x30 print, you'd want about 200ppi

...these numbers are pretty much what I would accept, too... (O:

By what standard
do you define 'acceptable', 'very good', excellent', 'best'?

Exactly. And then you throw in viewing distance as well? (O: No
wonder it gets argued!

Even these reduced zooms exaggerate the issue, since display pixels are
so much bigger and more distinct than high-resolution print dots. For
this reason display zoom needs to be reduced even further for meaningful
print judging, to about 25-33% (depending on display) for a high-quality
(8MP) 11x14 print.

I don't get this. Further reducing the zoom level doesn't improve
your screen res - you simply lose more detail. The only way to
achieve some sort of print-res 'equivalence' is to leave the image
large, and then *move back*...

If you can't see an
issue at this reduced display zoom, then you're not going to see it in
an excellent print either.
No, not correct. See comment above.

Thus my normal practice is to assess images on screen at no more than
33% zoom, zooming in farther only to examine the effectiveness of
sharpening and/or noise reduction.
Which contradicts what you said above - you have to zoom back in to
determine what it will really look like, as far as actual sharpness/
detail/noise goes.

Useful discussion, though. (O: