Interesting Leica product announcements today ...

David Dyer-Bennet wrote,on my timestamp of 18/05/2012 1:46 AM:


Given that cluming is the mechanism by which different densities are
produced, I wonder how good the tonality can be with Tech Pan, though.

No, it isn't. Not with Tech Pan or similar Pan films.

account is the nature of the file used to store the image. It is
useless to compare with jpg files: they work by REMOVING detail in the
first place! They cannot ever be employed as a base of comparison of
detail.

Absoutely. That's so ingrained I don't even think of it (and don't
think to mention it to others).

You'd be surprised how many "experts" here and elsewhere claimed over the years
jpg had enough detail to be used as a measure of detail-related size vis-a-vis
tiff (or any non-lossy compression)...

One of my heuristics for picking out the sharper shots (from adjacent
very similar photos) when they look very similar to my eye is to pick
the one with the larger jpeg. Kind of a tie-breaker when I can't find a
reason to prefer one to the other for any other reason.

Bingo! What did I say? LOL!
(narh, just joking: I'm aware you are doing a relative comparison between two
jpgs of similar compression settings, not between a jpg and a tiff. That's
fair. Just couldn't stop myself!).

Noons writes:

David Dyer-Bennet wrote,on my timestamp of 18/05/2012 1:46 AM:


Given that cluming is the mechanism by which different densities are
produced, I wonder how good the tonality can be with Tech Pan, though.

No, it isn't. Not with Tech Pan or similar Pan films.

"Pan" means "panchromatic", and all modern B&W films are panchromatic
(tri-x, plus-x, panatomic-x, t-max).

What Tech Pan is is an ultra-thin-emulsion film; not intended for
pictorial photography at all, and not intended to produce a
continuous-tone image in the first place. (Yes, with proper developers
it clearly can produce useful continuous-tone images; haven't used it
myself, but have seen plenty of examples.)

account is the nature of the file used to store the image. It is
useless to compare with jpg files: they work by REMOVING detail in the
first place! They cannot ever be employed as a base of comparison of
detail.

Absoutely. That's so ingrained I don't even think of it (and don't
think to mention it to others).

You'd be surprised how many "experts" here and elsewhere claimed over
the years jpg had enough detail to be used as a measure of
detail-related size vis-a-vis tiff (or any non-lossy compression)...

One of my heuristics for picking out the sharper shots (from adjacent
very similar photos) when they look very similar to my eye is to pick
the one with the larger jpeg. Kind of a tie-breaker when I can't find a
reason to prefer one to the other for any other reason.

Bingo! What did I say? LOL!
(narh, just joking: I'm aware you are doing a relative comparison
between two jpgs of similar compression settings, not between a jpg
and a tiff. That's fair. Just couldn't stop myself!).

Yep, two very-similar images, same dimensions, represented in the same
compressed format. All those things being the same is critical to the
size meaning anything at all (and even then it doesn't mean that much;
if I prefer one by eye I ignore the sizes, it's just helpful to make up
my mind when I can't find any other basis to prefer one photo).

(The fact that I do this fairly frequently could be taken as a sign that
I shoot too many copies of some of my photos!)
--
David Dyer-Bennet, ; http://dd-b.net/
Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
Photos: http://dd-b.net/photography/gallery/
Dragaera: http://dragaera.info

Noons writes:

John A. wrote,on my timestamp of 18/05/2012 4:15 PM:


It's obvious that he wishes he could scan at higher resolution not to
offer proof of the film's resolution to you or anyone else, but rather
so that he could have digital versions of the photos at the resolution
the film is capable of providing.

Aw, c'mon! You know perfectly well that moronic arsehole trolls like
"Wolfgang" are here with the express intention of distorting and
disparaging anyone that doesn't belong to their little idiot Canon
fan-club. Anything else is secondary!

Bull****. Wolfgang is opinionated and scrappy certainly, but quite
knowledgable. And, to your point, beats me up when I'm imprecise, but
NOT when say nice things about my Nikon gear. Your suggestion that he's
a Canon-specific fan-boi is clearly false.
--
David Dyer-Bennet, ; http://dd-b.net/
Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
Photos: http://dd-b.net/photography/gallery/
Dragaera: http://dragaera.info

In rec.photo.digital Mxsmanic wrote:
Chris Malcolm writes:

I think most DSLRs have menu-switchable long exposure noise
reduction.

Noise reduction also reduces image quality.

This particular kind of noise reduction (subtraction of an
equivalently exposed black image) seems to me on theoretical grounds
to be more likely to improve image quality than reduce it. It's
completely different from the kind of noise reduction processing used
in translating RAW images to jpegs in camera or RAW image processor,
which effects a compromise between noise reduction and detail loss.

Looking at the results in practice, same tripod photograph with it
switched on and off, it seems to me quite definitely to improve IQ,
even to a determinedly pixel-peeping scrutiny.

--
Chris Malcolm

"Mxsmanic" wrote in message
...
Chris Malcolm writes:

This particular kind of noise reduction (subtraction of an
equivalently exposed black image) seems to me on theoretical grounds
to be more likely to improve image quality than reduce it.

That's because it actually uses informmation from two separate images to
form
a single image, so it's possible for it to reduce noise without
degrading the
target image significantly.

However, noise reduction performed on a single image--without a
reference
image to provide extra information--will always degrade image quality.
It's
mathematically inevitable.

Not necessarily. You can often find reference patches within the same
image - areas which you know to be of a near constant brightness for
example - and measure the statistics of the image there. The fact that
noise reduction (for viewing by humans) can work so well shows that
perceived image quality can be improved rather than degraded.

David

David Dyer-Bennet wrote,on my timestamp of 20/05/2012 5:14 AM:


Bull****. Wolfgang is opinionated and scrappy certainly, but quite
knowledgable. And, to your point, beats me up when I'm imprecise, but
NOT when say nice things about my Nikon gear. Your suggestion that he's
a Canon-specific fan-boi is clearly false.

Like all the other Canon fan-boys. And any maker fan-boys.
Nothing but groupies. Rarely any substance or recults to show what they are
capable of. But oh-boy: do they know how to dump on others...

David Dyer-Bennet wrote,on my timestamp of 20/05/2012 5:12 AM:

Given that cluming is the mechanism by which different densities are
produced, I wonder how good the tonality can be with Tech Pan, though.

No, it isn't. Not with Tech Pan or similar Pan films.

"Pan" means "panchromatic", and all modern B&W films are panchromatic
(tri-x, plus-x, panatomic-x, t-max).

I said "similar Pan films"...
The image characteristics and formation for the techpan look alikes is
completely different from the traditional b&W stuff. Negative strips examined
on the microscope are completely different: there is no "clumping" anywhere.

What Tech Pan is is an ultra-thin-emulsion film; not intended for
pictorial photography at all, and not intended to produce a
continuous-tone image in the first place. (Yes, with proper developers
it clearly can produce useful continuous-tone images; haven't used it
myself, but have seen plenty of examples.)

Its original design purpose was as a micro-film.
The biggest difference I see between all these high-res films and the run of the
mill tri-x/pan-x/t-max is that the non-exposed portion of the negative comes out
totally transparent instead of with the usual grey "fog". To the point where
Adox CMS20 for example can be used as a b&w "slide" film with contact
duplication: plenty of folks at APUG have tried it and love the results. Same
for the Rolleis. It also gives the negatives a huge dynamic range that exceeds
what my ED9000 can do almost every time. That makes it a challenge to scan a
high dynamic range image in its entirety without losing something off the
"ends". HDR-like scanning works to "compress" it, but it's a RPITA time-waster...


Yep, two very-similar images, same dimensions, represented in the same
compressed format. All those things being the same is critical to the
size meaning anything at all (and even then it doesn't mean that much;
if I prefer one by eye I ignore the sizes, it's just helpful to make up
my mind when I can't find any other basis to prefer one photo).


(The fact that I do this fairly frequently could be taken as a sign that
I shoot too many copies of some of my photos!)


Who doesn't? :-)
I'm very much into bracketing. With the F6/F100 and spot meter I tend to stick
to the zone system. But with the dslrs and the Oly m4/3, bracketing is the
order of the day. Although I must admit I'm getting it right most of the time
first go with the Oly. Then again, I use it a lot more than the dslrs...

Noons wrote:
David Dyer-Bennet wrote,on my timestamp of 20/05/2012 5:14 AM:

Bull****. Wolfgang is opinionated and scrappy certainly, but quite
knowledgable. And, to your point, beats me up when I'm imprecise, but
NOT when say nice things about my Nikon gear. Your suggestion that he's
a Canon-specific fan-boi is clearly false.

Like all the other Canon fan-boys. And any maker fan-boys.
Nothing but groupies. Rarely any substance or recults to show what they are
capable of. But oh-boy: do they know how to dump on others...

Perfect description of Noons.

-Wolfgang

John A wrote:
On 19 May 2012 19:43:17 GMT, Chris Malcolm
In rec.photo.digital Mxsmanic wrote:
Chris Malcolm writes:

I think most DSLRs have menu-switchable long exposure noise
reduction.

Noise reduction also reduces image quality.

This particular kind of noise reduction (subtraction of an
equivalently exposed black image) seems to me on theoretical grounds
to be more likely to improve image quality than reduce it. It's
completely different from the kind of noise reduction processing used
in translating RAW images to jpegs in camera or RAW image processor,
which effects a compromise between noise reduction and detail loss.

Looking at the results in practice, same tripod photograph with it
switched on and off, it seems to me quite definitely to improve IQ,
even to a determinedly pixel-peeping scrutiny.

The idea is that any non-random noise sources will negate each other
in the two exposures, while random noise will tend to average out as
well.

Random noise (if observed statistically) will grow with the square
root of measurements, as it's a random walk.

A similar approach would be to take two or more exposures and average
the pixels together, provided you can get the registration right. In
theory, the average of a number of exposures approaching infinity
should be spot-on with zero random noise.

Actually, the total noise grows (see above), but much slower than
the total signal. Thus, the SNR goes to infinity.

As the main noise source is photon noise, you could just expose
longer (and thus add the inevitable read noise less often).
Of course, after some point your pixels will overflow, but who
really cares for such real-life limitations, when one can just
postulate infinitely deep electron wells?

-Wolfgang

"Mxsmanic" wrote in message
...
David J Taylor writes:

Not necessarily. You can often find reference patches within the same
image - areas which you know to be of a near constant brightness for
example - and measure the statistics of the image there.

If you can trust that portion of the sensor to be representative of the
rest.

Often sensors have irregular noise across the sensor. And sensors can
vary
greatly from one camera to the next. I've seen two cameras with
consecutive
serial numbers that had huge differences between them: one had no
visible
noise at all, the other was just a mass of noise.

That sounds like a faulty camera - or different default settings.

In practice, it works well in the version of Paint Shop Pro which I have.

Cheers,
David