Digital SLR'S

In message , Jeff R.
writes

wrote in message
oups.com...

Jeff R. wrote:
"aj" wrote in message
...
can a digitlal slr camera with a standard lens for example take good
quality pictures of a twilight scene like a crescent moon &
venus,compared
to an slr using 35mm film?

How's this: http://faxmentis.org/html/earthshine.html
(Standard lens shot at the bottom of the page)

or this: http://faxmentis.org/html/partial.html
(small mirror telephoto - partial lunar eclipse)

or this: http://faxmentis.org/html/partial.html

...but you asked "compared to".

The answer then, is: depends on the exposure required. DSLRs are awfully
noisy past a few seconds exposure, and cannot match film SLRs - even with
noise reduction and Photoshopping.

Anything less than a second or so - the DSLR wins through convenience and
speed.
Over a few seconds the film wins due to noise.


Way untrue.

Andrea T.

?
More info, please?

I didn't have time to do a search this morning but try this
http://web.canon.jp/Imaging/astro/index-e.html
Here's a page about a Nikon DSLR.
http://www.stargazing.net/david/NikonD70/
Don't forget you can easily stack and process digital images.
I'm getting awfully tempted, especially as my Nikon Coolpix is _not_
very good at long exposures!

wrote in message
ps.com...

Jeff R. wrote:
The answer then, is: depends on the exposure required. DSLRs are
awfully
noisy past a few seconds exposure, and cannot match film SLRs - even
with
noise reduction and Photoshopping.

Anything less than a second or so - the DSLR wins through convenience
and
speed.
Over a few seconds the film wins due to noise.


Way untrue.

Andrea T.


It means that is not true (for most of all the DSLRs out there anyway).
Assuming the right comparison (same resolution) is made the film is
considerable noisier.

Andrea T.

Respectfully I disagree.

My experience: http://www.mendosus.com/jpg/ghost-fungus-01.jpg
A 4 minute (approx) exposure on Kodacolor (!) taken in otherwise total
darkness of the self-illuminated Omphalotus Nidiformis. Quite acceptable
"noise" (grain) considering.

-but-

http://www.mendosus.com/jpg/ghost-fungus-02.jpg Same species, three years
later. Just as bright (the fungus, that is). DSLR set at lower sensitivity
and exposed for shorter interval (no reciprocity failure, right?)

Even with in-built noise reduction activated (which, BTW, is very good at
removing bright pixel noise) the noise is unacceptable *way* before
sufficient exposure is achieved.

Longer exposures were hopelessly spotty.

These two exposures are not identical, granted. The film shot, however, is
vastly superior to the digital, which is something less than one-eighth of
the exposure of the quite acceptable film shot.

Way true.

--
Jeff R.

Jeff R. wrote:
wrote in message
ps.com...

Jeff R. wrote:
The answer then, is: depends on the exposure required. DSLRs are
awfully
noisy past a few seconds exposure, and cannot match film SLRs - even
with
noise reduction and Photoshopping.

Anything less than a second or so - the DSLR wins through convenience
and
speed.
Over a few seconds the film wins due to noise.


Way untrue.

Andrea T.


It means that is not true (for most of all the DSLRs out there anyway).
Assuming the right comparison (same resolution) is made the film is
considerable noisier.

Andrea T.

Respectfully I disagree.

My experience: http://www.mendosus.com/jpg/ghost-fungus-01.jpg
A 4 minute (approx) exposure on Kodacolor (!) taken in otherwise total
darkness of the self-illuminated Omphalotus Nidiformis. Quite acceptable
"noise" (grain) considering.

-but-

http://www.mendosus.com/jpg/ghost-fungus-02.jpg Same species, three years
later. Just as bright (the fungus, that is). DSLR set at lower sensitivity
and exposed for shorter interval (no reciprocity failure, right?)

Even with in-built noise reduction activated (which, BTW, is very good at
removing bright pixel noise) the noise is unacceptable *way* before
sufficient exposure is achieved.

Longer exposures were hopelessly spotty.

These two exposures are not identical, granted. The film shot, however, is
vastly superior to the digital, which is something less than one-eighth of
the exposure of the quite acceptable film shot.

Way true.


I beg to differ, sir.

Both shots should have been taken with the same settings and the same
exposure length to be comparable and at the same time too (it might
well be that there are differences in luminescence between different
fungi samples, you never know). This said the D *ist is notoriously a
"pig" in both noise and low light capabilities, nowhere near to what
can be done with Canons and Nikons. OTOH I suspect the noise reduction
thing had something to do with the poor result of the digital shot.

BTW, not having reciprocity failure does not automatically guarantee
excellent results with short exposures!

A single shot in a moderately light polluted place like my backgarden
has shown about mag.8.5 stars with a Fuji 400 ASA film on a 300/f4 lens
after 15s and about mag.12.5 at 400 ASA with a Nikon D50 with a
105/f2.5 lens after 17s. Given the differences in lens sizes the
results are quite telling.

BTW, very nice shot you have there.

Andrea T.

wrote in message
oups.com...

Jeff R. wrote:
wrote in message
ps.com...

Jeff R. wrote:
The answer then, is: depends on the exposure required. DSLRs are
awfully
noisy past a few seconds exposure, and cannot match film SLRs -
even
with
noise reduction and Photoshopping.

Anything less than a second or so - the DSLR wins through
convenience
and
speed.
Over a few seconds the film wins due to noise.


Way untrue.

Andrea T.


It means that is not true (for most of all the DSLRs out there anyway).
Assuming the right comparison (same resolution) is made the film is
considerable noisier.

Andrea T.

Respectfully I disagree.

My experience: http://www.mendosus.com/jpg/ghost-fungus-01.jpg
A 4 minute (approx) exposure on Kodacolor (!) taken in otherwise total
darkness of the self-illuminated Omphalotus Nidiformis. Quite acceptable
"noise" (grain) considering.

-but-

http://www.mendosus.com/jpg/ghost-fungus-02.jpg Same species, three
years
later. Just as bright (the fungus, that is). DSLR set at lower
sensitivity
and exposed for shorter interval (no reciprocity failure, right?)

Even with in-built noise reduction activated (which, BTW, is very good at
removing bright pixel noise) the noise is unacceptable *way* before
sufficient exposure is achieved.

Longer exposures were hopelessly spotty.

These two exposures are not identical, granted. The film shot, however,
is
vastly superior to the digital, which is something less than one-eighth
of
the exposure of the quite acceptable film shot.

Way true.


I beg to differ, sir.

Both shots should have been taken with the same settings and the same
exposure length to be comparable


Yes, I mentioned that, but I disagree.
This is not an academic treatise, it is a simple comparison of systems.

My results showed (me) that my digital is substantially noisier *even at
shorter exposures*.
The longer ones (which I didn't keep) were even worse.


and at the same time too (it might
well be that there are differences in luminescence between different
fungi samples, you never know).

No, this was not a factor - or at least not a significant or measurable
factor.

This said the D *ist is notoriously a
"pig" in both noise and low light capabilities, nowhere near to what
can be done with Canons and Nikons.

My Nikon DSLR shares the same sensor as the Pentax.
That sensor may well be slightly noiser than a Canon, but the difference
here (between my digital and my film) is orders of magnitude, not slight
differences.

OTOH I suspect the noise reduction
thing had something to do with the poor result of the digital shot.

No. 'fraid not.
What is does, with its auto dark-frame subtraction, does not affect overall
noise noticeably. It does (as I said) brilliantly remove bright pixel
noise.



BTW, not having reciprocity failure does not automatically guarantee
excellent results with short exposures!

No, but...
(ne'er mind)



A single shot in a moderately light polluted place like my backgarden
has shown about mag.8.5 stars with a Fuji 400 ASA film on a 300/f4 lens
after 15s and about mag.12.5 at 400 ASA with a Nikon D50 with a
105/f2.5 lens after 17s. Given the differences in lens sizes the
results are quite telling.

Sigghhhh.
My stellar shots show similar noise results to my fungus shots.
Both *1stDS (*stupid* name for a camera!) and my D50.

My film shots (up to 5 mins) are universally cleaner. I'd do longer film
shots, but I don't have the patience to guide for that long.
Maybe cameras work differently here in the southern hemisphere.


BTW, very nice shot you have there.
Thank you.
Lots more (incl. flash shots) if you follow the links he
http://faxmentis.org/html/fungus2.html

Cheers
Jeff R.



Andrea T.

On Wed, 27 Sep 2006 01:29:36 +1000, "Jeff R."
wrote:

This said the D *ist is notoriously a
"pig" in both noise and low light capabilities, nowhere near to what
can be done with Canons and Nikons.

My Nikon DSLR shares the same sensor as the Pentax.
That sensor may well be slightly noiser than a Canon, but the difference
here (between my digital and my film) is orders of magnitude, not slight
differences.

But it doesn't share the same electonics. I was having a similar
conversation with a Sony sensor consultant who actually made the
comment that a lot of people believe that a camera which shares the
same sensor as another will perform identically. It doesn't!

I don't know the DS but I have used the DL. It was a nice camera but
noise was very evident for long exposures whereas the Canon's and
Nikons for similar exposures were very clean smooth and dark. If you
want to see the difference, take a 300s dark with the DS at a fairly
high ISO (record the temperature) and let me know the details. I'll
then do the same with a Canon and we'll compare notes. I think you'll
see that the difference is more than slight.
--
Pete Lawrence
http://www.digitalsky.org.uk
Last updated June 2006

Jeff R. wrote:
wrote in message
oups.com...

Jeff R. wrote:
wrote in message
ps.com...

Jeff R. wrote:
The answer then, is: depends on the exposure required. DSLRs are
awfully
noisy past a few seconds exposure, and cannot match film SLRs -
even
with
noise reduction and Photoshopping.

Anything less than a second or so - the DSLR wins through
convenience
and
speed.
Over a few seconds the film wins due to noise.


Way untrue.

Andrea T.


It means that is not true (for most of all the DSLRs out there anyway).
Assuming the right comparison (same resolution) is made the film is
considerable noisier.

Andrea T.

Respectfully I disagree.

My experience: http://www.mendosus.com/jpg/ghost-fungus-01.jpg
A 4 minute (approx) exposure on Kodacolor (!) taken in otherwise total
darkness of the self-illuminated Omphalotus Nidiformis. Quite acceptable
"noise" (grain) considering.

-but-

http://www.mendosus.com/jpg/ghost-fungus-02.jpg Same species, three
years
later. Just as bright (the fungus, that is). DSLR set at lower
sensitivity
and exposed for shorter interval (no reciprocity failure, right?)

Even with in-built noise reduction activated (which, BTW, is very good at
removing bright pixel noise) the noise is unacceptable *way* before
sufficient exposure is achieved.

Longer exposures were hopelessly spotty.

These two exposures are not identical, granted. The film shot, however,
is
vastly superior to the digital, which is something less than one-eighth
of
the exposure of the quite acceptable film shot.

Way true.


I beg to differ, sir.

Both shots should have been taken with the same settings and the same
exposure length to be comparable


Yes, I mentioned that, but I disagree.
This is not an academic treatise, it is a simple comparison of systems.

Yet it should be correctly factored to draw meaningful conclusions,
isn't it?


My results showed (me) that my digital is substantially noisier *even at
shorter exposures*.
The longer ones (which I didn't keep) were even worse.


and at the same time too (it might
well be that there are differences in luminescence between different
fungi samples, you never know).

No, this was not a factor - or at least not a significant or measurable
factor.

This said the D *ist is notoriously a
"pig" in both noise and low light capabilities, nowhere near to what
can be done with Canons and Nikons.

My Nikon DSLR shares the same sensor as the Pentax.
That sensor may well be slightly noiser than a Canon, but the difference
here (between my digital and my film) is orders of magnitude, not slight
differences.

Well, as Pete has mentioned, having the same sensor doesn't mean it
will perform the same. In fact the same sensor is on the SXV-M25 which
is a hell of a tri-colour CCD. Yet it would be fool to compare the D50
performance to that one. Just to give you another example, the D70/70s
and the D50 share the same sensore and most of the lectronics but the
noise performance isn't quite the same!


OTOH I suspect the noise reduction
thing had something to do with the poor result of the digital shot.

No. 'fraid not.
What is does, with its auto dark-frame subtraction, does not affect overall
noise noticeably. It does (as I said) brilliantly remove bright pixel
noise.

It also kills the signal if a median low pass filter is applied at the
same time, like the Nikons do.




BTW, not having reciprocity failure does not automatically guarantee
excellent results with short exposures!

No, but...
(ne'er mind)



A single shot in a moderately light polluted place like my backgarden
has shown about mag.8.5 stars with a Fuji 400 ASA film on a 300/f4 lens
after 15s and about mag.12.5 at 400 ASA with a Nikon D50 with a
105/f2.5 lens after 17s. Given the differences in lens sizes the
results are quite telling.

Sigghhhh.
My stellar shots show similar noise results to my fungus shots.
Both *1stDS (*stupid* name for a camera!) and my D50.

D50s are all the same, afaik, so you should get the same results. I can
send you a sample shot so you can check yourself. Or you could shoot a
5 min dark frame and send me the .NEF so that I can have a look at it.


My film shots (up to 5 mins) are universally cleaner. I'd do longer film
shots, but I don't have the patience to guide for that long.
Maybe cameras work differently here in the southern hemisphere.


BTW, very nice shot you have there.
Thank you.
Lots more (incl. flash shots) if you follow the links he
http://faxmentis.org/html/fungus2.html

Thanks. Very nice pictures. Wonder whether there are similar fungi here
in the UK, but I doubt it.

Andrea T.