A Photography forum. PhotoBanter.com

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » PhotoBanter.com forum » Photo Equipment » Medium Format Photography Equipment
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Hasselblad 56x42mm 60 mpix



 
 
Thread Tools Display Modes
  #1  
Old December 29th 08, 09:27 PM posted to rec.photo.equipment.medium-format
external usenet poster
 
Posts: n/a
Default Hasselblad 56x42mm 60 mpix

Noons said:

On Dec 29, 10:44=A0am, Peter Irwin wrote:


Every grain in film is either on or off. You get the impression
of continuous tone because there are a huge number of grains.


Completely false, of course. There is no such thing as
"on and off grain" in film, that is a demented and stupid conclusion
from an online site run by a moron who hasn't used film in decades.


It is always possible that I may be wrong about practically anything,
but I certainly didn't get this from an online site. I got it from books.

I'm sure you have seen books with electron micrographs of developed
film (some very old books show less clear optical micrographs) to explain
how the image formation in film works. The last time I looked at
these books it seemed that a grain either developed (became a speck
of metalic silver) or it didn't and was dissolved by the fixer.

If you know better, I would be glad if you could show me or tell
me where to look for imformation.

Peter.
--




  #2  
Old December 29th 08, 10:20 PM posted to rec.photo.equipment.medium-format
Noons
external usenet poster
 
Posts: 3,245
Default Hasselblad 56x42mm 60 mpix

wrote,on my timestamp of 30/12/2008 7:27 AM:


It is always possible that I may be wrong about practically anything,
but I certainly didn't get this from an online site. I got it from books.

I'm sure you have seen books with electron micrographs of developed
film (some very old books show less clear optical micrographs) to explain
how the image formation in film works. The last time I looked at
these books it seemed that a grain either developed (became a speck
of metalic silver) or it didn't and was dissolved by the fixer.

If you know better, I would be glad if you could show me or tell
me where to look for imformation.


Let me have a go. Please note that I am over-simplifying like
crazy, otherwise this would be a veeeery lengthy post.

Film grain is not the same as a pixel. The two couldn't be
more different. There are quite a few sites - and books - who
have tried to equate the two, but it is completely wrong.

This particular post:
http://photo-utopia.blogspot.com/200...nd-clumps.html
should set you on the correct path to determine for
yourself the truth.
I also have a pointer to a document from Kodak on
electron microscope photos that confirm this, can post
it later if you are interested. There are also heaps of
discussions on the subject in sites populated by folks who
actively use film and digital, like APUG or the rangefinder
forum.

Each grain is not a pixel. You get much more than one
pixel from a single grain speck, with full definition
and separate resolution. Colour is slightly different but
essentially the same principles apply.

In simplified terms - all sorts of nuances with colour film,
for example - each grain is a crystal, which is made up of many
thousands of molecules, each of which indeed IS the rough
equivalent of what we call a pixel in digital terms. Even then,
you still have a number of atoms in each molecule, not the whole
of which will be turned to silver.

Hence the gradual - analog? - gradation of the result, as opposed
to the digital pixel on-off, discrete nature. And the whole lot
is random in spatial distribution, as opposed to the regular
patterns of a digital sensor. Which also explains why anti-alias
sensor filters are needed for digital and not with film.

If you allow me a rough analogy, a single grain in an emulsion
will NEVER be simply on or off, because it is made up of many
thousands of "switches", which won't be all on or off. Unless
one has gone for complete block-out or blow-off, of course!

Oh, slightly off-topic: what you see as "grain" in b&w, for
example, is not. It is the space BETWEEN grains, which shows
up dark after reversed scans. That is what most people see as
"grain", and can easily be eliminated with noise reduction
software or adequate lighting during the scan.

If you take the care of examining a negative with a 40X
microscope for example, you'll notice the difference
immediately: clearly defined detail INSIDE each "grain".
But you need to be using a "high grain, high accutance" developer
like Rodinal. Modern low grain developers act by slightly
dissolving the silver in grain, thereby reducing somewhat the
"clump" nature of the spaces between each grain. They also
slightly lose accutance in the process by altering the contents
of each crystal, some more than others.
But all that is waaay beyond the point here.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Hasselblad 56x42mm 60 mpix Alan Browne Digital SLR Cameras 106 January 14th 09 01:35 PM
6 or 8 MPIX? Chuck Deitz Digital SLR Cameras 38 March 10th 05 12:01 AM
8 Mpix or 6? Chuck Deitz Digital ZLR Cameras 7 March 3rd 05 10:10 AM
Is 4 Mpix camera just as good as 5 Mpix when available light is the limiting factor? Woody Digital Photography 17 September 26th 04 06:44 PM


All times are GMT +1. The time now is 08:37 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 PhotoBanter.com.
The comments are property of their posters.