HDTenEightyP/NetNews huggingface dataset:
From: whheydt@pbhya.PacBell.COM (Wilson Heydt)
Newsgroups: rec.photo
Subject: Re: Designing fast non-50mm lenses
Date: 26 Aug 92 16:23:55 GMT
Reply-To: whheydt@PacBell.COM (Wilson Heydt)
Organization: Pacific * Bell, San Ramon, CA

In article <1992Aug25.164422.10594@cnmss.tredydev.unisys.com> kjm@cnmss.tredydev.unisys.com (Ken J. McFadden) writes:
>I believe the problem is due to the mirror in SLR's.  In non-SLR's you can
>place the rear element of the lens as close to the shutter curtain as you like,

Assuming yoou're using a focal-plane shutter at all . . .

>Just imagine, if there was no mirror to get in the way, the Nikon 6mm f/2.8
>would need a front element only 0.75mm in diameter and would sit just 6mm from
>the film plane (and even closer to the shutter curtain).  Of course, since the
>angle of view is around 180 degrees (or more?) that most of every picture
>taken with the lens would include the interior of the camera, a small
>portion of the center of the frame would show what's in front of the lens
>mount.

:-)

I'm afraid that's a bad choice for an example . . .  The Nikon 6mm has
to be used sith mirror lock-up because the back of the lens *does*
extend too far into the camera to clear the mirror.

Since the the field of view is 220 degrees, pointing it in the right
direction isn't all *that* much of a problem--though (apparently)
keeping your feet and/or tripod out of the picture is.

	--Hal
-- 
Hal Heydt                    |    "Boycott Time-Warner"
Analyst, Pacific*Bell        |         --J. Danforth Quayle
510-823-5447                 |    "... kill all the lawyers."
whheydt@pbhya.PacBell.COM    |         --William Shakespeare
Newsgroups: rec.photo
From: dranidis@informatik.uni-muenchen.de (Dimitris Dranidis)
Subject: Problem: Green spots on negative
Organization: Leibniz-Rechenzentrum, Muenchen (Germany)
Date: Thu, 3 Sep 1992 12:21:03 GMT



Hello, 

I've come back from my holidays, and I got my films developed.
I saw on some photos red spots, coming from nowhere, sometimes 
when even no sun in the picture was. I looked at the negatives and
I noticed green spots (negative) which are not only in the picture 
frame but outside also (see sketch).

--------------oooooooooooooooooooooo--------------------
 ==    ==    ==  ooooooooooooooooooooo   ==    ==     ==    
-----------+  +----oooooooooooooooo----------+  +-------
           |  |     ooooooooooooo            |  |
           |  |         ooooo  |             |  |
           |  |             |  |             |  |
-----------+  +-------------+  +-------------+  +-------
 ==    ==    ==    ==     ==    ==    ==    ==     ==    
--------------------------------------------------------

My camera is a Minolta X-700, my lens a zoom Minolta 28-70, the film 
Kodak Gold 100. Nor filters neither accesoires were used. I took
photos from lots of sunsets (Greece) and generally with the sun in 
frame. I've done this before and had no problems. I've never opened
the back of the camera neither heve I reloaded a film. I didn't even
changed the lens during the holidays. I developed the film in a cheap
photo store, from which never had problems before.

I would appreciate any help that will clear whose fault is it.
Should I worry for my camera?

Thanks in advance,

Dimitris
Newsgroups: rec.photo
From: arothmun@ntb.ch (A. Roth)
Subject: EF 100 lense for EOS
Reply-To: arothmun@ntb.ch
Organization: Neu-Technikum Buchs, Switzerland
Date: Tue, 25 Aug 1992 20:05:06 GMT



I have an EOS 100, and i am searching a fix-lense between 80 and 110 mm.
There are two possibilities:

1)To buy fix-lense between 80 and 110 mm, with f=1.8 or 2 or (max 2.8)
  Have anybody such a lense?
  Can you tell me which one and your experience (and costs)

2>I have already a 50 mm f=1.8 fix-lense.
  Now i can take a 2x or 1.7x converter to make a 100 mm
  or 85 mm.
  Have anybody such a lense?
  Can you tell me which one and your experience (and costs)

Please tell me thank you,
			Alex
From: gsnow@clark.edu (Gary Snow)
Newsgroups: rec.photo
Subject: Re: Vivitar 636AF vs. Canon 430EZ
Date: 2 Sep 92 20:50:45 GMT
Article-I.D.: clark.1992Sep2.205045.16255
Distribution: usa
Organization: Clark College, Vancouver, Wa.  USA

In article <Btx63J.8xt@nntp-sc.Intel.COM> svaradar@sangeet.intel.com () writes:
>
>I'm considering purchasing a powerful flash for my Canon 10s.
>
>I have heard about the Vivitar 636AF and the Canon 430EZ.
>The 636AF costs $109 and the 430EZ is available at $219.
>
>I'd like to know whether the 430EZ is worth the extra $110. What
>advantages does the 430EZ have over the 636AF, if any ? 

I don't know, what can the 636AF do. I have a 430EZ, and as far as
I am concerned, there is nothing like a dedicated flash (from the
original camera manufacturer). You can run into incompatibilities
with third party equipment.

>Also, has anybody out there had any good/bad experiences with the
>Canon 75-300 EF lens  ?

I have it, and although its not a really sharp lens, its definately
worth the price.

Gary

-- 
-----
Gary Snow
uunet!clark!gsnow  or  gsnow@clark.edu
Newsgroups: rec.photo
From: robert@sys.sweden.dg.com (Robert Claeson)
Subject: Re: Need film recommendation for baby's birth
Date: Sat, 29 Aug 1992 13:08:45 GMT
Organization: Data General AB, Akalla, Sweden

I wrote:

> If ISO 400 is enough for you, I'd use Fujicolor Super HG 400. I much
> prefer it over most other ISO 400 color print films. It has also became
> a standard film for many press photographers, sort of like Kodak Tri-X
> is (was?) the standard b&w film.

I also intended to add the following, but for some reason forgot to do so:

Another ISO 400 film that's especially good for images of people is
Fujicolor NHG 400. It has lower contrast and more natural skin colors,
much like Fujicolor Reala. It is a professional film, though, so it
may not be available everywhere. You may also find that many one-hour
labs may not give you good results with this film. Other than that,
it is a great film.

-- 
------------------------------ END OF MESSAGE ------------------------------
Robert Claeson                Internet: robert@sys.sweden.dg.com
Data General AB                         robert@sys.dg.se
Box 28                             CEO: robert@sys.sweden.dg.com:dg-smtp
S-164 93 KISTA                     Tel: +46 (0)8-92 55 00
Sweden                             Fax: +46 (0)8-751 36 22
From: bgbauer@watcgl.uwaterloo.ca
Newsgroups: rec.photo
Subject: Re: Teleconverter options (TC-16A)
Date: 2 Sep 92 19:25:41 GMT
Organization: University of Waterloo

In article <9209021735.AA26756@micro> chuang@micro (Michael Chuang) writes:
>asanders@sparta writes:
>
>> The Nikon TC-16A is a 1.6x teleconverter that provides 
>> "semi autofocus". If you manually adjust your lens til 
>> things are almost sharp, the TC-16A will criticially 
>> focus the lens when the shutter release is pressed half-way.
>> Actually, I believe this converter has been discontinued, 
>> but it can be found second-hand for around $125. The Nikon 
>> System Handbook says it's a good performer.
>
>The TC-16A is intended for use with lenses of 300 mm or shorter
>with maximum apertures of at least f/2.8, I believe, though
>these are of course conservative limits.  Nikon says that it
>will not work in its pseudo-AF mode with the N6006, N5005 or 
>the N4004/4004s (sorry, I am not sure of the non-US model
>designations).  For the N8008/8008s and F4 the AF-mode switch
>must be set to "C."  This is probably also true of the N2020 for which
>the TC-16A was originally released.
> ... lots of good stuff deleted...
I actually got the TC16A to work on my N2020 with a 600f/8 Sigma lens.
This in spite of the claim that the aperture of the prime lens need be
better than about 2.8.  My experience was that the AF converter became 
more of an AF assist in that I would manually focus the lens to a setting
near the focus of the subject then use the AF to fine-tune the focus.

By the way I received limited response to my quest for a thread to F-mount
adapter and any info available on a Takumar 400f/5.6 screw-mount lens.
From: browner@rm1.interlan.com (Michael Browner)
Newsgroups: rec.photo
Subject: Re: Guide No for Max 5400xi Flash?
Date: 28 Aug 92 18:23:29 GMT
Organization: Racal-Milgo, Sunrise, Florida

In article <92240.180927M05BC@CUNYVM.BITNET>, M05BC@CUNYVM.BITNET (Spartacus@Cuny) writes:
|> 
|>      Hi folks,
|> 
|>         Its been a while I've posted to rec.photo.  In the August issue
|>      of POPular Photography, they reviewed the new 9xi and the 5400xi flash.
|>      However they neglected to mention the new maximum guide number for
|>      this new flash.  I would like to know how much better it is than the
|>      5200i.  Would someone on the net know the guide number?
|> 

I'll take a stab at it.  How about a Guide No. of 54meters.  Minolta numbers
their flashes based on the guide number in meters for the flash.  A 4000AF
is about 40m, the 3200i is 32m and the 5200i is 52m.  The 5400i is a 
repackaged 5200i, with infared and fancier electronics.

|>         Also, POP didn't mention if the 9xi had rear-curtain sync.
|>      Does it?  Oh..could you Email me your response...Thanks.

Don't know.

Michael B.
-- 
Michael Browner     		browner@sun1.interlan.com or
(305) 846-6848                  browner@rd1.interlan.com
Racal-Milgo, MS E-112, 
P.O.Box 407044, Ft Lauderdale, FL 33340  
Newsgroups: rec.photo
From: cf043@cleveland.Freenet.Edu (Lance K. Chun)
Subject: RIT Students
Reply-To: cf043@cleveland.Freenet.Edu (Lance K. Chun)
Organization: Case Western Reserve University, Cleveland, OH (USA)
Date: Tue, 25 Aug 92 21:45:48 GMT


Any RIT students out there/here? If so, contact me via e-mail. I would
like to correspond with my rivals. :-)
 
But seriously, if you are a RIT student, I'd like to hear from you.
 
Lance
-- 
Lance K. Chun - cf043@cleveland.freenet.edu             | Live  |
Photography Major - Fashion/Illustration/Advertising    | Long  |
Brooks Institute of Photography, Santa Barbara, CA      |   &   |
Paul Tsongas '96! Paul Tsongas '96! Paul Tsongas '96!   |Prosper|
From: jack@dcs.glasgow.ac.uk (Jack Campin)
Newsgroups: rec.photo
Subject: Re: selenium wash
Date: 26 Aug 92 17:32:12 GMT
Reply-To: jack@dcs.glasgow.ac.uk (Jack Campin)
Organization: COMANDOS Project, Glesga Yoonie

cmcdowel@en.ecn.purdue.edu (Charles E. McDowell) wrote:
> If you are interested, Ansel Adams' "The Print" explains his alternate
> procedure which involves mixing the selenium toner with other chemicals.
> I think it might be hypo-clear but I'm not sure.  He says he does (did) it
> to all his B&W prints for the deepening of blacks and archival effect.  If
> you don't do it (tone it) for very long, the color change is not very
> noticeable.  If you can`t get hold of "The Print" and want to know the
> Adams procedure, send me some mail, I'll look it up.

Which reminds me of something else in that book.  He describes a procedure
he calls "clearing the whites" - dunking the print in dilute reducer after
fixing.  This was intended to produce more brilliant highlights.  He writes
as if he did it routinely.  I have never seen that recommended anywhere
else or heard of anyone else doing it.  Was it required because Adams'
paper/developer combination was exceptionally prone to fog, or what?
Anyone out there do it?

-- 
--  Jack Campin    room G092, Computing Science Department, Glasgow University,
17 Lilybank Gardens, Glasgow G12 8RZ, Scotland   TEL: 041 339 8855 x6854 (work)
INTERNET: jack@dcs.glasgow.ac.uk or via nsfnet-relay.ac.uk    FAX: 041 330 4913
BANG!net: via mcsun and uknet     BITNET: via UKACRL    UUCP: jack@glasgow.uucp
From: Rick.Ellis@ofa123.fidonet.org
Newsgroups: rec.photo
Subject: Popping slides and curved field lenses
X-Sender: newtout 0.02 Aug 21 1992
Date: 02 Sep 92  11:54:21

On <Sep 01 11:54> Frank Loffel writes:

 FL> Why do slides pop when projected (heated up)?

As the film gets hot it expands.  Since the edges are fixed in the slide
holder and something must give the center moves outward.
From: mpc@biosys.apldbio.COM (Morgan Conrad)
Newsgroups: rec.photo
Subject: Re: Seeking Comments on NIKON F4 and on a P&S
Date: 27 Aug 92 18:35:02 GMT
Reply-To: mpc@apldbio.com (Morgan Conrad)
Organization: Applied Biosystems Inc, Foster City, CA

steveh@pilot.dmg.ml.com (Steve Hannoford) writes:
>>My apartment was recently robbed, and the main thing stolen was
...
>>I would also like feedback from you F4/Nikon AF owners as to what (AF)
>>lenses to buy.  I plan on the F4s and SB-24.

badboy@netcom.com (Jay Keller) replies:
>Start with:
>  35-70 f/2.8 and 80-200 f/2.8
>These 2 should cover about 80% of all situations.

>Take the next thousand bucks and add:
> 20 f/2.8 and 105 f/2.8 micro
>Now we've got a great wide angle and a superb macro.

>Next I'd go for length and buy the 300 f/4 and the 1.4x and 2x teleconverters
>to go with it.

Jay's advice is excellent.  However, a lot depends on what and where YOU plan
to shoot.  I do a lot of backpacking, and use an FM-2 for ruggedness and
light weight.  Someyear I'll buy an 8008s or F4, so many of my lenses are AF.

Here's what I have:

The 105 macro is a must - fantastic optics, and a great focal length - IMHO, 
better than 60mm.  I have the older manual focus model, with extension tubes.  
The 300 f/4 is good.  With extension tubes, its a fun closeup/macro lens.
What will you shoot with it?  For mammals, it's fine, especially with the 1.4x.
If you crave birds, it's a bit short.  However, real "bird glass" (>= 500mm) 
is heavy and expensive - out of my league and interests.
I have the 28-70 f/3.5-4.5 zoom, not the 35-70 f/2.8.  For my style, it's 
lighter, wider, and fast enough.  But I don't do candids of people in subways.
I plan to get the 20mm to round out the wide angle end.

There's a big gap between my 105mm and 300, and I'm not sure what to do.
At this point, the 70-210, or 200 (maybe the macro?) are options.

If it were a bit faster, the 75-300 f/4-5.6 would be a great lens.  If you 
can live with the speed, (using faster film, always on a tripod, etc.) then
you'd be fine with two zooms - the 28-70 and the 75-300.  Compared to Jay's
suggestion, we are longer, lower (price), and wider, plus lighter, 
but much slower.  The 75-300 even has decent close-focusing for macros.
I decided it was too slow, but your mileage may differ.

Morgan Conrad              Cthulu for President!
Applied Biosystems
mpc@apldbio.com            Why settle for
415-570-6667               the lesser evil?
Newsgroups: rec.photo
From: clcp16@ccsun.strath.ac.uk ("S.C.Russell")
Subject: Re: Bogus Olympus Add
Organization: University of Strathclyde
Date: Fri, 4 Sep 1992 08:35:58 GMT

In article <SM.92Sep3141750@suns2.cel.co.uk>, sm@cel.co.uk (salim mehta) writes:
|> In article <1992Aug28.133202.20444@ccsun.strath.ac.uk> clcp16@ccsun.strath.ac.uk ("S.C.Russell") wrote:
|>  
|> > Nice as the mju-1's lens may be (The Infinity Stylus is called mju
|> > here, which caused a bit of friction) I don't think it could have
|>         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|> Sorry, I don't understand this! The Olympus mju-1 (or u-1 or micro-1) is so
|> called because of its size. The Greek letter "u" (=mju) is used in the SI
|> system to denote 10^-6 and is usually read as  "micro", as in um = micrometre
|> and uP = microProcessor. The camera *is* small, hence the moniker.
|> 
|> Only in the USA is it called the Infinity Stylus, this achieves the aim of
|> differentiating it from non-USA stock.
|> 
|> So why the friction?

	Sorry - rather poor mechanical engineering `joke' there.
Mu (well, alright, mju) is the coefficient of (dynamic? it was so
long ago) friction. It was meant to be funny; it won't happen again.

I've never heard the camera being called "micro-1" as it does actually
say "mju" on the case. I have heard it called the Miju-1, though,
but ISTR that was a rather dumb Jessop's person.

Newsgroups: rec.photo
From: cmc4a@galen.med.Virginia.EDU (Costa M. Colbert)
Subject: RE:FOR SALE! Nikon FG and Stuff
Organization: University of Virginia
Date: Tue, 1 Sep 1992 13:00:06 GMT

Due to unfortunate circumstances, I was unable to get a another Nikon to  
replace the FG. So I can't sell the FG and other stuff. But to those still  
interested, keep reading rec.photo. In a few weeks, I might be able to  
sell this stuff again.
Sorry for your trouble. Thanks.
YZ
Newsgroups: rec.photo,alt.cd-rom,gnu.misc.discuss,misc.int-property
From: brown@quorum.com (Robert E. Brown)
Subject: Photo CD patent info
Organization: Quorum Software Systems, Inc.
Date: 31 Aug 92 16:18:17 GMT


Here is some information I got when I called Kodak.  The Photo CD developers
toolkit contains a sample Photo CD with 24 images, some software, and a
reference that describes how to use the software.  The software consists of
binary libraries (for either the Macintosh or Windows), which can pull data
off of a Photo CD and translate it to other formats, and source code for a
sample application that uses the binary libraries.  Source code to the
libraries is not included with the toolkit.  A Unix version of the toolkit
with binaries libraries for Sun computers will be release some time in the
near future.  I don't know what their plans are for the computers the rest of
us own.

Kodak and Philips jointly developed the Photo CD system.  I was informed that
the file formats and other software aspects of the system are the subject a
software patent or patents.  For a sum of approximately $5000 one is allowed
to read the documentation for the file formats and techniques, but may not
base software on the knowledge.  For upwards of $100,000 one may license the
patents, and might be allowed to create an independent library that reads
images off the disks.

Isn't it amazing what power a patent confers!

                                bob
From: phaf@giraffe.ru.ac.za (MR A FERREIRA)
Newsgroups: rec.photo
Subject: Cibachrome life expectancy ?
Summary: Info needed on ciba life times
Keywords: Cibachrome
Date: 30 Aug 92 18:49:35 GMT
Article-I.D.: giraffe.phaf.35.715200575
Organization: Rhodes University, Grahamstown, South Africa

Greetings all

Does anybody know of any adverse effects to the life expectancy of 
Cibachrome prints that are mounted sandwiched between two sheets of glass.
The material type being used here is gloss. Could there be problems with 
trapped moisture ?
Cibachrome is reputed to have a life of 100 years, is this 
reasonable ?

If anyone has mounted Cibachrome prints in this way before I would be keen 
to hear how it was does (ie how the prints were kept in place etc..)

Thanks for any info
Andre

-- 
                           Andre Ferreira
        Internet: PHAF@Hippo.ru.ac.za or PHAF@giraffe.ru.ac.za       
     Department of Physics and Electronics_____Rhodes University   
                    Grahamstown____South Africa  
             " Physicists do it with freq until it Hz "
Newsgroups: rec.photo
From: CCGM <CCGM@MUSICM.MCGILL.CA>
Subject: RE: Demand focus (was photographing whales, nikon AF problem)
Organization: McGill University Systems Inc (MUSIC/SP)
Date: Wed, 2 Sep 1992 04:56:13 GMT

In article <1992Sep1.170908.1991@cbnewsm.cb.att.com> ka1gt@cbnewsm.cb.att.com (robert.m.atkins) writes:
>In article <1992Sep1.053347.27068@cello.hpl.hp.com>, jacobson@cello.hpl.hp.com (David Jacobson) writes:
>>
>> Secondly, and this is no help to you, I have often been wishing camera
>> manufacturers would include what I call "demand focusing".  On the
>> ...
>>   -- David Jacobson
>
>     What you need is a Canon EOS. With custom function (4?) you can transfer
>  ...
>Bob Atkins  AT&T Bell Labs  email (direct)  att!clockwise!rma

   With the Minolta cameras, (7000i, 8000i, 7xi, and 9xi - at least!)
you can use a custom card to program certain tele lenses which have
a button on them to NOT focus whenever the button is pressed. Eg., my
70-210 zoom has such a button, and I can press it and inhibit AF as
desired. The intent with this feature is in support of what you wanted,
I think.
   Also, with the 9xi you can switch the camera from AF priority to
"release" priority - this causes the shutter to be released when you
press the shutter release, regardless of whether or not the subject is
in focus - again, when the action is occurring. This feature allows you
to "get" some poor shots while the AF mechanism gets you closer to a
better shot. Is a shot of a whale in poor focus better than no shot at
all? Obviously, that depends on the photographer. This type of feature
allows you to ahve that choice.

Glen Matthews
MUSIC Product Group, McGill University
550 Sherbrooke St. West, Montreal, Quebec, Canada H3A 3C5
Phone: (514) 398-4477 Fax: (514) 398-4488 BitNet: CCGM@MCGILLM
Internet: ccgm@musicm.mcgill.ca   Anonymous FTP: vm.mpg.mcgill.ca
Newsgroups: rec.photo
From: phaf@giraffe.ru.ac.za (MR A FERREIRA)
Subject: Ilford's Fax number ???
Summary: Ilford's UK fax number needed
Keywords: Ilford
Organization: Rhodes University, Grahamstown, South Africa
Date: Fri, 28 Aug 1992 15:46:27 GMT

Greetings all

I am looking for Ilford's U.K. fax number, in particular their customer 
services division.

Thanks 
Andre

-- 
                           Andre Ferreira
        Internet: PHAF@Hippo.ru.ac.za or PHAF@giraffe.ru.ac.za       
     Department of Physics and Electronics_____Rhodes University   
                    Grahamstown____South Africa  
             " Physicists do it with freq until it Hz "

Newsgroups: rec.photo
From: tom@magnus.acs.ohio-state.edu (Tom Easterday)
Subject: multi exposure w/ Nikon6006 and leaving leader out after rewind
Organization: The Ohio State University
Date: Wed, 26 Aug 1992 20:51:58 GMT

Does anyone have advice for taking multiple exposures with the Nikon 6006?
Do you have to rewind the film back and then reload to the frame?  Is there
a way to keep it from advancing?

I saw an add or article in a photo mag recently that said for $20 (i think)
you can send your 6006 (and there were other models/makes) to a place and 
get it reprogrammed to rewind the film but leave the leader out.  Has anyone
had this done?

I have heard that there are FAQ posted here for various topics.  Could 
someone repost (or email me) the Nikon FAQ?

	Thanks,
	    Tom

Newsgroups: rec.photo
From: jpglori@srv.PacBell.COM (John P. Gloria)
Subject: Re: 1 day photo trips from San Jose, CA
Organization: Pacific * Bell
Distribution: na
Date: Thu, 3 Sep 1992 04:56:42 GMT

In article <355@biosys.apldbio.COM> mpc@apldbio.com (Morgan Conrad) writes:
>My favorite, lesser known 1 day trip around San Jose is to head
>up Mt. Hamilton, then continue east and north to Livermore.
>You travel through a lot of empty ranch country.  In the springtime
>it is really beautiful, though February (when robert.m.atkins plans
>to visit) is a bit too early for the fantastic wildflower displays.
>In September, it will be real dry and not as photogenic (to my taste).
>
>I would also suggest Pinnacles, about 1 hour south.  Neat rock
>formations and Vultures.  Again, hot and dry in September,
>lush and green in February.
>
>Basically, there's tons of stuff - the coast, the mountains,
>and the foothills - my two suggestions are in the latter.
>
Not knowing what the requester means by nature it is hard
to name a location.  I often go to San Francisco and shoot
what I consider nature pictures as defined by me.

The Golden Gate Park offers pleny of photo opportunties
for me.  The flower gardens are a haven for me.  There
opportunities for some great macor photography of flowers,
insects and last time I was there (about 2 months ago),
I shot some quail, blue jays and bumble bees, as well as
flowers.

-- 
        ---------  John Gloria - jpglori@pacbell.com	--------	
 		"You cannot depend on your eyes when your imagination
	       is out of focus."   -     Mark Twain
From: rlh32564@uxa.cso.uiuc.edu (Roger L. Hansens)
Newsgroups: rec.photo
Subject: Kodak RA paper?
Summary: kodak RA paper
Keywords: paper kodak
Date: 23 Aug 92 19:35:57 GMT
Organization: University of Illinois at Urbana

What is the difference between Portra, Supra, and Ultra RA paper?

Thanks
Roger
Newsgroups: rec.photo