HDTenEightyP/NetNews huggingface dataset:
From: stettbac@isibee5 (Juerg Stettbacher)
Subject: Re: Polarizing Filters
Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
X-Newsreader: Tin 1.1 PL5
Date: Fri, 4 Sep 1992 11:39:43 GMT

************************************************************

Linear or circular polarization has nothing to do with your
camera type.

Light is an electromagnetic wave, having an electric field
vector and a magnetic field vector. These vectors enclose an
angle of 90 degrees (and 90 degrees to the propagation axis).

  - The linear polarizer cuts off all waves, except the ones of
    the particular orientation. Electric and magnetic field have
    the same phase angle.

  - Light comming through the circular polarizer has the same
    orientation as with the linear filter, but the two field
    vectors do not have the same phase angle. The phase shift is
    90 degrees, so the sum vector seems to turn around the 
    propagation axis.

As far the physical facts (I hope it's true..).
For the effect on photos ask someone else..



juerg at ethz switzerland

**********************************************************
From: bjs@uts.amdahl.com (Barry Sherman)
Newsgroups: rec.photo
Subject: Re: large format, zone system, hat hair and other silliness
Date: 25 Aug 92 23:25:07 GMT
Followup-To: rec.photo
Organization: Amdahl Corporation, Sunnyvale CA

kjm@cnmss.tredydev.unisys.com (Ken J. McFadden) writes how great
single-frame 35mm rolls would be, and says:

|>And you have the added benefit that 35mm doesn't
|>promote hat hair.  8^)

Then feldman@hal9k.cxo.dec.com (james feldman) writes (quite correctly)
why single-frame 35mm rolls would still be vastly inferior to 4x5 film
holders, and says:

>I'll take hat hair any day!

Then Geoff Allen said:

>So, my question:
>
>	What's hat hair?  Do I have it?  Should I be concerned?  Unless
>	it's fatal, I'll probably keep the 4x5 camera.  I'm just
>	wondering what I should be looking for. 
>
>	Thanks to any and all for your help in this obviously serious
>	matter.
>
>:^)
>
>Geoff ``Possible Hat Hair Sufferer'' Allen

Geoff, I think that there's a significant chance that you suffer from
"Hat Hair".  Actually I interpreted it two ways.  1)  The effect of 
having a ring around one's head where a hat has crushed one's hair
down or 2)  The generally mussed up effect that comes from diving
under a focusing cloth, surfacing, diving, surfacing, throwing the 
cloth on the ground in frustration, picking it up again covered with 
twigs and leaves, diving again (thereby transfering massive quantities 
of detritus from the cloth to one's already severely mussed hair as
well as down one's shirtback, etc.).

My SO is so used to it that she doesn't even tell me when my hair
is sticking out in all directions and covered in odd bits of leaves
and twigs.  The effect is, of course, intensified if the hair is 
then crushed under a hat for a few hours in hot sunlight.  Really 
quite embarrassing in polite company ... :-)

Large format may make really sharp pictures but it makes *me* look much 
less than sharp.

Barry

P.s.  No need to thank the rec.photo community for its help.  We're
	  all concerned about matters of such import.  ;-)

-- 


|----------------------------------------------------------------------------|
| Barry Sherman, Amdahl Corp.       | "Any fool can face a crisis - it's     | 
| bjs@ruts.ccc.amdahl.com           |  this day-to-day living that wears you |
|                                   |  out." - Anton Chekhov                 |
|----------------------------------------------------------------------------|
| Amdahl, being a corporation, is a legal fiction.  Therefore it is incapable|
| of holding, let alone expressing, opinions.  Unfortunately, this has been  |
| said of me as well.                                                        |
|----------------------------------------------------------------------------|
Newsgroups: rec.photo
From: stettbac@isibee5 (Juerg Stettbacher)
Subject: What measures the flashlight
Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
X-Newsreader: Tin 1.1 PL5
Date: Fri, 4 Sep 1992 12:06:22 GMT


Hello world

My flashlight (Agfatronic 320 CBS) has a little eye on the front 
side, looking in the flash direction. Next to this window is a 
switch having 3 positions: Black, green and yellow.

On the back side is as usual some kind of a table, showing the 
aperture for a given film type. A green dot marks a fix aperture
and a green line ranges from 1 to 4 meters. The same exist for 
yellow, but the yellow line ranges from 1 to 8 meters.

-----------------------------------------------------------------
meter     1    2    3     4     6     8    10
         
(yellow)-------------------------------
 (green)-------------------           I
                          O           O

aperture       16   11    8    5.6    4    2.8
 
                          v
ASA              25  50  100  200 400
-----------------------------------------------------------------

(The aperture scale can be moved)

If I'm right, I'd say, that with green (and ASA 100) I should set 
an aperture 8 and can so take pictures in the range from 1 to 4
meters.


Now the question: What measures the eye on the front side, light,
distance or something else?


Thanks for help!
juerg at ethz switzerland   
Organization: Masters student, Industrial Administration, Carnegie Mellon, Pittsburgh, PA
Newsgroups: rec.photo
Date: Wed,  2 Sep 1992 15:53:51 -0400 
From: Predeep Menon <pm3l+@andrew.cmu.edu>
Subject: want to lease a slide projector

From: Predeep Kumar Menon (pm3l@andrew)

Hi, 

I'm interested in leasing a slide projector oer a weekend and am willing
to pay reasonable rental rates. If interested, please acknowledge.

Thank You.
From: barryg@hplsla.hp.com (Barry Gunn)
Newsgroups: rec.photo
Subject: Re: Bogus Olympus Add
Date: 29 Aug 92 17:47:57 GMT
Article-I.D.: hplsla.5360789
Organization: HP Lake Stevens, WA

>
>This doesn't bother me a lot with camera advertising - within the same
>general category (e.g. 35mm zoom lenses) there are no differences you're
>going to see in one reproduced picture anyway.
>
>----------
This isn't the same catagory though. The Stylus has a *fixed* 35mm lens.
the picture in question was shot with a 300mmish lens.
While I'm on the topic, I've also seen adds that supposedly compare
side by side pictures (theirs to ours, with or without exp. comp. etc)
where the pictures are printed from the same neg/slide with all the 
"differences" added at the printing stage. the one I remember off
hand is on an old Samsung(?) add (you know, the Pentax IQ105 clone) for 
fuzzy logic.
     _
    [o] Barry Gunn x2281
    /|\ barryg@lsid.hp.com
Newsgroups: rec.photo
From: usenet@adobe.com (USENET NEWS)
Subject: Re: Seek recommendations for 35mm AF camera.
Originator: asanders@sparta
Organization: Adobe Systems Incorporated
Date: Tue, 25 Aug 1992 23:13:00 GMT

| 1) Should I buy a standard 55m lens (f1.4-1.8) or 28-80/3.5? zoom ?
|     a. for a 55m lens, how useful is f1.4 ? Is f1.8 generally enough ?
|	(Considering f1.4 lenses are more expensive)
|     b. If I buy a 28-?? zoom, will f3.5-4.0 be too small for a lot of
|        occasions ?
| 2) How useful is the build-in flash, should I buy another flash.
|
|At the price of around $360, there are CANON EOS-10S, EOS-ELAN, 
| NIKON-6006, Minolta-7000i (3xi is much cheaper). Any comments on these models?

A zoom gives you much more flexibility than a 50mm lens. But a 28-85 Nikon
zoom is much more expensive than a 50mm lens. A more economical choice would
be the 35-70/3.3-4.5 AF Nikkor. There's also a 28-70 AF Nikkor which is
priced somewhere between the 35-70 and 28-85. 

Concerning 50mm lenses, the prevailing wisdom is that 50/1.8 is plenty fast
for most purposes; and the faster 50/1.4 may not be quite as sharp, even
though it costs more than three times as much. Personally, I wouldn't even
consider a 50mm normal lens. I'd go for either a zoom (35-105 is my choice)
or the 60/2.8 AF Micro Nikkor.

It's true that most zooms are relatively slow (f/3.5-4.5 is typical), but
ISO 400 films (especially color print films) are so good today that small
maximum apertures shouldn't be a problem. I do think that f/4-5.6 is getting
TOO slow for a wide-to-moderate-tele zoom, however. Note that some of 
Canon's inexpensive zooms are this slow.

Speaking of Canon, I wouldn't recommend their 28-80 zoom. A much better
lens is the now-discontinued 28-70/3.5-4.5 II. It should still be available
for around $175. Canon's old 35-105/3.5-4.5 (also discontinued) is also a
nice lens. Their new 35-105/4.5-5.6 is too slow!

I like Nikon cameras. They are well-built and easy to operate. And Nikon
lenses are first-rate, even the very inexpensive ones. Canon lenses, most
of them, are also first-rate; but Canon has been adding some fairly marginal
lenses to the bottom of their line recently, and all their lenses feel
kinda flimsy compared to the AF Nikkors. The Canon camera bodies don't
feel too solid either. I wouldn't bet big money on the durability of
their current product line.

That said--in terms of features, Canon probably gives more bang for the
buck than Nikon. But I still prefer Nikon! The N6006 is a very nice camera.
So is the Canon Elan. The camera you like best is the best camera to buy.

Can't comment too much on Minoltas. Their AF lenses may not be quite as
good as comparable Nikon and Canon optics.

				-Alan
Newsgroups: rec.photo
From: mayr@risc.uni-linz.ac.at (Herwig Mayr)
Subject: Photo Trip to TX/NM in Dec.92 -- Weather?
Organization: RISC, J.K. University of Linz, Austria
Date: Fri, 4 Sep 1992 07:55:39 GMT

Hi people in the SW of the US,

the question does not completely fit to the photo.group,
but nevertheless:

I will go for a photo trip to the southwest of the USA
coming December/January (in order to see the fantastic
landscape in a different season -- and to take pictures 
of course). For which temperatures shall I be prepared
in Texas (N/S/E/W), New Mexico, Oklahoma, and Arizona?

Travel guides here state nothing about the weather in winter,
they just say this is ``off-season''. What care should I take
for my camera (batteries, accus, etc.)? Might the (big?)
temperature differences between day and night cause troubles
for my camera?

Since this question is not directly of concern for the newsgroup,
may I suggest you to mail me the answers directly?

Thanx a lot,

Herwig.
(mayr@risc.uni-linz.ac.at)
From: lakhindr@ESD.3Com.COM (Lakhinder Walia)
Newsgroups: rec.photo
Subject: portrait lenses: 35mm-Format.
Keywords: 35mm Nikon Portrait
Date: 1 Sep 92 16:53:31 GMT
Distribution: rec

1. What is generally the range of a portrait lens' focal length..?
   I know 85mm lens is quite suitable for this. How about 105mm or 
   135 mm.? Of course these lenses will work very well for a studio, 
   I think, but going towards 135mm perhaps forces the subject to be 
   too far..! What is your experience in this please..? Would you like
   to use 85mm/105mm/135mm..? 
Thanks
-lakhinder walia
From: ajayshah@almaak.usc.edu (Ajay Shah)
Newsgroups: rec.photo
Subject: Here is some info on Nikon lenses
Date: 2 Sep 1992 16:02:37 -0700
Organization: University of Southern California, Los Angeles, CA
NNTP-Posting-Host: almaak.usc.edu

I asked them on the phone a short while ago:

                                     B&H price
14b   1.4x   for > 300mm               $400
14a   ditto  for < 300mm               $191 

301   2x     for > 300mm               $395
201   2x     for < 300mm               $205

Do you know what lenses the sigma 1.4x works well with?
Is it a good idea with the Sigma 400 mm?

        -ans.
-- 
Ajay Shah, (213)749-8133, ajayshah@usc.edu
Newsgroups: rec.photo
From: cjk4800@ritvax.isc.rit.edu (Ludwig van Halen Rocks RIoT)
Subject: Re: Film questions?(Kodak Safety film 5063)
Reply-To: cjk4800@ritvax.isc.rit.edu
Organization: Rochester Institute of Technology
Distribution: usa
Date: Tue, 25 Aug 1992 20:49:36 GMT

In article <1992Aug23.154821.8976@wam.umd.edu>, dhong@wam.umd.edu (Sze Yuen Hong) writes:
>
>  I've got a used Bulk film loader in a couples of weeks ago. It has some film 
>loaded already. After I shoot and process the film, it's appear to be KODAK
>SAFETY FILM 5063. Did anyone have the data of this film? Thanks in advance!
>
>David


KODAK SAFETY FILM 5063 is KODAK Tri-X Pan Black and White negative film.  It is
rated for amateur use at 400.  If you need the EI/Development Times recommended
for a particular developer, mail me.

Chris 


+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+Christopher J Kohanek          \\         CJK4800@RITVAX.isc.rit.edu 	      +
+Photo Systems Management        \\ 199 Golden Rod Lane; Rochester, NY 14623  +
+Rochester Institute of Technology \\% Eastman Kodak, Rochester, NY 14650-1202+
+        Disclaimer:  If my employers have opinions, it's news to me          +
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Newsgroups: rec.photo
From: usenet@adobe.com (USENET NEWS)
Subject: Re: What lens to get for EOS Elan?
Originator: asanders@sparta
Organization: Adobe Systems Incorporated
Date: Tue, 1 Sep 1992 18:50:44 GMT

In article <TJWU.92Sep1134138@e40-008-10.mit.edu> tjwu@athena.mit.edu (Thomas J Wu) writes:
>
>  I'm trying to decide among the following lenses for an EOS Elan:
>
>- Canon 35-80mm f/4-5.6 USM (fast, quiet), ~$150
>- Canon 35-80mm f/4-5.6 EF, ~$85
>- Sigma 35-80mm f/4-5.6, ~$70
>- Sigma 35-135mm f/3.5-4.5, ~$130
>
>Does anybody have any positive and/or negative experiences with these
>lenses?  Are these prices reasonable?  Either e-mail or post is okay.
>Thanks.
>
>  Thomas Wu
>  Internet:  tjwu@athena.mit.edu


The Canon 35-80 EF is an all-plastic dog, not worthy of the Elan.
The 35-80 USM is slow for its zoom range and not as good a lens
as the now-discontinued (but still available) 28-80/3.5-4.5 II,
which should cost about $175. Can't say much about the Sigma
lenses except that I wouldn't put ANY $75 zoom lens on a nice
camera like the Elan!

This reminds me once again: why do people put cheap lenses on
good cameras? You get much better results putting good lenses
on cheap cameras!
			-Alan
From: jacobson@cello.hpl.hp.com (David Jacobson)
Newsgroups: rec.photo
Subject: meter testing and lens flare (Pop Photo)
Date: 29 Aug 92 05:00:36 GMT
Distribution: usa
Organization: Hewlett-Packard Laboratories


I was looking through the September Popular Photography and saw what
seem to be at least 2 errors.  I want to bounce this off the wisdom of
rec.photo to see if the net agrees.

First, on page 46 there is a piece on checking your camera's meter.
The procedure described is to shoot a series of transparencies of an
18% grey card while bracketing the exposure, nominally by overriding
the ISO setting.  "When you've gotten the transparencies back, compare
the images to your gray card subject.  Determine which frame most
closely matches the gray card.  This is the ISO at which you should be
shooting that film and, probably, all films of that speed."

Is it true that ISO is defined such that a subject of uniform
brightness will come out 18% transmission?  (The statement I just wrote
assumed that the transparencies were viewed against a white card or
paper of 100% reflectance that was in the same light as the gray card.
The viewing conditions obviously make a big difference.  Laying the
transparencies directly on a white piece of paper so that light went
through twice would yield a transmission of 42%  (sqrt(.18)=.42.)

Second, on page 51 there is a discussion of lens testing.  It says "To
check flare, shoot a scene having a small, brightly lit, white or
reflective subject.  A white index card or sunlit reflections in an
automobile hood or fender will do fine.  Shoot at all apertures to
determine at what lens opening the bright card or reflection seems to
blur; the blur should go away at smaller apertures.  This will
indicate how far you should stoop you lens down to minimize flare."
The accompanying pictures show a parked car.  One frame, taken with a
50mm lens at f/1.7 is noticeably blurry all over.  The second frame,
taken at f/8 is quite a bit sharper all over.  (These two frames show
just the window area.  A third frame shows almost the entire car,
implying that the two frames in question were about a 4x enlargement of
the window area detail.)  Also the washed out area from the sun's
reflection in the f/1.7 one is larger.

Does this make any sense.  I thought flare was manifest by two things.
First ghosts of a bright object or images of the diaphragm.  And
secondly, a general reduction in shadow detail caused by light
scattering into it.  This is purporting that flare reduces the
sharpness of highlights.  That doesn't make sense to me.  

Also I think I can explain the larger washed out area phenomenon.  The
reflection is off the gently curved rear passenger window of a car.
The sun's reflection is really bright and if any of it passes through
the diaphragm, the image in the direction it coming from will be
completely washed out.  With a larger diaphragm, a larger range of
positions on the curved glass can cause light to get into get into the
lens, and hence a larger washed out area.

What do you all think?

  -- David Jacobson
Newsgroups: rec.photo
From: drraymon@watdragon.uwaterloo.ca (Darrell Raymond)
Subject: Re: T-Max films
Organization: University of Waterloo
Date: Sun, 30 Aug 1992 19:22:01 GMT

In article <30AUG92.10127537.0029@UNBVM1.CSD.UNB.CA>, Myron Gochnauer <GOCH@UNB.CA> writes:
> I seem to have missed the beginning of a discussion on T-Max films, but
> here's my 2 cents worth:
> 
> I, too, think the films are touchy, but in my opinion the results are
> worth the extra care. The major problem I had is with agitation. I get
> 'surge marks' on the first few frames when I use stainless steel reels.
> I switched to Paterson tanks and reels, and that solved the problem. I
> use 5 inversions on the minute and 5 'twists' on the half minute. Next,
> I always pre-soak in plain water for one minute (timed) before
> developing. Needless to say, I have to be very careful with temperatures

  For those who might be interested: I've been developing T-Max 100 and 
400 in Diafine, using a stainless steel tank, agitating by inversion on 
the half-minute, and getting very good results.  Diafine is a two-bath 
developer that is insensitive to time and temperature; anything around 
65-70 F and 3 to 4 minutes in each bath gives good results.  I find T-Max 
in Diafine to be no more touchy than Tri-X, development is even, the 
grain is nice, and you get a compensating effect that helps if you've 
overexposed.  Diafine is a lot cheaper than T-Max developer, too.

-Darrell.
From: sr36+@andrew.cmu.edu (Stephan A. Roth)
Newsgroups: rec.photo
Subject: Re: Seeking advice on solarization.
Date: 2 Sep 92 15:50:39 GMT
Organization: Junior, Physics, Carnegie Mellon, Pittsburgh, PA


	A technique that I have found to work well is to start with
a b.w. negative which is of fairly high contrast (mostly black
 and white with little grey.)  I then develop the picture on Kodak
Polycontrast FM paper in dektol.  I wait for the image on the paper
to be mostly developed, that is I can make out the image on the
paper, and I flip the light in my darkroom on and off.  Wait till
the paper fully develops (it may look black, but that's usually o.k.)
and then procede onto the stop bath and fixer.


-----------------------------------------
Stephan Roth: 	
	Life is hell, but so is death.
	You just can't win.
----------------------------------------
From: jay@metran.UUCP (Jay Ts)
Newsgroups: rec.photo
Subject: Silver Recovery
Date: 30 Aug 92 08:12:59 GMT
Organization: Metran Technology, Tampa, Florida


I recently purchased a Berg Silver-Saver kit, which is for recovery of
silver from used fixer and blix solutions.  When I got home and opened
the package, I was disappointed to find that it is necessary to get the
fixer/blix solution to pH 5.5 before adding the solution from the kit.
For this, pH paper, 28% acetic acid and Sodium Carbonate, which are not
included in the kit, are required.  As it happens, I have the chemicals,
but not the pH paper, and I don't know where to get pH paper locally.

It happens that the acetic acid I have is Kodak Indicator Stop Bath.
Is by any chance the indicator crossover color anywhere near pH 5.5?

I am now wondering if there is an easier way to perform silver recovery.

Someone on the net must have a method they can recommend, right?

Jay Ts
From: axman@acadia.Kodak.COM (Mike Axman)
Newsgroups: rec.photo
Subject: Re: Time to boycott Photo CD
Date: 28 Aug 92 14:57:50 GMT
Organization: Eastman Kodak Co., Rochester, NY

In article <4890@balrog.ctron.com>, smith@ctron.com (Larry Smith) writes:
>In article <1992Aug27.142714.12321@edscom.demon.co.uk>, rpt@edscom.demon.co.uk (Richard Tomlinson) writes:
>
>>I agree with the sentiments, but isn't Kodak going for a totally different
>>market? They are aiming at ordinary consumers who take snapshots and not PC
>>users who want to use the images for DTP or whatever.
>
 They are aiming at both.  The consumer market is not expected to flourish 
overnight in this economy, and commercial/professional/industrial applications
are already developing quickly.  They will hopefully force prices lower for 
consumer applications.

>>Personally, I can't see the attraction of having pictures on the telly.
>
>Apparently you've never taken a picture of something you wanted scanned
>into a computer, Richard.  This could be the cheapest method yet devised
>for entering images into hypertext documents, icons, or what-have-you,
>but because Kodak can get patents on this stuff, and because they don't
>percieve such a market to be lucrative enough for Great Yellow Father
>to address, it will die before it is ever born.  A classic example of
>why such patents are more than just evil, they are stupid and counter-
>productive.
>

I won't comment on the usefulness of patents, since it's a reality we
have to deal with.  Patents are not just a protection of intellectual 
property, but a bargaining chip to be treated "just like cash" in the 
industrial R&D world.  If U.S. companies don't accept this truth, then 
there won't be many U.S. companies remaining in the year 2000.

As far as the rest of your comments, you couldn't be more wrong :-)
First, most of the applications you've cited don't even require the high
resolution (compressed) data, and people have already posted info on 
"how to read" the BASE res on down.
Second, there are about a 1/2 dozen software companies who would disagree 
with your somewhat pessimistic view of Photo CD availability in these markets.

I'm willing to put my money where my mouth is with regard to where Photo CD 
will be in 5 years.  Is there anyone out there ready to make a wager? :-))

 
- 
Mike Axman  
CD-Imaging Advanced Development
Eastman Kodak Company
axman@acadia.kodak.com



DISCLAIMER:
Kodak gives me this Net access for free, but they aren't responsible for my postings.
Newsgroups: rec.photo
From: jpglori@srv.PacBell.COM (John P. Gloria)
Subject: Re: want to lease a slide projector
Organization: Pacific * Bell
Date: Thu, 3 Sep 1992 04:38:03 GMT

In article <gedFjDW00UhB03vq1d@andrew.cmu.edu> pm3l+@andrew.cmu.edu (Predeep Menon) writes:
>From: Predeep Kumar Menon (pm3l@andrew)
>
>Hi, 
>
>I'm interested in leasing a slide projector oer a weekend and am willing
>to pay reasonable rental rates. If interested, please acknowledge.
>
>Thank You.
I believe some of the better equipped photo stores rent out
slide projectors.  Use the "Yellow Pages" for your area.

-- 
        ---------  John Gloria - jpglori@pacbell.com	--------	
 		"You cannot depend on your eyes when your imagination
	       is out of focus."   -     Mark Twain