HDTenEightyP/NetNews huggingface dataset:
From: panos@burton.cs.colorado.edu (Panos Tsirigotis)
Newsgroups: rec.photo
Subject: depth of field question
Date: 6 Jan 93 18:26:50 GMT
Organization: University of Colorado, Boulder

As we all know, most lenses have a depth-of-field scale so that one can
estimate the parts of the image that will appear sharp in the picture.
However, whether a picture is sharp enough or not also depends on how
much it is enlarged.  So, I was wondering how does one know the size of
enlargement that the DOF is set for ?

Panos

-- 
Panos Tsirigotis, CS grad                        
Pmail: Computer Science Dept., U. of Colorado @ Boulder, Boulder, CO 80309-0430
Email: panos@cs.colorado.edu
Newsgroups: rec.photo
From: robert@sys.sweden.dg.com (Robert Claeson)
Subject: Re: T-MAX fogged by x-ray machines??
Date: Tue, 12 Jan 1993 13:54:58 GMT
Organization: Data General AB, Akalla, Sweden

In article <1993Jan6.013013.25176@src.dec.com>, jcollias@src.dec.com writes:

> Like an idiot, I let my camera with T-MAX 400 go through the airport baggage
> scanner not once, not twice, but three times.  Ouch.  The first time my friend
> put the bag on the belt before I realized it, the second time my brain was
> severely out to lunch, and then the security guy sent it through again because
> something looked like a bomb I guess.  Then my brain woke up.  Oh well.
> 
> I haven't processed the roll yet, but should I expect to see much more than fuzzy
> cloud-like images of my christmas vacation?  

Where was this? On a longer trip, I had a bag with many ISO 400, 800 and
1600 films sent through the X-ray machine not three, but eleven times.
I couldn't notice any fogging at all. This was completely within Europe,
though. X-ray machines may have higher radiation levels where you live.

-- 
--------------------- This mass of gibberish came from ---------------------
         ____
        |    |               Robert Claeson
        |    |               Data General AB
 _______|____|_              Box 28
|    |    _    |_____        S-164 93 KISTA
|_/\ |   / \   |     |       Sweden
| \/ |   \_/   |   . |
|    |    |    |_____|       robert@sys.sweden.dg.com
|____|_________|-
Newsgroups: rec.photo
From: PXY@ECLX.PSU.EDU (Pen-Li Yen)
Subject: For Sale: Excellent Screw Mount Pentax 35mm SLR
Organization: Penn State Engineering Computer Lab
Distribution: usa
Date: Fri, 08 Jan 93 00:57:43 GMT
X-News-Reader: VMS NEWS 1.24

The following items would like to sell as a whole set for Pentax
screw mount collectors.  I will consider to sell them separately if the
price is reasonable.  Almost all of them in mint condition w/original
caps.

1. Pentax Spotmatic body w/Pentax flash attachment; sn# 296390X
2. 50mm Pentax super-takumar 1.4 w/skylight & metallic pentax cap
	sn#380558X
3. 20mm 3.8 Auto Vivitar fisheye w/vivitar metallic cap
	sn#2200372X
4. 35mm 2.8 Auto Vivitar wideangle w/vivitar metallic cap
	sn#2200131X
5. 35-85mm 2.8 Vivitar series 1 w/72mm UV filter & cap
	sn#2250306X
6. 85-205mm 3.8 Auto Vivitar Tele-Zoom w/skylight & metallic vivitar cap
	sn#2200275X
7. 3X Vivitar auto custom teleconverter w/f stop measurment & original case
8. Vivitar 272 auto thyristor flash w/ wide angle diffusion screen,
	90degree vertical, w/external syn. cord; w/external power supply
	socket.  sn# 412252X

Serious collector only.

All of above are screw mount.

Asking $800

Yuesea
Newsgroups: rec.photo
From: ari@kolmogorov.physics.uiuc.edu (Aritomo Shinozaki)
Subject: Model Releases (re:Photographing people...)
Summary: model releases for photographs
Organization: University of Illinois at Urbana
Date: Fri, 8 Jan 1993 01:41:24 GMT
Keywords: model releases

Can anyone post a reasonable wording etc. for a model release?

Ari


--

Aritomo Shinozaki				ari@kolmogorov.physics.uiuc.edu
Beckman Institute				(217)-244-5286
University of Illinois, Urbana-Champaign
Urbana IL, 61801
     
Newsgroups: rec.photo
From: jacobson@cello.hpl.hp.com (David Jacobson)
Subject: Re: Sample model release:
Date: Fri, 8 Jan 1993 18:23:35 GMT
Organization: Hewlett-Packard Laboratories

In article <C0JovH.E9F@news.ucs.mun.ca> hamm@weejordy.physics.mun.ca
(Craig Hamm (Evil Spock)) displays a sample model release.  It contains
the clause
>	I hereby release and discharge the above, its assigns, and all
>	persons acting under its permission or authority or those for 
>	whom it is acting, from and against any liability as a result 
>	of any distortion, blurring, alteration, or optical illusion
                                     ^^^^^^^^^^
>	that may occur in the taking of the picture, or processing or
>	reproduction of the finished product.

If somebody wanted me to sign a release with the "alteration" clause,
I'd refuse.  There is just too much possibility for abuse, especially
since a previous clause (I didn't include it above) waives the right
to pre-publication approval.

  -- David Jacobson
From: robert@sys.sweden.dg.com (Robert Claeson)
Newsgroups: rec.photo
Subject: Re: Canon 10s Vs Nikon N90, Which one?
Date: 7 Jan 93 09:26:45 GMT
Organization: Data General AB, Akalla, Sweden

In article <1992Dec22.151322.21013@cbnewsj.cb.att.com>, rdb1@cbnewsj.cb.att.com (ronald.j.deblock..jr) writes:

> Nikon and Pentax put the motors in the lenses long before Canon did.
> This was back in the early '80s, with the Nikon F3AF and Pentax MEF.
> Both companis made a big mistake by also putting the batteries in the lenses.
> Adding 4 AA cells to a lens makes it very heavy, and the whole system becomes
> unbalanced (difficult to handle).

As I remember it, Canon had their FD 35-70mm autofocus lens out by then...

-- 
--------------------- This mass of gibberish came from ---------------------
         ____
        |    |               Robert Claeson
        |    |               Data General AB
 _______|____|_              Box 28
|    |    _    |_____        S-164 93 KISTA
|_/\ |   / \   |     |       Sweden
| \/ |   \_/   |   . |
|    |    |    |_____|       robert@sys.sweden.dg.com
|____|_________|-
From: jacobson@cello.hpl.hp.com (David Jacobson)
Subject: Re: f length equivalent to human eye???
Date: Mon, 11 Jan 1993 17:59:01 GMT
Organization: Hewlett-Packard Laboratories

In article <robinson.96@odie.ee.wits.ac.za> robinson@odie.ee.wits.ac.za (Michael Robinson) writes:
>Hi all,
>
>Happy new year.
>
>I have been thinking about the issue of what focal length is equivalent to 
>that of the human eye.  Most books say 50mm is the closes ito either angle 
>of view or perspective.  I accepted this as given until I came across an 
>article in a local magazine saying 105mm is the closest to the human eye.  
>This I did not believe but went out with my 35-80 zoom lens and, looking at 
>the moon, adjusted the zoom so that the moon through the lens was the same 
>size as the moon as seen by my left eye.  This gave a focal length of about 
>70mm.  Since eyepiece has a magnification of 0.8x I adjusted for this giving 
>56mm.  Is this accurate?  Is there a better way to do things?

You won't find the answer to your question by this kind of experiment.
The size will remain unchanged when the focal length of the lens
equals the focal length of the eyepiece.  So the question then becomes
"why are eyepieces about 50mm in focal length?".  The answer is
undoubtedly a combination of "that's considered the 'normal' focal
length" (so you've got a circularity) and its easiest to build.

Actually, I don't think there is a good answer.  We as humans look at
things in multiple ways.  If I go out to a sweeping panorama, like
Grand Canyon, as ask myself "how much do I see at one time?", its
quite a bit.  For this purpose something around 24 or 28 mm might
cover it.  If I'm looking for very close detail, I can resolve about 1
minute of arc; perhaps 300 mm gives the same impression.  (This is
just a guess.)  Historically, a focal length about the diagonal of the
film has been *called* normal, but its just a convention.

  -- David Jacobson
From: jay@metran.UUCP (Jay Ts)
Newsgroups: rec.photo
Subject: Re: Kodachrome longevity
Date: 8 Jan 93 17:45:28 GMT
Organization: Metran Technology, Tampa, Florida

ianchan@leland.Stanford.EDU (Ian Hin Yun Chan) writes:
: I understand that Kodachrome is less stable when exposed to light (ie when
: projected) than Ektachrome. Does anyone have any figures about how much
: Kodachrome can be projected before degeneration occurs?

Yes, Kodak does.  You can call them at 1-800-242-2424 and ask about
Kodachrome image stability data.

When exposed to projection-intensity light, any color film will undergo
dye fading immediately.  It's just that different films have different
rates of fading.  Kodachrome fades much more quickly under projection than
Ektachrome.  You may notice a difference after just a few hours.  If you
leave the slide projected for many hours, do not be surprised to have
ruined it.
-- 
Jay Ts
uucp mail: uunet!myrddin!tscs!metran!jay
phone: (813) 979-9169
Newsgroups: rec.photo
From: 871323o@dragon.acadiau.ca (Oliver Oey)
Subject: Re: F2AS --> F2A
Organization: Acadia University
Date: Wed, 13 Jan 1993 02:30:19 GMT

phg+@CS.CMU.EDU (Paul Gleichauf) writes:

>The F2AS has a solid state meter using a pair (fairly high drain) LED
>arrows to indicate exposure in a rather binary manner.  This means that 
>the display was not capable of indicating the amount of under and over
>exposure, but since one adjusted exposure manually there was tactile 
>feedback.  The standard galvanometer based meter movement on all the 
>Phototonic bodies (F and F2) suffered from a relative fragility and
>aging trouble.  The solid state F2AS series was very rugged.
>There were two variations of the F2AS (I believe the second had the
>first provisions for AI-S style lenses, but I only owned the first
>version).
>							Paul

Would anyone care to comment on the F2A?
-- 
Oliver Oey                              email: oliver.oey@acadiau.ca
Jodrey School of Computer Science
Acadia University
Wolfville, Nova Scotia, Canada
Newsgroups: rec.photo
From: panlilio@acs.ucalgary.ca (Victor P. Panlilio)
Subject: Re: Mac, of course (Was Re: IBM vs. Mac for stock business)
Summary: In which we get off tangent once again
Date: Sun, 10 Jan 93 21:07:23 GMT
Expires: Sun, 31 Jan 1993 05:00:00 GMT
Distribution: na
Organization: The University of Calgary, Alberta
Keywords: image manipulation
Followup-To: rec.photo

In article <1in3dfINN678@castor.hahnemann.edu> weinhous@castor.hahnemann.edu (Martin S. Weinhous Ph.D.) writes:
>
>In my environment, a Silicon Graphics Iris 4D340VGX and a DECStation 5000/240
>PGX+ are both serving as servers for a flock of Macs (via NFS and either

Ahem. I am familiar with the power of SGI hardware, especially
since I make it a point to board SGI's Magic Bus everytime it
makes its annual visit to our campus (and last time I saw the
SGI Reality Engine). The point of the original discussion was,
though, which PERSONAL computer platform would serve the needs of
a photographer who was planning to run her own stock photography
business, and I suggested that if she could only afford only ONE
computer ($3000) to run ALL aspects of her business, then the Mac
would probably be her best choice, since she's inexperienced in
dealing with computers. 486DX2 PC's with local-bus video running
Win3.1 are still too much hassle to deal with, and they're cheap
only when you choose to ignore the lost productivity and time in
dealing with the idiosyncrasies of an architecture in which the
role of graphics has always been an afterthought, or an add-on.

Victor 8^)
From: dcl@iago.caltech.edu (Darek Lis)
Newsgroups: rec.photo
Subject: 430EZ question
Date: 8 Jan 1993 14:04 PDT
Organization: California Institute of Technology
Distribution: world
NNTP-Posting-Host: iago.caltech.edu
News-Software: VAX/VMS VNEWS 1.41    

I've just bought a Speedlite 430EZ for my Elan and I'd like to find out if 
this combo provides a way to determine whether the object is within the 
flash range. I know that exposure warnings in the viewfinder don't work 
with the new EOS cameras (Elan, 10S etc.) However, I vaguely remember 
reading in this news group that it is possible to determine whether the 
object was within the flash range after the picture is taken. Is that right 
or am I just dreaming?

Thanks in advance,

Darek Lis
Newsgroups: rec.photo
From: ka1gt@cbnewsm.cb.att.com (robert.m.atkins)
Subject: Re: depth of field question
Organization: AT&T
Distribution: na
Date: Thu, 7 Jan 1993 23:34:26 GMT

In article <1993Jan6.182650.5972@colorado.edu>, panos@burton.cs.colorado.edu (Panos Tsirigotis) writes:
> As we all know, most lenses have a depth-of-field scale so that one can
> estimate the parts of the image that will appear sharp in the picture.
> However, whether a picture is sharp enough or not also depends on how
> much it is enlarged.  So, I was wondering how does one know the size of
> enlargement that the DOF is set for ?
> 
> Panos

I won't comment on the mathematics of DOF calculations (I'll leave that
for David), but there are a few things about DOF I will comment on.

First there is no depth of field. A lens forms an image of a plane (object
plane) in a second plane (image plane). Only objects located in the first
plane will be in focus in the second.

Depth of field is really related to the limits of acceptable sharpness.
This is highly subjective. Not only does it depend on the degree of
enlargement, but also the distance at which the enlargement is viewed,
the eyesight of the viewer, the viewer's standards of "sharp", and even
the nature of the subject (portraits are often acceptable at lower sharpness
than landscapes, for example).

The "depth of field" markings which (used to) appear on lenses are based
on fairly low standards of "sharpness". To quote from a paper by Biedermann
and Feng (SPIE vol. 549, p36-43) "Depth of focus scales are based on obsolete
and unsuitable criterion and deserve revision on a level of sophistication
matching that of today's lens and camera design"

Traditionaly, the blur circle diamter used for 35mm work is 0.03mm. That
implies a maximum resolution of about 30 lp/mm in the image. Assuming the
eye can resolve about 10 lp/mm at it's closest focusing distance (say
about 1 foot), then 3x5 is the maximum degree of enlargement you can get
that still looks critically sharp. For a critically sharp 8x10, you would
need 80 lp/mm, which is about the limit of most film/lens combinations
in perfect focus - i.e. there is no depth of acceptable focus.

Of course if you stand further away from the print, you can get away with
lower resolution, because the eye can no longer see the fine detail. That
is the only reason why 30x40 prints are "acceptable" - no-one looks at them
from a distance of 1 foot! The same applies to projected slides.

===============================================================
Bob Atkins  AT&T Bell Labs  email (direct)  att!clockwise!rma
===============================================================
From: jmw@random.asd.sgi.com (Jim Winget)
Newsgroups: rec.photo
Subject: Looking for Telephoto Flash Outfit (300mm+)
Date: 6 Jan 1993 22:35:59 GMT
Organization: sgi
Distribution: world
NNTP-Posting-Host: random.asd.sgi.com
Keywords: telephot, flash, howto


I'm trying to put together a flash "extender" for use with 300mm+
telephotos. Currently I use a Canon EOS camera with the 420EZ flash.
What I'm looking for is a "how to" article for building a flash +
fresnel (sp?) lens projection system to focus the flash out where it will
do the most good (420EZ has a 80mm min coverage). I thought I'd seen
an article in popular/modern/outdoor photography, but after hours of
searching back issues all I could find was a stock shot of George Lepp
holding a camera equipted in the manner I've discribed (ie page 16 of
November '89 Outdoor Photography).

Does anybody know the reference article that describes building/buying
this equiptment? I think there is also a parabolic mirror dedicated
flash unit available from Norman (?). I'd prefer the reuse and lower
cost of just adding a concentrator lens to my 420EZ but I'm open to
suggestions.

Thanks,
Jim
---
James M. Winget				Voice: (415) 390-3654
Silicon Graphics, Inc.			Email: jmw@sgi.com
Research & Development, 7U-005		FAX:   (415) 965-7651
2011 N. Shoreline Blvd			
Mountain View, CA 94039-7311
From: rickh@ems.cdc.com (Richard Herwig)
Newsgroups: rec.photo
Subject: Tripod question?
Date: 7 Jan 93 20:39:28 GMT
Organization: Empros Systems International, a division of CDC

Im going to buy a SLIK 444.  Ive picked this one because its fairly
light-weight (I do a lot of backpacking) and it is capable of raising
my 35mm camera to my eye-level (5-8).

Any comments, suggestions, flames will be greatly appreciated!

-- 
                Richard F. Herwig  -  email: rickh@ems.cdc.com 
-------------------------------------------------------------------------------

I came, I saw, I took a nap.
From: ewright@convex.com (Edward V. Wright)
Subject: Re: Mac, of course (Was Re: IBM vs. Mac for stock business)
Date: Mon, 11 Jan 1993 19:36:49 GMT
Distribution: na
Organization: Engineering, CONVEX Computer Corp., Richardson, Tx., USA
Keywords: image manipulation
X-Disclaimer: This message was written by a user at CONVEX Computer
              Corp. The opinions expressed are those of the user and
              not necessarily those of CONVEX.

Victor P. Panlilio writes:
>Glen Porter writes:

>>software market has turned to only writting such programs for MACs, but only 
>>because of the generally computer illiterate photography market.

>Now, now, insulting us photographers, are you? Fine, go ahead,
>accuse us of being computer-illiterate and see where it gets you.

Yeah, Mac users are bunch of bozos who only want to use their
computers for productive work instead of spending all their
time futzing with CONFIG.AUTOEXEC.SYS.BAT.INI's like *real*
computer users. :-)


>Photoshop 2.5 is now announced for Win3.1, but it appeared on the
>Mac first. Just like Adobe Illustrator bowed in 1986, and took a
>long time before it was ported to Windows. For very good reasons.

One of the PC magazines (PC World? -- I can never keep them straight)
had an issue last fall that compared the PC to Macs, UNIX, etc.  One
of the things they said about the Mac -- and remember, this was written
by a PC magazine -- was that Macintosh has had, and continues to have,
about an 18-month lead in the development of high-end graphics software.
From: b1hg0jv@kato.BELL-ATL.COM (Benash)
Newsgroups: rec.photo
Subject: Tokina Zooms Forsale
Summary: 100-300, 2x Conv, 28-85 Olympus Mount
Keywords: $150 Firm
Date: 11 Jan 93 16:11:29 GMT
Organization: Bell Atlantic

All Tokina Olympus OM Mount:


SZ10	100-300 f/5.6 One-Touch Zoom
	15 Elements 9 Groups
	Aperture Range 5.6 - 32
	Filter Size	55mm
	Max. Diameter x Length	64.5 x 163mm
	Weight	650g
	Includes: Polarzier, Factory Case, Factory Acces. Hood

2X Converter
	
	Matching for Lense above
	Includes Factory Case

SZ85	28-85 f/4 Two-Touch (Constant Focus) Zoom
	16 Elements 9 Groups
	Aperture Range 4 - 16
	Filter Size	72mm
	Length x Diameter	92 x 75mm
	Weight	580g
	Includes: Polarizer, Factory Case, Factory Acces. Hood

All are in Mint condition.
$150 for all Including UPS-COD
Price is Firm

Ray Benash
b1hg0jv@kato.bell-atl.com
215-466-6828
Newsgroups: rec.photo
From: bryon@telly.on.ca (Bryon Johnson)
Subject: Re: Spotone experience out there?
Organization: Somewhere just far enough out of Toronto
Date: Mon, 11 Jan 1993 05:15:51 GMT

In article <1993Jan10.233419.1034@netcom.com> hamish@netcom.com (Just Another Deckchair on the Titanic) writes:
>I've just spent an agonising few days trying to spot a variety of
>following papers:
>
>	Ilford Multigrade III Fibre, Glossy
>	Ilford Galerie, Glossy
>	Oriental Graded, Glossy (i.e. the "Oriental G3", etc. stuff)
>	Agfa Insignia, glossy.
>
>Hamish Reid   +1 510 596-3917   hamish@netcom.com   hamish@sybase.com

A few years ago, I obtained a pamphlet froma a dealer in Toronto on the
Spotone mixes for various papers.

The mixes for the papers you've requested are as follows:

Ilford Galerie - 10 drops of #3 plus 1 drop of #1
Oriental Seagull - 5 drops of #3 plus 18 drops of #1 plus 5 drops of #2

I don't seem to have a mix for Agfa Insignia.

You might want to write to the Spotone manufacturers at 
Retouch Methods Co. Inc.
Chatham, NJ  07928
to get a copy of this pamphlet.  The address I've given you is the one I have
from 1985 - they might have moved since then.




-- 
Bryon Johnson
Bryon Johnson Photography
Brampton, Ontario, Canada
bryon@telly.on.ca
From: otto@meaddata.com (Otto Burgess)
Newsgroups: rec.photo
Subject: 2-1/4 x 3-1/4 processing help!
Date: 8 Jan 1993 16:20:35 GMT
Organization: Mead Data Central, Dayton OH
Distribution: usa
NNTP-Posting-Host: mayberry.meaddata.com

Does anyone out there know of a good mail order place
to get 6x9 negatives processed and 3-1/2 x 5 or
4 x 6 profs done?  I would like to get the new
Fuji GS690III cameras, but can not find a local
lab to process my color negs. Please E-mail if
you please.  Thanks, in advance for any replys.

-- 
|Otto Burgess
|(513) 865 - 1024    
|Mead Data Central   
|P.O. Box 933        
|Dayton, Ohio  45401 
| 
|otto@meaddata.com
From: bu890@cleveland.Freenet.Edu (Brian Segal)
Newsgroups: rec.photo
Subject: Re: Hasselblad "C" vs "CF" lenses
Date: 7 Jan 1993 13:29:03 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
NNTP-Posting-Host: hela.ins.cwru.edu


According to The Hasselblad Manusl, Wildi says that you can use a C lens with a
2000 series (focal plane shutter) camera. The diference is that the CF lenses
have a special setting that, when engaged, keeps the lens open and allows you
to use the mirror control system.

brian
Newsgroups: rec.photo
From: zrepachol@cc.curtin.edu.au
Subject: Re: Shirt Pocket Cameras
Followup-To: rec.photo
Organization: Curtin University of Technology
Date: Tue, 12 Jan 1993 14:32:00 GMT

In article <5ejW02=g31zB01@JUTS.ccc.amdahl.com>, bjs@RUTS.ccc.amdahl.com (Barry Sherman) writes:
> Peter Davidoff writes:
> 
>>Recently I read an article about a 19th century vogue:  cameras in a hat.
...
> Oh no!  First we had to worry about the dreaded "hat hair".  Then there was
> "camera hair" from ducking under the focusing cloth.  Now we have to 
> worry about "hat-camera hair".  :-)  What's next?
> 

Well, I could mention the Nazi SS 'camera-in-the-belt-buckle', but you might
gross out, so I will refrain. :-) :-)

~Paul

Newsgroups: rec.photo