HDTenEightyP/NetNews huggingface dataset:
From: nyarko@ee.ualberta.ca (David Nyarko)
Subject: IR circuit less prone to ambient light
Organization: University Of Alberta, Edmonton Canada
Distribution: na
Date: Fri, 6 Nov 1992 17:59:18 GMT


Hi,
Could I have help (circuit diagrams etc.) for an Infra-Red
(IR) transmitter/receiver with a low tolerance to ambient
light. What I have in mind is the design of an obstacle
avoidance circuit. Sort of similar to the IR system used
in autofocusing cameras without the circuitry for
computing the distance.
			David

email address: nyarko@bode.ee.ualberta.ca
From: sog@craycos.com (Steve Gombosi)
Newsgroups: rec.photo
Subject: Re: Sharpness
Keywords: Sharp
Date: 5 Nov 92 20:14:36 GMT
Organization: Cray Computer Corporation

In article <1992Nov5.023325.20009@cs.mun.ca> michael9@cs.mun.ca (Michael Sullivan) writes:
>
>  This isn't exactly in the FAQ, so I hope someone can help me out.
>
>  The problem is, my pictures aren't coming out as sharp as I would like.
>Is the sharpness of a photo strictly a function of lense quality?  Or am
>I not doing something quite right?
>
>  I'm using a Pratika 35mm MTL-5 SLR, with a Tamron 70-210 f3.8, the exact
>model number I am not sure of.
>

There are *lots* of variables involved, unfortunately.

1) Lens sharpness (perceived sharpness is a function of both resolution
   *and* contrast). Keep the sucker *clean*, too.

2) Film flatness. If the film doesn't lie precisely in the plane of focus,
   it doesn't matter *how* good your lens is.

3) Focusing accuracy. Inaccurate focusing can be caused by "human factors"
   (poor eyesight, for example) or by mechanical deficiencies in the camera.
   If the lens to focusing screen path length isn't precisely the same as the
   lens to film distance, then you won't be focusing correctly - this can
   result from a misaligned mirror or focusing screen. 

4) Film sharpness.

5) Camera motion. This can be caused either by the user (if the camera is
   hand-held), or by mechanical vibration from the mirror and shutter.
   Are your pictures sharper when they're taken with faster speeds?
   Have you tried using a (sturdy) tripod and a cable release? Does this
   help? 

6) In the case of prints, the same general factors can also affect the 
   printing process. If the enlarger (or automatic printing machine)
   is not properly aligned and focused, if it vibrates during the printing
   exposure, etc. your results will not be sharp. Examine your negatives
   with a *good* high power loupe - if there is sharp detail which isn't
   rendered in the print, then get your negatives reprinted (preferably
   by SOMEONE ELSE!).

Are you shooting moving or stationary subjects? Are your pictures *always*
fuzzy? Try different apertures and different focal lengths (since you're
using a zoom) - are some noticeably better than others? Remember zoom lenses
are considerably more complex than single focal length designs - it's
extremely difficult (some would claim impossible) to achieve the same 
level of quality with a zoom as with a *good* single focal length lens.
Having said that, I would investigate the other causes first. 


Steve
From: zulu@sail.LABS.TEK.COM (V. S. Somayazulu; DSP/CSRL ; 50-370; (503)627-2071)
Newsgroups: rec.photo
Subject: Re: Nikon N8008S vs. N90 - opinions wanted
Date: 14 Nov 92 02:06:25 GMT
Article-I.D.: sail.12890
Organization: Tektronix, Inc., Beaverton,  OR.

In article <1992Nov13.200641.4118@leland.Stanford.EDU> krish@leland.Stanford.EDU (venkatraman) writes:
>
>So, I've finally saved up some money and decided to take the plunge and go for
>a top end Nikon system (relatively speaking to you F4S owners out there :-)).
>I've looked at both the N8008S and the N90 and I just can't make up my mind!
>
>nitin
>nitinm@kronos.ap.nisd.cam.unisys.com

Take the 8008s, spend the $ difference (between it and the N90) on good glass...
always works out better!!

IMO,
Zulu
Newsgroups: rec.photo
From: monson@hobo.ECE.ORST.EDU (Ty Monson)
Subject: Re: Reliable Strobe System (Speedotron,DynaLite, etc) ?
Organization: ECE Dept.,OSU,Corvallis
Distribution: na
Date: Wed, 11 Nov 1992 03:28:12 GMT

In article <1dp4s0INN1vo@sixgun.East.Sun.COM> marc@.East.Sun.COM (Marc Thompson-Sun-Vienna VA-Systems Engineer) writes:
>Gang,
>
>I am looking at purchasing a strobe system for a home studio. My main
 (stuff deleted)
>I have put each of these systems on the list for various reasons and strengths.
>
>Speedotron Black Line: Reliable, flexible, short recycle times, powerful.
                        ^^^^^^^^
>Speedotron Brown Line: More Affordable.
>DynaLite: Reliable, flexible, portable, short recycle times, powerful.
           ^^^^^^^^
>White Lightning Ultra: Affordable, portable, flexible. 
>
 (more deleted)

 I've been bewildered by the numerous choices in studio strobe lighting.
 Could you please tell me how to determine the reliability of various
 systems?

 Also, how does a person decide whether to buy mono lights or a set of
 lights and a separate power supply?
From: philg@zurich.ai.mit.edu (Philip Greenspun)
Newsgroups: rec.photo
Subject: Re: SCUBA questions (new Ektachrome + Nikon Action Touch)
Date: 10 Nov 92 22:13:16
Organization: M.I.T. Artificial Intelligence Lab.
Reply-To: philg@martigny.ai.mit.edu
NNTP-Posting-Host: zug.ai.mit.edu
In-reply-to: zrepachol@cc.curtin.edu.au's message of Mon, 9 Nov 1992 14:36:01 GMT


In article <1992Nov9.233601.1@cc.curtin.edu.au> zrepachol@cc.curtin.edu.au writes:

   > 
   > 1) Does anyone know when the new Kodak SCUBA Ektachrome will be
   > available?  Has anyone ever seen it either here or in Europe (where
   > Kodak lately seems to be introducing its best stuff first rather than
   > here in the Third World)?  I leave for the Great Barrier Reef on Dec
   > 11th and I'd like to get some by then.
   > 

   Have you more details? Ill ask Kodak over here for you... Are you just visiting
   the east, or are you crossing the 'great divide' and comming over west?

Sorry, no more details, but I think it is called "Ektachrome UW" or
something.  I'm actually just stopping off on my way to New Zealand.
For the same extortionate fare, I get a free stopover in Cairns.

Thanks,

Philip

--

      -- Philip Greenspun

-------------------------------------------------------------
MIT Department of Electrical Engineering and Computer Science
545 Technology Square, Rm 433, Cambridge, MA 02139
(617) 253-8574
From: rbirrell@gssec.bt.co.uk (Rob Birrell)
Newsgroups: rec.photo
Subject: Copying/Bellows
Date: 5 Nov 92 15:20:17 GMT
Organization: BT, SDDG, Scotland

I'm just thinking about investing in some copying equipment and was thinking of purchasing
a bellows unit for my Canon SLR. I want to be able to copy photos (B & W and Coulour), artwork
and transparencies. Does anyone have any recomendations on , techniques, lighting setups, film (can I sucessfully
use standard film or should I use specialized copying film?), bellows equipment, extension
tubes etc. Any advice would be gratefully received.
From: dtalmage@guvax.acc.georgetown.edu
Newsgroups: rec.photo
Subject: Re: YASHIKA LYNX-1000 (Anybody had experience with it?)
Date: 9 Nov 92 14:12:14 -0500
Distribution: world
Organization: Georgetown University

In article <CMM.0.90.2.721328442.chribrud@gyda.ifi.uio.no>, chribrud@ifi.uio.no (Christian Brudevoll) writes:
> The light-meter is to little sensitive. Set to 800 asa,
> which is maximum, it's like about 125 asa on my SLR's.
> 
> Is it hard to adjust such light-meter?
> (Might it be the battery? - what battery?)

You could always do what John Shaw suggests: Calibrate the meter using
the "Sunny f/16" rule.  On a sunny day, set the camera for f/16 at the 
reciprocal of the film speed.  For ISO 125, use 1/125.  For ISO 400, 
use 1/500.  Now set the lens at infinity and point it at a neutral 
subject (e.g. a grey card).  Adjust the film speed dial until the 
meter reads "right on".

Do this for all of the films you're likely to use.  I did it for both 
of my cameras and I wrote it down on an index card I keep in my bag.
You can use this for any kind of light meter, be it handheld or 
built-into a camera.
From: uli@i13d5.ira.uka.de (Uli Bodenhausen)
Newsgroups: rec.photo
Subject: Re: Comments on 55mm Takumar for 6x7?
Date: 9 Nov 1992 15:36:56 GMT
Organization: University of Karlsruhe, FRG
Distribution: world
NNTP-Posting-Host: i13d5.ira.uka.de

In article <LSWAB.92Nov9093300@bmerh953.x400gate.bnr.ca>, lswab@x400gate.bnr.ca (Lyndon Swab) writes:
|> This is related to the recent medium format debate.
|> 
|> Does anyone have any experience with the 55mm f3.5 Takumar for the
|> Pentax 6x7?  This is an old lens - all metal.  From what I can tell,
|> it is now discontinued.  B+H lists a 55mm f4.0, which I assume, is a
|> different beast.  All comments welcome.

I can't comment on the old f3.5, but the new one rated *very* well
in a German Photo Magazine (I think it was Color Foto).

	Uli

Newsgroups: rec.photo
From: alix@netcom.com (Alexandria North)
Subject: Re: Reliable Strobe System (Speedotron,DynaLite, etc) ?
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Thu, 12 Nov 1992 19:07:04 GMT

In article <BxKu0L.51x@fc.hp.com> pdn@fc.hp.com (Paul Nuber) writes:
>Marc Thompson-Sun-Vienna VA-Systems Engineer (marc@.East.Sun.COM) wrote:
>
>: 1. What would be the minimum amount of strobe power needed to do decent
>: head shots, and full body shots (500 w/s, 800 w/s, etc).
>
>For headshots, your flash will be close to the subjects head in an
>umbrella or softbox, so 100 w/s will be enough.
>
>I use a White Lightning Ultra 600 (300 w/s) and have plenty of light for
>full length shots.  For large groups, I wish I had more.
>
>--
>Paul Nuber
>pdn@fc.hp.com
>Hewlett-Packard Co.
>Fort Collins, CO

I also a White Lightning Ultra 600 as well (which is supposedly equivalent 
to 600 w/s, not 300!), and I think you need to qualify "plenty of light."
I use a Photoflex medium Multidome, and plenty of light depends on how 
close I can get to my subject with the light, and what kind of panels I 
use in the box. Using a soft box and a telephoto lens, I'd like a little 
more power for a full-length body shot. Still, there is an awful lot you 
can do with this one unit and some ingenuity...

Alexandria

P.S. I also have two White Lightning 10,000s. If anyone is looking into 
the Paul Buff units (which are great!) I recommend that, if you can only 
get one strobe, get an Ultra. I went with the 10,000s for my second and 
third lights because I couldn't afford more, and I figured that I could 
always use them for hair/accent and background lights, even as my 
setup grows. But I really love the versatility of the Ultra unit, and am 
glad I was able to afford at least one. Now I'm lusting after that Ultra 
1800...not that I need it.

Newsgroups: rec.photo
From: hsong@ardour.bellcore.com (G. Hugh Song)
Subject: Re: Information about tripods needed
Organization: BCR
X-Newsreader: Tin 1.1 PL5
Date: Fri, 6 Nov 92 02:05:22 GMT

Steve Gombosi (sog@craycos.com) wrote:
: In article <1dape7INNs83@panda.usc.edu> mx@panda.usc.edu (ICBM) writes:
: >3) The most outrageous question: are tripod heads from different manufactures
: > interchangeable? 
: > i.e. can I mount a Slik head on Bogen legs or vice versa?
: 
: Most tripods use a standard 3/8" screw thread to connect the legs and head.
: They should be freely interchangeable. You shouldn't have any problem doing
: this - try it in the store.

When I was in Adorama shopping for an umbrella, a guy was buying a Slik
tripod about 5' long with a center post and three spokes.   Sorry,
I did not pay attention to the model number.   Its screw was not 3/8",
it was a 1/20 standard camera screw.   Of course, my Bogen 3046 tripod
has a 3/8" screw.

	Hugh
From: campbell@sab59.larc.nasa.gov (Bryan Campbell)
Newsgroups: rec.photo
Subject: Re: Creative Backgrounds
Date: 9 Nov 1992 20:55:45 GMT
Organization: NASA Langley Research Center, Hampton, VA  USA
Distribution: world
NNTP-Posting-Host: sab59.larc.nasa.gov
Keywords: backgrounds

 Alexandria,

 Your response was fantastic!  Thank you.  I'll be trying a few of
 your suggestions real soon--(as soon as I clear enough space in my
 garage!).
 Another idea I came up with was to use a "layered" background.
 That is: Use a dark background as the "base", then use large
 swags of white material draped in front of the base.  Then for
 added creativity, I was going to try different color gels in 
 front of my background lights.  A variation would be to use a
 translucent base and light it from behind to create a soft
 "curtain in front of a window" effect.
 If you have tried anything like this before, or if you have
 any other helpful suggestions, let me know.
 Thanks again!

 Bryan.

 
Newsgroups: rec.photo
From: alix@netcom.com (Alexandria North)
Subject: Re: Creative Backgrounds
Keywords: backgrounds
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Wed, 11 Nov 1992 07:54:52 GMT

In article <1dmj8hINNlhk@rave.larc.nasa.gov> campbell@sab59.larc.nasa.gov (Bryan Campbell) writes:
> Alexandria,
>
> Your response was fantastic!  Thank you.  I'll be trying a few of
> your suggestions real soon--(as soon as I clear enough space in my
> garage!).
> Another idea I came up with was to use a "layered" background.
> That is: Use a dark background as the "base", then use large
> swags of white material draped in front of the base.  Then for
> added creativity, I was going to try different color gels in 
> front of my background lights.  A variation would be to use a
> translucent base and light it from behind to create a soft
> "curtain in front of a window" effect.
> If you have tried anything like this before, or if you have
> any other helpful suggestions, let me know.
> Thanks again!
>
> Bryan.


Bryan, I like your idea. I was thinking of doing a similar thing, but 
with swags of white or colored lace. The whole idea is very intriguing.
A good place to get ideas from is a background supplier's catalog. I 
have several of these (and I intend to order a few things from them when 
I have more $$, so I'm not just stealing ideas) that have given me 
plenty of ideas. Let me know if you need the names and addresses of 
some companies.
 
Alexandria
 
P.S. Please note that I have a completely new address, if you care to 
email a response.
From: bruceb@mpd.tandem.com (Bruce Burden)
Newsgroups: rec.photo
Subject: Re: Incredible blue sky
Date: 10 Nov 92 19:59:57 GMT
Organization: Tandem Computers (MPD) Austin, TX

In article <1992Nov10.150923.20228@organpipe.uug.arizona.edu> frankenp@argon.gas.uug.arizona.edu (Paul Frankenstein  ) writes:
>In article <1992Nov9.031341.8468@umr.edu> tonyp@cs.umr.edu (Tony Phillips) writes:
>* 
>* My question is, how in the world did the photographer get the sky to be that
>* dark, yet the balloons to be so bright?
>
>As well as a polarizer, which many have suggested, the picture may have been 
>taken in the early morning.
>--


	In addition, the burners were probably on, so you have the additional
     illumination from the flames. A friendof mine did that, with very nice
     early morning results.

	You don't need to be at high altitude to get very dark skies, you 
     just need the proper conditions, and know where the darkest sky will
     be found. I have a photo of one of the churches in St. Augustine, Fl.
     (elevation 1.5m, maybe) with BLACK skies, but proper exposure on the
     church. It helped that the church was in bright sun, and was white,
     so the meter underexposed the sky by two stops already, but I used
     the "thumb rule" to find the darkest sky.

	The "thumb rule" is to point the index finger at the sun, then the
     thumb (at right angle to the index finger) will describe an arc through
     the sky indicating the darkest portion of the sky when the wrist is
     rotated. This is due to the scattering of the light in the atmosphere. 



							Bruce
	



-------------------------------------------------------------------------------
  Bruce Burden
  bruceb@mpd.tandem.com
  Tandem Computers Inc.
From: feltman@hpscit.sc.hp.com (Robert Feltman)
Date: Thu, 5 Nov 1992 17:37:55 GMT
Subject: Re: medium format advice
Organization: Hewlett-Packard, Santa Clara, CA
Newsgroups: rec.photo

I second Daves's advice. Investment is low, optics are fine. 

Bob
From: robert@wsooti11.info.win.tue.nl (Robert Lukassen)
Newsgroups: rec.photo
Subject: Re: Regular AF Lenses vs. USM Lenses
Date: 9 Nov 92 10:06:49 GMT
Organization: Eindhoven University of Technology, the Netherlands
In-reply-to: tjwu@athena.mit.edu's message of 5 Nov 92 23:12:40 GMT


>In article <140642@lll-winken.LLNL.GOV> agosta@llnl.gov (Keith Agosta) writes:
>>
>>  I am new to photography, but I just bought a Canon EOS Elan Camera with a
>>  Sigma 35mm-115mm AF lens for the Canon. Is there any advantage to Ultrasonic
>>  Motor Lenses, in terms of spped of focus, quality, etc., as opposed to the 
>>  regular AF lenses?
>
>Ultrasonic Motor (USM) lenses focus much faster than ordinary AF lenses and
>you can't hear the motor turning (unless you have your ear against the lens
>barrel :)  The Canon 35-135 USM is optically better than the Sigma 35-135,
>and I believe it also lets you use the focusing ring in AF mode.
>
>Thomas Wu
>Internet:  tjwu@athena.mit.edu

Well, the USM lenses also actually instruct the camera in some modes. In macro mode,
USM lenses detech the distance between the camera and the object in the foreground
and the distance between the camera and the background and based upon that, it
will instruct the camera to photograph the background sharp or faint. It will also
do this in portrait mode.

Robert
--
+--------------------------------------+--------------------------------------+
|  Robert 'MacBear' Lukassen           |  Eindhoven University of Technology  |
|  Email: robert@info.win.tue.nl       |  The Netherlands                     |
+--------------------------------------+--------------------------------------+
| 'So logically ?  If she weighs the same as a duck, she's made of wood...    |
|  And therefore ?  ...a WITCH !!!!'   - Monty Python, the Holy Grail.        |
+-----------------------------------------------------------------------------+
Newsgroups: rec.photo
From: mills@magnus.acs.ohio-state.edu (Douglas K Mills)
Subject: Big/fast EOS lens advice sought
Organization: The Ohio State University
Distribution: usa
Date: Tue, 10 Nov 1992 21:55:01 GMT

I am an amateur wildlife photographer (my income is unaffected by any
choice shots), who would really like to have a good long lens for the
expeditions into the less populated areas of the North American 
continent.  I use Cannon's EOS equipment, and currently have a Rebel.
I have considered two new purchases to make - a new EOS body (like an
Elan), and a big lens.  The lens I currently use is the 100-300 USM, 
which is very easy to use and works well in good lighting conditions.

The most choice shots seem to happen at dawn or dusk or in the rain.
These, of course, are low-light times.  What I seem to need is a big, 
fast lens.  I had in mind a 300mm 2.8 type lens, but don't know who
makes good ones, what to look out for, or whether it is worth going 
for used or new.  I have also considered getting a teleconverter for 
the 300mm lens to get even closer (and still be faster than my 
100-300).

Any comments on what to watch out for in the lens, which lens is 
better or worse, or anything else that is _experience_based_ would 
be appreciated.  I go to used camera equipment stores several times
each week, but have only heard of 300mm 2.8 lenses (never seen any).
Of course the local new camera stores don't stock anything as nice as 
that. 

I hope to have a lens in hand for a Christmas trip down south where
it is warm and there is plenty of wildlife still brousing around.  
AdvTHANKSance !!

=-= Doug

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Doug Mills                                                Audio: (614) 292-2429
HCGL Manager                                           Internet: mills+@osu.edu
1971 Neil Ave Rm 406                 "Who would claim these views but myself ?"
Columbus, Ohio  43210         T h e   O h i o   S t a t e   U n i v e r s i t y
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Xref: sparky rec.photo:19548 alt.censorship:8732
From: jack@dcs.glasgow.ac.uk (Jack Campin)
Newsgroups: rec.photo,alt.censorship
Subject: Re: photomanipulation
Date: 10 Nov 92 19:24:10 GMT
Reply-To: jack@dcs.glasgow.ac.uk (Jack Campin)
Followup-To: alt.censorship
Organization: COMANDOS Project, Glesga Yoonie

hdevine@alfred.carleton.ca (Heather Devine) writes:
> I am looking for specific examples of photographs that have been
> manipulated and used as a picture of reality.  For example, the
> National Geographic photo which moved the pyramids closer together for
> a horizontal rather than vertical photo.  I need examples that date
> back no farther than two years, and I prefer those that have been used
> in newspapers.

I can think of three British examples of rather more significance than
that, though they're all a bit older, and they show that tools no fancier
than a pair of scissors can do the trick.

During the UK miners' strike of the mid-80s, Murdoch's "Sun" ran an image
of the miners' leader Arthur Scargill addressing a rally: he was holding
both hands straight out, palms down, in the usual gesture to call for
quiet.  The "Sun" cropped away his left hand and added a text that
suggested he was giving a Nazi salute.  The Press Council (a newspaper
watchdog body of astonishing gutlessness) eventually ordered the "Sun" to
print a retraction.

During the same strike, another newspaper photo ran a picture of a miner
shouting at a policeman on a picket line.  He *was* in fact shouting at the
cop, but the picture editor removed several yards of empty space between
them to put them apparently inches apart and make the cop look like he was
being seriously threatened.

More a case of censorship than manipulation: when Bassam Shaka'a, the Arab
mayor of Nablus on the West Bank, was bombed by Israeli terrorists, only
one UK paper ran the whole of the photo the agencies gave them.  That
showed Shaka'a full-length in his hospital bed with his legs blown off at
the knees.  Other papers gutted the impact of the picture by only showing
him from the waist up.

Followups to alt.censorship.

-- 
--  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