Re: Pinhole-Discussion digest, Vol 1 #409 - 14 msgs

From: ROGER ARMOUR <roger_at_domain.name.suppressed> Date: Tue 21 Aug 2001 - 09:50:10 PDT · > Send Pinhole-Discussion mailing list submissions to

--
> Jean Daubas,  auteur-photographe
> Rue de Bourg-Sec    25440  LIESLE    France
> tél.   03 81 57 50 13   /   06 81 53 12 89
> jean.daubas@freesbee.fr
>
>
>
> ----- Original Message -----
> From: <taticosta@starmedia.com>
> To: <pinhole-discussion@pinhole.com>
> Sent: Tuesday, August 14, 2001 5:13 AM
> Subject: [pinhole-discussion] Courses
>
>
> > Hello!
> > Does anybody know about pinhole courses or studies groups at UK? I'm
going
> to London on a trip and I would like to make a pinhole course there! If
you
> know any school or arts center when I could fins something, please, write
> me!
> > Thanks, Tati.
> >
> >
>
> --------------------------------------------------------------------------
> ----
> >
> > Abra grátis sua conta no StarMedia Email. Inscreva-se agora mesmo!
> http://www.br.starmedia.com
> >
>
> --------------------------------------------------------------------------
> ----
> >
> >
> >
> > _______________________________________________
> > Pinhole-Discussion mailing list
> > Pinhole-Discussion@pinhole.com
> > unsubscribe or change your account at
> > http://www.pinholevisions.org/discussion/
> >
>
>
>
>
>
> --__--__--
>
> Message: 5
> From: Rustart@aol.com
> Date: Sun, 19 Aug 2001 20:13:20 EDT
> To: pinhole-discussion@pinhole.com
> Subject: [pinhole-discussion] Re: changing colours
> Reply-To: pinhole-discussion@pinhole.com
>
> Another solvent to try is WINTERGREEN OIL synthetic. It is nontoxic,
smells
> good, works great and you can usually get it from your local drug store.
> Rusty
>
>
> --__--__--
>
> Message: 6
> From: "Murray" <uptown@uptowngallery.org>
> To: <pinhole-discussion@pinhole.com>
> Date: Thu, 16 Aug 2001 23:40:11 -0400
> Subject: [pinhole-discussion] Color Xerography transfers
> Reply-To: pinhole-discussion@pinhole.com
>
> Hello:
>
> We have a few of those from a local photographer...I'm sure technique,
> patience and materials play a role...she hasn't been happy with all color
> copy machine or their operators (copy-jockies?)...some are interesting,
some
> are 'lame'.
>
> Maybe I could try that with my first pinhole roll which is color...what
> chance do I have of lucking out and getting accurate color as a pinhole
> beginner anyway, so why not experiment?
>
> Murray (local ISP and 'normal' e-mail address still suffering technical
> difficulties - I feel sorry for them - down a week, so you know they're
> catching grief!)
>
> Murray
>
>
>
> --__--__--
>
> Message: 7
> From: "Murray" <uptown@uptowngallery.org>
> To: <pinhole-discussion@pinhole.com>
> Date: Thu, 16 Aug 2001 23:49:41 -0400
> Subject: [pinhole-discussion] sharpness vs. depth-of-field
> Reply-To: pinhole-discussion@pinhole.com
>
> Hello:
>
> Excuse me if I already asked this - if I did, I forgot the replies already
> (but I don't think I did).
>
> Oh, firstly, apologies for the html forwarding garbage characters...I
don't
> think AOL software lets one too picky about how they do things.
>
> I am a little confused, perhaps only by my expectations. I have picked up
on
> the concept that pinhole gives phenomenal (am I overenthusiastic?)
> depth-of-field due to the typically large f-stops attained by usual camera
> designs.
>
> BUT, people are telling me I will probably be disappointed by anything
> larger than 5 x 7 or so from my 35 mm pinhole negatives because they say
> pinhole images are "not very sharp".
>
> Is this just anecdotal advice from people who simply poked a hole without
> consideration of all the things that play a role....(that wasn't supposed
to
> rhyme, it was an accident)? (Optimal hole diameter/focal length, thickness
> and roundness of pinhole material and resultant hole, etc.)
>
> Thanks
>
> Murray
>
>
>
> --__--__--
>
> Message: 8
> From: "Richard M. Koolish" <koolish@bbn.com>
> Subject: Re: [pinhole-discussion] questions & comments
> To: pinhole-discussion@pinhole.com
> Date: Mon, 20 Aug 101 10:52:13 -0400 (EDT)
> Reply-To: pinhole-discussion@pinhole.com
>
> Murray writes:
> >
> > BUT, people are telling me I will probably be disappointed by anything
> > larger than 5 x 7 or so from my 35 mm pinhole negatives because they say
> > pinhole images are "not very sharp".
> >
> > Is this just anecdotal advice from people who simply poked a hole
without
> > consideration of all the things that play a role....(that wasn't
supposed to
> > rhyme, it was an accident)? (Optimal hole diameter/focal length,
thickness
> > and roundness of pinhole material and resultant hole, etc.)
>
>
>     Just as an example, the optimal pinhole for 100 mm focal length will
>     resolve about 5 line pairs / mm.   That will make a fairly sharp
>     looking contact print but doesn't come close to the resolution of
>     a lens, which can be in the 80 to 100 lines/mm range.  So unless you
>     want the artistic effect of enlarging a pinhole negative, it's best
>     to contact print them.
>
>
> --__--__--
>
> Message: 9
> Date: Mon, 20 Aug 2001 10:15:36 -0700 (PDT)
> From: George L Smyth <glsmyth@yahoo.com>
> Subject: Re: [pinhole-discussion] questions & comments
> To: pinhole-discussion@pinhole.com
> Reply-To: pinhole-discussion@pinhole.com
>
> Murray writes:
> >
> > BUT, people are telling me I will probably be disappointed by anything
> > larger than 5 x 7 or so from my 35 mm pinhole negatives because they say
> > pinhole images are "not very sharp".
>
> Actually, what they are telling you is that THEY will be disappointed by
> anything larger than 5X7.  How could they know what you are looking for?
Just
> maybe you are seeking results that they may not desire.  Thank goodness we
all
> enjoy something different!
>
> Cheers -
>
> george
>
> =====
> Handmade Photographic Images
> http://members.home.net/hmpi/
>
> __________________________________________________
> Do You Yahoo!?
> Make international calls for as low as $.04/minute with Yahoo! Messenger
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>
>
> --__--__--
>
> Message: 10
> Date: Mon, 20 Aug 2001 18:36:10 +0200
> To: pinhole-discussion@pinhole.com
> From: Michel Dusariez <dusariez@pano360.org>
> Subject: [pinhole-discussion] sharpness
> Reply-To: pinhole-discussion@pinhole.com
>
> About pinhole sharpness.
>
> An other field in photography is to consider the artistic results first,
> put your magnifiers in your pocket and
> stop to search indefinitelly the performance,
> take pictures and enjoy.
>
> In the fields of sharpness nothing is never perfect,
> I know photographers who devote their entire life in search of
performance,
> and never do real photography .
>
> Only tests, and test again !
>
> Winners are only photography materials suppliers.
>
> Take your camera and take pictures.
>
> Michel DUSARIEZ
>
>
>
>
> --__--__--
>
> Message: 11
> From: "Guillermo" <penate@home.com>
> To: <pinhole-discussion@pinhole.com>
> Subject: Re: [pinhole-discussion] sharpness vs. depth-of-field
> Date: Mon, 20 Aug 2001 20:11:15 -0400
> Reply-To: pinhole-discussion@pinhole.com
>
>
> ----- Original Message -----
> From: "Murray" <uptown@uptowngallery.org>
>
> > BUT, people are telling me I will probably be disappointed by anything
> > larger than 5 x 7 or so from my 35 mm pinhole negatives because they say
> > pinhole images are "not very sharp".
> >
> > Is this just anecdotal advice from people who simply poked a hole
without
> > consideration of all the things that play a role....(that wasn't
supposed
> to
> > rhyme, it was an accident)? (Optimal hole diameter/focal length,
thickness
> > and roundness of pinhole material and resultant hole, etc.)
>
> Murray,
>              Thanks for giving us another chance to answer your
question...!
> :-)
>
> Pinhole, is not about sharpness, it is about enjoyment.  Don't let anybody
> trouble you with ideas of sharpness or unsharpness.  As I have said
before,
> if you want it sharp, surely you can get it, if you want it soft,
definitely
> you can get it, too.   It is up to you and you alone.  For me, the beauty
of
> some of my images resides not in the fact that some one else likes them,
but
> in the fact that I like and enjoy  them.
>
> Having said that, take a look at this image (forget about its artistic
> redeeming value, pls :-) made from a 35mm frame:
> http://members.home.com/penate/fire.html
> Now take a look at this 9X enlargement of a piece of the image (this is a
> raw scanning, no digital manipulation whatsoever):
> http://members.home.com/penate/originales/firepiece.jpg
> I'd let you decide if that image is sharp enough for you (in case you
wanted
> it sharp), coming from a 35mm and being a 9X enlargement.
> Here is the full image (150Kb)
> http://members.home.com/penate/originales/big.jpg
>
> Guillermo
>
>
>
>
>
>
>
>
> 9X enlargement of a piece of 35mm frame
>
>
>
> --__--__--
>
> Message: 12
> Date: Mon, 20 Aug 2001 23:19:50 -0600 (CST)
> From: "Gordon J. Holtslander" <holtsg@duke.usask.ca>
> To: pinhole-discussion@pinhole.com
> Subject: [pinhole-discussion] compensating zone plate
> Reply-To: pinhole-discussion@pinhole.com
>
> A question for all the mathematicians and physicists.  Is it possible to
> make a zone plate that compensates for fall-off.  When one makes an
> extremely wide angle shot the edges of the image are underexposed due to
> the signifcant difference in the focal length from the center to the edges
> of the film.
>
> Is there a way of altering the line pattern and or line thickness of a
> zone plate so that the edges of the picture get more illumination?
>
> And just to make it interesting, if this is possible, is there a way of
> calibrating or predicting the difference in exposure from one region of
> the picture to another?
>
> The things I end up talking about over lunch with another pinholer!
>
> Gord
> ---------------------------------------------------------
> Gordon J. Holtslander Dept. of Biology
> holtsg@duke.usask.ca 112 Science Place
> http://duke.usask.ca/~holtsg University of Saskatchewan
> Tel (306) 966-4433 Saskatoon, Saskatchewan
> Fax (306) 966-4461 Canada  S7N 5E2
> ---------------------------------------------------------
>
>
>
> --__--__--
>
> Message: 13
> From: "Guillermo" <penate@home.com>
> To: <pinhole-discussion@pinhole.com>
> Subject: Re: [pinhole-discussion] compensating zone plate
> Date: Tue, 21 Aug 2001 08:33:43 -0400
> Reply-To: pinhole-discussion@pinhole.com
>
>
> ----- Original Message -----
> From: "Gordon J. Holtslander" <holtsg@duke.usask.ca>
>
>
> > A question for all the mathematicians and physicists.  Is it possible to
> > make a zone plate that compensates for fall-off.
>
> I am no mathematician or physicist, just a plain guy that sort of remember
> some of the math I studied more than 25 years ago.
>
> > Is it possible to
> > make a zone plate that compensates for fall-off.
> > Is there a way of altering the line pattern and or line thickness of a
> > zone plate so that the edges of the picture get more illumination?
>
> This are some thoughts:
>
> A ZP behaves just as a pinhole as far as fall-off is concerned.  You could
> elongate the ZP so when you see it off-axis it resembless more a circle
than
> an elipsis. But the only "edges" that will see the ZP more as a circle
will
> be those toward which the ZP has been elongated.  Also, you can only
> elongate vertically or horizontally (if you do both, you are effectively
> just making the ZP bigger and not good for the focal length in use,
> anymore).  Fall-off is a relative measurement, the difference between the
> center and the edges, by elongating the ZP you will be getting not only
more
> light at the edges but also at the center of the image, so the end result
> may not give us less fall-off than before.
>
> > And just to make it interesting, if this is possible, is there a way of
> > calibrating or predicting the difference in exposure from one region of
> > the picture to another?
>
> Thanks G*D is not possible (IMO) otherwise I'd have to give you an
answer!!
>
> Having said the above, the way to calculate it would be a Cos^4 law
modified
> by the effect of the eliptical shaped aperture.
>
> > The things I end up talking about over lunch with another pinholer!
>
> If you were in Quebec I'd probably ask you: "what were you guys smoking",
> but probably in Saskatoon as well as in Toronto, eateries are smoke free
> places by law.  :-)
>
> Guillermo
>
>
>
>
>
> --__--__--
>
> Message: 14
> Date: Tue, 21 Aug 2001 10:01:05 -0400
> From: Howard Wells <sandwell@earthlink.net>
> To: pinhole-discussion@pinhole.com
> Subject: Re: [pinhole-discussion] sharpness
> Reply-To: pinhole-discussion@pinhole.com
>
> I agree with Michel. All the advertising for conventional photographic
> materials makes one think sharpness is the goal.  I suppose it can be a
> legitimate goal for some purposes but not necessarily for expressive
> photography.  I've spent a lot of time experimenting with ways to make
> modern materials less sharp. And I have been delighted with the quality
> of 35mm pinhole photographs for years--either with homemade cameras,
> bodycaps or one of Dominique Stroobant's lens-less leica lenses. A
> couple of those images are at the address below. Both enlarge to make
> fine 8x10 prints. "Take pictures and enjoy."
>
> Howard Wells
> http://home.earthlink.net/~sandwell/work.html
>
> Michel Dusariez wrote:
> >
> > About pinhole sharpness.
> >
> > An other field in photography is to consider the artistic results first,
> > put your magnifiers in your pocket and
> > stop to search indefinitelly the performance,
> > take pictures and enjoy.
> >
> > In the fields of sharpness nothing is never perfect,
> > I know photographers who devote their entire life in search of
performance,
> > and never do real photography .
> >
> > Only tests, and test again !
> >
> > Winners are only photography materials suppliers.
> >
> > Take your camera and take pictures.
> >
> > Michel DUSARIEZ
> >
> > _______________________________________________
> > Pinhole-Discussion mailing list
> > Pinhole-Discussion@pinhole.com
> > unsubscribe or change your account at
> > http://www.pinholevisions.org/discussion/
>
>
>
> --__--__--
>
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> Pinhole-Discussion@pinhole.com
> http://www.pinholevisions.org/discussion/
>
> End of Pinhole-Discussion Digest
>