Re: [pinhole-discussion] questions comments

2001-08-20 Thread George L Smyth
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

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Re: [pinhole-discussion] questions comments

2001-08-20 Thread Richard M. Koolish
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.



Re: [pinhole-discussion] questions comments

2001-08-17 Thread Guillermo
- Original Message -
From: Gordon J. Holtslander hol...@duke.usask.ca

 You are more or less correct, as you enlarge your image from a pinhole
 negative on 35 mm film you will be making the limited resolution of the
 image more apparent.

 If you want a really sharp 8x10 pinhole images the best way to produce
 this is with a pinhole camera that takes 8x10 inch negatives.  This can be
 done without a full-fledged darkroom

That is right, for sharpness an 8x10 contact print is best.

Long time ago, I was told: 35mm pinholes images fall apart when enlarged.
See how this one falls apart:

Warning: 150Kbytes
http://members.home.com/penate/originales/big.jpg

The above image is the raw scanning (no digital manipulation whatsoever) of
an 8x10 print obtained by enlarging a full 35mm format frame, If you use
your monitor with a 1024x768 resolution, the above image would show up us a
9X (or so) enlargement of the original 35mm negative.  I'd let you decide if
it is possible to have relatively sharp images larger than 5x7 from your
35mm format pinhole camera.  BTW, the camera was a 35mm disposable camera
with a pinhole 14mm from the film, here is a picture of it:
http://members.home.com/penate/cameras/14f.jpg

Having said all that, unsharp pinhole images like this one, by Tom Lindsay:
http://www.???/pinholer/exhibits/TL.html  have nothing to
envy from sharpones.

Guillermo




Re: [pinhole-discussion] questions comments

2001-08-17 Thread Gordon J. Holtslander
Hi:

I _think_ this is what happens - knowledgeable people feel free to
correct me.

There are two things that limit the pinhole resolution:

I believe a pinhole image's - the negative - limit of resolution is the
size of the pinhole - The finest detail the image can create is the same
as the diameter of the pinhole.

If this were the only factor then one could make an infinitely small
pinhole and create images with infinite detail.  Unfortunately light
diffracts around the edges of the pinhole.  The smaller the pinhole the
more diffraction.  At a certain point making the pinhole smaller makes the
image less sharp.

There are formulas for determining the ideal pinhole.

It is still possible to get very sharp pinhole images.  The ideal method
is to not enlarge the negative but contact print it.

You are more or less correct, as you enlarge your image from a pinhole
negative on 35 mm film you will be making the limited resolution of the
image more apparent.

If you want a really sharp 8x10 pinhole images the best way to produce
this is with a pinhole camera that takes 8x10 inch negatives.  This can be
done without a full-fledged darkroom.

See my website for examples and details:

http://cyano.usask.ca/cgi-bin/photo/index.cgi

If you  want color images this becomes a little more challenging - you
could use large format color film or ilfochrome.  If this is what you
really want to do I would recommend getting used doing this in blackwhite
first.


On Thu, 16 Aug 2001 mvdtempor...@aol.com wrote:

 Hello:

 Excuse me if I already asked this - if I did, I forgot the replies already
 (but I don't think I did).


 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



-
Gordon J. Holtslander   Dept. of Biology
hol...@duke.usask.ca112 Science Place
http://duke.usask.ca/~holtsgUniversity of Saskatchewan
Tel (306) 966-4433  Saskatoon, Saskatchewan
Fax (306) 966-4461  Canada  S7N 5E2
-




Re: [pinhole-discussion] questions comments

2001-08-17 Thread William Erickson
My standard, sincere, reply to questions about 'will it work? is try it'. 
Pinhole is not primarily about sharp anyway, depth of field issues aside. You 
may especially like soft, glowing color pinhole images. 

. - Original Message - 
  From: mvdtempor...@aol.com 
  To: pinhole-discussion@p at ??? 
  Sent: Thursday, August 16, 2001 10:49 PM
  Subject: [pinhole-discussion] questions  comments


  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.) 

  We have a few of those color xerography transfers 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'. 

  She won't tell us what solvents she uses. 

  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 

  Thanks 

  Murray 



RE: [pinhole-discussion] questions comments

2001-08-17 Thread Chuck Flagg

  Murray wrote

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.  

   Murry,
  My favorite pinhole camera is a large popcorn tin.  It uses 11x14 photo
paper with a 2.5 to 4 min exposure time in the sun.  My lens is highly
technical, I poked a hole with a straight pin in an old piece of pop can, no
idea what size it is. :-)
  The photos are very sharp and if I EVER get better with stiching scans
together I plan to publish them to the gallery.  My newest large format
pinhole, I am working with this fall, will be 24 in dia and 36 tall.  I
plan on using roll mural photo paper.

  Good luck,
  Chuck Flagg