another newbie question

Hello all,

I don't see a newsgroup for "pinhole" cameras, so I hope y'all don't mind:

The question is;

Should I be able to see a preview image on "ground glass" thru' a
pinhole camera?

I'm assuming from my web research that with a smaller pinhole the image,
if there is one, on the glass will be sharper and darker, and as the
hole gets bigger, the image will get brighter and fuzzier?

--
regards from ::

John Bartley
43 Norway Spruce Street
Stittsville, Ontario
Canada, K2S1P5

( If you slow down it takes longer
- does that apply to life also?)

"John Bartley" wrote in message
...

I don't see a newsgroup for "pinhole" cameras, so I hope y'all don't mind:

I don't mind.

The question is;

Should I be able to see a preview image on "ground glass" thru' a
pinhole camera?

It's not likely, but remotely possible with a large format camera if you
have good, young eyes: for example an 8x10 or larger camera with a
relatively large aperture (pinhole) might give you a faint image, but for
smaller cameras it's highly unlikely. To see an image in a small camera with
the typical pinhole you need rather ideal conditions: subject in
daylight-bright circumstances when your eyes have become accustomed to total
darkness. You can see how that combination is hard to come by. If you could
ever go into a walk-in pinhole camera (camera obscura) you would see an
image. Quite fun.

That said, a bit of experimentation will show you how your camera frames and
then you can fashion a wire-frame viewer. You really don't need anything
more than that. Your experimentation will show you the typical DOF and view.
Then you can take pictures and enjoy.

For a great deal of very good information, please see:
http://pinholeresource.com/
The site may not answer all your questions, but it is owned and authored by
the experts who have decades of experience.

jjs wrote:

For a great deal of very good information, please see:
http://pinholeresource.com/
The site may not answer all your questions, but it is owned and authored by
the experts who have decades of experience.




Thank you,

The "lack of light" idea had crossed my mind, but I was unsure of how
major a problem it would be. Having had my curiosity piqued by the idea
of large format cameras, I thought maybe I would start with a large
format (8 x10) pinhole camera with the idea being that I could always
subsitute a "lens and shutter" front board for the same body that I use
for the pinhole. I sense some experimentation and learning ahead :-) !

cheers

--
regards from ::

John Bartley
43 Norway Spruce Street
Stittsville, Ontario
Canada, K2S1P5

( If you slow down it takes longer
- does that apply to life also?)

In article , John Bartley
wrote:

[...] I sense some experimentation and learning ahead :-) !

And it will be heartening and fun! Somtimes I wish I could start all over,
or at least experience some of the early "new eyes" wonder and energy.

Best,
jjs

"John Bartley" wrote in message
...
jjs wrote:

For a great deal of very good information, please see:
http://pinholeresource.com/
The site may not answer all your questions, but it is owned and authored
by
the experts who have decades of experience.




Thank you,

The "lack of light" idea had crossed my mind, but I was unsure of how
major a problem it would be. Having had my curiosity piqued by the idea
of large format cameras, I thought maybe I would start with a large
format (8 x10) pinhole camera with the idea being that I could always
subsitute a "lens and shutter" front board for the same body that I use
for the pinhole. I sense some experimentation and learning ahead :-) !

cheers

--
regards from ::

John Bartley
43 Norway Spruce Street
Stittsville, Ontario
Canada, K2S1P5

( If you slow down it takes longer
- does that apply to life also?)

First, your signatu Not necessarily. When you get over the hill you
speed up.
Second, Why not? An appropriately sized pin hold for an 8x10 should
compensate somewhat for the "loss" of light to the film.

"dr bob" wrote in message
( If you slow down it takes longer
- does that apply to life also?)

Not necessarily. When you get over the hill you speed up.

The slower you go the faster everything else goes - and when
you stop it all races away, leaving you behind.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Your thinking is correct. A technique some pinholers use with view cameras
is to use a rather large pinhole (about the diameter of a 10 penny nail) for
compositional purposes. Then the smaller, working pinhole is substituted
for the exposure. The larger pinhole does create a much brighter image on
the ground glass, but it is definitely less sharp.

KB


"John Bartley" wrote in message
...

Hello all,

I don't see a newsgroup for "pinhole" cameras, so I hope y'all don't mind:

The question is;

Should I be able to see a preview image on "ground glass" thru' a
pinhole camera?

I'm assuming from my web research that with a smaller pinhole the image,
if there is one, on the glass will be sharper and darker, and as the
hole gets bigger, the image will get brighter and fuzzier?

--
regards from ::

John Bartley
43 Norway Spruce Street
Stittsville, Ontario
Canada, K2S1P5

( If you slow down it takes longer
- does that apply to life also?)

In article k.net, "Ken
Burns" wrote:

Your thinking is correct. A technique some pinholers use with view cameras
is to use a rather large pinhole (about the diameter of a 10 penny nail) for
compositional purposes. Then the smaller, working pinhole is substituted
for the exposure. The larger pinhole does create a much brighter image on
the ground glass, but it is definitely less sharp.

Ken, does the coverage change with the different sized aperture? My sense
tells me it does not - that only the COC changes.

jjs wrote:

Ken, does the coverage change with the different sized aperture? My sense
tells me it does not - that only the COC changes.



If I may jump in with some speculation here;

I hadn't thought at all about Mr. Burns suggestion for using two sizes
of pinhole plates. That is a quite a good one, and one that I'll
certainly try. Now for the speculation:

My thinking is that the factors that would affect the coverage would be
1) the distance from the pinhole to the negative and, 2) the thickness
of the pinhole material. I'm thinking that the thinner the material is,
the smaller the hole can be and still be closer to the negative for a
given field of view. This, to my way of thinking would also allow more
light to hit the negative with a smaller hole?

I don't know what COC means, I wonder if you could educate me on some of
the short-form terms used in this hobby?

cheers

--
regards from ::

John Bartley
43 Norway Spruce Street
Stittsville, Ontario
Canada, K2S1P5

( If you slow down it takes longer
- does that apply to life also?)

On 5/22/2004 10:01 AM John Bartley spake thus:

jjs wrote:

Ken, does the coverage change with the different sized aperture? My sense
tells me it does not - that only the COC changes.

If I may jump in with some speculation here;

I hadn't thought at all about Mr. Burns suggestion for using two sizes of
pinhole plates. That is a quite a good one, and one that I'll certainly
try. Now for the speculation:

My thinking is that the factors that would affect the coverage would be 1)
the distance from the pinhole to the negative and, 2) the thickness of the
pinhole material. I'm thinking that the thinner the material is, the
smaller the hole can be and still be closer to the negative for a given
field of view. This, to my way of thinking would also allow more light to
hit the negative with a smaller hole?

Um, not really: so far as the brightness of the image goes, the crucial factor
is the diameter of the hole. You're correct, of course, that thinner material
is better in that you get closer to the ideal hole (which is two-dimensional)
rather than the 3-dimensional tube you inevitably get in the real world. But
so far as getting a brighter image goes, you need a bigger hole.

I don't know what COC means, I wonder if you could educate me on some of
the short-form terms used in this hobby?

Circle of confusion.

I won't go into the full explanation, which is a complex aspect of optics and
could generate a miles-long thread here. Suffice to say that it's a
theoretical construct that supposes a circle on the image plane (film in this
case) corresponding to a point on the subject. The smaller the COC, the more
in focus the image is. The smaller the pinhole, the smaller the corresponding
COC; therefore, smaller pinholes give sharper images.

(Until, of course, one hits the dreaded diffraction limit as the hole gets
smaller, which then works against sharpness. But that's a whole 'nother can of
worms. Which is why there are pretty well agreed-on optimal pinhole sizes,
depending on focal length.)

Don't worry, you'll grasp all this and figure it out eventually. Direct
experimentation is the best guide (and the most fun).


--
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imagined, some new and unspeakable form of sexual debauchery practised
by young persons of dubious morality, but a way of providing news
articles to the cybernetic publishing moguls of the World Wide Wait so
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