[Leica] Pinhole camera quality

[Malcolm McCullough <MM4@mm-croy.mottmac.com>]

Erwin Puts (or possibly an impostor trying to get Erwin into trouble) wrote, 
among other things:

>There has been some discussion on this list about the image quality that can
>be attained with a pinhole camera.
>
...snip...
>
>Anthony commented on pinhole quality and some typical responses are quoted
>above. One of the reasons for me to stay out of discussions as long as
>possible is the agressive tone and low quality of many exchanges of opinion.

I thought that the responses, especially those from John Brownlow, were 
technically sound and were definitely not 'low quality'. However, I am glad 
that you are now here to drag us hoolies* out of the gutter. Aggressive? Who 
are you calling aggressive? Me? Step outside and say that. Let me take my 
glasses off first though. Hey, wait a minute, that big black book you are 
brandishing has sharp corners - looks like it could hurt me.

>But before proving/stating some persons ignorance one might want to look up
>the facts in an optical handbook.

There is plenty of evidence that shows that both John and, I hope, myself do 
know our optics. I would welcome any criticism of, or correction to, either 
of my previous posts on the subject, including the resolution details 
included in my lighthearted FS notice. I have much to learn, and appreciate 
guidance. An aside: I think that optical handbooks are not the only source 
of valuable information; looking at original pictures taken with pinhole 
cameras and doing one's own experiments are also valid.

>While Anthony's statement is not exactly true, there is more value in it
>that the commenters want to belive.

Anthony was comparing pinholes with Leica lenses. Refuting the suggestion 
that pinholes suffered in this comparison only in terms of convenience, by 
pointing out the scientific reasons why they also suffer in terms of image 
resolution, does not mean that we are also saying that pinhole cameras 
should be dismissed as junk. They are capable of remarkably fine pictures, 
especially with large format film. I agree that there is some value in 
Anthony's statement - not only in itself but also because it has provoked 
discussion about the relative performance of very different imaging devices 
(can't call them both lenses).

By the way, how can you know what we 'commenters want to believe'?

>In Jenkins/White: Fundamentals of Optics you can see a reproduction of a
>picture taken with a pinhole that some would assume could have been taken
>with an older Leica lens.

'Some would assume could'  Yes, I kind-of partially agree, quite possibly, 
or maybe not, perhaps?
Would you like to comment on how that picture was printed or what size the 
negative was?

>
>So before you hang a man at the willows, do your home work.
>

Erwin, on this occasion I humbly submit that if it is really you, you should 
do your homework. A good place to start would be your statement: 'Of course 
the edges of the pinhole will generate diffraction but I wonder if it is 
more than that
what you would get when stopping down a lens to f/16.' I am not being 
sarcastic. The size of the Airy disc created by a pinhole or other aperture 
is a trivial calculation, but the relative brightness of the Airy disc to 
the disc formed by the direct rays is not. A study of that issue might show 
that the simple formula used for diffraction limiting does not tell the 
whole story.

Fortunately there are experimenters out there who ignore the rules and try 
these things anyway (ie pinholes smaller than the theoretical 
diffraction-limited diameter). I experimented with pinhole photography many 
years ago, though not to the limits of resolution. Both the experiments and 
the process were enjoyable and informative. The type of pictures were not 
what I wanted, so I stopped.

Best Wishes,
Malcolm
*hoolie = hooligan