Re: need a pinhole

Wolfgang Thoma wrote:

> jamesromeo wrote:
>
>> The book that came with the camera list specification
>> pinhole effective focal length 55 mm
>> pinhole aperture f 259
>> neg size 48mm x 125 mm
>> it is a pan camera view angle 130 deg
>>
>> I would like to get a new pinhole made
>>
> So, let's calculate: focal length 55 devided by f/stop 259 makes a
> pinhole of 0,212 mm devided by 2,56 makes the same as 0,083 inch. If
> you are not an absolute newcomer, you must know that in pinhole we
> don't look at the very fine, absolute details. Some time ago, I bought
> a set of different sized micro-drilled pinholes from the pinhole resource
> http://www.pinholeresource.com/
> and still have a spare one of 0,087 inch. Not exactly the required
> size, but quite close to it, making it an f/stop of 222.
> If you are interested, please send your snail mail address to my
> private e-mail address at
> taco@thoma.be
> and you can have it for free.
> Taco

P.S.: I just read again the shipping list of my pinholes: they claim
that the optimal focal length for a 0.220 mm is 35 mm. David Balihar
states on his pinhole designer file that the best for a focal length of
55 mm would be a 0,330 mm opening, but the shipping list indicates for a
0,32 mm opening a FL of 73 mm and for 0,35 mm a FL of 88 mm, so just
keep on smiling and learning by trial and error.
taco

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Received on Tue Sep 14 10:00:23 2004