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Re: Pinhole shots of the Civil War (re-enactments)

 
 
Rob
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      01-29-2013
On 28/01/2013 4:03 AM, Alan Browne wrote:
>


>
> I don't feel like shooting film for such, but I might use a lens adaptor
> and shoot some digital pinholes... the very long exposures may be quite
> noise prone, however...
>




Just noticed this item after reading the exposure problem.

You can use a body cap and make a pinhole through that, if that is too
close then use an extension tube. Drill a hole through the cap and
stick some aluminium tape and make a pin prick through it. I usually use
a thick sewing (darning) needle.
 
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Whiskers
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      01-29-2013
On 2013-01-29, Rob <(E-Mail Removed)> wrote:
> On 28/01/2013 4:03 AM, Alan Browne wrote:
>>

>
>>
>> I don't feel like shooting film for such, but I might use a lens adaptor
>> and shoot some digital pinholes... the very long exposures may be quite
>> noise prone, however...
>>

>
>
>
> Just noticed this item after reading the exposure problem.
>
> You can use a body cap and make a pinhole through that, if that is too
> close then use an extension tube. Drill a hole through the cap and
> stick some aluminium tape and make a pin prick through it. I usually use
> a thick sewing (darning) needle.


The "state of the art" method for making a photographic pinhole, as I
recall, is to use a centre-punch (or a good round nail) to make a dent in a
piece of metal sheeting, and then gently file off the dimple. That gives
reasonably good control over the shape and size of the hole - but getting a
really small hole of a precise size isn't easy!

--
-- ^^^^^^^^^^
-- Whiskers
-- ~~~~~~~~~~
 
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Doug McDonald
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      01-29-2013
The real state of the art for pinholes is twofold:

1) Laser drilling
or
2) spark erosion drilling

Both make nice pinholes down to about 0.001 inch. Lasers go smaller.

One can buy such pinholes at reasonable prices (i.e. a few to a few tens of dollars).

Doug McDonald


 
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me
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      01-29-2013
On Tue, 29 Jan 2013 16:21:52 -0600, Doug McDonald
<(E-Mail Removed)> wrote:

>2) spark erosion drilling


AKA EDM or Electric Discharge Machining,
http://en.wikipedia.org/wiki/Electri...arge_machining

 
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Rob
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      01-30-2013
On 30/01/2013 7:57 AM, Whiskers wrote:
> On 2013-01-29, Rob <(E-Mail Removed)> wrote:
>> On 28/01/2013 4:03 AM, Alan Browne wrote:
>>>

>>
>>>
>>> I don't feel like shooting film for such, but I might use a lens adaptor
>>> and shoot some digital pinholes... the very long exposures may be quite
>>> noise prone, however...
>>>

>>
>>
>>
>> Just noticed this item after reading the exposure problem.
>>
>> You can use a body cap and make a pinhole through that, if that is too
>> close then use an extension tube. Drill a hole through the cap and
>> stick some aluminium tape and make a pin prick through it. I usually use
>> a thick sewing (darning) needle.

>
> The "state of the art" method for making a photographic pinhole, as I
> recall, is to use a centre-punch (or a good round nail) to make a dent in a
> piece of metal sheeting, and then gently file off the dimple. That gives
> reasonably good control over the shape and size of the hole - but getting a
> really small hole of a precise size isn't easy!
>

Size doesn't matter, its the desired results.
 
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Whiskers
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      01-30-2013
On 2013-01-30, Rob <(E-Mail Removed)> wrote:
> On 30/01/2013 7:57 AM, Whiskers wrote:
>> On 2013-01-29, Rob <(E-Mail Removed)> wrote:
>>> On 28/01/2013 4:03 AM, Alan Browne wrote:
>>>>
>>>
>>>>
>>>> I don't feel like shooting film for such, but I might use a lens
>>>> adaptor and shoot some digital pinholes... the very long exposures may
>>>> be quite noise prone, however...
>>>>
>>>
>>>
>>>
>>> Just noticed this item after reading the exposure problem.
>>>
>>> You can use a body cap and make a pinhole through that, if that is too
>>> close then use an extension tube. Drill a hole through the cap and
>>> stick some aluminium tape and make a pin prick through it. I usually
>>> use a thick sewing (darning) needle.

>>
>> The "state of the art" method for making a photographic pinhole, as I
>> recall, is to use a centre-punch (or a good round nail) to make a dent
>> in a piece of metal sheeting, and then gently file off the dimple. That
>> gives reasonably good control over the shape and size of the hole - but
>> getting a really small hole of a precise size isn't easy!
>>

> Size doesn't matter, its the desired results.


Well a big hole makes for a faster exposure but less sharpness, so size
does matter! (Calculate the aperture by dividing the diameter of the hole
into the distance from the hole to the film; eg if the hole is 1mm diameter
and 100mm from the film, the aperture is 1/100 - usually expressed as 1:100
or f/100. There will be about 1mm of fuzzines in the image in this
example).

--
-- ^^^^^^^^^^
-- Whiskers
-- ~~~~~~~~~~
 
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Whiskers
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      01-30-2013
On 2013-01-29, Doug McDonald <(E-Mail Removed)> wrote:
> The real state of the art for pinholes is twofold:
>
> 1) Laser drilling or 2) spark erosion drilling
>
> Both make nice pinholes down to about 0.001 inch. Lasers go smaller.
>
> One can buy such pinholes at reasonable prices (i.e. a few to a few tens
> of dollars).
>
> Doug McDonald


Oddly enough, though, whereas I can easily lay hands on a bit of bean can
and a nail and a rough lump of rock (or even a hammer and a file!), I can't
seem to find either a laser drill or a spark erosion drill in my tool box
)

--
-- ^^^^^^^^^^
-- Whiskers
-- ~~~~~~~~~~
 
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Wolfgang Weisselberg
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      01-30-2013
Whiskers <(E-Mail Removed)> wrote:
> On 2013-01-30, Rob <(E-Mail Removed)> wrote:


[Pinhole photography]

>> Size doesn't matter, its the desired results.


> Well a big hole makes for a faster exposure but less sharpness, so size
> does matter!


Well, a small hole makes for a slower exposure but less
sharpness as well, so size does matter. (Think Airy disk)


> (Calculate the aperture by dividing the diameter of the hole
> into the distance from the hole to the film; eg if the hole is 1mm diameter
> and 100mm from the film, the aperture is 1/100 - usually expressed as 1:100
> or f/100. There will be about 1mm of fuzzines in the image in this
> example).


The optimal pinhole is perfectly round and has a size of
d = SQRT(2 f λ)
with f = focal length and λ the wavelength of the light.

-Wolfgang
 
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PeterN
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      01-31-2013
On 1/30/2013 7:31 PM, Alan Browne wrote:
> On 2013.01.29 08:19 , Rob wrote:
>> On 28/01/2013 4:03 AM, Alan Browne wrote:
>>>

>>
>>>
>>> I don't feel like shooting film for such, but I might use a lens adaptor
>>> and shoot some digital pinholes... the very long exposures may be quite
>>> noise prone, however...
>>>

>>
>>
>>
>> Just noticed this item after reading the exposure problem.
>>
>> You can use a body cap and make a pinhole through that, if that is too
>> close then use an extension tube. Drill a hole through the cap and
>> stick some aluminium tape and make a pin prick through it. I usually use
>> a thick sewing (darning) needle.

>
> I have an adaptor for Hassy lenses for my A-mount (Sony). So I can
> "adapt" all manner of extensions to that. Making the aperture itself
> (alu paper/pin) is the least trouble. I have a micrometer to measure
> the aperture of the pin or needle and the film plane is well marked to
> get the FL. I'll probably go for a wide-ish FOV - the adaptor alone
> will probably be enough.
>


I am looking forward to seeing the results.
please share them.
--
PeterN
 
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