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#11
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Pinhole shots of the Civil War (re-enactments)
bugbear wrote:
Consider 6 x 10 second exposure versus a single 60 second exposure. Apart from the tiny gaps between the 6 separate shots, once you've added them up (literally...) you've done something VERY similar to the 60 second exposure. Instead of accumulating (adding!) photons on a CCD site, you've done the adding in a computer. "the Digital Pinhole Photography Group" http://www.flickr.com/groups/95279410@N00/discuss/ BugBear |
#12
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Pinhole shots of the Civil War (re-enactments)
On 2013-01-29, 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. 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 -- ~~~~~~~~~~ |
#13
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Pinhole shots of the Civil War (re-enactments)
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 |
#14
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Pinhole shots of the Civil War (re-enactments)
On Tue, 29 Jan 2013 16:21:52 -0600, Doug McDonald
wrote: 2) spark erosion drilling AKA EDM or Electric Discharge Machining, http://en.wikipedia.org/wiki/Electri...arge_machining |
#15
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Pinhole shots of the Civil War (re-enactments)
On 30/01/2013 7:57 AM, Whiskers wrote:
On 2013-01-29, 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. 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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Pinhole shots of the Civil War (re-enactments)
On 2013-01-30, Rob wrote:
On 30/01/2013 7:57 AM, Whiskers wrote: On 2013-01-29, 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. 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 -- ~~~~~~~~~~ |
#17
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Pinhole shots of the Civil War (re-enactments)
On 2013-01-29, Doug McDonald 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 -- ~~~~~~~~~~ |
#18
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Pinhole shots of the Civil War (re-enactments)
Whiskers wrote:
On 2013-01-30, Rob 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 |
#19
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Pinhole shots of the Civil War (re-enactments)
On 2013.01.29 05:26 , bugbear wrote:
Alan Browne wrote: http://civilwar150pinholeproject.com/ A writeup by the photographer on his pinhole cameras and his quest to document civil war re-enactments. One of my favourites: http://civilwar150pinholeproject.fil...tysburg149.jpg 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 take multiple exposures at a duration where noise isn't an issue, and merge (average) them. Good point. In the film days I'd occasionally bulb expose to over 30 seconds up to about 2 or 3 minutes. In the digital days I've been avoiding that. I can also boost the ISO more than what this fellow is using to pop down the exposure times. -- "There were, unfortunately, no great principles on which parties were divided – politics became a mere struggle for office." -Sir John A. Macdonald |
#20
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Pinhole shots of the Civil War (re-enactments)
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. -- "There were, unfortunately, no great principles on which parties were divided – politics became a mere struggle for office." -Sir John A. Macdonald |
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