Denis,
A 0.65mm pinhole is "optimum" for a 320mm or around that focal length -anyway-, thought to mention it just for reference. F/stop of such set up: f/492 .
A pinhole that big is certainly not that difficult to estimate as you did, nevertheless, if you have the use of a flat bed scanner, you could try measuring the pinhole with it. You will find a link to an article explaining how in one of my web pages. There are some other links there you may be interested in reading, take a look.
>> I shall follow the procedures that you suggest and will most
surely get on the right track. Just one little note though. I think that a
meter behind a filter in some cases doesn't react the same way as
at least a film. Metering without a filter and then adding the filter
>>factor will probably give a more precise result -
You may be right, unFORTUNATELY, this pinhole stuff is -ultimately- imprecise enough that those kinds of deviations won't prevent you from getting an image, on the contrary, one is very seldom pleasantly surprised with "beautifully wrong" unexpected results.
>>all right, I am very accurate.
Guilty as charged!! :-)
Guillermo
http://members.home.com/penate/pinhole.html
Received on Tue Jul 10 19:21:59 2001
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