Re: [pinhole-discussion] Re: Exposure scale
You can always convert it to a .pdf file using a program called Pstill. Get it at http://download.cnet.com/downloads/0-10074-100-1628951.html?tag=st.dl.10001- 103-1.lst-7-4.1628951 If the url is broken, COPY AND PASTE IT TOGETHER! Rob - you might want to put up the .pdf version. John I have nice paper one. Two discs that work together just like Zernike's. You can find it at http://www.panix.com/~reynolds/photography/pinhole/pincalc.html It's the second link on the page. It's a POSTSCRIPT file... if you don't know what to do with a Postscript file (which is really meant for sending directly to a Postscript printer)... I'd recommend opening it with Adobe Illustrator. Otherwise, you may need to download Ghostscript, MacGS, or something similar - all of which have been big headaches for me personally. UNIX systems normally have utilities to open postscript files. It's possible that MacOS X does as well. Again, Adobe Illustrator is probably your best bet. If you download it and can't get it to work, PLEASE EMAIL ME... I don't want to be responsible for starting a big Postscript debate on the list!!! In the worst case, I'll just print it out and mail it to you! :) Rob. BTW, if you have one and you're wondering if it's the same.. this is the one that says Belichtungswert-Erweiterung (Exposure Value Extension) on it.
Re: [pinhole-discussion] Re: image circle relative to focal length/fstop
- Original Message - From: Zernike Au zern...@zeroimage.com If you want to control the circular image to 2' or 3 (the range is quite big!), the main factor is the thickness of the front panel of your camera that hold the pinhole and where you mount the pinhole, and also the size of the opening of the front panel. Sure, that's a way to restrict the size of the image circle. If you go that way, instead you may just want to make a circular cut out of opaque material, print the image with your enlarger then place this circular cut out in the center turn on the room lights some seconds, presto! you have your circular image! Photoshop would make it even easier/faster to achieve it. Not quite sure the aesthetics would be what Thom is looking for, tho, but as always, I may be wrong. Guillermo
[pinhole-discussion] Re: image circle relative to focal length/fstop
Hello Thom, Is that you want to get a circlar image with dark corner or dark edge? What film format are you going to use. I try to make pinhole camera to avoid dard corner, my 1 inch focal legnth cameras can cover the whole 4 x 5 film! If you want to control the circular image to 2' or 3 (the range is quite big!), the main factor is the thickness of the front panel of your camera that hold the pinhole and where you mount the pinhole, and also the size of the opening of the front panel. Focal length is also a factor. Try to draw a section view (1:1) of your camera with the pinhole, front panel(with opening) and the film plan, then draw a projection line starting from the pinhole, through the upper and lower edge of the opening of the front panel, then you can get the image circle (you can get the diameter from the drawing). Adjust the thickness of the front panel or the distance between the pinhole and the front panel, or the focal length will change the size of the image circle. You can also control the sharpness of the circular image by adjust the distance between the pinhole and the front panel. ***We don't take in consideration of the thickness of the pinhole material, the one I use is 0.001 inch. Hope this may help. Zernike - Original Message - From: Thom Mitchell tjmi...@ix.netcom.com To: pinhole-discussion@p at ??? Sent: Monday, March 25, 2002 5:44 PM Subject: [pinhole-discussion] image circle relative to focal length/fstop How can I quickly determine the size of the image circle for a given focal length and f/stop. I want to be able to keep an image circle from getting too big, i.e. I want it to be 2' or 3''. Any quick help would be appreciated as would simple rules of thumb as opposed to some of the derivative calculus I sometimes
