Posted: 11/14/2009 11:02:12 AM EDT
So, I just got my new-to-me 20D delivered today. Of course, my lens isn't here yet, so I decided to try my hand at making a pinhole lens from the body cap.  Here are few of the results!    I think I'm going to have to find out how to clean the sensor!  (I did put a piece of clean, clear tape on the other side of the hole, so as to not aggravate any more dust buildup.) |
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Quoted: This is very cool. I love this type of experimentation.  It was so easy, I don't know why I didn't try this before! It took all of five minutes to find the center of the cap with a caliper, mark and drill it by hand with a 1/16" bit, (which is too big a hole for an APS-C sensor,) and tape the aluminum foil over it and poke the smaller hole through it. They do work best with larger sensors, though. |
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Quoted: Quoted: That's cool. What kind of shutter speeds do you have to use? Depending on the ISO and outdoor/indoor lighting, between 3-13 seconds if I remember correctly. I'm guessing it would be a few stops less on a non-overcast day. The F-stop is probably huge on that thing. Just a very rough estimate would be: 1/2 inch focal length and 1/64th inch aperture. This would give you f/~128 which is 3 stops darker than f/16 and 6 darker than f/5.6. One must increase shutter length accordingly. Sunny 16 rule states, ISO 100 would give you an exposure of 1/100th @ f/16. Therefore, sunny 16 rule would predict that the pinhole camera would be 1/12th in bright sunlight. Of course, it looks cloudy outside, and I could be significantly off with my estimated measurements. |
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Quoted: Quoted: Quoted: That's cool. What kind of shutter speeds do you have to use? Depending on the ISO and outdoor/indoor lighting, between 3-13 seconds if I remember correctly. I'm guessing it would be a few stops less on a non-overcast day. The F-stop is probably huge on that thing. Just a very rough estimate would be: 1/2 inch focal length and 1/64th inch aperture. This would give you f/~128 which is 3 stops darker than f/16 and 6 darker than f/5.6. One must increase shutter length accordingly. Sunny 16 rule states, ISO 100 would give you an exposure of 1/100th @ f/16. Therefore, sunny 16 rule would predict that the pinhole camera would be 1/12th in bright sunlight. Of course, it looks cloudy outside, and I could be significantly off with my estimated measurements. It was overcast that day. The 1/12th sounds about right for regular sunlight. Indoors, I can take some nice closeup exposures when illuminating the object with the 120 lumen G2. |
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Quoted:
I think I'm going to have to find out how to clean the sensor! (I did put a piece of clean, clear tape on the other side of the hole, so as to not aggravate any more dust buildup.)A blast of air from a bulb-squeezer might be worth a shot. Does the camera have an ultrasonic cleaning mode you can access? My wife's Nikon D60 does this every time it starts up, it's like a dog shaking off dust essentialy. |
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Cool stuff Tony. I had actually considered doing that one time when I was bored. I stopped short of drilling a hole in the body cap though for some reason. Maybe I'll go ahead and try it! I have yet to figure out how to make the perfect hole however. If you use a needle, you end up with a slightly irregular hole, and the material pushed to the sides makes for a flawed image. If only I had a laser... Oh by the way, you aren't getting dust in there from using the pinhole. Maybe you already knew this, but running at such an incredibly high f-stop actually reveals dust already on the sensor. At reasonable f-stops the dust is far enough out of the focal plane to be blurred away. Take a pic of a white wall, and you will see every grain of dust using a f/128 lens. |
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Quoted:
Cool stuff Tony. I had actually considered doing that one time when I was bored. I stopped short of drilling a hole in the body cap though for some reason. Maybe I'll go ahead and try it! I have yet to figure out how to make the perfect hole however. If you use a needle, you end up with a slightly irregular hole, and the material pushed to the sides makes for a flawed image. If only I had a laser... You know, you actualy could do that. A piece of black electrical tape, and a diode from a DVD burner. That's the low end of how guys make their own burning pen pointers on places like Candlepowerforums. 
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Quoted: Quoted: Cool stuff Tony. I had actually considered doing that one time when I was bored. I stopped short of drilling a hole in the body cap though for some reason. Maybe I'll go ahead and try it! I have yet to figure out how to make the perfect hole however. If you use a needle, you end up with a slightly irregular hole, and the material pushed to the sides makes for a flawed image. If only I had a laser... You know, you actualy could do that. A piece of black electrical tape, and a diode from a DVD burner. That's the low end of how guys make their own burning pen pointers on places like Candlepowerforums. OOoooh! Good idea! Hadn't considered the DVD laser diode. With some trial and error it might work, as long as the tape melts into a perfect or nearly perfect circle. |
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Quoted: Quoted: Quoted: Cool stuff Tony. I had actually considered doing that one time when I was bored. I stopped short of drilling a hole in the body cap though for some reason. Maybe I'll go ahead and try it! I have yet to figure out how to make the perfect hole however. If you use a needle, you end up with a slightly irregular hole, and the material pushed to the sides makes for a flawed image. If only I had a laser... You know, you actualy could do that. A piece of black electrical tape, and a diode from a DVD burner. That's the low end of how guys make their own burning pen pointers on places like Candlepowerforums. OOoooh! Good idea! Hadn't considered the DVD laser diode. With some trial and error it might work, as long as the tape melts into a perfect or nearly perfect circle. Or you could buy one already made...  But that takes all the fun out of it! |