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02/26/2009 06:59:52 AM · #1 |
Hi,
How do you make pinhole images not blurry? |
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02/26/2009 10:00:45 AM · #2 |
What do you mean by "not blurry"?
There are several factors that will affect sharpness, but pinhole images are pretty much all going to be blurry to some degree. They do have the somewhat unique property of being uniformly blurry from front to back.
Ideally, you'll have a fairly small hole (0.3mm or so depending on the sensor/film size) that has a nice circular shape and a sharp edge.
Do you have some images you can post or link to that show your results and maybe an example of what you're trying to achieve?
Message edited by author 2009-02-26 10:03:44. |
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02/26/2009 10:02:59 AM · #3 |
| My guess would be how clean the pinhole is. When I made a pinhole camera back in university, we would cut a whole in the box, and tape aluminum foil across the hole, because it was easy to punch a clean hole in the aluminum foil, as opposed to through a thick object such as cardboard. |
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02/26/2009 03:19:39 PM · #4 |
Originally posted by jeger:
My guess would be how clean the pinhole is. When I made a pinhole camera back in university, we would cut a whole in the box, and tape aluminum foil across the hole, because it was easy to punch a clean hole in the aluminum foil, as opposed to through a thick object such as cardboard. |
Maybe it helps if I specify digital pinhole, made by drilling a hole in a lens cap. All images I've seen so far are not sharp. What does the sharpness depend on? |
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02/26/2009 03:20:06 PM · #5 |
Originally posted by jeger:
My guess would be how clean the pinhole is. When I made a pinhole camera back in university, we would cut a whole in the box, and tape aluminum foil across the hole, because it was easy to punch a clean hole in the aluminum foil, as opposed to through a thick object such as cardboard. |
Thanks. that makes sense. I wonder if there are any other requirements |
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02/26/2009 04:00:09 PM · #6 |
Part of the beauty of a pinhole image is its 'etheral' quality, if you want a 'pin' sharp image its not the way forwards. And I agree with the others, the sharper the hole the better quality the result.
The best way to create a pinhole in a lenscap is to make the hole larger than required then insert a thin bit of (say) tin foil with your pinhole in that.
Message edited by author 2009-02-26 16:00:26. |
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02/26/2009 04:04:38 PM · #7 |
The size of the hole depends on how far away the negative is from the front of the lens. Here is a chart that will help you.
1)Focal Length(pinhole to film distance)
2)Pinhole diameter(approximate)
3)Nearest sewing needle size
1) 2) 3)
50 mm 0.26 15
75 mm 0.32 14
100 mm 0.45 10
150 mm 0.55 9
200 mm 0.63 8
250 mm 0.71 7
300 mm 0.77 6
350 mm 0.83 5
400 mm 0.89 4
500 mm 1.00 3
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02/27/2009 08:02:39 AM · #8 |
Thanks guys. The reason I asked was because this was a question on my homework. Here is the exact question
Is nearly every object in a photograph taken with a pinhole camera in focus or out of focus?
Prove your answer as correct (you may use your answer to the previous question as evidence, if
applicable). If you determine that all objects are in focus, and assuming the camera was perfectly still
during the exposure, what are other possible explanations for a pinhole photograph to be blurry?
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02/27/2009 09:47:42 PM · #9 |
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02/27/2009 10:09:54 PM · #10 |
| The distance of the actual hole from the sensor or film makes a difference as well. I am playing with a body-cap pinhole and there is a discernible difference when placing the foil on the outside vs. the inside of the cap. |
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02/27/2009 10:19:40 PM · #11 |
do some googling too... there are a ton of pinhole sites... many use photo paper or film, but lots use digital, and do it effectively.
I've only done it with photopaper--I've made them out of shoe boxes and drilled the hole through a piece of brass that was taped to the inside of the box with electric tape. Also drilled into a coffee can--that was the best results. A super small drillbit provided the best results... a crisp clean hole, and then w/ photo paper we'd set them out for about a minute long exposure. Results were surprisingly sharp.
I think you have a variety of factors... size of hole, size of sensor, distance of hole to sensor...etc...
If you look up focal lengths and depth of field on wikipedia there is a whole bunch of optical physics mumbo jumbo that I can't make up or down out up, but it sure looks scientific! |
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