The quest for f500.

Grandpa Ron

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Since I have some nice pin hole shots with 200 ISO film at f360 I am going to try f500.

I have at least three different formulas for pinhole size vs. focal length. One of which requires more than 10" of bellows.

I was wondering if others have tried f500 and how successful they have been.
 

ic-racer

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I used somewhere around f700 for the last eclipse.
 

Jim Jones

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The diameter of any pinhole near the optimum pinhole size displays characteristics of both geometric and wave theory optics. At this diameter the image displays finer detail than either geometric optics or wave theory predict. Thus, there is an advantage in using pinholes accurately sized if the best sharpness is the photographer's goal. In photographing the USAF 1951 test target, an optimally sized pinhole will clearly resolve target line pairs with a spacing finer than the pinhole diameter. This defies logic until analyzed by someone with a better grasp of math and physics than me. While diffraction usually limits image detail in photography, perhaps we could call its effect on pinhole photography as constructive diffraction.
 

RalphLambrecht

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finding the right pinhole size is a balance between increasing sharpness and limitin diffraction. I find that around f/256 is a 'sweet spot' for me at this point resoution and diffraction are till OK and contrast is good.smaller openings theoetically increase resolution but in reality, diffraction takes over and 'optical' qulity suffers too much.
 

Donald Qualls

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The longer the focal length, the smaller the aperture ratio of an optimum pinhole. For Pintoids (made from Altoids tins, focal length around 10 mm) it's f/100 or so; for a camera like the Ondu 135 (25mm or so FL) and CCB 6x6 (30mm FL) it's around 1/150, for my Zeiss Ideal plate camera with pinhole shutter (135mm FL) it's about f/270.
 

Jim Jones

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The highest f/ number I know of was achieved by temporarily converting a large building into a pinhole camera: https://en.wikipedia.org/wiki/The_Great_Picture. It was about f/2750. For photographing a solar eclipse I used a camera with a focal length of about 25 feet, about f/2400. Much easier to handle was its baby brother with a focal length of about 8 feet (f/1400). Both of these were fabricated and operated by one person. The one in the link above required a large crew. It's image was 107x37 FEET!
 

jeffreyg

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I'm not into the mechanics s o I went with the Ilford Titan. With their shorter cone they suggest F206. I imagine the specs are online. They also had a handy exposure dial that I printed and plasticizes and assembled. I take an incident reading and interpolate. I figured out a reciprocity table for HP5 -my go to film I print most of the negatives as pt/pd contact prints. Here is an example

http://www.jeffreyglasser.com/

http://www.sculptureandphotography.com.

 

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pbromaghin

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Oh, my. NEVER seen a pinhole photo that was so clear.
 

jeffreyg

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Thanks. It was eary in the morning and dead calm. 4x5 film and a very sturdy tripod. Here is another.
 

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jeffreyg

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A couple of coments appeared tom to indicate the begonia leaf image was not legit. I Never misrepresent my work and I do use my real name. I recently retired after 58 years of practicing dentistry and during that time i had photographs in 60 exhibitions the most recent of which was a one person exhibition at the IPC ArtSpace curated by Carl Juste a Pultizer Prize winning photo journalist also in previous years on the Hasselblad and Ilford websites, in Black&White magazine several times and printed a limited addition series of images in platinum/palladium for an internationally prominant photographer. Here are a couple of images from the same session (all in my back yard) as the begonia leaf and one that i happened to be a shadow with as you can see the Titan on my tripod. All on HP5 scanned with SilverFast Studio 8Ai

http://www.jeffreyglasser.com/

http://www.sculptureandphotography.com/

 

Ces1um

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Hope you didn't think my comment wasn't inferring anything. It wasn't meant to. As a current practicing dentist I have a harder time believing you were able to practice for 58 years! There's no way I'll be able to do that. I'll be deaf from the drill by the time I'm 60!
 

MattKing

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jeffreyg said:
Thanks. It was eary in the morning and dead calm. 4x5 film and a very sturdy tripod. Here is another.
View attachment 274294
Click to expand...
For some strange reason I see two different images here, when the wording seems to imply there should be just one.
I can understand why people are amazed by the quality of the begonia negative - but other than the possibility of jeffrey posting the wrong file in error (and not noticing), I certainly wouldn't doubt his veracity.
 

jeffreyg

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Matt,
The additional begonia images are: one and it's negative image and another separate image. The three total images : the original that sparked the comment, a positive and negative and the third horizontal. All exposures were made in my back yard on the same morning one after another. We don't have dead calm that often. It was early in the morning shortly after sunrise. We have a large yard with close to two hundred trees with a natural canopy. I didn't mix up any files. I had to go back and scan the negatives to make the posts.
Thanks,

Jeff
 

MattKing

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Jeff - I didn't think the begonia related images were mixed up, but I was confused about the "Kill your Idol" and "Ficus" images in post #16, which accompanied the words "Here is another" (not "Here are two more").
 

jeffreyg

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Sorry about any confusion I clicked the ficus as a thumbnail but posted the kill as full image
 

grat

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I've done similar to that on here-- the trick is to edit the post and delete the thumbnail from the upload area at the bottom of the post.

... if you care.
 

MattKing

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And as for confusing me, there are lots of ways to do that - and I'm sure lots more that are yet to be discovered!
 
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