f250 and 0.2 mm for 4 x 5. Is it the best?

[norm123]

Hi

I am new in pinhole photography. I just got a 4x5 pinhole camera with a 0.2 mm hole size, f250 and a focal of 50mm.

I began to read about pinhole photography and I think that my best hole size should be 0.3 mm.

Is there an optimum combo for focal/hole size? or format/hole size?

I'm a bit confused for now.

Regards

Normand

 

[ciniframe]

Are you sure the focal length is 250mm? A 10 inch focal length? That's a short tele angle of view on a 4X5, roughly the same as 75mm on 35mm cropped to to the same aspect ratio. If it is, then the f ratio would be f1250, that is going to translate into some long exposures, even for pinhole. If I were building a pinhole with that FL then I go for a 0.5mm pinhole working at f500

Just my 2 cents.

 

[norm123]

Are you sure the focal length is 250mm? A 10 inch focal length? That's a short tele angle of view on a 4X5, roughly the same as 75mm on 35mm cropped to to the same aspect ratio. If it is, then the f ratio would be f1250, that is going to translate into some long exposures, even for pinhole. If I were building a pinhole with that FL then I go for a 0.5mm pinhole working at f500

Just my 2 cents.

I'm sorry the focal lenght is 50mm

 

[DWThomas]

Hmmm do you mean a "focal" length of 250mm or an f-stop of 250? If it is the pinhole-to-film distance, I agree with ciniframe.

In my earlier 4x5 pinhole setup I used a .46mm pinhole at about 175 mm pinhole-to-film distance (approx f/375). This was in a press camera where I could vary the pinhole-to-film distance easily, but a series of tests showed a broad range of usable dimensions.

Later I built a fixed distance box with a 62mm film to pinhole distance and a 0.30 mm pinhole, about f/210. This is a fairly wide angle of view and was/is a pretty satisfactory camera; more so than the earlier attempt. I also think I did a better job of fabricating the actual pinhole (the earlier was in soda can sidewall blackened with marker, the latter in 1 mil brass shim stock chemically blackened).

There are some calculators (Pinhole Designer and Mr. Pinhole {who needs to rethink his color scheme!}) available to work out pinhole designs and a bunch of resources at the Worldwide Pinhole Photography Day site.

EDIT: I missed your response while digging up data .... 0.20mm is probably a reasonable pinhole; I believe there is a tradeoff between edge-to-edge and center sharpness when optimizing the hole, but you should be in the ballpark for decent results.

 

[ciniframe]

Yeah, for a 50mm focal length then a 0.2mm diameter pinhole working at f250 should be OK.

 

[NedL]

I agree 0.2mm should be a good size for 50mm "focal" length. Maybe 0.25 for color film, but erring on the side of slightly too small is probably better than 0.3mm.

 

[scheimfluger_77]

There are sooooo many ways to go. Pick up this book by Eric Renner; http://www.amazon.com/Pinhole-Photo...F8&qid=1420752619&sr=8-2&keywords=eric+renner. He's kind of the guru on this stuff. He has historic formulas and methods to calculate the "best" pinhole/focal length it boggles the mind. Get the book.

 

[Jim Jones]

.2mm is a bit small, but try it out. You might like the results. If your camera permits swapping pinholes without too much trouble, experiment. Pinhole photography thrives on experimenting, as there is room for widely varied personal preferences.

 

[SMBooth]

Agree with Jim, my 55mm is .3 but if you happy then go for it. Don't get to hung up about optimum pinhole size.

 

[NedL]

Absolutely agree with the previous 2 posts. On another forum I was just mentioning that I usually don't measure them if they are somewhere in the right ballpark... it's fun to just try them and see if I like them. I'm almost sure that my favorites are not "optimal", they just make pictures I like.

 

[bergytone]

I agree with Ned... optimum is a matter of opinion, in the sense of: does it give you the image you are looking for? Normand, try the pinhole you have and see if you like the results. Its a starting point, and once you see the results, go from there. Read everything you can on APUG and F295 (if you can get in) by posters like NedL and Joe VanCleave and most of all, have fun with it. I'm still at the very front end of my pinhole learning curve... trying to get some nice images by next WWPD so I can be ready to shoot on that day. But most of all, don't get too technical, be experimental and have fun with it.

 

[norm123]

Thank you everybody.

I'll put some sheets in the soup during the weekend.