# Large Format Landscapes

Show 50 post(s) from this thread on one page
• 5-Jan-2014, 16:38
csxcnj
Re: Large Format Landscapes
Quote:

Originally Posted by StoneNYC
Oh! Thanks

Yer welcome. Go to B&H and check out pinholes to see the range and size/focal relationships. Go to the Bender website (still up after all these years) to see a really cool pinhole system, one that allows ground glass viewing of the image. Bender is out of business of course so I can't order the system but I'm going to attempt making something similar.
• 5-Jan-2014, 22:30
Nathan Potter
Re: Large Format Landscapes
Pinhole cameras are wonderful devices with infinite DOF (with some reservations). There is generally an optimum pinhole diameter size d for a particular focal length F and wavelength of light lambda, a relationship first postulated by Petzval (yes that famous that old timer), such that D = (2 X FX lambda)^1/2.

So for the image above when we apply the Petzval relation we have D = (2 X 75 X .0005)^1/2, which is the sq. root of 0.075 which is .274 mm. That is 274 µm or about 11 mil diameter hole.

The f/no would be FL/d which is 75/.274 which is f/274. He obviously used a slightly different aperture diameter or a different value for lambda. :)

Nate Potter, Austin TX.
• 5-Jan-2014, 23:27
jcoldslabs
Re: Large Format Landscapes
I have a Zero Image 4x5 pinhole camera with two extension frames. This means I can shoot 25mm, 50mm and 75mm focal lengths all using the same 0.18mm pinhole. Ideally I would use the "optimal" pinhole diameter for each separate focal length, but I haven't found it to be a problem other than the fact that the f/138 aperture at 25mm becomes a whopping f/417 at 75mm.

Jonathan
• 6-Jan-2014, 06:51
StoneNYC
Re: Large Format Landscapes
Quote:

Originally Posted by Nathan Potter
Pinhole cameras are wonderful devices with infinite DOF (with some reservations). There is generally an optimum pinhole diameter size d for a particular focal length F and wavelength of light lambda, a relationship first postulated by Petzval (yes that famous that old timer), such that D = (2 X FX lambda)^1/2.

So for the image above when we apply the Petzval relation we have D = (2 X 75 X .0005)^1/2, which is the sq. root of 0.075 which is .274 mm. That is 274 µm or about 11 mil diameter hole.

The f/no would be FL/d which is 75/.274 which is f/274. He obviously used a slightly different aperture diameter or a different value for lambda. :)

Nate Potter, Austin TX.

I wish I understood that math... My head hurts... I used to be good at this stuff but it's been 10 years since I did any math at all.
• 6-Jan-2014, 09:27
OCM
Re: Large Format Landscapes
Quote:

Originally Posted by Jose Rodriguez
http://farm8.staticflickr.com/7004/6...e5a11651_o.jpg

The Jarama river

Santa Barbara Pinhole 75mm 4X5 Camera
Fuji Acros 100
8 sec.
f231
Minolta Spotmeter F

Qué maravilla, Jose. No sabía que tenías una de éstas. Abrazos.

Great photo, Jose. I didn't know that you had that camera. Nice surprise. ;-)

Best regards.
• 6-Jan-2014, 10:30
Nana Sousa Dias
Re: Large Format Landscapes
Quote:

Originally Posted by Ken Lee
http://www.kenleegallery.com/images/...2013-12-13.jpg
Massachusetts, 2013
Kodak 2D, 300mm Fujinon A
5x7 HP5+, D-23

Beautifull...
• 6-Jan-2014, 10:32
Nana Sousa Dias
Re: Large Format Landscapes
Quote:

Originally Posted by Nguss
Great stuff Alex. This is one on Ektar 100 converted to black and white because of the light in the foreground and across the boats. And because I forgot to take any proper black and white film with me.

http://farm6.staticflickr.com/5508/1...a95ce3ac_z.jpg
Those boats at Holy Island Ektar 100 Large Format by NGUSS, on Flickr

I like this, very much...
• 6-Jan-2014, 10:33
Nana Sousa Dias
Re: Large Format Landscapes
Quote:

Originally Posted by Preston
McGee Creek, Sierra...

http://www.gildedmoon.com/images/npn...-sq-lg-Web.jpg

Tachihara 4x5
135mm Fujinon
Velvia 100F
October 2005--recently reworked some.

--P

Well done, Preston.
• 6-Jan-2014, 10:39
Nana Sousa Dias
Re: Large Format Landscapes
Quote:

Originally Posted by ScottPhotoCo
Yes, it does. My self imposed rule for PS is that I don't do anything that couldn't be done in the traditional darkroom. Nothing is moved, added or taken away. I use the dodge, burn and simple contrast adjustments to try to get what I'm after.

Tim
www.ScottPhoto.co

I try to do the same but, I use split-contrast, too, wich gives me a lot more possibilities, but, sometimes it's hard to get what I want. What's really missing in the darkroom is the "undo" button! ;-)
• 6-Jan-2014, 10:48
Nathan Potter
Re: Large Format Landscapes
Stone, I hear ya. Math is a bit like language - if you don't use it regularly it slips into the dark recesses of the mind where it can't be easily extracted. I have that trouble with higher math and I work high tech solid state physics all the time. Notice that Einstein and Stephen Hawking had fellow mathematicians helping them. I believe Einstein used David Hilbert and Hawking uses Roger Penrose.

My note above only uses simple algebra and my example should suffice for the novice. But the notation may be unfamiliar, particularly the form of ( X )^1/2. That is just another way of saying the square root of X. Or √X. Use of the ^ indicates something like X raised to a power or an exponent - rather awkward notation due to the standard keyboard being unfriendly to math symbols.

Nate Potter, Austin TX.
Show 50 post(s) from this thread on one page