PDA

View Full Version : K-20 Aircraft Camera



ziplock
07-28-2005, 08:40 PM
Has anyone tried to make a pinhole camera from one of the old large format roll-film aerial cameras? There's a Graflex K-20 aircraft camera that is near enough to me to pick up myself (and not pay shipping for this monster) and I am going to buy it as long as it's not over $20 or so. These cameras are fixed focus and take 5 inch wide rolls of film. I believe it takes 4x5 frames and will hold something like 200 feet of film in it's cartridge.

Any info on film for it? Has anyone tried to convert something like this before? It caught my attention because it's so different and I love the bizarre. If I can find true B&W film for it somewhere perhaps I could develop it at home on a spool or something. Attached files http://f295.f295.org/uploads/c9_12_sb_1320.jpg (http://f295.f295.org/uploads/c9_12_sb_1320.jpg)

Tom Persinger
07-28-2005, 11:16 PM
if you watch ebay that film pops up with surprising frequency, and as there are limited users it usually goes for a good price... sounds like a great idea!

ImageMaker
07-29-2005, 05:13 PM
There's a seller who routinely has Plus-X Aero film on eBay, usually in 9.5 inch wide rolls, but I think he's also had it from time to time in the 4" rolls that would drop into that big Graflex. If nothing else, you could slit one of the 9.5" rolls (which are 1000 feet long) and get ten rolls for the Graflex, then make about 700 rolls of 828 out of the middle. :)

murrayatuptowngallery
07-29-2005, 09:18 PM
I don't want to doubt Donald/ImageMaker's 4" film identification because he has more confidence in his answer, and I'm hedging, but I recall something 'wrong' with the K-20 vs modern aerial film...I can't state with confidence that it is or isn't 4" but it is awkwardly diifferent from 5"...my initial thought was 5-1/4", but Donald probably has it right.

Cutting sheets off a big roll of thinner film is one headache. I would think an amateur slitting job to keep it in roll length would be unpleasant.

If it has a 7" Aero-Ektar radioactive lens you could easily sell it to pay for the camera. Hmmm,.....no, I better not offer...

ziplock
07-29-2005, 09:36 PM
Yeah, I'm hesitant to try cutting a roll to fit this camera. I checked around and it is 5 inch film and I found one closed auction on eBay for a roll of 5" film, so it's out there.

ImageMaker
07-30-2005, 04:21 PM
If you get a roll of that film, I'd love to read about the adventure of developing it once you manage to expose about 600 frames...

ziplock
07-30-2005, 05:28 PM
If you get a roll of that film, I'd love to read about the adventure of developing it once you manage to expose about 600 frames...

Hah, yeah. I've considered both those problems. I figured I would be able to load a partial roll somehow and only have 10 to 20 exposures on it.

I haven't seen anything about whether or not it's possible to x-process B&W aerial film in normal B&W chemistry, I think the Tri-X that is sold in the 9.5" rolls on eBay uses normal chemistry.

My sister-in-law works at a small airport so I think I'll see if she knows any friendly aerial photographers who would be willing to try to answer bizarre questions. :)

If worst comes to worst I've seen some people online discussing adapting it to take 4x5 sheet film holders.

ImageMaker
07-30-2005, 08:58 PM
The Plus-X Aero certainly will process in normal B&W chemistry -- it's a silver-based B&W film, the only difference is in the sensitizing dyes, to give the extended red sensitivity (BTW, it would probably also show Wood effect with a suitable filter). The aero films may require some adjustment of EI and times due to both age and varying spectral sensitivity, but they're still just B&W films.

Adapting for a ANSI 4x5 holders might be the simplest method. At its most basic, you could just cut through the body at the correct distance, graft on a Graflok back, verify the focus, and have at it.

ziplock
07-31-2005, 03:35 PM
Alas, the price on the auction has gone past the point where I could justify buying this camera "to see what I can do to it".

murrayatuptowngallery
08-02-2005, 12:52 PM
OK, I've read about wood or Wood effect, but guessed what it meant (still no clue).

What does it mean...is it named after Mr or Mrs or Ms Wood, or...
and what would look like wood, other than wood?

Wood someone answer this? (har)

Murray

Daryl
08-02-2005, 01:18 PM
None of the above.

Professor R.W. Wood (infrared photography pioneer) was first to document the effect in 1910.

And the R.W. Wood prize is bestowed by the Optical Society of America.
http://www.osa.org/aboutosa/awards/theawards/awardsdesc/award14.asp

ImageMaker
08-02-2005, 02:17 PM
Murray, just to clarify a little, Wood effect is the brightening of foliage with an infrared sensitive film and deep-red or infrared filter. Turns out chlorophyll reflects strongly starting in the deep red (around 700 nanometers, IIRC), and fairly far out into the infrared, and a suitably sensitized film protected from shorter wavelengths will thus record healthy foliage as bright compared to dead or dying foliage and most inert materials. Many panchromatic and extended red sensitivity films can record Wood effect; it doesn't absolutely require an IR sensitive film.

Daryl
08-02-2005, 02:43 PM
It was thought, early on and widely published (by Kodak?),
that the effect was due to chlorophyll reflecting infrared.

We now know that chlorophyll is transparent to infrared.

The most recent thing I heard was that the reflection has to do something with the cell walls and air pockets called the "sponge parenchyma" and is usually on the underside of leaves. The integrity of this layer is breached in dying or diseased foliage and won't show the effect.

Of course our understanding could change at any time without notice. :-/

ImageMaker
08-02-2005, 08:50 PM
Ah, okay, so the chlorophyll, transparent to IR, lets it pass through to the parenchyma layer and then reflect back from that. Nice to know (I'll let you know if it's every of any use, but still nice to know).

Effect is the same, though -- only healthy foliage shows this very bright IR reflectivity.

murrayatuptowngallery
08-03-2005, 10:30 AM
Thanks D&D for the explanation.

I previously thought it meant something like clouds appearing to be hand carved and grainy :O).

So I see I'm now a Journeyman...I thought that took 8 years...and that's for asking a lot of questions?

M

ImageMaker
08-03-2005, 05:48 PM
So I see I'm now a Journeyman...I thought that took 8 years...and that's for asking a lot of questions?

And I'm a grandmaster after less than a year of activity. Yeah, sure...

As far as I can tell, it's based solely on number of posts. The software used to just display number of posts (presumably so if we weren't paying attention otherwise we could tell newbies from old hands); now we get these rankings instead.