Fastest possible shutter speeds for pinhole?

[NathanBell]

Hey All,
I'm becoming very interested in pinhole photography and am considering desinging and building a 5x7 camera.
Almost all of my applications would require a high shutter speed (of say 1/125) so I'm wondering if decent exposure at this high shutter speed is possible?

Getting a shutter to work that fast shouldnt be a problem, as I'll modify a shutter system from an old SLR and fit it to the pinhole (I'm a fitter machinist by trade, so I like building/destroying things)

I'm just woried that with such a high shutter speed that it wont expose the negative enough.
I was thinking of using Ilford HP5 400asa 5x7 Sheet film. Pushed if nessessary.

Is this at all possible?

 

[Ray Heath]

g'day Nathan

i don't understand your basic premise, why a fast shutter speed?

pinhole, by it's very nature means long exposure times

the problem i have with my homemade cameras is keeping the exposure time greater than a second so that i can use the lens cap as the shutter

just as in any other type of camera the exposure is a combinatiopn of shutter and aperture, if you blindly want to use a particular shutter speed then yes the exposure may well be wrong

the determining factor in pinhole photography is that the pinhole has a constant relative aperture, a huge number something like f256 for example

Ray

 

[DWThomas]

Well, it's late, and maybe I'm befuddled, but I tried a quick check. Consider that using the "Sunny 16" rule, you would use ISO 125 film exposed at 1/125 at f16. Since pinholes run more like f256 -- 8 stops less exposure, you would need a film speed up around (2^8) x 125 = 32,000. That's pretty hot film.

I had a similar experience to Ray. Using 400 film, I needed exposures in the 1 to 2 second range (which jibes pretty well with Sunny 16), so I switched to 100 film to get a more manageable exposure length for a hand operated flap.

DaveT

 

[rwyoung]

Figure out some baseline exposure times.

1) Box speed of film, lets say you picked ISO 400. Sunny-16 "rule" says with the sun over your shoulder and crisp shadows, your base exposure at f-16 is 1/400.
2) Correct for your pinhole size. I'll just guess at your camera focal length since you said 5x7 and pick 8.5 inches (film diagonal) or 215mm (rounding liberally). And I'll assume your pinhole diameter is 0.5mm, close to "optimal" for said focal length. Now we know your effective f-stop is f-430
3) do the math: (430 / 16)^2 = 722 (again with the liberal rounding). So your base sun over the shoulder exposure is 722 / 400 = 1.8 seconds.
4) apply reciprocity failure factor, this depends on the film. If you were shooting HP5+ I'd say you need 2.5 seconds. Lets just call it 3 seconds.

So, 1/125 second is a bit on the fast side.

 

[Sirius Glass]

My Nikon with the f/180 pinhole shoots 400 ASA film at about 0.25 seconds on a sunny day.
f/ seconds @ ASA 400
16 1/400
22 1/200
32 1/100
45 1/50
64 1/25 AA'sfavorite f/stop
90 1/15
128 1/8
180 1/4 <= what I use on a sunny day
256 1/2

Steve

 

[Murray@uptowngallery]

I started trying to come up with an analytical example of what you'd have to do to make this fly. It didn't come to me right away, so I started with a sunny-16 example.

f/16, 1/400

If you were metering with an EV meter, that would be (APEX) AV8+TV8.6 = 16.6

say EV16.5

If you were shooting 5x7 and wanted 'normal' angle of view, let's assume about 220 mm camera length. One opinion of optimal pinhole diameter is 0.625 mm, say you had a 0.6mm pinhole. that's about f/366. Call it 360 for easy math.

If you'll take my word for it, f/360 is an APEX aperture value of 17.

Let's say it's wee bit brighter and we call the lighting EV17

EV-AV=TV
17-17=0

Again, take my word for it, an APEX time value of 0 = 1 second.

At ISO400 you are roughly 7-8 stops off.

That would be a lot of pushing for the film...right?

Say you went somewhat wide angle, 4.5" or 115 mm camera. One pinhole calculator gives you a suggested pinhole of 0.45 mm, this gives you a roughly f/256 camera.

This only gained you one stop advantage over the previous design.

I have heard of people doing handheld pinhole work with the Ilford 3200 of the old 3000 Polaroid, but can't tell you the math behind how well it should work.

It is said that because pinhole resolution is so much lower, one can hand-hold a pinhole camera at much lower shutter speeds than a lensed camera and tolerate the appearance. I think I heard a factor of 5. That doesn't solve your need for 1/125 sec. If that's based on presuming that is necessary for handheld work, the rule of thumb would be that you could roughly get away w/1/25 sec with pinhole.

Now, some people do manage some amazingly sharp work with slightly smaller than 'optimal' calculator pinholes (say 75% of optimal diameter).

If you want sharpest possible, I wouldn't but all my money on the 1/5 speed rule compared to lens (and that rule for a lens was 1/f.l., so 1/220 s, that gives you about 1/45 for pinhole, between 1/30 and 1/60).

 

[Murray@uptowngallery]

I took too long typing.

 

[mmmichel]

I agree with most of the posters here that 1/125 sec does not seem doable. However, as Murray mentioned, you can get a little more speed by going wider. My favorite focal length for pinhole on 4x5 is 50mm. That translates to about 67mm on 5x7, which (with a .4mm pinhole) yields roughly f/168. With EI = 400, this should get you to about 1/4 of a second on a sunny day.

I've seen photographers go as wide as 25mm on 4x5 (Zeroimage sells such a camera), which is roughly 34mm on 5x7. Using this wide a camera with 400 ISO film pushed to EI 1600, you can get to 1/32 of a second, or 1/64 of a second at EI 3200, which is probably the practical limit. At this point, the cos^4 falloff, along with the lost shadow detail will start to severely restrict your usable image circle.

Melchi

 

[Murray@uptowngallery]

Sorry, I can't resist the irony here.

If someone wanted to build a ULF 20x24" giganto camera and wanted a cheap 12" lens that would cover, the peanut gallery would tell him to go pinhole.

Here, the proposal almost says 'get a lens'.

He's not down & out yet. Maybe the 1/125 requirement can be relaxed a bit. Landscapes instead of sports.

 

[Ray Heath]

g'day Nathan

"get a lens" as Murray suggests is exactly what i did with my homemade cameras

wanting to avoid extremely long pinhole exposures i experimented with magnifying glasses as simple lenses

i came to prefer the look created by these cheap optics, sharp in the centre blurring to the edges, somewhat like the old lenses people here rave about, (Petzvals?)

these magnifying glasses are very cheap, $2 or so, the camera is then designed around the lens, i now have 8 cameras in various sizes, 4x5, 5x8, 5x7, 8x10 and am currently building an 11x14

using FB paper gives a look i prefer and keeps the ISO at about 6, this then equates to exposure times of seconds and minutes

Ray

 

[Jim Jones]

Here are several approaches to increasing shutter speeds in lensless photography. They all involve a reduction in image quality.

1. Reduce the film size.

2. Reduce focal length.

3. Use fast film: ISO 3200 film can be pushed to even higher speeds with a loss of shadow detail.

4. Use flash.

5. Use zone plates.

Pinhole cameras have been used for high speed photography. 70 years ago General Electric built a high speed pinhole camera to record the progression of electrical arcs at 120,000 frames/second (page 42-43, Photo Technique, October 1939). However, this special project has no application in conventional photography.

 

[Christopher Walrath]

I switched to Efke25 in my 35mm matchbox pinhole cameras which, at f/90, put about EV15-EV15.5 at about 1 second. I use TMX in my 6x6 homemade pinhole for an EV16 at one second (f/256).

 

[Greg_E]

Chris,

How do you like the Efke 25 for pinhole? I have a couple rolls for testing in my 645, thought I would test both lens and pinhole on that platform. Also bought some Efke 50 to shoot along side the 25. Planned on having it DR5 processed for positives.

 

[mmmichel]

Hyperfocal Camera?

If you're willing to accept a little bit of field curvature, a hyperfocal camera might be a better idea (you can find more information on these at http://pinhole.stanford.edu/hyper.htm). The idea (consistent with Ray's suggestion) is to get a simple positive lens element and stick it behind a slightly enlarged pinhole. You can get positive lenses in specific focal lengths from Anchor Optics for between $5-$10. I took the attached photos (on TMX) using a 50mm 4x5 hyperfocal camera that I built using an element from a trashed lens. The pinhole on this camera is about .45mm, creating an f-number of about f/107. With such a camera, your desired shutter speed should be possible (e.g., by pushing 400 film two stops on a sunny day).

 

[Murray@uptowngallery]

That's a good compromise.

Where'd he go?

 

[NathanBell]

Where'd he go?

I'm still here. I have been spending a bit of time trying to take this thread in before I replied and demonstrated my total novice apprach.

I understand what everyone has said about not getting a great exposure with my suggested method and am trying to read up on your comprimises (which I thank you all for giving me! )

Firstly I should explain what I want to do and why...

I've always been told to shoot what I love and what inspires me.

My #1 passion in life is mountain biking, (followed closely by music and photography) so I want to concentrate on Mountain Biking as a subject.
Telling a story of not only the personalities, but also the reason those people compete which is the traveling, the social life it provides, and the action and adrenelene etc.

This last point is the reason for this post. I really want to capture the action utilising something I'm also interested in, lensless photography.

Most other aspects of this sport (the places it takes us, the social life it provides and the personalities it involves) can be covered by relativelly low shutter speeds.

I have an idea for making a pinhole camera out of a full face mountain bike helmet (similar to a motorcycle helmet) so a smaller format size would suit this application.
The pinhole would be inside the helmet and the framing of the image would try to replicate the cyclist's view. i.e. the image would be framed by the opening at the front of a helmet.
This would be used to shoot the courses we compete at from the riders perspective. Some of which is the most beautiful scenery in Australian.

While taking action images through pinhole, is it possible to take multiple (sequenced) images of a single rider descending the course (all taken from the same position) and will the rider become visible in multiple positions across the image?
What I mean is, if the appropriate shutter speed is 8 seconds, can I take 16 x 0.5 sec exposures, and would the rider become visible in the image. I'm guessing not.

Hope this explains my intentions...
And thanks again for all the advise, I'll spend some time reading up on your sugestions and try to take it all in!

 

[Ray Heath]

g'day Nathan

there are probably easier/faster/more effective ways to achieve what you have in mind

great ideas, but what will aspects such as using a helmet camera add to the final images?

why do you need to do the activity whilst you photograph it?

your multiple exposure idea, any object within the image area that does not move will be recorded and exposed correctly, anything that moves constantly will record a 16th less/thinner than normal/correct

Ray

 

[NathanBell]

great ideas, but what will aspects such as using a helmet camera add to the final images?

why do you need to do the activity whilst you photograph it?

I'm not talking about photographing whilst doing. I mean I want to frame the image to give the illusion that the viewer is seeing what a rider would be - From the inside of a full face helmet.
The camera would be set up on a stationary tripod and mounted inside a full face helmet.
Blured movement by moving the camera forward whilst exposing would definatelly add to the sense of speed, but I dont think I could come up with a practicle way of achieving this other than setting up a rail system. :confused:

Once I have a camera made, I might do some experiments to this effect though!

your multiple exposure idea, any object within the image area that does not move will be recorded and exposed correctly, anything that moves constantly will record a 16th less/thinner than normal/correct

Ray

Yep, thats what I thought...

 

[Jim Jones]

A subject recorded in several exposures as it moves across a stationary background will appear like a transparent ghost, if at all. When the subject is brightly illuminated and the background is quite dark it works somewhat better. To best combine your interest in mountain biking, music, and photography you might bike to a scenic destination, set up a traditional pinhole camera, and time the exposure with music as Leopold Mannes and Leopold Godowsky did in the darkroom while they were doing the research that led to Kodachrome.

 

[Murray@uptowngallery]

Two Leopold's on the same project. That's synergy. Maybe that's why such things aren't discovered every day.

Nathan - you need a second Nathan on this project.

 

[2F/2F]

Hey All,
I'm becoming very interested in pinhole photography and am considering desinging and building a 5x7 camera.
Almost all of my applications would require a high shutter speed (of say 1/125) so I'm wondering if decent exposure at this high shutter speed is possible?

Getting a shutter to work that fast shouldnt be a problem, as I'll modify a shutter system from an old SLR and fit it to the pinhole (I'm a fitter machinist by trade, so I like building/destroying things)

I'm just woried that with such a high shutter speed that it wont expose the negative enough.
I was thinking of using Ilford HP5 400asa 5x7 Sheet film. Pushed if nessessary.

Is this at all possible?

If you need '125, you are going to simply have to use a very fast film.

HP5 at 500 gives you '125 at f/32 in bright sun. Pinholes are usually at least four stops higher than that.

Your best option in this case would be a high-resolution, low noise digital SLR such as the Canon 5D set at a high ISO. It's the only way you can get high resolution and a fast shutter speed using a pinhole.

Otherwise, what is wrong with a smaller format? It will make it a bit more easy, anyhow.

2F/2F

 

[orto]

The best option is to build a simple pinhole, put a shutter behind the hole, put the thing in the helmet, take some pics, get home - and start to think in real terms about pinhole photography. It costs less than a low noise digital SLR.

 

[Ray Heath]

ah, possibly the best option is to let go of the fixation with 1/125th, it's just not pratical for pinhole imaging

 

[2F/2F]

By "best option", I meant best option for the OP's requirements, which were '125 sec and high resolution.

Of course a DSLR is an expensive and silly option.

But then again, I would say the same about any pinhole in this situation...not the expensive part, but the silly part.

 

[NathanBell]

Hmmm yes, I think I was getting a bit ambitious.
I've recently picked a Mamiya C220 TLR so I will learn to use that for the time being.
I just bought about 20 rolls of 120 film, so I might make myself a pinhole camera to suit the 120 Delta 3200 film and give that a try.

Another newbie question.
Can someone please explain the maths behind pinhole designing? (calculating camera sizes, angle of view, f'stops, exposures etc)
There have been quite a few calculations in this thread given as examples. Can some explain each of the formula's to me? Or give me a link to someone else's?