Film: Kodak Ektar 120 film – ISO 100
Camera: terraPin 6X9 3D printed pinhole camera, 40mm, f/174
I have greatly been enjoying wider angles in my pinhole photography, and my terraPin 6X6 recently evolved to a wider 6X9. Of course, the format size is wider, but the angular width of the photo is actually a function of “focal length”. 35 millimeters is deliciously wide in a 6X6 format, but with the move to a 9 centimeter-wide frame, I was worried that the corners would be too underexposed owing to the greater distance from the aperture. I decided on a 40 mm “focal length”, and based the working f/number and subsequent exposure calculations on the point half-way between the center and the edge. Metering off-center gives a slightly over-exposed center and slightly under-exposed outer margins. This effect is clearly visible in the photo of the crane, made at Seattle’s Fisherman’s Terminal, below.
And in this shot of a navigational light at Shilshole Marina.
Seattle’s Warren G. Magnuson park includes land and structures that date back to the Puget Sound Naval Air Station at Sand Point. This hanger is still used for recreational purposes.
Smart brick offices dating to the second world war have also been repurposed for use of small businesses and non-profits. These photos were made in a race with the setting sun and required progressively longer exposures. I adore the way Ektar captures the reds of dusk and dawn, and shows off the brickwork. There is a ghostly self-inclusion in one of the photos below – see if you can spot me. (edit – I don’t know for sure the age of the pictured brick structures, they might be much newer than WW2)
This roll was processed and scanned by Moon Photo in Seattle; all images are as scanned without alteration. More photos from this and my other 52Rolls can be found HERE.
11 thoughts on “Roll 8: A Wider Shade of Pinhole”
I am really enjoying your pinhole photography. Some amazing results and a lot of interesting technical detail slipped in which could be really helpful when I get around to making one.
I have all the parts now, it is just a matter of making a pinhole the right size and installing it. But time is short right now so it could be a few weeks.
Thanks! Let me know if I can help in any way. I love talking about pinhole cameras.
Here’s a link to how I make my pinholes:
I get really good results using a digital caliper rather than a micrometer.
Thanks schlem! I may well come to you for help. I was planning on trying an insect pin if I can get one from an entomologist friend – they come in some very fine diameters at 0.05mm increments from 0.25mm and larger (http://bit.ly/19M5XKj). The accuracy of the hole might still be a problem with side-to-side movements and so on.
Your link is very interesting – especially as the object I am adapting happens to have a focal length of 190mm. What I am working with is a polaroid attachment for microscopes (NPC MF-10) – it has a circular opening at one end, a shutter (open / closed only, requires cable release) located well back (about 3cm) of the outer edge of the opening and a polaroid 100 film pack back. Essentially its a long plastic tapering rectangular tube that is about 19cm in length from the inside surface of the shutter mount to the film plane. Given that it is a light tight box, with a shutter and a way of holding film but no lens, it seems the ideal starting place for a pinhole camera. And otherwise a good use for an otherwise obsolete piece of kit.
What I am not sure about is whether I must put the pinhole on the outside of the whole works, or if I can put it inside behind the shutter, or in the circular opening immediately in front of the shutter, where it would be protected from impacts and so on. The circular opening in front of the shutter is about 3 cm deep and 4.5cm diameter and then steps down to about 1.25cm diameter for another cm or so into the shutter. The outer part in front of the shutter (with the circular opening) is removable, but I think it might be integral to light-tightness at the front. The question is whether with this focal length there would be vignetting from the circular opening if I put the pinhole near the shutter, or if it would be just fine. I am going to need to chart this out somehow, unless there is a handy on-line app of some kind that I can use.
The other challenge will be setting up some kind of viewfinder for framing the shot.
Here is a picture of what I am working with. Mine is missing the short tube. The picture can be slightly enlarged by clicking on the link under the thumbnail: http://bit.ly/17kiL8Y
Oh, that is an exciting pinhole conversion project! I like the idea of protecting your aperture behind the shutter and it would be nice if there weren’t any vignetting of your image. A little bit of simple trigonometry can help here. What you want to know is the angle of view for the wider dimension of the frame. You’ll need to know how far your pinhole is from the film.
For ease (read laziness), I use this online calculator:
It won’t give you the angle of view directly, but you can easily calculate it from 180 – 2(ϴ). Now you can calculate the angle of view from the pinhole forward to the various diameters and their distances from the aperture. You want the angle of view out of the camera to be greater than the angle to the film. You can also assess this qualitatively, but simply mounting the pinhole and then just viewing from the rear of the frame, and checking for full light through the pinhole at the corners of the frame. If you see the pinhole in full brightness at the corner the frame, so too will your film. I can draw you a picture if that is not clear.
Hope that helps!
Thanks schlem – that is great info. Looks like it will work from the inside – the forward angles of view for the two different forward openings are nearly identical to each other and nearly twice the rearward one. This all means I can mount the pinhole inside the camera behind the shutter which is the optimal location. BTW, I used the mrpinhole.com calculator which provides angle of view (I compared it to your method and they come out the same).
With an angle of view of 36 degrees it looks like this will have coverage similar to a short telephoto lens on a 35mm camera. I thought it was going to be narrower than that, so this is also a good outcome of the calculations. The f-stop will be f323 which means using the Fuji 3000b in sunny weather is going to be difficult (1/8th sec) with a manually controlled shutter, but Fuji 100 colour should be fine (4 seconds).
Now for making the pinhole. It turns out that ideally it needs to be 0.574mm and the insect pin available to me is 0.550mm. I expect with some careful ‘wriggling’ in the hole, I can get it a bit wider. I don’t have a micrometer, so will try to measure it by scanning the pinhole and counting pixels, if I can find the reference for doing that again.
I have a packet of brass shims which are said to be 0.001, 0.002, 0.003 and 0.005. It does not give units, but I am assuming mm though it is an American manufacturer, so ….
Q – Is thinnest best?
Q – Should it be painted flat black on the inside of the camera?
After that will be a view finder of some kind and then it should be done. Perhaps I can scavenge one from a broken polaroid land camera (if I can find a cheap one) and mask it to the right size with help of a ground glass.
Did I mention this unit comes with a tripod mount? Just one more reason it is a great candidate for a pinhole camera.
In no particular order:
-Yes, thinner is best. Your shim stock is most certainly in thousands of an inch. I use 0.001 inch stock and it is still very durable. Thicker stock is more prone to “tunnelling” and vignetting at the corners.
-Black on the inside is cheap insurance. Shapie is fine.
-Jeff McConnell has some kind of method for masking off a viewfinder with elec. trape.
– ++ tripod mounts
-A little smaller pinhole is just fine, but calculate your exposures based on your best measurement of its diameter.
-Actually, I steered you wrong on the angle of view calculation. You want to use the length of the frame’s diagonal instead of the width. This will give you an angle across the corners ( the widest part of the frame, radially). For compositional purposes, I use the angle subtended by the width.
– Do you have reciprocity failure data for the instant film you want to use?
Thanks so much schlem,
Thinner it is then.
Thanks for the sharpie hint – that is so much easier than paint
I found the Jeff McConnell pics on Twitter – thanks for the clue. I have some old cold shoe mounts from my Spotmatics that slide in grooves beside the eyepiece and arch above the top of the camera to hold a flash. No use for them, till now! I should be able to modify one of those no problem. The top plate unscrews easily, so all I need is to figure out how to fix it to the plastic edge in that area. And to find a cheap viewfinder to mount on it (ironically I got rid of one that I thought I would never need a couple of months ago).
Good to know a slightly smaller pinhole should be fine as it is more likely to stay round than if I start trying to enlarge the hole.
I figured out to use the diagonal, but only by accident, and was thinking of going back and recalculating based on length just to be sure – now I don’t need to!
I have some reciprocity failure data from the Fuji data sheet for the two films in question. The Fuji FP-100C has values to 16 seconds, along with colour correction for filters, something I won’t be bothering with I don’t think. The Fuji FP-3000B has a graph out to 10 seconds which given the speed of the film, is probably going to be more than enough if I use it in lower light settings, as I will have to without the right kind of shutter.
I do have some small diameter ND filters that would fit in the outer opening without causing vignetting, so that may be a solution to the speed of the black and white instant film.
This is all seeming quite possible, all of a sudden. Thanks for all your help.
Oh good, I forgot to mention ND filters. ND8 give you 3 stops slower, which is good, because shutter-induced camera movement sucks. Just make sure your ND is spotless – Remember that infinite depth of field?
Wow. The imagery gives the illusion of almost being taken though a lens. Great work.
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