is anyone shooting pinhole?

[big_ben_blue]

I still do - sometimes. But not with the S2 (yet). Haven't found any suitable adapter for it so far. So I'm using an Zeroimage 6x9 for the time being.

Chris

[coolrun]

Those are really nice. I have a precision pinhole lenscap (.351mm, f/256) for my RB67 but have never had a chance to use it.

Freestyle Sales has a "Finney Pinhole Body Cap for Nikon F" for $30.00. Size .011" pinhole appoximates a 50mm lens at f/180.

http://www.freestylephoto.biz/sc_prod.php?cat_id=2201&pid=5633

Loreo has an f/64 pancake lens/lenscap. I have one for K-mount cameras. It is available in a Nikon mount for $19. Loreo makes a lot of interesting products.

http://www.loreo.com/pages/products/loreo_lenscap.html

[smunky]

i do sometimes, but not with the s2
um, april 25th i think is national pinhole photography day.

[Serge]

I find it fascinating, that we still want to return to the basic beginings, just like playing with basic musical instruments, when we have the latest wiz bang electronic technology, like rolling your own, I guess. I too share that fascination.

[KeithM]

Yes - I've had a go with the S2 - used an old m42 body cap ( plus adapter ), hole drilled and covered with tinfoil and created a rough pinhole.

Results were soft and the focal length a bit long. I've ordered another nikon-m42 adaptor that has an 'infinity focus' lens. I intend taking the lens out and replacing with a brass shimm. The reason is that the pinhole will be slightly inside the S2 body and give a shorter focal length.

Of course the big problem is getting a small enough hole to give some resolution without getting too much diffraction distortion... some quick maths ( which I think I've got right ) .... the optimum hole for 30mm focal length is about 0.2mm but to give a resolution of 640 pixels across ( with 23mm of sensor ) needs 0.035mm. The fun is trying it though so with summer coming, more light and shorter exposures ( to avoid those pesky hot pixels ) ! :)

Keith.

[big_ben_blue]

Keith,

thanks for your notes; can you let me in on the "math" used to determine the optimal diameter for the hole?

One of the reasons, why I didn't use the S2 for my pinhole shooting is the fact, that would loose the wideangle feel in the images (30mm focal length is a far way from ultra wide).

Thanks,
Chris

[KeithM]

Hi Chris.

Sorry - I just re-read my post and I made it sound as though I did the calculation :o .... I can't claim doing the maths for calculating the pinhole size - there are equations on this Pinhole page (http://www.photo.net/pinhole/pinhole.htm) but I used a well known calculator on mrpinhole (http://www.mrpinhole.com/holesize.php).

The only bit of maths I actually did was to estimate the size of pinhole to get a VGA resolution image off the S2 sensor ( based on the simple assumption that the pinhole creates a disk of light on the CCD surface the same size as itself with near-parallel light from a distant point source ). I'm not sure what results you would get if you could make a small, say 0.05mm, pinhole - would the difraction distortion make a worse image than if you'd used a 0.1mm hole. Most commercial products seem to be 0.2mm !

I've now done a rough measurement of focal length with the adaptor which comes out at 40mm and of course this gives an angle-of-view equivalent to a 60mm lens in 35mm format so it's a bit longer than normal ! :rolleyes: . If I can make a 0.1mm hole, that gives a 'resolution' of 230x155 (ish) - exposure would be about 1/4s for iso100 using the sunny 16 rule. Only one way to find out - take some pictures !! :)

Keith.

[KeithM]

Just a quick addition to the last post. More googling has revealed a simple equation. In mm:

Pinhole diameter = 0.03679 * square-root (focal length)

So with 40mm focal length, this gives 0.232mm hole size.

Another snippet I found was that diffraction effects, as well as getting worse for smaller holes, gets worse for thicker edges to the hole. So the aim is to get as narrow an edge as possible to the hole - this means that instead of punching, or drilling, the hole through, the technique is to gently punch a dimple in the metal and then gently file off the top of the dimple... I've got a soft-drink tin on its way to me so I'll see if it's easier done than said ! :p

Keith.