Arcane Details: B/W Filters on Pinhole Camera

kier · Mar 9, 2015

Hi All -
I want to put a red filter behind the pinhole on a few of my cameras, and have some detailed questions for which I cannot seem to derive the right googles. I think my primary concerns are 1) image distortion from the filter being too far from the pinhole and 2) polluting the image with artifacts from the filter materials.

My questions are:

Is there a distance between the filter and the back of the pinhole that is optimal?
Does it matter if I go with a glass (e.g. B+W) vs gel (e.g. LEE) filter?

Any specific recommendations for a product would be greatly helpful. Thanks!

John Koehrer · Mar 9, 2015

I'm not fond of Lee filters. Or any plastic filter for that matter.
Depending on the thickness of the filter ring, glass may vignette if it's too small a diameter. So. Use a large filter or take it out of the mount.

Personally Wratten gels from Kodak or Calumet is my choice. But, they're very delicate. A nice thing is with a 3" or 4" filter, they're easy to cut. Shouldn't have any distortion or degradation from them.

There are several reds, 23a light, 25 medium, 29 dark. 25 is most common.

kier · Mar 9, 2015

Thanks John! When you use the wratten gels, are you putting them right up against the pinhole? Or is there some space? Care to guesstimate how much space? Thanks so much!

dasBlute · Mar 9, 2015

I use glass in front, it is taped to the camera with gaffer's tape I

tried behind, but: I like it protecting the pinhole,
and when placed behind, I have found artifacts in the images...

I use yellow, but that's because I use paper negatives which are blue sensitive..

-Tim

Jim Jones · Mar 9, 2015

The color of filters has a slight effect on the optimum pinhole size. Many pinhole formulae and programs such as PinholeDesigner include light wavelength to correct for this.

tony lockerbie · Mar 9, 2015

Yes, I have tried both but now use it externally. The filter must be scrupulously clean to avoid the dust spots showing as big blobs on the image....too much dof see

kier · Mar 9, 2015

two of my cameras are zero images, so I can't mount it externally without interfering with the shutter. thanks all for the extra info!

John Koehrer · Mar 10, 2015

The gels just sit behind the pinhole, so the thickness/depth depends on the camera.
If you use the 3" gel you can use a frame but that slightly increases the distance(<1mm) from pinhole to filter. It makes the filter much
easier to handle and you can use tape to stick it onto the "lensboard". The gel itself would be a bit fragile for tape.
I've got a couple of extra frames & can send you one if you want to take a look-see. I won't need it back.

kier · Mar 11, 2015

Thanks John - I appreciate the offer. However, I'm not sure I can use the 3" gel frame because I don't think it'll fit. I think what I'm gonna do instead is get a filter step ring and mount that in camera. Then I can screw filters onto that

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bvy · Mar 11, 2015

I used a blue or green filter once with a very small pinhole and was able to capture a sun trail over a period of several hours exposure. This was on a paper negative with regular developing and fixing.

marciofs · Apr 10, 2015

I often use orange or neutral grey in front of my pinholes. I use the square Cokins.
It has always worked very well.
I carry cloth to clean it to avoid spots from durtness on the filter.

paul_c5x4 · Apr 10, 2015

Filters can be placed in front of the lens, behind, or even dropped in to a slot in the middle (look up catadioptric lenses - They would require monster filters on the front). On that basis, I wouldn't have thought the distance from the pinhole would make the slightest of difference.

If you are using small film (35mm or 120), you could place the filter just in front of the film plane.

Joe VanCleave · Apr 10, 2015

@Paul: You're correct - except that to avoid the appearance of dust spots on the filter media from being evident in the image, the closer to the pinhole the better; this is due to the intrinsically wide DOF of pinholes.

~Joe

amellice · Apr 13, 2016

marciofs said:
I often use orange or neutral grey in front of my pinholes. I use the square Cokins.
It has always worked very well.
I carry cloth to clean it to avoid spots from durtness on the filter.

do you hold them by hand?

Theo Sulphate · Apr 14, 2016

Some of the new Zero Image cameras have filter rings. Mine doesn't, but I've thought about just holding the filter close to the camera for short exposures.

Poisson Du Jour · Apr 14, 2016

Get any multicoated filter for B&W (plain uncoated filters can cause extreme spectral flare, while plastic filters will degrade the natural definition of a pinhole), and trim it with a glass cutter to the size of the enclosure inside the camera where the pinhole is (usually a press-fit). Paint the edges black. Exposure must be adjusted to take account of the filter in place behind the pinhole. In the case of a 25A or deeper filter, it can result in exposures becoming very long, to which reciprocity must also be added.

A few of the bespoke Zero Image Camera Co. cameras are optioned with front filter threads now to easily take any sort of filter. Internal cut-to-size filters cannot be removed until the roll is finished. In my Zero Image 6x9 multiformat, I have a cut-to-size Y2 filter behind the pinhole.
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[[ EDIT: Just saw Theo Sulphate's post (above) mentioning the ZI filter-optioned cameras. ]]

BetterSense · Apr 14, 2016

When I used filters with pinhole cameras i held the filter in my hand and tried to keep it moving slightly in front of the pinhole. That makes the dust blobs disappear, and no mounting solution is needed.

amellice · Apr 14, 2016

Theo Sulphate said:
Some of the new Zero Image cameras have filter rings. Mine doesn't, but I've thought about just holding the filter close to the camera for short exposures.

true but without the shutter release, it's either this or that I think, I was looking at the 6x18

marciofs · May 5, 2016

amellice said:
do you hold them by hand?

No. I use tapes.

Arcane Details: B/W Filters on Pinhole Camera

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