3D-Printed Anaperture Single-Shot Anaglyph Aperture

3D Gunner wrote:

ProfHankD wrote:

1. A typical 50mm f/1.4 will vignette badly until somewhere between f/2.0 and f/5.6. If it happens to be one of those f/5.6 ones, 50/5.6 is just 8.9mm, so your 5mm holes 9mm apart would not work. You need 19mm clear, and that would require no significant vignetting by f/2.6. Being a FF lens on APS-C helps your odds, and a medium format lens typically will do even better, but it's entirely dependent on the lens. Vignetting is usually not the quality metric people look for, but it is pretty much THE metric here.

BTW, longer focal length lenses work better because the same f/number gives a larger diameter for your two stops to fit within.

Using this procedure, I expect to be able to obtain a better image quality in terms of resolution, but with severe limitation to the anaglyphic mode and a lack of uniformity in terms of horizontal color distribution.

2. Lack of color uniformity => vignetting.

3. Anaglyph capture effectively interleaves the left/right image pixels, so arguably the resolution is the same as side-by-side half-sensor shots. Biggest advantage is you get the native aspect ratio and effective focal length, and you get to use favorite lenses. It also wins in that the rig doesn't add significant size to the lens, unlike the mirror adapters and dual-camera rigs.

2. This phenomenon is not about "vignetting" in the common sense about "lens vignetting" = "Vignetting, also known as “light fall-off” (sometimes spelled “light falloff”) is common in optics and photography, which in simple terms means darkening of image corners when compared to the center."

The "vignetting" we're talking about doesn't diminish as I close the aperture, but on the contrary, it gets more pronounced, so that at f:5.6 the frame is already "split in two", half red and half cyan.

Yes, it's vignetting -- look at my talk slides above.

You should NEVER be closing the native lens aperture when doing these anaglyphs!If your aperture holes are way too far apart, they don't act as apertures at all, but as vignetting elements on the native lens aperture. That's what stopping down the host lens does. Follow the rays.... 

1. As I already mentioned, I used a 50mm f:1.8 FF lens.
The system works as in the images shown, only at maximum lens aperture, i.e. at f:1.8 (5mm aperture with 15mm inter-axial distance).
At an inter-axial distance of 9mm (reduced from 15mm), the system works much better, as anticipated, with much better horizontal color uniformity.

I also tested the version with 5mm apertures and a 9mm inter-axial distance (4mm distance between holes) with a 90mm f:2.8 Macro (FF lens) and the results are as I anticipated, i.e. good with reasonable lateral uniformity (only with the aperture open at maximum, i.e. f:2.8).

Again, it's a matter of correctly sizing the anaglyph aperture WRT vignetting....

The results obtained with two cameras are clearly superior, without being limited to short shooting distances.

Well, sort-of. My original anaglyph capture work was NOT to create images to be viewed as anaglyphs, but to enable the same types of reprocessing as people do with lightfield cameras. In fact, 3 color channels are useful for that, and provide more info than two cameras shot normally. In fact, this method offers both higher accuracy and resolution than lightfield cameras, but it is computationally much more demanding.

Now I am preparing a thin black disc (the material in which the holes are made is recommended to be as thin as possible) which will be laser cut, both the disc and the holes.
The disc with the colored filters will be mounted in place of glass from a UV protection filter, in an attempt to see how much the image quality improves.

In my experience, a programmable paper cutter can actually do better than a laser. It's not a huge difference, but the pivoting knife in a paper cutter gives an edge only CNC milling of rigid materials can match. Lasers basically degrade the material they are cutting, giving a slightly damaged and rough edge; they also leave an angled kerf in thicker material. Anyway, if you're cutting thin material, it will not make much difference.

3. The two lenses in the macro system I mentioned do not have the optical quality comparable to that of quality photo lenses, but still offer separate full color images at reasonable quality.

Expected, although it isn't hard to find good lenses suitable for that approach from either C/CS/D mount lenses or old rangefinder/point-and-shoot cameras. Basically, I'd 3D-print a TLR-like focusing dual mount, probably rail driven, if I were going that route.

Incidentally, for non-macro stereo capture, I've often done things with pairs of cameras, especially CHDK-supported Canon PowerShots. That makes it easy to exactly match the typical human baseline... as I did in:

3D-printed stereo rig using CHDK sync of two Canon PowerShots