There are a lot of co-axial lighting setup for coins, but this one is compact, using easily accessible material (62mm UV filter) except 3D printer. In my opinion, it is particularly useful for phone -- most of the time, phone is blocking lights, but not this setup.
Not sure where to upload the 3D printing file here, let me know please so that people can use it or let 3D printing service to print it.
Actually, the best glass is not UV filter, it seems it is casting some tint on image, but should be corrected in software like PS. The best glass I tested is K9 optics grade glass plate. A 55mm by 55mm such glass actually can handle larger coins, up to 39mm vs 32mm for 62mm UV filter.
I used parametric design approach, so the model can be as big as we want, but printing time will be so long, it probably does not make sense to print it. For example, with 82mm filter, giving us about 46mm diameter viewing circle, print time will be roughly 21 hours. this one with 62mm filter (34 viewing diameter), it is about 9 hours.
But I think it would be better to use square glasses and half mirror.
Looks great! I like the felt absorber and the coin pedestal, nice touches. One thing you might suggest for folks is to place a piece of black paper hanging from the camera to block any stray light coming in from the light.
Most of the "real" beamsplitters I've tried are too thick. I see in the video that the filter you're using is 1.1mm (correct?) which is in the lower range of what is available. Most are 3mm or more, and create optical aberrations. I've tried using large format microscope slides, and also slide cover slips, and these are quite thin. The slides are typically either 0.7mm or 1.1mm, while the cover slips are 0.17mm (!). These thin pieces of glass create minimal internal reflection offsets and thus minimize the visual aberrations.
I do see one possibly suitable 50/50 beamsplitter available on eBay. Many may be available on other sites like TaoBao or whatever, and maybe much cheaper. Anyway here's one example, at 80x80mm and 1.1mm thick, that might work very well with @mjkzz's creation:
@Shantiom, yes, I want to make it open source, but I do not know where to put it :-)
@rmpsrpms, yes, initially I did not have that pedestal, but after using it for a while, that idea became essential, so I can almost "blindly" put the glass holder on top of the coin and have it centered, blocking out all ambient light.
@rmpsrpms, yes, I actually have that same half mirror (80x80), but I thought it would be too big, I wanted to have one as small as possible. Also printing similar cage would take about 21 hours. Maybe I can change the design and print out different pieces. Here is one done with half mirror, but it is attached to the lens:
half mirror is better, but more expensive and less accessible for "normal" coin photographers. Or maybe I will do a 80x80 half mirror design. It will give us 56.6mm viewing circle, I think that is enough for most coins.
If you mount the axial light to the lens as you have shown in last post, then you don't need the mirror to be so large. In fact you can get by with a much smaller mirror, such as the more common 30x30mm mirrors, and the case can be much smaller, so would print much faster. However, the light will be more "axial" and give a higher contrast than what you are doing now. That can be good for some coins, bad for others. It's an interesting tradeoff.
Ray, you must have eyes of measurement :-) The device measures as 31x31x45mm, it has 30.5mm thread, which can be adapted to other lenses. The longer dimension, 45mm, is designed to block out ambient lights from entering light path.
Yes, it takes a lot less time to print, about 2 hours, mostly because of the support material for the square tube where light comes in. The half mirror is cheap, too, 29.5x35mm.
I think this one is really convenient to use. There is a tube placed on top of the coin, this is to block ambient light from reaching the coin directly, but reducing the height of this tube, let some ambient light in, we can reduce that "contrasty" look, get more "materialistic" feel, so to speak.
I have one of Ray's intro level systems and would be happy to pay for this accessory, I will be using a Canon 70D with a standard 35 mm lens, or an old Canon Rebel iOS with a Pentex 35 mm lens. I can also send you some toned coins if you want to try out the color popping on the photo.
@shantiom: OK, I will try out a coin with copper in the center. The camera used in video is Canon 550D, 12 years old, the lens is the famous El-Nikkor enlarger lens. I am waiting for Sony A7R5 to be available in China.
Could not find a new penny, this is an old one. Only adjusted contrast, to make background "blacker". I think I need to put black velvet at bottom. No sharpening, no other adjustments. To make the file size less than 300KB, quality is only 88%
Very interesting, I really like the design! I've been researching the parts I would need to make a simple axial lighting setup over Christmas break, but this looks much better. I have several friends with 3d printers, have you found out a way to upload the STL files?