EEVblog #1372 - DIY PCB Photography Light Box - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: February 07, 2021, 10:35:54 pm
content: How to build your own DIY light box for photographing PCB'sDave experiments with a cardboard box, some alfoil, and a hacked YujiLED high cri studio light.

author: chekhov
author_rank: Regular Contributor
timestamp: February 07, 2021, 11:31:15 pm
content: Hi,Looks great as concept, but what about angles ?Box does not allow camera distance to be as physical conditions may need - in order to make a bit more flat image you need higher distance, narrow angle lens.

author: wilmer
author_rank: Contributor
timestamp: February 07, 2021, 11:56:00 pm
content: Dave,Very impressive results, I do Machine vision and lighting is always a problem. Even professional solution gives trouble as side shadows.If you project light against the walls first and have an almost white wall, you don't need lens.If you want to delete the shadow, you need side lights.I attach a picture of a prototype that may help you. Notice that we not use box or dome as the direct light was good enough for the image.

author: Tek_TDS220
author_rank: Regular Contributor
timestamp: February 08, 2021, 04:41:42 am
content: Nice! Anybody who hasn't tried to take a photo of a board won't appreciate how difficult it is to get a good image. I've been taking my boards outside on sunny days. Still, the quality is marginal because of reflections and shadows.

author: Domagoj T
author_rank: Frequent Contributor
timestamp: February 08, 2021, 06:57:02 am
content: Visible improvement over just ambient light.To cut down on the shadows being cast on the paper below, try lifting the object away from the paper (a couple of cm should be enough).

author: EEVblog
author_rank: Unknown
timestamp: February 08, 2021, 11:17:14 am
content: Part 2:

author: tszaboo
author_rank: Super Contributor
timestamp: February 08, 2021, 01:23:30 pm
content: What I found with my endeavor of photographing PCBS is this. While lighting matters, and it should be diffused and even, what matters the most is the background. If I place the PCB on a white background, especially reflective surfaces, like a desk bench, it is usually oversaturated. I started placing the PCBs on matte grey surfaces, or cardboard, or maybe an ESD mat. Then the images are much better, because the dynamic range is much smaller.On phones, it is better to move the camera further away and use the telephoto lens, if your phone has them.I actually think white light with high CRI might be worse for these sort of pictures, than some other color, but I haven't played around with that.

author: chekhov
author_rank: Regular Contributor
timestamp: February 08, 2021, 01:44:28 pm
content: Even though it's a different technique, I found these advises very helpful -https://xdevs.com/guide/hwphoto/Comparing to the light box, described method does not require a box basically, but requires more time, has less repeatable result (which might be compensated when skills grow), takes more time for each single item to be photographed, but it has very good flexibility.Btw, maybe I watched the video in too small resolution, but most of the time where side-by-side images were show, I only thought "zoom MOOOORE".

author: gjsmo
author_rank: Contributor
timestamp: February 08, 2021, 09:08:51 pm
content: @EEVblog It looked like you might've done this for the multimeter shot but in general it's very good to set a manual exposure that's "too high" and blow out the background, meaning that it's solid white. After that you can adjust your curves and such to get a nice contrast bug as long as you keep pure white set to maximum brightness the background will remain perfectly, well, white. In the film days you would have done this in the camera, with digital photography of course it can be adjusted later but it's usually easier to do it in camera for me. Gets rid of those pesky shadows and makes for an overall more professional shot.

author: DrG
author_rank: Super Contributor
timestamp: February 09, 2021, 12:10:57 am
content: First of all, the photography in the vid is very good and that should be the starting point.At this section (~12:00) you are comparing two lighting set ups.To my eye, the one on the left is "better" and the exposure on the right is slightly greater. I tend to try to focus my eye on particular spots for comparisons and, in this case, the 'embossed' orange label/tag. On the left there is clearly better detail. Again, they are both very good.Coincidentally, I was shooting an RPi PICO with a still camera and took a break (because my back was killing me) and watched the vid. If I am motivated, I use a copy stand with a light diffusing tent, a light board under, two side lights and a light from above. I deal with overexposure stuff all the time. Below is a clearly overexposed shot, but, look at the detail on the chip to the right of the RP2040 - that is the detail I wanted. I could not "meter" my way out of the overexposure and still get the detail.This one is not as over-exposed, and if I had to pick, it would be this one, but reading that same chip's printing is more difficult.Not sure what my amateur photographer point is, but while yes, you want more light, you want it in certain places and not others (which again makes me think about the camera's metering modes). Optimizing that for different sized boards is a skill or art that I still struggle with.

author: Razor512
author_rank: Regular Contributor
timestamp: February 09, 2021, 02:22:03 am
content: If you don't mind something really janky looking, you could arrange a bunch of high CRI LEDs in a circle, then take strips of paper and loop them around the LEDs to diffuse the light. Then hold them at level around 1 inch behind where your lens hood ends (to avoid any washing out).As long as the ring of light has a diameter that is 2-3 times the diameter of what you are photographing, the lighting comes out pretty even with no need for a light box, Though it is also more limited in terms of angles you can photograph at while keeping a very even look.If you can use a tripod, then it also does not need to be very bright either, as you can just compensate by adjusting shutter speed while keeping the base ISO.Beyond that, for your first test shot, use the aperture that is sharpest for your lens, and adjust from there (you can make further adjustments to aperture for more DOF, but at a certain point you will get a significant drop in detail and sharpness due to diffraction.

author: Razor512
author_rank: Regular Contributor
timestamp: February 09, 2021, 02:48:38 am
content: Wanted to also add, another option if you want something sub par but extremely fast to set up while taking up very little space, you can simply take a small video light (along the lines of those CN-160s, and then place it on one side of the object (feathering the light on the object), and then pointing it at a sheet of paper which will reflect some light back to fill in the shadows a bit. The shadows will be noticeable, but it will also be quick to do for really basic results.It works decently for at least showing text printed on various components.You can also do this method with a basic off-camera flash, though with a tripod, it is not really needed. Furthermore constant lighting allows you to finetune the setup without the need for a bunch of test shots.Results of taking a photo of an ancient CPU using that method.

author: DrG
author_rank: Super Contributor
timestamp: February 09, 2021, 03:06:26 am
content: @Razor512 That first one is a really nice shot. There is a sticky thread on the forum for Photo tips RE boards and such...https://www.eevblog.com/forum/chat/how-to-make-decent-photographs-for-forum-postsarticlespublications/Sounds like you could contribute some good stuff.

author: Razor512
author_rank: Regular Contributor
timestamp: February 09, 2021, 04:52:29 am
content: Cool, I will have to check it out and see if there is anything simple that I can contribute.

author: IAmBack
author_rank: Regular Contributor
timestamp: February 09, 2021, 09:05:07 am
content: Back in a days I was making so called "packshots". Having such subject as pcb I would build box of Styrofoam - white, but not "metallic". Light shouldn't be directed towards the surface of the pcb, it rather should be reflected from the walls. For a black background the best solution is black velvet, even better is self adhesive velvet/flock. Placing pcb 3..4 cm over the plane of velvet may help in even light distribution over the plane of the subject. It may be good idea to install some "directed" light inside, pointing at the board from above corners/edges, to add an "accent" to the non-directional lighting. It may be a led spotlight with mr11 fitting, fitted on rigid stick, that can be "operated" from outside our "light box". Light intensity should be controlled. To minimize effects of light flickering (50/60hz), shutter should be opened for 1/10sec or so. I doubt if there's "universal" setup giving excellent results for all boards (we need different light for different surface finishing of ic-s). BTW, in a automatic qc machines for testing pcb assembly I've seen the light source, that was half-dome with a number oh small flash tubes, giving ability to implement over a hundred of different lighting scenarios.

author: RenThraysk
author_rank: Regular Contributor
timestamp: February 09, 2021, 03:01:27 pm
content: Guessing a polystyrene cool box would be the cheapest and easiest way to go?

author: Peabody
author_rank: Super Contributor
timestamp: February 10, 2021, 04:15:59 pm
content: Dave, I can only judge from the video, but your pictures all look too dark to me. Underexposed. Compare BigClive's latest where he shows his photo setup. His pictures just look much brighter to me. Maybe he's turned on HDR on his Moto6 Play. :-)