How Can I Achieve Uniform Lighting for iPhone Camera Photos?

[gfd43tg]

Hello,

I am working on a project where I am trying to take a photo of paper that I insert into a slot of an iPhone cover that I created with a 3D printer. My goal in this stage of design is to be able to take a photo that will disperse the light evenly across so that the lighting is uniform throughout the photo.

I was wondering if I could get some ideas for the design.

In my first photo, I used a 5 mm thick block of PDMS
Here is the data sheet
http://web.mit.edu/6.777/www/matprops/pdms.htm
it has an index of refraction of 1.4. I placed the block over the flash and it dispersed the light more.

The second photo is without anything, one can see that the left side of the photo is more illuminated because the flash is on the left side of the camera.

For the third photo, I placed aluminum foil on the left side of the case next to the flash in order to reflect light over to the other side. It seems to be less effective that the PDMS, and it also seems to have those spots on the photo that are undesirable.

Anyways, any thoughts on how to get this to be even across the photoview?

 

[gfd43tg]

PDMS over the flash

Nothing

Aluminum foil

 

[gfd43tg]

this is the case where I insert the iPhone and am trying to take a photo with the SD card as my test

 

[gfd43tg]

Anyone have any ideas for how I can spread the lighting across more evenly?

 

[gfd43tg]

Does anyone know of a gel like substance that has a high index of refraction? The PDMS was just a 5 mm thick gel square that I put over the flash, but has an index of refraction around 1.4. I wonder if I had a material with a high index of refraction.

I was also thinking of spraying a reflecting coating on the inside near the flash, so that it will reflect to the other side

 

[NascentOxygen]

I don't exactly understand what you are doing, but a bunch of optic fibres could convey the light to where it's needed...

 

[gfd43tg]

Well you can see I put the iPhone into the case. There is a hole where the flash and camera are at. I put an SD card into the slot so that I can take a photo inside. I just want even dispersion and I only have a few mm of space to work with

 

[NascentOxygen]

The iPhone camera can focus down to a few mm from the lens? Neat.

 

[trollcast]

I'm not 100% sure if this is what you're wanting it to do but you could try a piece of diffusion filter (its used in stage lighting to produce a diffuse lighting effect) depending on the density or grade of the filter it can scatter the light through a pretty large angle.

If you're going to look for it then its also called diffusion gel but its not a gel its like paper.

 

[NascentOxygen]

A piece of baking paper might go partway to achieving this. It's used in the kitchen to line baking tins.

 

[gfd43tg]

I increased the height of the slot and covered the flash with PDMS. I got a pretty good image.

I'll look into that diffuser because I need the light to be diffused.

Nascent, I don't need a focused image for my project. I just need an evenly spread image.

 

[gfd43tg]

The strangest thing has been happening. On the one that gets a perfect video with evenly dispersed light, the image comes out completely white. The other ones that aren't perfect take the image just fine, but the image of course is not evenly dispersed.

 

[NascentOxygen]

The strangest thing has been happening. On the one that gets a perfect video with evenly dispersed light, the image comes out completely white. The other ones that aren't perfect take the image just fine, but the image of course is not evenly dispersed.

Could the dispersive medium be transmitting light directly from the flash into the lens, and overwhelming that reflected from your object to be photographed?

 

[gfd43tg]

That could very well be the case. The large flash of light that comes from the camera could be the cause. If I put the flash light on in the phone (not as intense as the flash right before a photo is taken) then the image is evenly dispersed. It's only when that pulse of light when the flash is taken does the image become white.

Is it possible to take a photo with the iPhone with the flash light on, but not the actual flash? It seems like normal functionality on the phone does not allow this. Maybe there is an app for that.

 

[NascentOxygen]

I know nothing about the iphone. If no better ideas are forthcoming, could a small piece of aluminium foil with multiple pinholes attenuate the flash intensity?