Looking for camera specifications for a project

[bangaham]

Hi,
my first post so bear with me. I'm an electrical engineering student working on a project and need help figuring out what camera specs I need.

The idea is to have a prism system to overlap two images and a camera to show the merged image on a monitor/TV. Now the prism system I have figured out and it works like its supposed, but don't know what camera specifications I need. The whole unit is in a small enclosure (approx. 16x9x6 cm) and the prism area to capture is 5x5cm. I need a camera that can capture the needed area at a low distance shown in the attached image. My original idea was to use a small digital camera but I can get it to focus but at a far distance and can't focus if I zoom in.

Basically I need to know what camera specs (lens size, F stop, ...) I need to achieve this. And how would I achieve zoom? I can implement a mechanism that brings the camera module further from/closer to the prism if it helps. I can get a bigger enclosure if this configuration is hard to achieve.

I hope you can give me some pointers on what camera specifications to look at. Thanks in advance.

 

[Jeff15]

Hello and welcome, I cannot answer your question but there are people on this forum that may be able to help you......

 

[Derrel]

Cannot quite read your dimensions...are they 5 and 8 centimeters?

 

[Designer]

Hi,
my first post so bear with me. I'm an electrical engineering student working on a project and need help figuring out what camera specs I need.

The idea is to have a prism system to overlap two images and a camera to show the merged image on a monitor/TV. Now the prism system I have figured out and it works like its supposed, but don't know what camera specifications I need. The whole unit is in a small enclosure (approx. 16x9x6 cm) and the prism area to capture is 5x5cm. I need a camera that can capture the needed area at a low distance shown in the attached image. My original idea was to use a small digital camera but I can get it to focus but at a far distance and can't focus if I zoom in.

Basically I need to know what camera specs (lens size, F stop, ...) I need to achieve this. And how would I achieve zoom? I can implement a mechanism that brings the camera module further from/closer to the prism if it helps. I can get a bigger enclosure if this configuration is hard to achieve.

I hope you can give me some pointers on what camera specifications to look at. Thanks in advance.

There is no way I can decipher your request. Where is the camera? What are you trying to photograph? If the camera is close to your subject, you might want to consider a "macro" lens, which means it will focus at close distances.

I suggest you ask whoever is trying to teach this course.

 

[weepete]

ok, first of if you are talking to engineers don't use cm, convention is to use mm or meters. Yes, I know they won't teach you that at uni and it may not be entirley rational but having spent the best part of 20 years in the engineering industury myself and worked my way up from a workshop floor trust me on this one

So you're 80mm away from a subject that's 50mm wide. That's pretty close, normally lenses have a minimum focal distance, anything closer than that your image wil always be out of focus. I think my closest one is 220mm.

Now we need to figure out how big your image needs to be and what you are expecting. Lenses are pretty complicated things and can contain a lot of elements like this:

http://www.dpreview.com/files/p/articles/4273095999/1124mmcutinhalf.jpeg

The first thing you need to consider is do you need to fill the frame, or do you need a 1:1 reproduction on the sensor of the camera?

The 1:1 reproduction is called "macro", but a lot of lenses have a macro mode but not true 1:1 reproduction (what us camera nerds would say is close focus).

A 50mm lens approximates what the human eye sees but there is usually a bit of distortion.

if you can work out the MFD of your current camera you could use a macro focusing rail to fine tune and get the largest image you can without too much extra gear. Also counter intuative but max zoom then place the camera as close as you can get focus. Extention tubes or a diopter may get you close.

Otherwise you're into say a 60mm or 100mm 1:1 macro or if that's not good enough something like a Canon MP-E 65mm and supplimental lighting which can bring other issues and the last one is a specialist macro lens.

 

[Derrel]

Keep in mind that the image might be at an optical distance that is much farther away than the surface of the prism. Back in the day Modern Photography magazine used to review cameras, and it was interesting to see that the optical distance of the viewfinder image In the typical 1980s single-lens reflex camera was around 72 inches, even though the typical user would put his or her eye About 1/2 to 1/4 of an inch behind the eyepiece.

 

[bangaham]

Can't really ask anyone since this is more of a personal project. I'm an EE student, I know how a camera works electrically, but optics are not my strong side.
If I understand correctly I need to be looking into macro photography. Will do some more research on the topic and get some test lenses and experiment and see what works best.
Thanks very much from a total beginner. Will update if I have some more questions.

 

[stk]

If I understand this correct, you want to take a picture of an 5x5 cm object but only have 8 cm room for the camera?

I think a bigger enclosure is the way to go, or maybe keep the camera on the outside and make a hole for the lens.

 

[bangaham]

Quick update!
After doing some research and experimenting, I ended up using a 720p webcam that I modified and I am now able to adjust the focus manually close which is exactly what I needed.

The point of the project is to align a BGA chip on the PCB. Basically, you have the chip that has small solder balls (~0.5mm) over the prism's and under them is the board. You shine a different color light on each and you can see the alignment on the output of the prism's, you see the balls and the pads in different colors and you use a mechanical system to align them.

The issue is that in order to fill the camera capture window, I have to move the prism's very close to the BGA chip/board, but that is not always possible because not all BGA chips are the same size. I want to put the prism system in a fixed height and implement optical zoom. How would I go about adding optical zoom? Can I take the lens mechanism from an old small digital camera or video camera and put in in front or will that mess with the focus? Or possibly add magnifying lenses before the prism's input sides? I'm open to ideas.