failed modding attempt with kodak disposable lens

I saw on Youtube that you can use the lens from a Kodak disposable camera and mod it to you camera.

No one told me that actually you cannot do it for a Canon DSLR because of the Incompatible Flange Focal Distance (FFD), which basically means that you need to place the lens so close to the sensor that it is impossible mechanically to get a picture.

No camera has been damaged during this test

Test steps:

1. Save the lens from the Kodak disposable camera

2. Drill hole into EF MOUNT body cap

3. Add the lens

4. First test failed - no image in focus except macro scenario where the camera needs to be at max 5 cm from the subject

5. Changed the position, no proper results. Reversed the lens, no results.

6. Added gaffer tape to the lens so I can play with the position, no real progress.

Test results

Reason why it is failing for DSLR Canon cameras found on google:

he lens from a Kodak disposable camera (typically a 30mm or 31mm f/10 single-element plastic lens) does not work on Canon cameras—specifically Canon DSLRs—primarily because of flange focal distance incompatibility and physical constraints. 

Here is the breakdown of why this DIY hack rarely works without significant modification:

1. Incompatible Flange Focal Distance (FFD)

The "flange distance" is the space required between the back of the lens and the film/sensor. 

• Disposable Cameras: These lenses are designed to sit very close to the film plane, typically at a distance of around 20mm–25mm.

• Canon DSLRs (EF/EF-S Mount): These cameras have a long flange distance (approx. 44mm) to accommodate a mirror box.

• The Problem: The lens needs to be positioned inside the camera mirror box (closer than the camera mount) to achieve proper focus. If you just tape the lens to a body cap, it is too far away, resulting in only extreme macro (near-focus), blurry images, or a failure to focus at all. 

2. Mirror Interference (DSLR Specific)

If you try to mount the disposable lens on a Canon DSLR (like a Rebel, 90D, 5D, etc.), the lens must be positioned so close to the sensor that it will likely physically obstruct the movement of the mirror, causing the camera to lock up or damaging the mirror mechanism. 

3. Fixed Focus and Aperture

Disposable camera lenses are fixed-focus, designed to keep everything from about 1 meter to infinity in focus. When forced onto a camera with a different flange distance, this focus range is lost, and the lens cannot be adjusted, making it impossible to fix the focus manually. 

Why it Works on Mirrorless (But Not DSLRs)

You may see people online using these lenses on Sony or Canon mirrorless cameras (RF/EF-M mount). This is possible because:

• Mirrorless cameras have a very short flange distance (e.g., 20mm for RF).

• There is no mirror, allowing the lens to sit deep enough in the body to achieve focus.