I Turned Tiny Keychain Cameras Into Interchangeable Lens Cameras

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The quick answer

I turned three tiny keychain cameras into interchangeable-lens experiments by removing their original lenses and adding mounts. One takes small M12 lenses; the others use C/CS-style mounting setups, including one adapted to a full-size Canon EF lens. The result was ridiculous, surprisingly fun and still limited by the little cameras themselves.

Did bigger lenses make the photos good? Not necessarily. In several comparisons, the modified G6 wasn't even better than my unmodified Kodak Charmera. I also ran into a flashing blue light leak and an extremely shaky telephoto view. This was a creative experiment, not a practical way to turn a cheap keychain camera into a high-end mirrorless camera.

Watch the full build, lens tests and image comparisons.

Why put interchangeable lenses on a keychain camera?

I've collected a bunch of these tiny cameras, even though the image quality is usually terrible. They're just fun to use. So I wanted to see what would happen if I could swap their lenses: a fisheye, a zoom, a macro setup and even a full-size EF lens on a camera that fits on a keychain.

There isn't a mirror or reflex viewfinder in these little cameras, but calling the result “mirrorless” doesn't mean it has the sensor, controls or image quality of a conventional mirrorless system. The interchangeable lenses are the point of this project.

The three cameras and what I changed

Camera	Modification	What I tried
Vivitar keychain camera	Removed its original lens and attached an M12, also called S-mount, holder.	An 8mm fisheye lens and a 2.8-12mm f/1.4 M12 zoom; close-up focusing by adjusting the lens.
Gold keychain camera	Added a C/CS-style mount and an 850nm bandpass filter.	A 5-40mm f/1.6 CS-mount lens and near-infrared experimentation.
G6 thumb camera	Added a C-mount-style setup and a visible-light IR-cut filter; used an EF adapter.	A full-size EF zoom and a comparison with my unmodified Kodak Charmera.

The Vivitar was about $12 when I bought it at Walmart; that was my purchase price, not a current price. Its photos were approximately 0.3 megapixels, or VGA resolution. A different lens doesn't add pixels to that sensor.

Building the first M12 camera

I started with the Vivitar as a proof of concept. After opening it, I tried to unthread the tiny original M7 lens while leaving the rest of its housing in place to help protect the sensor. Small drops of glue held the lens in place, which made it difficult to remove, and I did damage the surrounding assembly in the process.

My first plan was to drill the camera's front piece and attach the M12 mount there. The spacing didn't work out, so I removed that front piece and epoxied the mount directly to the front of the camera. I first secured it with a few drops, let those cure, then filled around the mount for strength and to reduce gaps where light could get in.

This is a hands-on modification of a fragile camera, not a standardized conversion kit. Opening the body and removing a glued lens can damage the camera or contaminate the sensor; exact construction and lens spacing vary by model. The video shows the approach I used on my particular cameras.

What happened to the fisheye and macro shots?

My first test lens was an 8mm f/1.8 fisheye intended for a larger sensor than the one in this camera. Because the tiny sensor captures a smaller portion of the lens's image, it didn't give the ultra-wide fisheye view I expected from the lens name. On this setup it looked more like a regular wide-angle view.

I estimated a roughly 22mm full-frame-equivalent field of view in the video, but that number wasn't independently measured, so treat it as a rough guess rather than a specification. The actual field of view depends on the sensor's active dimensions and the lens's projection; the lens itself remains 8mm.

Adjusting the threaded lens changed focus. Moving it farther from the sensor let me focus closer for macro-style shots, although available focus range depends on the lens and mount placement. The video includes examples from this setup and the 2.8-12mm zoom.

The G6, a full-size EF lens and a very shaky view

For the second build, I kept my Kodak Charmera intact and modified a similar-looking G6 thumb camera instead. I added a mount and adapter so I could attach a full-size Canon EF lens. The size difference between the camera and lens was as ridiculous as I'd hoped.

At the 400mm setting on the lens, I could see details on a distant tractor. Finding the subject and focusing were difficult because even a slight touch caused the view to shake. The tiny sensor's narrow view makes movement especially noticeable, so supporting the lens and camera securely matters.

In the video I estimated an equivalent range of roughly 4,000-7,600mm, but I didn't verify the sensor's active dimensions or measure that field of view. Those figures are estimates, not a measured focal length or a promise of telescope-like detail. The lens's actual focal length does not change when it is attached to a smaller sensor.

C-mount versus CS-mount: spacing matters

C-mount and CS-mount lenses share a one-inch, 32-thread-per-inch thread, but their standard flange distances differ: approximately 17.526mm for C-mount and 12.526mm for CS-mount. A lens that screws on is not automatically positioned correctly to focus. See Edmund Optics' lens-mount guide for the standards.

My handmade camera bodies aren't precision factory C- or CS-mount cameras. I used a 5-40mm f/1.6 CS lens on the gold camera because it worked with the spacing in that particular build. Don't assume the same combination will focus properly on another conversion. Lens coverage, spacing, clearance and secure support all need to be considered.

Infrared filters and an unexpected light leak

Removing a tiny camera's original lens can also remove a filter that was part of its optical assembly. For the G6, I used a 650nm IR-cut filter for ordinary visible-light imaging. For the gold camera, I installed an 850nm bandpass filter to experiment with near-infrared photography. These filters do different jobs: the first reduces infrared reaching the sensor, while the second selects a band around 850nm. Results depend on the filter, illumination and the sensor's sensitivity.

I got the filters and some mounts and adapters from Commonlands; the video wasn't sponsored by or affiliated with the company. Infrared was new territory for me in this project, so I wouldn't treat this as a complete infrared conversion guide or a guarantee of a particular result.

On the G6, I also noticed blue flashing across the video. The camera's own internal blue LED was spilling light onto the sensor. Sealing gaps around the sensor might address that leak, but I didn't fix or retest it in the video. It's a reminder that light can reach the sensor from inside a modified camera as well as through the lens mount.

Did the new lenses improve image quality?

Not consistently. I compared my modified G6 with a CS-style lens against my unmodified Charmera, and in a lot of situations the modified camera wasn't even better. I hadn't compared the original G6 against the Charmera before taking it apart, so this wasn't a controlled before-and-after test of the same camera.

That matters because the lens is only one part of the image. A tiny low-resolution sensor and the camera's processing still limit the result. This project was more about trying unusual combinations and seeing what they could do than getting clean professional images.

If you want a closer look at the unmodified camera, read my Kodak Charmera review. You can also check the Kodak Charmera listing; the linked option was a single blind-box camera when I checked, so review its current details before ordering.

Frequently asked questions

Can you put interchangeable lenses on a keychain camera?

I did it with three specific cameras by removing their original lenses and modifying the bodies to accept different mounts. The process is not universal, and it can damage the camera. Lens spacing, coverage and light sealing all affect whether a particular combination works.

Does an EF lens turn the tiny camera into a 7,600mm lens?

No. The actual focal length stays the same. The tiny sensor produces a much narrower view than a full-frame camera with the same lens. My 7,600mm-equivalent figure in the video was an unverified estimate, not a measured result.

Are C-mount and CS-mount lenses interchangeable?

They have the same thread but different standard flange distances, so focus depends on the camera and adapter spacing. A lens physically attaching doesn't guarantee it will focus as intended.

Did the modified G6 beat the Kodak Charmera?

Not consistently in my comparison. I also didn't test the G6 before modification against the Charmera, so I can't isolate the effect of the lens swap from the differences between the two cameras.

My verdict

If you want better image quality, this probably isn't the project for you. If you enjoy experimenting with cheap cameras and odd lens combinations, though, it was a ton of fun. The macro experiments, infrared setup and absurdly large EF lens all made these little cameras more interesting, even when the images were still terrible.

Watch more camera experiments on FoxTailWhipz.