The Core Problem: Mismatched Resolution and Coverage
* Resolution Bottleneck: Medium format cameras have *massive* sensors compared to even full-frame 35mm cameras. They are built to resolve *tremendous* amounts of detail. An $8 lens, even if functional, is highly unlikely to have the resolving power to take advantage of that sensor. The lens will become the limiting factor. You'll be throwing away the sensor's potential.
* Image Circle and Vignetting: Medium format lenses need to project a large enough image circle to cover the entire sensor. A very cheap lens is likely designed for a much smaller sensor (like a phone camera or a toy camera). This means you'll almost certainly experience severe vignetting (dark corners and edges), where the lens simply doesn't project light to the corners of the sensor. You might even see the circular aperture of the lens intruding into the image.
Likely Image Quality Issues:
* Extreme Softness/Blur: The image will probably be incredibly soft, especially towards the edges and corners. The lens elements in a cheap lens are likely poorly made, potentially using plastic with poor coatings and very basic optical designs.
* Chromatic Aberration (Color Fringing): Expect to see color fringing around high-contrast areas. Cheap lenses rarely correct for chromatic aberration well (or at all).
* Distortion: The lens probably won't have good distortion control, leading to warped lines (barrel distortion or pincushion distortion).
* Low Contrast: Expect flat, washed-out colors and low contrast. Cheap lenses often lack effective coatings to reduce flare and internal reflections.
* Flare: Flare will be a major problem, especially when shooting into the light. Cheap lenses typically don't have good flare resistance.
* Sharpness Fall-off: Sharpness will rapidly decrease from the center of the image to the edges.
Physical Challenges:
* Mount Compatibility: The biggest hurdle is whether you can even physically attach the lens to the camera. Medium format cameras have unique lens mounts (Hasselblad V, Mamiya 645, Pentax 67, Fujifilm G-mount, etc.). An $8 lens almost certainly won't have the correct mount. You'd need a highly custom, probably jerry-rigged adapter, which may not even be possible.
* Focusing: Even if you get the lens mounted, focusing will likely be extremely difficult. You'll probably have to resort to zone focusing, estimating the distance and setting the focus manually. Accurate focusing will be a challenge.
* Aperture Control: The $8 lens might have a fixed aperture, or very basic aperture control. You might not have much control over depth of field. Some cheap lenses are simply a pinhole.
In summary:
You'd get an image. But it would likely be a technically flawed image. It would be soft, vignetted, full of aberrations, and generally low-quality. The experiment would be more about seeing the limitations of extreme mismatching of components than about creating a usable photograph.
Why even try? (Potential Motivations)
* Artistic Effect: Sometimes, intentionally using low-quality gear can create a unique, lo-fi aesthetic. The imperfections could be used to create a particular mood or style. Think of it as a creative "filter."
* Curiosity/Experimentation: The sheer novelty of it might be enough to drive someone to try it. Just to see what happens!
* Conceptual Art: The act of juxtaposing such a high-end camera with a ridiculously cheap lens could be a statement in itself.
* Technical Demonstration: Showing the importance of good glass!
The Bottom Line:
The $4,500 medium format camera's sensor would be vastly underutilized. You'd get a photo, but one that looks far worse than you'd expect from a basic smartphone. However, if done intentionally and creatively, it *could* result in a unique artistic statement. Just don't expect sharp, high-resolution images!