Lens adapters solve a common mismatch: your lens mount and camera body don't line up. Maybe you have a drawer of M42 screw-mount lenses but now shoot Pentax K, or you own Canon FD lenses and a Canon EOS body, or you want Canon EF/EF-S glass to work on a Sony E camera. The adapter you choose changes how you focus, whether exposure stays manual, and whether autofocus and image stabilization survive the swap. These four adapters cover that range.
Quick Take
- If your lens is M42 and your body is Pentax K, the K&F Concept M42-to-PK adapter is the direct manual fit.
- If your lens is M42 and your body is Canon EOS, the Lens Adapter Ring M42-EOS is the lowest-price manual route.
- If your lens is Canon FD and your body is Canon EOS, the K&F Concept FD-EOS with optic glass is the one that keeps infinity focus.
- If your lens is Canon EF/EF-S and your body is Sony E, the 7artisans EF-SE is the autofocus-enabled adapter.
Listed Price Comparison
| Adapter | Listed Price | Price Bar |
|---|---|---|
| K&F Concept M42 to PK Pentax K | USD 19.35 | |
| Lens Adapter Ring M42-EOS for Canon EOS | USD 6.67 | |
| K&F Concept FD-EOS with Optic Glass | USD 35.19 | |
| 7artisans EF-SE Canon EF/EF-S to Sony E | USD 87.99 |
The listed prices span from $6.67 to $87.99, a spread of $81.32. The low end is a simple manual ring for M42-to-Canon use; the high end is a Canon EF/EF-S-to-Sony E adapter with autofocus.
Decision Matrix
| Question | Adapter to Start With | Why |
|---|---|---|
| Putting M42 glass on Pentax K? | K&F Concept M42-PK | Manual focus with infinity focus on Pentax K/PK bodies. |
| Putting manual M42 glass on Canon EOS? | Lens Adapter Ring M42-EOS | AF-confirm chip for manual M42 lenses on a Canon body. |
| Adapting Canon FD lenses to Canon EOS EF/EF-S? | K&F Concept FD-EOS with Optic Glass | Brass and aluminum build with an optical glass element. |
| Want autofocus from Canon EF/EF-S lenses on Sony E? | 7artisans EF-SE | Autofocus, IS support, eye AF, and EXIF transfer. |
Product Notes
K&F Concept Lens Adapter for M42 to PK Pentax K
The K&F Concept M42-to-PK ring is for Pentax K/PK camera bodies such as the K-7, K-5, K-3, K-70, and KP. It takes M42 screw-mount lenses and allows infinity focus, but it is a manual adapter: auto focus is not available, and both focus and exposure are set by hand. The mount is made of brass and aluminum, not plastic. If your lens collection is M42 and your body is a Pentax K-series DSLR, this is the direct match among the four. The trade-off is that nothing is automated; there is no electronic communication between the lens and the camera.
Lens Adapter Ring M42-EOS for Canon EOS
The Lens Adapter Ring M42-EOS is the lowest-priced adapter in this set, with a listed price of $6.67. It lets you mount a manual M42-format lens on a Canon EOS body, and it includes an AF-confirm chip that gives you a focus confirmation signal while you focus by hand. It is an aluminum ring, it supports aperture-priority and manual modes, and it allows manual infinity focusing. The limitation is that the lens is not electronically controlled: the camera body does not adjust the aperture, and EXIF data records a fixed 50mm f/1.4 value. This is a direct route for reviving M42 glass on a Canon body.
K&F Concept FD-EOS Lens Adapter with Optic Glass
The K&F Concept FD-EOS adapter fits Canon FD and FL 35mm SLR lenses onto Canon EOS EF/EF-S mount cameras, with a listed price of $35.19. It includes an optical glass element and is built from brass and aluminum, and it allows infinity focus. Operation is manual: you focus manually, set exposure manually, and control the lens yourself. The limitation is the direction: it is for Canon FD lenses going to an EF/EF-S body, not for EF lenses. If you have older FD glass and a Canon EOS DSLR, this is the adapter with the added optic glass for infinity focus.
7artisans EF-SE Lens Adapter for Canon EF/EF-S to Sony E
The 7artisans EF-SE is the autofocus option here, and its listed price is $87.99. It is designed to mount Canon EF/EF-S lenses on Sony E-mount bodies, with autofocus modes for PDAF phase focus and CDAF contrast focus, image stabilization support, real-time eye autofocus, and EXIF transfer. That makes it the fit if you want to keep electronic features while moving Canon EF/EF-S glass to a Sony camera. The trade-off is the price and the specialization: it is made for Canon EF/EF-S lenses going to Sony E, not for older manual mounts. If autofocus and electronic communication are the goal, this is the one built to do it.
Final Recommendation by Use Case
For M42 glass on a Pentax K body, the K&F Concept M42-to-PK adapter is the straightforward fit, with manual focus and infinity focus on a brass-and-aluminum mount. For M42 glass on a Canon EOS body, the Lens Adapter Ring M42-EOS gets you there at the lowest listed price while keeping focus confirmation. For Canon FD lenses on a Canon EOS EF/EF-S body, the K&F Concept FD-EOS with optic glass is the one to use. And if you need autofocus from Canon EF/EF-S lenses on a Sony E body, the 7artisans EF-SE is the adapter designed for that task.
