Understanding the differences to choose the right lens without mistakes

Lens and camera compatibility is a key topic for anyone who wants to get the most out of their gear. Knowing mount rules and sensor formats helps avoid purchase mistakes and lets you make the most of every combination. In this RCE Foto guide you’ll find everything about Full Frame, APS-C, Micro 4/3, L-Mount and Leica M lenses, with practical examples and actionable tips.

All Full Frame lenses are compatible with both FF and APS-C cameras

Which one should you choose?

Since the mount for Full Frame and APS-C lenses is the same, how do I understand which one to choose?

• Full Frame lenses are compatible with both FF camera bodies and APS-C cameras.
• If you use a Full Frame lens on an APS-C camera, the focal length must be multiplied: ×1.5 on Nikon and Sony and ×1.6 on Canon.
• The multiplication factor depends on the camera’s sensor, not on the type of lens being used.

📌 Example: a Nikon AF-S 50mm f/1.8 G Full Frame lens mounted on an APS-C camera becomes a 75mm in equivalent focal length.

All APS-C lenses are only compatible with APS-C cameras

Which one should you choose?

• Lenses designed for APS-C cameras are compatible only with APS-C cameras.
• Using them on Full Frame DSLRs would lead to the well-known “vignetting” effect or, in the case of mirrorless cameras, it would trigger auto-crop, without fully taking advantage of the FF sensor.
• Please note, however, that (except for Canon) APS-C lenses can also be used on Full Frame cameras, with the limitations described above.
• Since an APS-C sensor is about one third smaller than Full Frame, all focal lengths must be multiplied by:
  • ×1.5 on Nikon and Sony
  • ×1.6 on Canon

📌 Example: an APS-C Nikon AF-S 55-200 lens mounted on a Nikon APS-C camera has an equivalent focal length of 82-300mm.

Micro 4/3 lens system

Compatibility guide

• Olympus became OM-System, but kept the same mount.
• Panasonic and Olympus created the Micro 4/3 system together, ensuring full interchangeability and compatibility.
• This offers a very large and versatile lens lineup.
• It’s worth remembering that, due to the smaller sensor, lens focal lengths must be doubled.

📌 Example: an Olympus 25mm lens on a Micro 4/3 mirrorless camera becomes a 50mm equivalent.

L-Mount Alliance

One mount, many possibilities

• The L-Mount was created through a collaboration between Leica, Panasonic and Sigma.
• Lenses from the three brands with L-Mount are fully compatible with each other.
• All Panasonic L-Mount lenses are compatible with Leica L-Mount cameras.

Leica: a duality between past and present

Digital results with analogue lenses

• The historic Leica brand began with the film-era M-Mount.
• It is still produced today, allowing you to mount analogue lenses on Leica M digital bodies.
• The opposite also applies: modern lenses can be used on analogue bodies.

📌 All Leica M lenses (analogue and digital) are compatible with Leica M cameras, both analogue and digital.

L-Mount by Panasonic and Leica

One mount for two major brands

• Panasonic entered the full-frame world by creating the L-Mount together with Leica.
• Used on Leica SL and Panasonic S bodies, it provides full lens interchangeability.
• All Leica L-Mount lenses are compatible with Panasonic L-Mount bodies and vice versa.

Sigma L-Mount: a rising star

A brand making its mark among the giants

• Sigma lenses with L-Mount are fully compatible with Sigma, Panasonic and Leica L-Mount cameras.
• Thanks to the L-Mount Alliance, photographers can freely choose camera body and lenses without constraints.

The continuation of the Leica dynasty

Coexistence between present and past

• Leica has always used the M mount, including on digital cameras.
• This allows you to use analogue lenses on digital bodies and vice versa.

Two brands, one mount

An alliance to satisfy everyone

• Thanks to the L-Mount Alliance, photographers can use Leica and Panasonic lenses interchangeably on their respective SL or S bodies.

One mount for many camera bodies

One lens, many possible results

• All Leica, Panasonic and Sigma camera bodies with an L mount can use Sigma L-Mount lenses.
• This ensures maximum flexibility and consistently high-quality results.

How to choose the right option

Knowing compatibility between Full Frame, APS-C, Micro 4/3 and L-Mount is essential to invest wisely.

In RCE Foto stores and in our catalog you’ll find used lenses tested and covered by a 2- or 4-year warranty by our specialized technicians, selected for maximum reliability.

Compatibility table between cameras and lens systems

To help you navigate your gear choices, we have collected in one table all the main camera brands with their respective mount systems and compatibility across different sensors.
This overview helps you understand which lenses you can use on your camera and what limitations or advantages apply.

From classic Canon EF and EF-S mounts to modern Nikon Z and Sony E mirrorless, up to the Micro Four Thirds system shared by Olympus (OM-System) and Panasonic, the table clearly shows which combinations work without adapters and where you need to pay attention.

It also includes the Leica, Sigma and Panasonic systems within the L-Mount Alliance, as well as specialized brands such as Fujifilm and Hasselblad for medium format.
A useful tool for anyone looking to buy RCE Foto guaranteed used lenses, confident they will be compatible with their camera.

Compatibility table between lenses and camera bodies

Note:
All Full Frame lenses are compatible with both Full Frame and APS-C cameras.
All APS-C lenses are compatible only with APS-C cameras.
The Micro 4/3 system ensures full interchangeability between Olympus (OM-System) and Panasonic.
The L-Mount Alliance enables full compatibility between Leica, Panasonic and Sigma.

Camera body sensor table

Notes:
Leica M-mount analogue and digital lenses are compatible with both Leica M-mount analogue cameras and Leica M-mount digital cameras.
All Leica L-mount lenses are compatible with Panasonic L-mount.
All Sigma L-mount lenses are compatible with Sigma L-mount, Panasonic L-mount and Leica L-mount cameras.