Can We Use FX Format Lenses on DX Format Cameras?

The compatibility between different camera formats has been a popular topic among photographers for some time. Specifically, there is much discussion around the use of FX format lenses on DX format cameras. This article explores why and how the use of FX lenses on DX cameras can benefit photographers, what to consider, and provides some practical examples.

Compatibility Explained

Yes, you can use FX format full-frame lenses on DX format crop sensor cameras. The key concept to understand here is the crop factor. DX sensors, which are found in many entry-to-mid-range DSLRs, have a crop factor of approximately 1.5x for Nikon cameras. This means that when you attach an FX lens to a DX camera, the effective focal length of the lens will be multiplied by this factor.

Example of Focal Length Multiplication

For instance, if you use a 50mm FX lens on a DX camera, the effective focal length becomes 75mm (50mm x 1.5). This adjustment in focal length is the primary reason why FX lenses can be used on DX bodies. However, it's important to note that the image circle produced by the FX lens is much larger than the smaller DX sensor requires, so there will be no vignetting issues.

Practical Aspects and Considerations

Despite the successful use of FX lenses on DX cameras, there are a few factors to consider before making the switch:

Image Circle and Crop Factor Impact

As mentioned, the enlarged image circle from the FX lens will not cause any vignetting. However, the lens's depth of field (DoF) and its aperture performance will remain the same as they are designed to work with full-frame sensors. The effective DoF, however, may seem to be deeper than expected due to the crop factor. This is especially noticeable with wide-angle lenses, which might lose their wide-angle character when used on a DX camera.

Use Cases and Examples

Many photographers, particularly those with an existing collection of FX lenses, find this practice useful and convenient. For instance, a photographer named John, who uses a Nikon D7000, often enjoys the versatility of his older AF film era lenses such as the 70-210mm f/4 lens. John appreciates that his camera body has an internal focusing motor, allowing him to utilize these very lenses successfully.

Similarly, another user, Michel, notes that he has more FX lenses than DX ones and has used many of them on a DX body. This is an economical and practical approach for photographers who anticipate upgrading to a full-frame body in the future.

Personal Experiences and Benefits

A frequent use of FX lenses on DX cameras is highlighted by Sara, who shoots portraits with a Nikon D7500. She finds that the 50mm lens becomes a 75mm equivalent when mounted on her DX body, perfectly suitable for portraits between 85-105mm focal lengths. This realization led her to embrace the Nikon FX MICRO-Nikkor 60mm f/2.8 lens, which is an ideal choice for her setup. The lens, despite being an FX lens, functions optimally on her DX camera, providing excellent sharpness and close-up macro capabilities.

Unique Applications

Another user, David, uses a wide-angle 200-500mm f/5.6 lens for bird photography. He explains that his Nikon D7500 turns this lens into an "UBER-zoom" with a wide range of 300mm to an impressive 750mm. This scenario demonstrates the power of using FX lenses on DX cameras for extreme focal length applications.

Pros and Cons of Using FX Lenses on DX Cameras

While using FX lenses on DX bodies offers numerous benefits, it's also important to weigh the pros and cons:

Pros

Vertigo-level framing potential with wide-angle lenses. Access to a wider range of lenses without the need for additional purchase. Exposure to full aperture and optimal lens performance.

Cons

Wide-angle FX lenses might lose their wideshot capability when used on DX bodies. The crop factor can affect the appearance of the depth of field. May not be cost-effective for those not planning to upgrade to FX in the future.

Conclusion

In summary, using FX format lenses on DX format cameras is indeed possible and beneficial for many photographers. While it does come with certain limitations, such as a change in focal length and depth of field, the advantages, including cost-effectiveness and versatility, often outweigh these issues. Whether for portrait photography or extreme long-range shooting, this compatibility provides a flexible and practical solution.

So, the next time you find yourself with more FX lenses than DX ones, consider utilizing them on your DX body. Embrace the full potential of these lenses and continue to enjoy the boundless possibilities of photography.