Achieving Infinity Focus with M42 Lenses on a Nikon F Mount
When working with M42 lenses on a Nikon F mount, achieving infinity focus requires understanding the differences in flange distances and employing specific adapters and modifications. This guide walks you through the process of setting up your M42 lens on a Nikon F mount for clear, sharp infinity focus.
Understand Flange Distances: M42 vs. Nikon F Mount
To achieve infinity focus with an M42 lens on a Nikon F mount, it's crucial to understand the flange distances of both systems. The M42 mount's flange distance is approximately 45.5 mm, while the Nikon F mount has a longer flange distance of around 46.5 mm. This difference necessitates the use of an adapter that can compensate for this discrepancy.
Get the Right Adapter for Your M42 to Nikon F Mount
Select a high-quality M42 to Nikon F adapter that is suitable for achieving infinity focus. Some adapters come with a slight protrusion which can help in obtaining the required focus. Ensure the adapter is correctly positioned to avoid interference with the lens.
Check for Correctness and Test for Infinity Focus
After attaching the M42 lens to the adapter, check if the lens is seated properly. Focus on a distant object to test the infinity focus. If the lens doesn’t reach infinity, you may need to adjust or even replace the adapter to achieve the desired focus.
Consider Additional Modifications for Enhanced Focus
If you still face issues with achieving infinity focus, you may need to consider additional modifications. Shimming techniques can help by adjusting the distance between the lens and the sensor. However, these modifications require careful handling and are not recommended unless you have experience in lens modifications.
Use Manual Focus with Your Nikon F Mount Camera
Most M42 lenses are manual focus, so ensure your Nikon F mount camera is set to manual mode for proper focusing. Utilize features such as magnified center of image to aid in focusing.
Verify with a Test Shot
Take a test shot at infinity focus to confirm that your setup works as expected. This step is crucial to ensure that your focus is accurate.
Considerations and Solutions for Manual Focus
Due to the inherent differences in the rear element distance, achieving infinity focus with an M42 lens on a Nikon F mount is not always straightforward. You might need to adjust the focus slightly to achieve the sharpest image. Manual focus on the M42 lens will rely on the camera's manual focusing system, which, while reliable, isn't as precise as some do it may be perceived.
In cases where the infinity mark doesn’t align perfectly, the sharpness will be slightly reduced, though the overall image quality can still be outstanding. For instance, with a lens like the Opteka f/8 500mm reflex lens, the infinity point is typically just short of the marked distance, often around 300 meters. Nonetheless, manual adjustments and experimentation can help you reach the desired focus point.
For those seeking autofocus capabilities from an M42 lens on a Nikon F mount, it's important to note that no autofocus adapters currently exist. The eyeball focusing method remains the preferred approach for this setup.
Final Tips for Optimal Focus
To achieve the best possible focus, use any manual focusing aids available on your camera. Slowly twist the focus ring back and forth while using the magnified center of the image feature to find the sharpest image. Additionally, consider diopter correction settings on your viewfinder if your vision requires it.
By following these steps and tips, you should be able to achieve accurate infinity focus with your M42 lens on a Nikon F mount camera. Happy shooting!