M77 Samyang 135 mm Step Down Adapter & Nikon D750 Full Frame Flats and Vignettes.

M77 Samyang 135 mm Step Down Adapter & Nikon D750 Full Frame Flats and Vignettes

In this post we describe some adapters used to mount 27.7 mm and 48 mm diameter filters to a Samyang 135 mm lens to a Nikon D750 full frame body. Note that the mounts shown in this post are prototypes - they are available free (with no guarantee) with the purchase of a filter but please contact before ordering.

Broadly two types are compared via the resulting flats; step down adapter in threaded onto the M77 thread of the lens and a clip on filter (clips onto the lens, not the body). This specific adapter is tested in two configurations; with a standard retaining ring, and with a Leviathan ultra low profile retaining ring typically supplied with mounted filters. Also shown but not tested is a a Nikon in body adapter.

A step down ring is threaded onto the Samyang filter threads. This mounts a 47 mm diameter filter.

An adapter clips onto the rear of the lens. Note here a 3D printed adapter is used to adapt the Canon EF lens onto the Nikon body. This adapter also works with Canon EF / Samyang 135 lenses.

This mount is for a Canon DSLR body and unrelated to the testing but is used to show the difference between a standard retaining ring (1.5 - 2 mm thick) and a Leviathan low profile retaining ring (1 mm).

The flats and vignettes 

Note, these are flats with a full frame sensor, the vignettes are much less with an aps-c sized sensor.

No adapter - baseline

M77 step down with 47 mm clear aperture.

Lens clip on with standard retaining ring.

Lens clip on with low profile retaining ring.

For fun, stepdown and clip on with standard retaining ring.

Conclusion

Step down rings on the Samyang filter thread with a 47 mm diameter thread and a clip on adapter to the rear of the lens will both induce a vignette on a Nikon D750 full frame sensor. The severity or acceptability of such a vignette is user preference. For minimal vignette the step down adapter is the smallest when compared to no 'adapter'.

The data show that the Leviathan low profile retaining rings show an improvement in minimising vignette when compared to standard retaining rings when coupled with a full frame sensor.