Samyang Optics (Rokinon) 135mm MF Lens

Users in team Dwarfstar: Manijeon, Namkyeong Lee, etc...

• Specification

1. Optical design: UMC Coated ED Lenses, 11 Elements in 7 Groups

2. Lens aperture: F/2.0~22

3. Focal length: 135mm

4. Weight: ~830g

• Pros

1. Cost efficiency

2. Very fast lens (up to F/2)

3. Light lens

• Cons

1. Helical focuser

2. Front lens filter is 77mm. Astrophotography filters for this size are hard to find and expensive

3. Stars on the edges may be distorted

4. Diffraction patterns around stars are not that great

• Verdict

One-line summary: RASA for the poor

Although developed as a camera lens, the Samyang 135mm UMC ED lens is a great tool for astrophotography. With its short focal length and low focal ratio, it is perfect for wide-field astrophotography!

However, since its main purpose is not an astrograph, it has certain problems when used for astrophotography. Using filters with this scope is a bit troublesome, since it is a camera lens after all. Also, the stars may be distorted on the edges of the frame. Finally, diffractions around stars may be seen when the focal ratio is low.