The Samyang 14mm F2.8 is an excellent and affordable lens for astrophotography. The build and glass is excellent, as is the performance of this wide angle lens. However, the focus ring seems to be off on some lenses and it is a ‘guess’ where the infinity focus (or the hyperfocal distance) actually is located for your lens. This can be quite annoying, since it can be quite difficult to focus with a wide angle lens at night. Luckily you can quite easily adjust the focus ring for your lens and have the marking of infinity at the correct focus point.
Calibrate the focus on the Samyang 14mm F2.8
All you have to do is loosen a few screws, get in focus on an object far away (infinity, past hyperfocal distance), move the focus ring and then re-align the markings.
This video explains it very well;
Step by step
It is best to setup your camera with the Samyang at a hyperfocal distance away from a window. The hyperfocal distance for a crop sensor with the 14mm lens is around 3.5meters at F2.8. This way you can see the focus shift from the window frame to the objects in the distance behind the window.
- Move the focus ring to slowly shift focus from the window frame to the objects you want to focus on behind the window
- Tape down the focus position so it won’t change
- Peel back the rubber band on the focus ring, this will reveal the 3 screws you need to loosen
- Loosen the screws with a 1.2mm (or 1mm) screwdriver. NB: Just loosen the screws, don’t take them out!
- Loosening the screws will free up a ring you can see through the hole in the focus ring. Move this ring by pushing gently on it with the screw driver through the hole. Move it till the end.
- Fasten the screws and move back the rubber band
- Move the ring with focus distance markings towards the body. Note that this might take a bit of force
- Move the ring and align the infinity marking
- Move back the ring with markings. You’re done!
Now it’s really easy to focus the Samyang at night; just move it to infinity and you have focussed!