How to correct diopter
The viewfinder eyepiece is neutral and not adjustable. But you could install an extra Nikon DK-20C diopter corrector onto it with the viewfinder kit in the box.
install the viewfinder kit
- Nikon DK-20C diopter range：-5 ~ +3
- -, negative for nearsighted
- +, positive for farsighted
- You could refer the glass degree and divide 100 to calculate the diopter
The diopter of updated Mark I is neutral. And the diopter of early batch SL42 Mark I is native -3 and you could adjust it based on this diopter.
The viewfinder kit is also available for Nikon DK-21 eyecup.