Filter thread size for 8-1/4" Red Dot Artar

[Steve Goldstein]

Putting this out there for posterity.

Yesterday I discovered that my 8-1/4" Red Dot Artar (s/n 8169xx) accepts 40mm filters. I'm not sure if the threading is exactly the same as the filter's 40mm x 0.5mm but filters from my Canon LTM kit screw in all the way and seem tight.

40mm is a pretty uncommon size but for some reason SRB Photographic in England make a 40-49 step-up ring (now on order). From there it's easy to get to wherever you'd like, in my case 52mm.

[Dugan]

Steve,
Thanks for posting this.
Mine (8249xx) measures 40mm as well.
Useful info...thanks!

[Steve Goldstein]

Just another tidbit…

A 42mm Series VI slip-on adapter is also a perfect fit. I use series filters with my 120 folders so I now have two options. The series filter path is marginally smaller and lighter (four of them fit into a “large” B+W filter case) if I’m carrying just the one lens, otherwise I’ll probably stick with the SRB adapter and another step-up to 52mm.