Photography M42 Thread Test rhysb123 May 10, 2015 No Comments Canon 5D MK2 plus Helios 44mm f2.8 – using an M42 to EF adaptor. Full manual exposure and focus, works well though. Leave a Reply Cancel reply Your email address will not be published. Required fields are marked *Comment Name * Email * Website Notify me of follow-up comments by email. Notify me of new posts by email.