Belairgon 114 mm Uses 46 mm Filters
One of my complaints about the 114 mm Belairgon lens is the lack of necessary markings. It doesn’t have the filter size marked, it doesn’t have depth of field markings, and it doesn’t have the infrared focus point marked.
Today I was in the camera store. I was wanting to find the filter size. The store has boxes of old filters, and as we started seeing if they had a size that fit the person that was helping me thought to look at the lens cap. I felt silly that I didn’t look there. The cap was marked 46 mm.
Unfortunately, 46 mm is an odd filter size. They didn’t have any new 46 mm filters, and the only used filter they had was an 85B. (They had dozens of 49 mm filters, and some assorted smaller filters.) There was one thing that did help me out, though. He looked in a box of adapter rings and found one that will allow me to use my 52 mm filters, and if I can find my 52 mm to 55 mm adapter I can also use my 55 mm filters.
I was also hoping to use Cokin filters, but as I looked at the camera I saw a potential problem. I suspect that a Cokin holder will partially block the poorly-placed photocell for the metering circuit. I may have to restrict the use of Cokin filters to either Bulb exposures or (by removing the battery) fixed 1/125 second exposures.
For all of my complaints, I am still very happy with the quality of the 114 mm lens. I was especially happy that they included filter threads.