EX3-Cavision Matte Box and 4x3 filters
 

Just wondering if anyone with the aforementioned combination has tried using 4x3 filters in the rear, rotatable filter holder.
I seem to have a plethora of 4x3 graduated filters left over from my medium format days and have found that they fit into the rear holder of the Cavision but when oriented for proper graduated effect there is a 1/2 gap, as one would expect for a 4x4 holder, on the left and right sides of the holder. The gap, however, is slightly beyond (lateral to) the lens opening and might not be an issue but I am concerned about the possibility of light leaks and before I risk marring the edge of the filters with gaffer tape I was hoping that someone might have already tried this combination.

Thank you in advance.

You can simply cut 2 1/8" x 4" x 1/2" black plastic strips and make them fit tight on the sides of glass to be used when using undersize filters.

Or even order a replacement holder from Cavision and customize it for smaller filters by epoxying them into filter frame, you may also need to relocate or shorten springs. This should be a fairly easy job.

Excellent idea (more reasonable than gaffer's tape) and before reading your post this morning I rummaged through the studio looking for suitable plastic of an acceptable thickness but, alas, none was to be found but locating a sheet somewhere should be possible.
Thanks again.

You can order here.

DELRIN® - DELRIN Sheet & Delrin Rod- Order Online

Hello and thank you for the link.
It appears that I would be required to order an entire sheet (48x96) for, in the range of $100.00. I may try searching for a piece of scrap, after all, all I really need are two pieces of plastic 1/2" wide and +/- 4" long.

How thin would you like? I think I might have a small scrap piece of black Delrin type plastic that I can send you for the cost of postage. If you can get an exact measurement, I can probably laser cut a piece for a modest cost.

Hello and thank you for the offer. I will take the measurements and post back to you.

Ron

I have made several test shots with the 4x3 filters in the Cavision's rear filter holder and, so far, there have been no light leaks suggesting that the baffles and flags are doing a good job and that fillers may not be necessary. In addition, after careful consideration, if fillers were to be required, a small piece of high density foam might be more practical than rigid plastic given the anticipated need for a tight fit as well as allowing for easy removal of the filter.
Thanks again for your offer, it was genuinely appreciated.