In the old days, I believe the general rule was after around 2,000 cycles. Denice Barsness, CRA, COMT, ROUB, CDOS, FOPS Ophthalmic Diagnostic Center CPMC Department of Ophthalmology 2100 Webster Street Suite 212 San Francisco CA 94115 (415) 600-3937 FAX (415) 600-6563 From: optimal-bounce@xxxxxxxxxxxxx [mailto:optimal-bounce@xxxxxxxxxxxxx] On Behalf Of Nelson, Ryan Sent: Friday, October 18, 2013 12:14 PM To: optimal@xxxxxxxxxxxxx Subject: [optimal] FA Filters Hello all, How often does everyone change out their FA filters? We seem to be getting a small amount of pseudofluorescence when shooting control frames at a high flash setting. We use Zeiss FF450s with OIS. Any feedback is appreciated, thank you for your time. [cid:image001.jpg@01CECE32.8B71A2D0]