I used a BPM bellows unit occasionaly with film SLRs, but have just tried with my Olympus D M5, with a Canon FD 50 mm lens on the bellows unit. I use a conservatory as a 'studio'. There is an unacceptable amount of flare visible in the viewfinder, and in the digital files, but I am at a loss as to why it is happening, or how to avoid it. Any ideas would be very welcome.