I was outside after dark tonight with an -A 1.4 50mm at f2 1/60th playing with fill flash on the front of the house, getting ready for Halloween night.
I was horrified to see the most awful flaring off the compact fluoro lights on the house entry way.
https://www.pentaxforums.com/forums/members/wombat2go-albums-wombatspics-pict...ngprob3818.jpg
(Hope this link works, it is my first try)
I recently purchased (based on price) quite a large number of filters called Kokonor HQ UV 49 mm with the idea of leaving new, clean filters permanently on my -M and -A collection .
Some tests:
Take the filter off the lens : Flaring disappears completely.
Put an ancient worn and dusty Hoya UV(0) japan filter on : Flaring is very much reduced, slightly visible against black.
Put the Kokonor back on, switch off the compact fluoro lights , switch on fill flash : no flaring visible.
Put the Kokonor back on, switch on the compact fluoro lights , switch off fill flash : no flaring visible.
The flaring only occurs when the Kokonor is on and the flash is on and the compact fluoros are on. I suppose it will take an optics person to explain it .
Any comments will be appreciated.
best regards to all