The Hoya RM90
High quality, superior results.
This filter has become very widely known as the filter to have. It performs very well indeed in both daylight and to some extent artificial light too.
There is a draw-back however - the Hoya RM90 is not available from Hoya in 30, 37 or 43mm mounts. If you happen to acquire one of these highly sought-after objects you can get a specialist glass company or local optician to cut it down to size for you.
Alternatively you could opt to use an adapter to take it down to size, but this may make your camera somewhat obvious in its appearance.
Due to the demand for this filter in 37mm, some suppliers now make a pre-cut 37mm version mounted in a ring and ready to use. 30mm and 43mm sizes are not usually available.
The filter begins transmission at around 900nm making it a good choice. It is constructed from quality glass which is coated on both sides for protection and to make the image optically correct. The results obtained with this filter are impressive. Some of the finer examples of "x-ray" on the internet were taken using it.
Buy from a reputable dealer if possible. Contact the supplier and confirm they are in stock before placing an order or you may be faced with a long wait. Buying a 37mm pre-cut version may actually be quicker because companies producing them are likely buying RM90 glass in sheets and cutting out the filters from that rather than waiting for new 49mm RM90 filters to be made.
Testing has shown that this filter combats Sony's modification and can be used to film in overcast conditions or artificial light without further work-arounds or modifications.