Hi - a bit of a novice question so humour me :

The spec sheet for new Velvia 50 gives the following advice on correcting for reciprocity failure:

Exposure speed (s) : 4 8 16 32 64
Filter correction : 5m 7.5m 16m 12.5m nr
EV correction (stop): +1/3 +1/2 +2/3 +1 nr
(sorry the columns don't line up )

Note: nr = not recommended.
EV correction includes adjustment for the filter

My question is this - does anyone out there actually follow the filtering advice this closely = i.e. do serious LF photographers carry a set of magenta filters (5m through 12.5m) to correct for the shift to green as exposure speed increases (and where do you get such a set as the Lee set I've seen increases in larger steps). Or, is it enough just to use a tiffen 812 (as most US LF shooters seem to) or a Lee 85C (as some UK LF shooters do).

Thanks

Paul