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Thread: Reciprocity correction on new velvia 50

  1. #1

    Join Date
    May 2007

    Reciprocity correction on new velvia 50

    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).



  2. #2

    Join Date
    May 2007

    Re: Reciprocity correction on new velvia 50

    Okay - so after reading around here's what I've found:

    Joe Cornish sometimes uses a Lee 85c warming filter to compensate for reciprocity failure on old Velvia 50. The 85C apparently contains an element of magenta which provides the compensation for the shift to green at long exposures. However, although the Velvia 50 spec sheet says to start using compensating filters for exposures as low as 4s, Joe only seems to use the 85C at exposures of above 8 seconds. Also it seems that Joe does not always use this filter, and will go for longer exposures without any compensating filter - there are plenty of examples in his book First Light of exposures over 8 seconds where no magenta filter was used, and yet there is no green cast on the image.

    Jack Dykinga seems happy carrying a Tiffen 812 (slight warming with a magenta cast) or B&W 05 Magenta for the purposes of dealing with reciprocity failure. However, its not possible to confirm on which images these are used as he does not give detailed exposure info for each image in his book (Large Format Nature Photography).

    Elsewhere in this forum there seems to be some confusion as to the colour impact of reciprocity failure (shift to green) versus cool light situations (shift to blue) so it seems that sometimes the colour shift due to recip failure might be outweighed by colour casts due to shooting in shade.

    So what have I done? The Tiffen 812 seems difficult to get in the Uk so I've opted for the Lee 85c, and a Lee 10 M special for experimental purposes - I hope I don't waste too much 5x4 film trying to figure it all out.

    Hope this is helpful to others.


  3. #3

    Join Date
    May 2002

    Re: Reciprocity correction on new velvia 50

    I've never used CC filters to compensate for reciprocity effects. Unless you're projecting the original trannies, you should be able to compensate in scanning/printing/duplicating.

    I have obtained interesting (and strange) color shifts in long exposures of waterfalls on Velvia RVP 50. With exposures in the 20 to 30 second range, parts of the waterfalls have gone cyan, magenta and lavender colors. I don't believe a magenta CC filter is going to cure that.

    FWIW, Ektachrome E100SW gives me good color rendition even up to 30 seconds; at least the white water remains neutral. When I run out of E100SW, I'll use the current E100GX, which should (I hope) give similar, maybe better results.

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