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on Sept 21, 2019 22:14:00 GMT
Posted: Sept 21, 2019 22:14:00 GMT
Hi All,
I bought a Minolta Autocord G 0 (Yellowish-Green) filter at a local camera junk show last weekend. My intention was to use this with my Yashica 124G and my Minolta Autocord L model as they all have Bay 1 mount. Initially I thought this was a Yellow filter Y2 for B&W but then realised that it is a G 0 filter. I have no idea what a G 0 filter is. From the Minolta L manual, this is what it says for this filter: -
""Colour corrects panchromatic film so that green becomes lighter and brighter. For foliage, grass etc""
Here are my questions: - 1) Based on the above instruction, is this filter for colour film or B&W or both? 2) Would it be fair to say that this is for outdoor photography where the surroundings are open field / grass / trees (it's obviously from the manual recommendation) 3) Any compensation is required when using this filter?
Thanking you all in advance.
Cheers Kai
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Status: Failed treatment for L.B.A. and G.A.S,
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on Sept 22, 2019 6:46:45 GMT
Posted: Sept 22, 2019 6:46:45 GMT
It's been a while since I've tried to find equivalencies for 2 manufacturer's filter types by the 'numbering/labeling' they'd use, but there are some general guidelines that should apply for each color type. Depending on which film is chosen and what formula it uses, it could be more sensitive to a certain part of the light spectrum than another B&W film, but generally B&W can 'see' most colors - but - it will drop off sharply at the red end (the spectrum goes from blue, to green, to red). 1. Panchromatic film will only be B&W, and that's what the filter was intended for. Use on color film gives a color cast over the entire spectrum, and not a selective tonal enhancement or a color correction effect. 2. Generally, yes, it's probably more useful in outdoor B&W scenes. 3. It will have some measurable effect on exposure by about 1 stop, and it might be up to 2 or 3 stops, depending on the film used. Not every flavor of B&W film will react to filters in the same way, so it takes time in experimenting, and digging through resources like film spec sheets to get exposure data for filter factors. It would also depend on the light source, i.e., daylight versus tungsten. Some resources that might help... Kodak Reference Handbook (not portable like a PDF - in the Web Archive)... archive.org/details/KodakReferenceHandbook... showing the Plus-X page... archive.org/details/KodakReferenceHandbook/page/n95Hoya Filter's reference on B&W filters, with Before/After comparison photos... hoyafilterusa.com/how-filters-for-black-white-photography-work/Dig up the data sheets for Tri-X or HP5, or whatever film you use for details and the manufacturer's recommended filters... either the paper from the box, or online. FreeStyle has spec sheet links for most brands : www.freestylephoto.biz/category/1-Film |
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on Sept 22, 2019 7:19:32 GMT
Posted: Sept 22, 2019 7:19:32 GMT
There's one more thing that might make filter factors easier to deal with when you might not have anything to go by from the filter maker. I always carry a Gossen Digisix 2 light meter with me when I shoot, and it can take readings as ambient or incident. I can pull back the dome and get 2 EV style readings in a row to compare exposures - with and without a filter held in front of the sensor cell. That would give an accurate multiplier without having to calculate or guess at anything. If you have a meter to use in the same way, at least you would have a base figure as a starting point to compare with the film data sheets.
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on Sept 27, 2019 1:03:26 GMT
Posted: Sept 27, 2019 1:03:26 GMT
Thanks Lumiworx.
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