JMC Posted September 20, 2017 Share Posted September 20, 2017 Having an eBay browse at the weekend, and found this OG570 filter (excuse the slightly shaky picture - too much coffee today I think). The vendor was a second hand photographic equipment seller, and all he knew about it was that it had been made by a company called Mason Vactron for forensics work. As it was threaded in 52mm (and was only £20 including delivery) I thought 'why not'. It turned up today and I've run a transmission test on it. Looks pretty good to me, I don't think it got used much. Apparently Mason Vactron were dissolved in 2016, but from the directors list I'm guessing they are now Freeman and Foster, who are a big forensics manufacturer here in the UK. Link to comment
Andy Perrin Posted September 20, 2017 Share Posted September 20, 2017 Can't wait to see the photos with it! Link to comment
JMC Posted September 21, 2017 Author Share Posted September 21, 2017 Quick trip to Kew Gardens in London today. Sun was out for, oooh, about 10mins (that's good for Britain) for the entire time we were there. Anyway, did get a few shots - Monochrome EOS 5DSR, with 40mm pancake lens and Schott OG570 filter for all of them. Some of them have been cropped and the contrast upped slightly. Link to comment
Cadmium Posted September 21, 2017 Share Posted September 21, 2017 Schott OG550 is what B+W 099 is made from,. they are the same, at the same thickness of course. Is there a thickness shown on your filter?Thickness is usually not that critical, especially with non stacked longpass filters, but will change the cut off point slightly. Link to comment
JMC Posted September 21, 2017 Author Share Posted September 21, 2017 No thickness on it, but just measured it at 3mm. Mines a 570 though, not a 550. Link to comment
Cadmium Posted September 21, 2017 Share Posted September 21, 2017 My mistake! OG570 has no B+W equivalent, they don't make a 570nm filter. Link to comment
Andrea B. Posted September 22, 2017 Share Posted September 22, 2017 Nice find! ADDED: The OG filters have some wild false colors: http://www.ultravioletphotography.com/content/index.php/topic/2362-update-13-aug-filter-series-water-land-sky-k5-white-balanced-raw-composites/page__view__findpost__p__17073 Link to comment
JMC Posted October 6, 2017 Author Share Posted October 6, 2017 Bit of an update on this one. Turns out the vendor I got the filter from specialises in used forensics equipment, and he had a load more filters - 3 more from Mason Vactron (OG550, GG495, and GG455, all marked up as Schott), and 5 by a different company called Quaser. The Quaser ones are marked up a bit differently, not with the glass type, but by where they reach 1% transmission (415, 476, 510, 549 and 593nm). All in 52mm mounts. So I made an offer, and got what he had left. Here are the filters and the transmission spectra (all spectra measured on a Perkin Elmer Lambda 650S UV-Vis spectrometer with a 150mm integrating sphere, between 250nm and 800nm, 1s collection time per nm; Mason Vactron filters Quaser filters Link to comment
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