Stefano Posted January 20, 2020 Share Posted January 20, 2020 I already talked about my hand-made pen ink filter. It is basically a sandwich made with two clear sheets of plastic and the ink of a black pen in between. This is the front side and this the rear side They are actually the same, but I have always used this filter like this. For all shots I used a Panasonic DMC-F3, with the ink filter of course. WB on a paper tissue if I remember correctly.Since I posted a lot of images I kept them smaller than usual (I usually resize them 1000 px wide, this time I did only 800 px wide). And now some images, taken on January 2, 2020. f-stop: f/2.8, ISO 80, 1/500 s exposure f-stop: f/2.8, ISO 80, 1/1000 s exposure f-stop: f/2.8, ISO 80, 1/320 s exposure f-stop: f/2.8, ISO 80, 1/500 s exposure f-stop: f/2.8, ISO 80, 1/1000 s exposure f-stop: f/2.8, ISO 80, 1/125 s exposure f-stop: f/2.8, ISO 80, 1/400 s exposure f-stop: f/2.8, ISO 80, 1/640 s exposure f-stop: f/7.1, ISO 200, 1/400 s exposure Those were LEDs for Christmas. f-stop: f/7.1, ISO 200, 1/320 s exposure f-stop: f/7.1, ISO 200, 1/400 s exposure ...and that's me! It wasn't easy to keep my eyes open under the direct sun. f-stop: f/7.1, ISO 200, 1/500 s exposure f-stop: f/7.1, ISO 200, 1/250 s exposure f-stop: f/7.1, ISO 800, 1/160 s exposure Hopefully the data is correct. So, the filter is uneven and blurry, but it works. I think it is similar to an Hoya R72, maybe with a slightly lower cut-on at around 700 nm. Link to comment
eye4invisible Posted January 21, 2020 Share Posted January 21, 2020 Interesting effect, even if the corners are quite blurry (I guess that's just the smearing from the ink). Might be worth trying to sandwich the ink between 2 pieces of clear filter glass within a spare UV filter ring (to reduce the smearing). Have you tried inks of other colours, such as red, or blue? Link to comment
Andy Perrin Posted January 21, 2020 Share Posted January 21, 2020 So, the filter is uneven and blurry, but it works. I think it is similar to an Hoya R72, maybe with a slightly lower cut-on at around 700 nm. Yeah, I think so also, somewhere near the 720nm mark. Since there are probably thickness variations in the ink, potentially different parts of the image might have different cut-on wavelengths. Maybe someone with a spectrometer could measure it for you? Link to comment
Stefano Posted January 21, 2020 Author Share Posted January 21, 2020 Have you tried inks of other colours, such as red, or blue?No, not yet. Link to comment
Stefano Posted January 21, 2020 Author Share Posted January 21, 2020 Maybe someone with a spectrometer could measure it for you?If I have the occasion to do that I will surely measure it. Link to comment
dabateman Posted January 21, 2020 Share Posted January 21, 2020 I think Lee filters are just a polyester fabric dripped in some ink to give the color effect. You can wash out the dye from a Lee filter and be left with a clear polyester filter.So looks like you maybe reverse engineering the dyes.If you play with different inks, you might find different cut offs. Just need an optically good plastic to soak in your ink. Link to comment
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