| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| cfastie | "For some reason it's hard to find spectra of glow-in-the-dark pigments. Really, a thousand Public Lab spectrometers out there and no one has done t..." | Read more » | about 11 years ago | |||
| nathanathan | "I would like to know how glow in the dark paint compares to LEDs. Postcards with glow in the dark rainbows painted on them could be packaged with s..." | Read more » | about 11 years ago | |||
| cfastie | "Would the LED have to be placed outside the entrance slit? Otherwise the grating would form an image of the entire bulb. Standard single color LED..." | Read more » | about 11 years ago | |||
| warren | "I'm interested in something similar for spectrometer exposure calibration -- putting an LED and battery inside each spectrometer, on one side, so y..." | Read more » | about 11 years ago | |||
| cfastie | "The Canon A2200 (refurbished) is on sale today (November 21) for $48.99 (free shipping) with a one year warranty: http://shop.usa.canon.com/shop/e..." | Read more » | about 11 years ago | |||
| nedhorning | "Hi Thorsten, Glad to hear you're making progress. When you run the plugin are you specifying that the channel from the visible image to use for th..." | Read more » | about 11 years ago | |||
| Thorsten | "Ned, I followed your advice and now have processed my first dual camera images (RGB and 850nm IR) using your PhotoMonitoring plugin, which works li..." | Read more » | about 11 years ago | |||
| mathew | "cool test! this is definitely the most pixels in a research note, as far as I've seen. " | Read more » | about 11 years ago | |||
| mathew | "sorry, I was confused. clearly dual camera. " | Read more » | about 11 years ago | |||
| mathew | "I think doing calculations based on red and green might be two ways to get to the same result that Chris was seeking in his Oaktober note-- the cha..." | Read more » | about 11 years ago | |||
| warren | "It's weird because we think of green being reflective, but compared to IR, it's very absorbent. " | Read more » | about 11 years ago | |||
| cfastie | "Mathew, To make sure there is no confusion, the (NIR-Red)/(NIR+Red) formula is not used for the BG3 filter because there is no red visible channel...." | Read more » | about 11 years ago | |||
| cfastie | "Mathew, That does seem to be a consistent pattern. I think you are right that a green filter might offer the purest visible light channel in a sing..." | Read more » | about 11 years ago | |||
| mathew | "looking at the sensor sensitivity graph for the Nikon D200, its interesting that green is the least sensitive channel in the infrared band, implyin..." | Read more » | about 11 years ago | |||
| cfastie | "Hi Pat, The Wratten 25A is an old standard photographic filter that is still widely available in glass and gel. I think Ned bought a genuine Kodak ..." | Read more » | about 11 years ago | |||
| patcoyle | "Thanks Chris and Ned, this is an encouraging line of inquiry. Remind me on the source for the Wratten 25 filter material, or is it in the prior not..." | Read more » | about 11 years ago | |||
| cfastie | "The aperture mechanism definitely varies among Powershots. By peering into the front of the lens I learned that the high end ones have an actual ir..." | Read more » | about 11 years ago | |||
| timmm063 | "Have you considered watching other sites for cameras that are refurbished? One I would recommend is canonpricewatch.com. It also shows prices for o..." | Read more » | about 11 years ago | |||
| danbeavers | "The filter should have nothing to do with the difference in quality between the center and edge of the image since it is uniform in density. Lense..." | Read more » | about 11 years ago | |||
| cfastie | "I was assuming that the best way to preserve image quality when removing a glass filter would be to replace it with another glass filter. Plastic, ..." | Read more » | about 11 years ago | |||
| warren | "Very interesting line of inquiry. I've always been a bit confused about the role of the filter material itself in focus -- my assumption has been t..." | Read more » | about 11 years ago | |||
| nedhorning | "Chris, So many questions... I think more testing is necessary but I'll take a shot at answering each question. I'd like to hear what other folks th..." | Read more » | about 11 years ago | |||
| cfastie | "Ned, The NDVI image made from the Rosco 2008 photo by stretching the histograms is surprisingly similar to your calibrated NDVI image from the red ..." | Read more » | about 11 years ago | |||
| nedhorning | "If you use a dual-camera setup I suggest using an unmodified camera and a NIR-pass (visible cutoff) filter for the other camera. Some people use un..." | Read more » | about 11 years ago |