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The way this technique combines knowledge of mechanical and human optics is really fascinating. Of course the calibration could also be done by recording an im
by jayceedenton 4y ago
The way this technique combines knowledge of mechanical and human optics is really fascinating.
Of course the calibration could also be done by recording an image to film and developing it, but it would be very slow and inconvenient. This technique is literally using the film-like qualities of the retina, which has just enough permanence to record the required pattern. Genius.
- flipthefrog 4y agoFilm isn't linear the way digital is. 30% under exposure doesn't give an image that is exactly 30% brighter, but may show up more as less shadow detail, compressed mid tones, etc. Also, negative film can handle a huge amount of over exposure and still look good. You can get a better idea with positive/slide film, which is much more sensitive to exposure, but that is very expensive. Slower shutter speeds (1/30 second and lower) ar usually the speeds that are the most incorrect with old shutters. That can be tested more or less reliably by filming it with a high speed camera (I use a Fuji XT3 at 120 fps). You can also measure the speed by recording the sound of the shutter. Filmomat have a free app for measuring shutter speeds using audio, as well as a light sensitive doodad that you plug into a smartphone, which is accurate to up to 500th of a second. https://www.filmomat.eu/shop/photoplug https://www.filmomat.eu/shop/photoplug
- kqr 4y agoI think what they mean is exposing a frame with the stroboscope-and-shutter combination, not just shooting anything at a known light level. So the same thing as here, but instead of shooting with the back open, doing it with film inside and back closed.