Sunset in Kruger

by MrFrench

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You probably will have trouble for your purposes improving on this Sekonic EV - Lux inter-conversion table "Close enough"* Lux = 2.5 x 2^EV EV = log_2(Lux/2.5) ie 2 raised to the power of the EV value and multiplied by a constant. *_The above Seconic table best fits about Lux = 2.502442 x 2^EV 2.5 will be fine enough for mere mortals. ...


There are some applications, that run on the Android OS, that calculate the equivalence between the EV and light energy per unit area (in lux, never in lumen as CherryCola has already answered). They also measure and give the value as a normal photometer, using the camera sensor of the Android device on which they are installed. Some are free, some not. I ...


The light IS (inversely) proportional to the focal length. A long telescope at high magnification sees a dim image. Binoculars are short, and see a brighter smaller image. Yes, a 200 mm f/4 lens is 2 times the diameter, and 4x the area, which passes 4 times the light, compared to a 100mm f/4 lens. However, focal length also involves magnification, and ...


I think you may not be factoring in the distance needed to make the image the same. If the image isn't the same then the light can't be the same and so you have to factor that in. You are right that the bigger lens collects more light at the same f-Stop because the iris is an actual different size. But you're assuming the same distance, and that's not how ...

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