I would like to photograph the Milky Way, but I had problems with the ambient light. The first attempt suffered from street lights. The second attempt, away from street lamps that suffered from the full moon, was surprisingly bright as I had to take pictures in the moonlight shadow of a building. I'll try again if I can work outside the moonlight hours.
I have used the following exposures:
- ISO 6400, 5 s, f / 2.8 (for a 24 mm image)
- ISO 1600, 15s, f / 2.8 (17mm wide with this 17-55mm lens)
… especially because higher ISO values cause too much ambient light during longer exposures. Nevertheless, I see no Milky Way in my pictures. However, the pictures have a lot of ambient light, which I think is my problem.
I have seen some conflicting information about stopping the Milky Way exposition. One answer says that ISO 6000 * Fstop ^ 2 / Lock should be. Another source recommends ISO 1600, 1: 2, 30 s (or equivalent). There is a factor of 2 (one point) between these recommended positions.
At least the shutter speed (or should I say the exposure time) seems pretty much in agreement: the first answer recommends 600 / 35mm equivalent focal length, whereas the other source recommends 500 / 35mm equivalent focal length, and the two sources differ only by 20% stops, only a quarter Stop).
With this 17-55mm lens at 17mm, I can go as long as 18-22 seconds according to the 500 / f or 600 / f rules. What would be the optimal ISO for that? Should I go:
- ISO 3200, 20 s, f / 2.8, which is slightly underexposed by the second source but is slightly overexposed according to the first source and is valid under the 600 / f rule, but not in accordance with the 500 / f rule
- ISO 6400, 15 s, f / 2.8, ie correct exposure according to the second source
- ISO 3200, 15 s, f / 2.8, ie correct exposure according to the first source
…or something else? The camera is a low-end crop sensor, so I think ISO 6400 might be a bit too high (it's the maximum non-expanded ISO sensitivity of this camera), and I even have to use the 24 megapixel images at 6 megapix, reduced noise downscaled even at ISO 3200, which would give preference to ISO 3200, 20 s, f / 2.8. The manual ISO setting works on this camera only with dot.