What does focal length means?
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Willoughby@piefed.world 1 week ago
Won’t work and if it does work, the resulting image has little to nothing to do with the original.
Source: I opened a badly taken .raw file a few thousand times and I know what focal length means, come at me.
msage@programming.dev 1 week ago
tigeruppercut@lemmy.zip 1 week ago
It’s the distance from the lens to the focal point, as in where the picture focuses on the sensor behind the lens. If you have a very long focal length like a telescope, you can see things further away but the range you can see is very small. With a short focal length you can’t see as far but you can see a much wider view. Check out this chart:
If you get very close to something with a short focal length or far away from it with a long focal length you can get essentially the same picture of a main subject (although what you can see in the background will be different), but even then a short lens will sort of taper your subject closer to a single point and a long lens will widen it. You can see this effect easily on faces: see this gif or this gif or this picture for an example.
msage@programming.dev 1 week ago
Wow, what an amazing reply, thank you very much. Those images help a lot.
HereIAm@lemmy.world 1 week ago
Do you have a good way to remember which way fast and slow f. stops go? I always have to trail and error when adjusting camera settings to go the right direction or especially listening to someone talk about aperture.
Krauerking@lemy.lol 1 week ago
Wider open you let in more light, and want faster shutter speed, more closed you get less light and want a longer shutter speed.
And f stops work backwards. Think of it as percent of sensor covered. The bigger the number the more covered it is and the smaller the hole/aperture.
HereIAm@lemmy.world 1 week ago
So Wide open = low coverage = small f stop -> lots of light -> “fast” shutter speed. And then the other way around. I think you finally worded it in a way it can stick in my brain! I like thinking about the f value as how much you’re covering the lens.
Zink@programming.dev 1 week ago
To add more specifics here for you, note that the f-stop is usually shown as a fraction, like f/2.8, f/4.0, etc.
So first of all, since the number is on the bottom of the fraction, there’s where you get smaller numbers = more light.
It’s also shown as a fraction because it’s a ratio, between your lens’s focal length (not focal distance to the subject) and the diameter of the aperture.
So if I’m taking a telephoto shot with my 70-200 @ 200 with the aperture wide open at f/2.8, that means the aperture should appear as 200/2.8 = 71.4mm. And that seems right to me! If you’re the subject looking into the lens the opening looks huge.
Krauerking@lemy.lol 1 week ago
I like trying to simplify stuff to basic language and I am happy it was helpful