>That’s wrong. The size of the sensor, the aperture size (and of course the distance between the two) are all factors that together on this.
For a given angle of view, the amount of light incident on the sensor depends solely on the diameter of the aperture (the absolute diameter, not the f number). You can see this visually in the comment I made here: https://news.ycombinator.com/item?id=33426540
If you really want to think of it in terms of a combination of sensor size and f number, you can do so. But it's easier just to look at the size of the hole the light is going through – which not surprisingly, determines how much light ends up being collected, once you fix the angle of view.
>If I was shooting at night, why would I use 400 iso?
Because films with higher ISOs are unacceptably grainy for most uses.
I agree on your first point, it is the amount of light coming in through the aperture. A wide open aperture lets more light in.
The point is just that they have to balance DOF and brightness in their designs. It’s a multi-variable equation, and sensor size is one of the factors that constrains the options you have available all things considered.
Like you said
> once you fix the angle of view.
And of course they’re limited to relatively small apertures anyway.
> Because films with higher ISOs are unacceptably grainy for most uses.
Not in my experience! This is just nitpicking now.
We can keep getting more and more technical, but I think you understand how it works.
You’ve made your point. You don’t like gatekeeping. I’m not gatekeeping.
Sorry, there’s something about discussions of the relative merits of camera systems that seems to get everyone very hot under the collar. Indeed, I think we have both made our points based on our own experience.
For a given angle of view, the amount of light incident on the sensor depends solely on the diameter of the aperture (the absolute diameter, not the f number). You can see this visually in the comment I made here: https://news.ycombinator.com/item?id=33426540
If you really want to think of it in terms of a combination of sensor size and f number, you can do so. But it's easier just to look at the size of the hole the light is going through – which not surprisingly, determines how much light ends up being collected, once you fix the angle of view.
>If I was shooting at night, why would I use 400 iso?
Because films with higher ISOs are unacceptably grainy for most uses.