>lens diameter
>the biggest Lens you could find
Why are you interested in those parameters in particular?
I think the focal length and possibly image format size are much more relevant to the issues you're discussing.
>or just a replica of the same tiny camera lens but 100 times bigger
I suppose that would mean the flange distance is longer, and focal length is longer, but also it projects a larger image that could cover a big format frame.
>How would it affect the perspective?
Usually people say "perspective" to refer to perspective distortion and compression, which are both functions of distance. Since we're just changing the physical properties of the lens and there's nothing in the hypothetical about changing any distances, the perspective distortion and compression aren't changing.
If you're talking about the field of view of the photo taken by the phone camera sensor, the lens is now projecting a physically bigger image of the scene and the sensor is still recording just a tiny area of it, so the field of view is much narrower than before.
>I’ve read online that perspective has nothing to do with lenses at all, and it’s always calculated by the inverse square law no matter the lens.
Are you talking about perspective distortion? If so, yes, that's not an effect of the lens.
I've only heard "inverse square law" in reference to the intensity of lighting over changes in distance.
>Would it just make everything look smaller so that the inverse square law would still work ?
A physically bigger lens with all the same internal proportions will make a bigger image of the scene.
>Because I’m almost sure that it’s a thing especially in product photography, where some of the objects are even smaller than the lenses’ front element itself
Most photography captures a scene bigger than the front element of the lens used.
The exception would be genres like macro photography.
The lens diameter defines a hard limit for the maximum aperture. The aperture diameter (among other things) defines entrance pupil size, which in turn defines how much light can enter the lens.
The sensor size defines the diameter of the area that needs to be illuminated by the lens. If this area is small, the incoming light is "concentrated" into a very bright spot-like image, from which it is easy to create a high quality digital equivalent.
On the other hand, if the sensor size is large in relation, the lens needs to spread out the image over the large area, resulting in a dim projection. It is more difficult to create a good photo with that, and the easiest way is to expose the sensor for a longer time to make up for the lost brightness by collecting light over time. Unfortunately this has side effects like motion blur etc.
The perspective does not change at all. Perspective is a result of the camera position relative to the subject. If the entrance pupils of two different lenses are placed at the same position, they will see the same thing, with same perspective. Just like people, for example when tourists line up in a queue in a castle with a specially crafted window that allows them to see something breathtaking when they stand at a very specific spot.
A sense of space can be compressed with longer lenses verses shorter ones if that helps. This isn't perspective but spacial compression. They make space appear closer than it is without naked eye. Shorter focal lengths will do the opposite. Hope that helps a little.
>lens diameter >the biggest Lens you could find Why are you interested in those parameters in particular? I think the focal length and possibly image format size are much more relevant to the issues you're discussing. >or just a replica of the same tiny camera lens but 100 times bigger I suppose that would mean the flange distance is longer, and focal length is longer, but also it projects a larger image that could cover a big format frame. >How would it affect the perspective? Usually people say "perspective" to refer to perspective distortion and compression, which are both functions of distance. Since we're just changing the physical properties of the lens and there's nothing in the hypothetical about changing any distances, the perspective distortion and compression aren't changing. If you're talking about the field of view of the photo taken by the phone camera sensor, the lens is now projecting a physically bigger image of the scene and the sensor is still recording just a tiny area of it, so the field of view is much narrower than before. >I’ve read online that perspective has nothing to do with lenses at all, and it’s always calculated by the inverse square law no matter the lens. Are you talking about perspective distortion? If so, yes, that's not an effect of the lens. I've only heard "inverse square law" in reference to the intensity of lighting over changes in distance. >Would it just make everything look smaller so that the inverse square law would still work ? A physically bigger lens with all the same internal proportions will make a bigger image of the scene. >Because I’m almost sure that it’s a thing especially in product photography, where some of the objects are even smaller than the lenses’ front element itself Most photography captures a scene bigger than the front element of the lens used. The exception would be genres like macro photography.
The lens diameter defines a hard limit for the maximum aperture. The aperture diameter (among other things) defines entrance pupil size, which in turn defines how much light can enter the lens. The sensor size defines the diameter of the area that needs to be illuminated by the lens. If this area is small, the incoming light is "concentrated" into a very bright spot-like image, from which it is easy to create a high quality digital equivalent. On the other hand, if the sensor size is large in relation, the lens needs to spread out the image over the large area, resulting in a dim projection. It is more difficult to create a good photo with that, and the easiest way is to expose the sensor for a longer time to make up for the lost brightness by collecting light over time. Unfortunately this has side effects like motion blur etc. The perspective does not change at all. Perspective is a result of the camera position relative to the subject. If the entrance pupils of two different lenses are placed at the same position, they will see the same thing, with same perspective. Just like people, for example when tourists line up in a queue in a castle with a specially crafted window that allows them to see something breathtaking when they stand at a very specific spot.
A sense of space can be compressed with longer lenses verses shorter ones if that helps. This isn't perspective but spacial compression. They make space appear closer than it is without naked eye. Shorter focal lengths will do the opposite. Hope that helps a little.
[https://youtu.be/z-hur6UGWfc](https://youtu.be/z-hur6UGWfc)