When the Focal Length goes very large, can we assume all the lights that go into the camera are parallel?
JaxonZeng
Using the 35mm-format film standard (also called full-frame format in digital cameras), a majority of people argue that 35mm or 50mm lenses have the closest field of view to human eyes (that why they're called normal lenses). But by measuring the structure of our eyeballs, the calculation shows that the eyeballs' field of view is close to a 17 or 24mm lenses. The main point is that only part of the retinal information is processed by our brain. That's also called the cone of visual attention.
S-Muddana
@KevinXu02
When the focal length of a camera lens becomes very large, it approximates what's known as a "telephoto" lens. In this scenario, if the lens is focused at infinity, the light rays entering the camera become nearly parallel. This approximation holds true for objects at a considerable distance from the camera compared to the focal length of the lens. As a result, for practical purposes, when the focal length is very large and objects are at a significant distance from the camera, it's reasonable to assume that the light rays entering the camera are effectively parallel. This assumption simplifies certain calculations and can be useful in various optical and imaging contexts. However, it's important to note that this approximation might not hold for objects closer to the camera or when dealing with extremely large focal lengths beyond the capabilities of standard lenses.
stang085
I wonder how those 360 cameras compare to regular cameras in this aspect. Since they are able to pick up video from every angle, I wonder how that affects the aspects of the camera
keeratsingh2002
How do camera manufacturers calculate the "equivalent" focal length for devices like cell phones with much smaller sensors compared to traditional 35mm film?
jacky-p
I was a bit confused by the equivalent focal lengths when the lenses were different, but I see now, from my understanding, that it also depends on the size of the sensor associated with the camera. Therefore multiple variations/combinations can produce what would be "equivalent" focal lengths between each other.
srikartalluri
This is really interesting as many films are shot on different types of lenses that are supposed to capture different types of scenes. Specifically, for the movie Oppenheimer shot in 70mm was able to capture the intracacies of characters faces that were a bit deeper into the background than most other movies. Moreover, for shooting nature or landscape, an increased focal length might generate cleaner looking images.
danielhsu021202
I looked it up and the human eye has a focal length of around 17-24mm, so on the wider side of things!
I think we don't really perceive the fisheye effect/artifact that wide angle lenses would because our brain just corrects for it, but I could be wrong.
yangbright-2001
I recall that my phone always says the photo was taken with approximate 28mm "equivalent" focal length... The so-call "wide-angle" camera lens we used typically have smaller focal length
saif-m17
Adding on to @S-Muddana, in the case of an infinite focal length, a camera lens would essentially produce images where all objects in the scene appear in focus regardless of their distance from the camera. This means there would be an infinite depth of field, resulting in sharpness from the nearest point to the farthest point in the scene. This would eliminate the depth cues provided by selective focus as well.
When the Focal Length goes very large, can we assume all the lights that go into the camera are parallel?
Using the 35mm-format film standard (also called full-frame format in digital cameras), a majority of people argue that 35mm or 50mm lenses have the closest field of view to human eyes (that why they're called normal lenses). But by measuring the structure of our eyeballs, the calculation shows that the eyeballs' field of view is close to a 17 or 24mm lenses. The main point is that only part of the retinal information is processed by our brain. That's also called the cone of visual attention.
@KevinXu02 When the focal length of a camera lens becomes very large, it approximates what's known as a "telephoto" lens. In this scenario, if the lens is focused at infinity, the light rays entering the camera become nearly parallel. This approximation holds true for objects at a considerable distance from the camera compared to the focal length of the lens. As a result, for practical purposes, when the focal length is very large and objects are at a significant distance from the camera, it's reasonable to assume that the light rays entering the camera are effectively parallel. This assumption simplifies certain calculations and can be useful in various optical and imaging contexts. However, it's important to note that this approximation might not hold for objects closer to the camera or when dealing with extremely large focal lengths beyond the capabilities of standard lenses.
I wonder how those 360 cameras compare to regular cameras in this aspect. Since they are able to pick up video from every angle, I wonder how that affects the aspects of the camera
How do camera manufacturers calculate the "equivalent" focal length for devices like cell phones with much smaller sensors compared to traditional 35mm film?
I was a bit confused by the equivalent focal lengths when the lenses were different, but I see now, from my understanding, that it also depends on the size of the sensor associated with the camera. Therefore multiple variations/combinations can produce what would be "equivalent" focal lengths between each other.
This is really interesting as many films are shot on different types of lenses that are supposed to capture different types of scenes. Specifically, for the movie Oppenheimer shot in 70mm was able to capture the intracacies of characters faces that were a bit deeper into the background than most other movies. Moreover, for shooting nature or landscape, an increased focal length might generate cleaner looking images.
I looked it up and the human eye has a focal length of around 17-24mm, so on the wider side of things! I think we don't really perceive the fisheye effect/artifact that wide angle lenses would because our brain just corrects for it, but I could be wrong.
I recall that my phone always says the photo was taken with approximate 28mm "equivalent" focal length... The so-call "wide-angle" camera lens we used typically have smaller focal length
Adding on to @S-Muddana, in the case of an infinite focal length, a camera lens would essentially produce images where all objects in the scene appear in focus regardless of their distance from the camera. This means there would be an infinite depth of field, resulting in sharpness from the nearest point to the farthest point in the scene. This would eliminate the depth cues provided by selective focus as well.