India Point Park

India Point Park
by matt-ball                

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16

The effect is called field curvature. A good discussion comes from Nikon. It is a lens aberration that can reduce the resolution of the lens when coupled with a flat sensor. In the old days, the film could be bent a little to try to follow the image plane and reduce the effect, but our sensors today are rigid. It can be reduced with lens design.


7

Why does it seem like large sensors are necessary for good low-light performance? Because for the same amount of light passing through a lens a larger sensor will collect more of it. Your tire size analogy is seriously flawed. A better analogy would be increasing the diameter of the engine's cylinders. The size of the individual molecules of the ...


6

A single converging lens with real thickness has a curved focal plane. Most lenses offered by manufacturers include corrective elements to flatten the focal plane to one degree or another. There are some well known and highly desired lenses known for flattening the focal plane particularly well: The Zeiss Planar series for example. There are also lenses ...


4

With an optically perfect lens, the focal plane is parallel to your sensor, and it has the same shape as it, i.e. it is actually a plane. With a real-life lens, I guess you can get a bit of distortion of the plane, but it will essentially remain a plane. It has to be so for landscape photography where you want the whole image to be focused at infinity at the ...


4

The first question would be: "...a difference compared to what?" Most camera lenses have been multicoated for decades now. Before that (from around the '50s to the '70s) they were single coated. Before that, most were un-coated. Uncoated lenses typically lose around 4-8% to reflection. Single-coated lenses lose around 2-4% to reflection. Multicoated ...


3

A larger sensor requires a larger focal length to deliver the same field of view. Given the same entrance pupil size, this increases the f-number, cancelling the effect of capturing more light. This is at least part of your misunderstanding. f-number is not affected by sensor size. Field of view is, of course, because a smaller sensor sees only a part ...


2

I think that a missing element to the obviously-otherwise-correct answers given is connecting to the wrong intuition in the question. The intuition in the question is coming (I believe) not from some question about lens abberation, but from a wrong sense that the focal plane is based on the distance from the lens. This question could perhaps be paraphrased ...


2

Let us pretend that sensors are ideal photon detectors with infinite dynamic range [...]. Let us also assume that all these sensors have the same number of photosites. The question "Why are larger sensors better at low light?" does not answer my question as all the answers assume constant f-number, which is exactly the proposition I would like to ...


2

The shape of the focal plane is dependent of the optical formula. In particular the Zeiss Planar was named after its particularly flat focal plane which made it good for photography of books, but in general it looks more like your second drawing.


1

One thing to consider is that the size of the image that the lens projects is completely independent of its f-number and focal length, but a factor of the lens design. F-number is a product of the width of the aperture, and the focal length. The focal length is the distance between the point of convergence, and the sensor, completely ignoring factors beyond ...



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