Alley in Pisa, Italy

by Lars Kotthoff

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10

You are focusing on objects, which are reflected. So you are not focusing on reflected surface. You are interested in light rays, which go from object "through reflection" to your camera. Not only from reflective surface to camera. You can try to shot for example puddle - try to focus on ground and you will se that reflection is blurred. Then try to focus ...


8

No. This is like saying you can determine the height of a house by counting steps to get up. The size of steps matters and so does the number. Dynamic-range should be determined by the well-depth (size of capacitors at a photosite) and noise floor (how much noise in the system when these is no signal). Knowing these two, one can compute the dynamic-range of ...


7

An aperture could be closed which is effectively an infinitely large f-stop number since no light gets through. The fastest possible (smallest f number) is a bit harder. The speed of a lens is limited by the ratio of the entrance pupil to the focal length of the lens. The longer the focal length, the bigger the entrance pupil must be. In theory you could ...


5

Physics plays a role in answering your question and that information is out there. The basics from that linked discussion are that the index of refraction of the lens material will affect the maximum aperture you can achieve, so for pure glass that has an index of refraction of 1.5, the maximum aperture would be f/0.5 or thereabouts. Better substances, such ...


5

Here's a good simulation of the 'perfect' sensor that you describe (one having zero electrical noise, thus recordning every incident photon perfectly) reacting to widely differing levels of light, from 0.001, 0.01 & 0.1 photons per pixel (top row), 1, 10 & 100 photons per pixel (middle row) to 1000, 10000 & 100000 photons per pixel across the ...


5

Simple: You are focusing on the reflected subject, not the reflective surface. Ok, I'm not good at explaining this sort of stuff, I just understand how it works, but here's a drawing You see, when you are focusing on a subject, it's a reflection on the reflective surface, but the subject it's not there, it's further away, to explain better, lets say the ...


4

The focus distance is the distance to the object via the reflecting surface. Try taking a photo of yourself in a mirror at various distances, the distance from the camera to you, via the mirror, is twice the distance to the mirror. Your camera will indicate the focus distance as that.


4

Well, sort of. Think about the sun shining through a lens — it's immediately apparent that the focused spot of light is brighter than the unfocused. However, the catch is that your "real view" also goes through a lens which focuses the light: your eye. So, in a sense, the real comparison is simply "Is there a lens which is brighter than the human eye?" — ...


3

Through @MichaelClark's help to clarify my question and @Achifaifa's hint to look at film curves, I found the answer to my question. It turns out that answer lies in the film characteristics curve. It plots the density of the silver halide in the film (i.e. how opaque the film is) as a function of the amount of light the film is exposed to (measured in ...


3

When you are calculating the "correct exposure" ("Correct exposure" being the amount of light necessary to achieve a negative with a given density) you are actually playing with shutter speed, aperture and film sensitivity. If you restrict those variables to a fixed value, the only things you can do is overdeveloping or underdeveloping the film after the ...


1

There is a standard concept in photography called "exposure value". The question and answers at What is the EV scale? go into this in detail, but the quick version is that this is a series of numbers representing the amount of light in different scenes. Different combinations of aperture, shutter speed, and ISO can correspond to the same exposure (see the ...


1

I'd like to disagree with the other answers - we'll maybe just question them. Take your magnifying idea. You are not making the sun brighter! You are just focusing the caught by the lens into a small point, making it appear brighter. Light gets "lost" through every surface it passes through or bounces off of. You may change the appearance of it's ...


1

This should be possible since the eye samples light from a relatively small surface area where as a lens samples light from a much larger area. The bigger problem is the huge discrepancy between the sensitivity of the eye and the sensitivity of sensors. I can already take photos with my Canon 5D Mark iii with fairly short shutters (sub 1/3 second, ...


1

Theoretically, yes. The human eye reportedly only opens as far as f/3.2, and there are many lenses faster than this. The Canon 50mm f/1.0 for example was marketed as being "faster than the human eye", although the f/3.2 figure suggests it shares that award with most prime lenses. The biggest obstacle is designing a reflex mirror, pentaprism and focus screen ...


1

It's hard to provide a definitive answer to your question, because it depends on what you subjectively deem “useful”, as well as on many other factors like the strength and quality of the denoising algorithm, the output medium, etc... Thus, this is not really an answer, only some hints to help you find your answer. First, about the parameters to consider. ...



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