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The diameter of the "blur disk" in the focus plane is the same as that of the "entrance pupil", the visible (rather than actual) aperture opening (f/a where f is the actual focal length and a the aperture number). How big is the visible aperture opening on a smartphone in relation to facial features? This should give you a clue about ...


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You appear to be seeking to maximize the amount of background blur. My personal experience with sensors smaller than APS-C has been disappointing. The difference among most compact camera sensor sizes usually has a greater effect on camera marketing than photographic results. However, there are compact(ish) cameras with APS-C and full-frame sensors that you ...


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Calculation of the equivalent lens range Classically, to calculate the equivalent lens focal range f, you need to use the diagonals (D1, D2) of the two films/sensors to calculate the 'crop factor' k = D1 / D2. The equivalent lens focal range is then given by the formula :f2 = f1 / k In your case (from the clarification part of your question): For 24x36mm ...


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I'm assuming you are talking about the darker internal ring. That appears to be different from the typical bright edge (nisen) bokeh caused by overcorrecting spherical aberrations. And it does not appear to be "onion ring" from the molding of the lens. IMO, the dark inner ring is almost certainly due to an internal lens element/boundary. It could ...


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Lenses suffer from defects called aberrations, there are 7 major types. One type is called chromatic aberration. Chromatic aberration is always present, the lens maker strives to mitigate but can’t eliminate. Each color of light, as it traverses the lens, is refracted at a slightly different angle. This results is, each color coming to a focus at a different ...


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What follows is not an answer to the question but rather a request for clarification put in this answer section due to the formatting limitations of the comments section. The size of the circle of confusion has nothing to do with the lens but with the size of the sensitive surface (analog film or digital sensor). The circles of confusion (C1, C2) for two ...


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The job of the camera lens is to handle each point on the subject (or vista) and project that point on film or digital sensor as a point of light. This projected point of light is the smallest fraction of an image that carries intelligence. The image thus consists of countless such points of light. These show up as tiny circles, juxtaposed with neighboring ...


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As to exposure, the lens aperture is unchanged. Your lens is always f/3.5, it is never affected by film size. It is affected by very close macro focus distances (fstop Number = focal length / aperture diameter). As to Field of View, any Equivalent focal length is computed from the diagonal, so it matters if your film is 6x6 cm, 6x7 cm, or 6x9 cm. Assuming ...


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