Before the rush

Before the rush
by evan-pak

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What causes lens flare along specific axes? Diffraction spikes occur perpendicular to the edge the light is diffracting around. For example, if the aperture were single vertical slit (much taller than it is wide), the diffraction spike would a wide horizontal spike (it would appear similar to the much loved-or-loathed lens flare JJ Abrams used liberally in ...


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These flares are a diffraction pattern caused by something in the optical path. Their number and orientation tell you something about what caused them. In a refractive system, it could be a stray hair, a piece of dust, even very mild striae in one of the lenses, when one uses something ultra-bright as a light source. If they are oriented along a ...


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Can be due a specific star filter https://www.google.com/search?q=star+filter A dirty lens, for example fingertips smudged. This can be very specific, and actually controlled with the direction of the wipe. Some internal element of the lens. (difraction spikes as you mentioned)


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You cannot alter the back focal length of a lens without changing its optics. Specialized adapters exist to do this, but there is usually a large loss of image quality. Your best bet is to not use a DSLR lens, but to use a large format lens designed for use with bellows. They will have considerably longer back focal lengths and allow you the requisite ...


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I think there were a number of real reasons for 'a look', and most of those no longer apply...but others may have taken their place. The real ones IMHO are historic. 35mm Changed Photography Leica invented 35mm and suddenly a lot of professional reportage and suchlike became infinitely more portable. This meant that there were Leica type photographs, ...


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The answer is that the pentaprism is actually a roof pentaprism. The image is laterally-inverted (left-right inverted) because the image actually bounces an additional time due to the roof of the pentaprism. Pentaprism diagram from Wikipedia: Single-lens reflex camera, CC-BY-3.0


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The image forming lens flips the image once. For the imaging sensor, there is one flip. The viewfinder is made up of a fold mirror, the one in the mirrorbox of the camera, a focusing screen, and either a pentaprism or two mirrors. The fold mirror flips the image once, restoring it to "normal" parity. This means there are two inversions in a waist-level ...


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The image forming rays from the camera’s lens are intercepted by a hinged first surface (reflex) mirror set at a 45⁰ angle. This first reflection rights the upside down image, but, being a mirror image, it is reversed right for left. This image is projected onto a viewing screen. The bottom side of this screen has been roughened by scrubbing it with fine ...


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It sounds like you are referring to the thin lens formula, but your interpretation of the geometry has led to some wrong conclusions. It seems to me that if a given lens geometry has a given focal length, then image sensor placed at that focal length would just have a dot at the center pixel as the entire collimated light entering the lens is focused to ...


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The camera lens acts just like a movie or side projector lens in that it projects an image of the outside world on the surface of the digital imaging chip or film. Now the lens works by causing light to change directions. As the light rays from objects transverse the lens, they are caused to bend inward. This action is called refraction. It is the shape of ...


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The facial deformations you are worried about are due to perspective distortion. Perspective is determined by one thing and one thing only: subject distance. If you take a picture with a 50mm lens on a FF camera from a distance of 10 feet and also take a picture with a 30-35mm lens on an APS-C camera from a distance of 10 feet both pictures will have the ...


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Short answer no - it will be approximately equivalent to the 50mm lens on a full frame camera. What you are referring to are issues of perspective. The perspective is not a property of the lens but is due to the position of the camera relative to the subject. If you are at the same distance from the subject you will get the same perspective no matter what ...


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What exactly “professional-grade” means in Nikon line of lenses? It means nothing. It means nothing because Nikon doesn't designate certain lenses as "professional grade" and other lenses as "non-professional grade". Anyone outside of Nikon who uses such terms is doing so based on their own arbitrary definition, not on a definition of "professional grade" ...


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One reason "professional grade" is hard to define is because it's going to get manufacturer's in trouble by setting unreasonable expectations. It's easy, for example, to say that a metal bodied lens is more durable than a plastic composite... but that's not strictly true. The metal body will show dings; the plastic composite won't. The metal body will ...


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The major manufacturers do not mark lenses as "pro" or "non pro" and they probably have a good reason for that. There are very good professionals that use cheaper "amateur grade" equipment because their back can't handle heavy expensive lenses anymore. There are professional photographers for whom top of the line lenses with latest features are not ...



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