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1

When considering longitudinal CA, one must see the range of colors as a linear spectrum, rather than a circular color wheel. Infrared light with its very long wavelengths is on one end of the spectrum, ultraviolet with a very short wavelength is on the other. In between you have the visible spectrum: red, orange, yellow, green, blue, indigo, and violet in ...


0

https://photographylife.com/what-is-chromatic-aberration I found this article. Apparently the color changes once you past the focal point in the photo. In the foreground it's violet (just for Stan) and green in the background. Hope this helps.


0

This shape together with the hardness of the lens causes light rays to be redirected, they are bent inward as they transverse the lens. This action is called refraction. The light rays are caused to trace out a shape that resembles a cone of light. The length of this cone is measured when imaging a far distance object. This distance is labeled the focal ...


-4

The word lens is from the Latin, shaped like a lentil seed. This is a disk that bulges out of both sides, we call this lens shape, convex – convex. A single transparent convex – convex lens will do the deed. We task the camera lens to gather image forming light rays from a 3 dimensional world (object at different distances) and project their image on a flat ...


3

Take a look at these two Schneider lenses that both have 90mm focal length: The first has coverage for "35mm" format, the second coverage for large format. I am not sure, but I think the main reason for the difference in size is the fact that the large format lens is a "simpler" design, i.e. fewer elements/groups. The reason a large format lens can use a ...


2

A few points to consider (mostly adding to mattdm's answer): A manually focusing 135mm Nikkor 2.8 lens in F mount is about 91.5mm long, and looking at a drawing of the lens most of the optical elements are in the front. So a comparison with a zoom lens isn't really fair -- it is a much more complicated lens. Strictly speaking, a telephoto lens is one ...


19

The focal length is the distance from the (theoretical) center of the lens to the image plane. On the large format camera, there's a lot more camera between the lens and the film. The lenses are also often relatively simple — there's no need for a focusing mechanism in the lens itself, for example. @osullic gives the example of the Schneider PC TS ...


1

The older (50's-60's) large format Schneider Symmars that are "convertible" fit this description when used with the front group removed. My 135/235 isn't wonderful used as a 235 with the front group removed, but it's not awful either, at least by f16. Suspect there are other convertibles (Cooke?) that this is also true for.


1

I eventually found out that MS SuperTriplet Perar 24mm F4 and MS SuperTriplet Perar 28mm F4 were objectives which I tried to recall. They are M-mount objectives meaning that they are not tied to a specific camera. I did not find any concrete words about iris placement but every photograph of these objectives suggests that iris is in front. Here is an ...


0

In other words, a 50mm f/1.8 lens on an APS-C camera would act more like a 80mm f/2.8 (approx. 1.8 * 1.6x) lens in 35mm equivalent — for depth of field, not considering exposure. Yes, a 50mm f/1.8 lens on an APS-C camera would act more like a 80mm f/2.8 (approx. 1.8 * 1.6x for Cannon) lens in 35mm equivalent, as far as DOF and to some extent image noise ...


2

Your eyes are very sensitive once they become accustomed to the dark (rods can respond to single photons, although a higher flux is needed for actual image formation). You could probably see your mime on stage (under bright stage lights) dimly but intelligibly enough. If you needed a brighter image you could use a lens instead of a pinhole without violating ...


0

I have found Edmund Optics/Scientific to be a good source of different types, quality, and grades of optical supplies for prototyping. I have also used LEGO™ blocks for building various types of cheap lens mounts and component assemblies. The parts are standard, and can be modified for any kind of custom piece. Sugru™ is another wonderful material for ...


0

First, you link to an article about Gaussian Optics which is a specific branch of optics using coherent radiation/light that has nothing to do with conventional photography. That aside, a lens has a "front" and a "back" so there are two of everything since there is one kind of optical point or optical plane for each side of a lens. In other words, the back ...



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