Napioa - Wind Origins

Napioa - Wind Origins
by octopus                

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Mar
23
comment Any cameras move the sensor instead of lens elements for focus?
This occurred to me as well; but I'm not sure if it's valid. The focuser is part of the telescope (lens equivalent); and it's only the camera moving not the telescope because in most cases its the scope attached to the tripod with the camera hanging off the back. (IIRC similar weight/balance reasons cause a lot of telescope sized telephoto lenses to use similar mounting mechanisms.) The position of the imaging sensor within the camera remains fixed.
Jan
14
awarded  Critic
Jan
13
comment How to photograph frost and snow sparkling?
If you want to try a getto DIY option, you might be able to get that sort of effect by crossing 2 or 3 pieces of thick thread/thin string across the face of your lens. The source of the diffraction spikes that filter is creating in images taken by telescopes comes from the spider veins that are used to hold a secondary mirror in front of the primary. Since they're pieces of sheet metal edge on to the light path, string would simulate their impact directly.
Oct
8
awarded  Caucus
Sep
17
comment What does it mean when a TV “supports HDR”?
Could be a new buzzword attached to the existing gimmick in back illuminated LCDs (vs edge illuminated ones) of varying the illumination level in different parts of the screen to fake a higher contrast ratio than the LCD is directly able to achieve.
Aug
10
comment Do I need a UV filter?
Are the sensors themselves less sensitive to UV, or is it just that the camera makers put a UV filter into the camera body itself. I know an IR filter is a standard feature.
Apr
29
comment Why are some big telephoto lenses so expensive compared to telescopes?
@MichaelT You'd never use them as macro lenses; but near focus for most telescopes is 20-30 feet on the small end to maybe a few hundred feet for some really big ones. In particular, smaller telescopes and spotting scopes used by birders/etc use the same type of optics. The most important difference being that a spotting scope will generally be paired with a correct image diagonal (or an erecting prism if looking strait through); while for astronomical use the prism is either dropped entirely or a design that leaves the image mirrored is used to maximize light transmission.
Apr
28
comment Why are some big telephoto lenses so expensive compared to telescopes?
@ErwinBolwidt that's from a design that has a mirror in the center to make it more compact while allowing for a large aperture and long focal length. Schmidt/Maksutov-Cassegrains are the telescopes that look like paint cans/buckets. From the outside a refracting telescope looks a lot like a telephoto lens.
Apr
14
awarded  Nice Answer
Apr
11
awarded  Yearling
Apr
10
answered Is there any point in photographing directly to black & white?
Sep
4
comment Hour long exposure of the sun
IF you're shopping for solar filters; be sure to check if they've got a neutral color balance. Like with welders glass, many of the more inexpensive ones don't. They're acceptable for taking sunspot images through a telescope/long focal length lens; but wouldn't be suitable for what Clint appears to be trying to do.
Aug
13
comment How can I capture the movement of a bullet?
@gpuguy If you don't know anyone who reloads and is willing to spend a fair amount of time in trial/error work to figure out how low the gun you're using can go while still working well (abnormally low velocities can cause reliability problems; mostly for semi-auto designs); looking for sub-sonic ammunition will get you on the bottom edge of what's available commercially (mostly this will be for older low power handguns).
Jul
13
comment Why do circular fish eye lenses create circular images?
In theory I think you could install a ring of prisms partially overlapping the outer edge of the lens to capture light from behind and divert it into it. IN practice it sounds like something that only Mr. Goldberg would think was a good idea.
Oct
16
comment Why don't mainstream sensors use CYM filters instead of RGB?
In long exposure astrophotography, one of the few areas where the total amount of light captured is a major concern, a common approach is to use a pure monochrome sensor and combine (relatively) short exposures periods taken with red, green, and blue filters to color the image, with a much longer interval where no filter is used to maximize the detail in the final result.
Aug
23
comment Is rotation an intrinsic lossy operation (for angles not multiple of 90 degrees)?
The actual loss of data doesn't occur until you re-rasterize the rotated image. If your image editing software stored intermediate work internally as an image and rotation value, but only rasterized to display it on the screen or when explicitly saved in a bitmap based format, then you could give a second rotation of equal magnitude but opposite in direction and undo the rotation without loss. (Caveat, I don't know how Photoshop/GIMP/etc projects store your data.)
May
3
comment Does this RGB-patterned reflector have benefits for digital photography?
I wouldn't trust an apparent snake oil seller to cheat in comparison results. Nothing short of positive comparison images from a trusted 3rd party would be convincing.
Apr
9
comment Is GPU or CPU more important for Photoshop and Lightroom?
A number of Puget Systems computers have been reviewed favorably by Anandtech: anandtech.com/…
Mar
21
comment When and why should I consider buying a speedlight/external flash?
@MattGrum much better now. :)
Mar
6
comment Why is the main sensor not used instead of the separate AF sensor to focus a DSLR?
I think another advantage, especially historically (with modern designs supporting HD video this is less of a factor), is that the few dozen pixels on an AF sensor can be read much faster than the millions on the primary sensor allowing for a faster feedback loop.