星空photo-taking心得一問

riricky815

我想問通常用dslr影星係咪多數用大光圈定焦/fisheye/廣角鏡?如果用單支長鏡300mm以上or macro鏡可以影星嗎?

PTS

我想問通常用dslr影星係咪多數用大光圈定焦/fisheye/廣角鏡?如果用單支長鏡300mm以上or macro鏡可以影星嗎? ...
riricky815 發表於 2012-5-3 19:22

This all depends on what is your target.

If you want to take image of large sky area, like the Milkyway, large constellation (like Canis Major), etc. you will need a wide angle lens.
On the other hand, if you want to image small objects (by small I mean small in angular size, such as planets, etc) then you will need a lens with very long focus.

Surely any lens will be useful, depending on your target object.  A 300mm lens will be good for small constellations, large nebula (such as M42).

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riricky815

我見好多人都用cannon,但我個部係nikon,影出泥有咩唔同?同埋d人改機影,咁nikon有無?and用dslr影出泥同用天文專用ccd 加telescope又有咩分別?

PTS

我見好多人都用cannon,但我個部係nikon,影出泥有咩唔同?同埋d人改機影,咁nikon有無?and用dslr影出泥同用天 ...
riricky815 發表於 2012-5-4 18:55

There is not much difference in Nikon or Canon, except for the availability of modification for Canon, and in the RAW images.  The RAW in Nikon is not really RAW as Nikon did some noise reduction even in the RAW.  The RAW in Canon is truely RAW.

Astronomical CCD's are designed for long-exposures, with cooling to reduce thermal noise (this is not usually available for DSLR's).  In addition, the software that comes with astro ccds are much more suitable for our purposes.


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