Reply to thread

Message

<blockquote data-quote="WayneF" data-source="post: 145934" data-attributes="member: 12496">I don't know what aspect you are asking about, but the easy answer is no, in that both do the same job of offering an enlarged view of the subject.&nbsp;&nbsp; Telephoto lenses work well in astronomy, within the limits of their size (focal length and aperture).There are construction details however.&nbsp; The major property of either is about size, which is focal length (magnification) and aperture diameter (resolution, and of course exposure).&nbsp; There are different types of telescope construction (refractor, mirror, cassegrain, etc), and also a few types of camera lens.&nbsp; Telescopes are used wide open, and normally don't offer adjustable aperture.&nbsp; The smaller size of camera lenses allows more glass elements, and better optical correction is feasible.&nbsp; The inexpensive mirror lenses are pretty poor on a camera.The word &quot;telephoto&quot; does not necessarily mean a &quot;long&quot; lens, but instead means a lens built with physical length shorter than its focal length (which is handy on long lenses).&nbsp; For example, a 400 mm telephoto camera lens will be less than 400 mm long (makes transport easier). But a wide angle lens is typically longer than its focal length.&nbsp; Multiple lens elements makes that possible.&nbsp;&nbsp; Whereas, the telescope is full length (except cassegrains of course).But both offer a longer focal length for greater magnification of the subject.</blockquote>

[QUOTE="WayneF, post: 145934, member: 12496"] I don't know what aspect you are asking about, but the easy answer is no, in that both do the same job of offering an enlarged view of the subject. Telephoto lenses work well in astronomy, within the limits of their size (focal length and aperture). There are construction details however. The major property of either is about size, which is focal length (magnification) and aperture diameter (resolution, and of course exposure). There are different types of telescope construction (refractor, mirror, cassegrain, etc), and also a few types of camera lens. Telescopes are used wide open, and normally don't offer adjustable aperture. The smaller size of camera lenses allows more glass elements, and better optical correction is feasible. The inexpensive mirror lenses are pretty poor on a camera. The word "telephoto" does not necessarily mean a "long" lens, but instead means a lens built with physical length shorter than its focal length (which is handy on long lenses). For example, a 400 mm telephoto camera lens will be less than 400 mm long (makes transport easier). But a wide angle lens is typically longer than its focal length. Multiple lens elements makes that possible. Whereas, the telescope is full length (except cassegrains of course). But both offer a longer focal length for greater magnification of the subject. [/QUOTE]

Verification