(meteorobs) Fisheye lens misunderstanding and photography update

[Chris Peterson]

Aliasing is more obvious with high quality fast lenses because they produce 
a small spot size. A slow lens, or one with poor optics will spread the 
point source meteor image over several pixels and essentially act as an 
anti-aliasing filter.

I've seen Tom's images, and the effect is definitely aliasing, not any kind 
of lens artifact.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: "Leo S" <l.stachowicz at btinternet.com>
To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
Sent: Monday, December 07, 2009 10:53 AM
Subject: Re: (meteorobs) Fisheye lens misunderstanding and photography 
update


> Hi Thomas,
>
> In general, lenses for still photography are much better corrected for
> aberrations than lenses made for video cameras, since moving pictures
> hide many of the flaws that are easily seen in stills. That means
> extreme wide angles are very hard and expensive to make to a standard
> that will be good enough for still photography.
>
> The upshot is that you won't find anywhere near as many super-wide
> lenses for still photography, and when you do find them, they are
> usually super expensive.
>
> Here is a good example, the Nikkor 8mm/2.8 :
> http://www.naturfotograf.com/lens_fish.html
>
> If you can find one, it'll cost you many thousands of dollars!
>
> Don't forget, if you are using Canon EOS, you can get adapters to mount
> most other makes of lens, including Nikkors, although in general I think
> Canon's lens line up is better for fast-wide lenses.
>
> I'm afraid if you want to cover the whole sky, you will need multiple
> still cameras. I'd recommend using Canon 20Ds since they are fairly
> cheap and easy to come by now, and the sensor offers excellent
> performance, even compared to the current generation of DSLRs.
>
> Could you post an example of one of the meteors you shot that has a
> "spiral look"? It sounds more like a lens artifact (coma perhaps?) than
> aliasing, which would be due to the sensor.
>
> Leo