(meteorobs) Fisheye lens misunderstanding and photography update

[Leo S]

That makes sense now, after seeing Tom's shot the penny dropped.

Thanks Chris.

Leo


Chris Peterson wrote:
> 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
>>     
>
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