TTartisan updated "girlwatcher" lens might be fun to use

RichA

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Sep 23, 2023, 7:14:26 PMSep 23

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May also be good for astrophotographers, but I'd need to see 100% images to be sure. Price is right and considerably less than Borg, William Optics (which I suggested to them 20 years ago) and Omegon offerings of similar type.

https://petapixel.com/2023/09/22/ttartisans-new-500mm-f-6-3-full-frame-mirrorless-lens-is-just-329/

Alan Browne

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Sep 23, 2023, 9:05:40 PMSep 23

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On 2023-09-23 19:14, RichA wrote:
> May also be good for astrophotographers, but I'd need to see 100% images to be sure. Price is right and considerably less than Borg, William Optics (which I suggested to them 20 years ago) and Omegon offerings of similar type.
>
> https://petapixel.com/2023/09/22/ttartisans-new-500mm-f-6-3-full-frame-mirrorless-lens-is-just-329/

Not sure how one gets to "Large Aperture" claims with an f/6.3 lens...

--
“Markets can remain irrational longer than your can remain solvent.”
- John Maynard Keynes.

RichA

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Sep 26, 2023, 12:12:03 AMSep 26

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In astronomy, anything faster than f.7 is fast, and f/2.8 is virtually non-existent. For whatever reason, astronomers don't use high-end (not many) telephoto lenses, preferring to loose a couple stops and use telescopes. i presume cross sensor correction in camera lenses isn't good enough, but I've yet to see any real comparisons between top end telescopes used as lenses (Takahashi FSQ-106 which is a fast scope with 4 inch aperture) or top-end modern telephotos.

Whisky-dave

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Sep 26, 2023, 8:21:10 AMSep 26

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I'm guessing there's very little point in comparing the two types, as telephotos are mostly for those that want something portable
and capture close moving objects. Here's also a differnce between astronomical telescopes and terestrial ones in that the terestrial
reverse the images so they are the right way up and they normaly don't need a close focus point.

RichA

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Oct 1, 2023, 11:14:19 PMOct 1

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Astro scopes reverse the image and render it upside down, but it's inconsequential because you can just flip or re-orientate the image any way you like.

Whisky-dave

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Oct 2, 2023, 8:32:31 AMOct 2

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Which will add weight and more distotion for no gain in image quality. Nowerdays it''s done digital but in an optical atromomy
telescopes these extra optics were left out.

geoff

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Oct 3, 2023, 6:11:06 PMOct 3

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But who is to say what is the 'right way up' ? It's all relative, and
wrong for one of Earth's hemispheres' point of view anyway.

geoff

RichA

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Oct 3, 2023, 9:09:11 PMOct 3

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The Earth rotates so we see rising of astronomical objects in the East and setting in the West. That doesn't change with hemispheres, all you see is a different area of the sky in a specific place at a
specific time. So, the moon as it waxes (goes from cresent to full) shows its unilluminated side being its left side while waning, it's the right side.

m-m

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Oct 4, 2023, 10:54:02 AMOct 4

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Any astrophotography with this lens (except for the moon) would require an equatorial tracking mount and a several minute exposure.
The astro images from the article are definitely not "snapshots"

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m-m
www.mhmyers.com

RichA

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Oct 5, 2023, 4:58:27 AMOct 5

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Except for the moon, the sun and brighter planets, few astro-shots are snapshots.

Whisky-dave

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Oct 5, 2023, 8:41:34 AMOct 5

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The British decide what's right same as we did with driving on the roads and spelling of English words, we have GMT too. :-)

> It's all relative,

So is incest.