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Archive 2012 · Astro landscape images, wide angle corner lens distortion...
  
 
dgdg
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p.1 #1 · p.1 #1 · Astro landscape images, wide angle corner lens distortions, options


I have a pancake Voigtlander 20mm f3.5 lens that is great for travel and have been pleased with quite a bit. Lately I have been doing some long exposure start photos and I find that although quite good, at f3.5 the stars nearing the corners take on a cross shaped streak look. Kind of like a cross. Small amount of fringing as well. Otherwise I am very pleased. Anyone not critically examining the photo will care or notice, but if I were to print, I'd have to go in and fix it one by one. Not all stars are affected. It is worse the brighter the star, and the closer it is to the corners.

So, my question is others' experiences with star photos and wide angle.
Is the Canon 16-35 II much better in the corners at 2.8 and 3.5?
How about the Samyang 14mm 2.8? Certainly cheaper.
Will I see a significant difference with either of these or do I just need to stop down to 5.6 with what I have.



Sep 12, 2012 at 08:43 PM
plubbry
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p.1 #2 · p.1 #2 · Astro landscape images, wide angle corner lens distortions, options


The latest Samyang 14 2.8 would perform great for this type of shooting.

http://www.lenstip.com/239.7-Lens_review-Samyang_14_mm_f_2.8_ED_AS_IF_UMC_Coma_and_astigmatism.html

BTW, one of the things I like about lenstip.com is that they look at coma and astigmatism when reviewing lenses, something not everyone does.



Sep 12, 2012 at 10:53 PM
Alex Nail
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p.1 #3 · p.1 #3 · Astro landscape images, wide angle corner lens distortions, options


dgdg wrote:
So, my question is others' experiences with star photos and wide angle.
Is the Canon 16-35 II much better in the corners at 2.8 and 3.5?
How about the Samyang 14mm 2.8? Certainly cheaper.
Will I see a significant difference with either of these or do I just need to stop down to 5.6 with what I have.


The 16-35 II still isnt that great in that regard, you will see similar issues. I can't comment on the Samyang. The Zeiss 21mm is outstanding in this regard but the vignetting at 2.8 is an issue (one of the reasons I returned mine) and it is also expensive.



Sep 13, 2012 at 12:21 PM
dgdg
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p.1 #4 · p.1 #4 · Astro landscape images, wide angle corner lens distortions, options


Do you think stopping down to 5.6 would improve the corners?
I guess it is astigmatism that I am seeing in the corners that make a bright dot turn into a cross similar to a plus sign.

I just posted my images for example. the first two images show the corner issues. It may not be symmetric anymore since it is a composite of stacked images and cropped when I overlayed the sharp foreground. Appreciate your analysis of the bright stars in the corners.

http://www.fredmiranda.com/forum/topic/1148433



Sep 13, 2012 at 04:53 PM
dgdg
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p.1 #5 · p.1 #5 · Astro landscape images, wide angle corner lens distortions, options


Thanks everyone, you answered my question.
Looking at the voigtlander on the review site, I am dealing with coma.
The 16-35 II certainly is better, but still some coma.
17-40 looks very good on lenstip.com. I have a vixen polarie so f/4 will not always be an issue. Certainly would like the convenience of f2/8 when I want a single exposure.
The Samyang seems great too.
Perhaps the 17-40L and the Samyang would fit all roles and give low coma.
The 16-35 would allow one lens in the bag, but would be a compromise in IQ and more expensive than the other two lenses combined.
On my last trip never used my midtelephoto zoom, so that will give me a place in the bag.



Sep 13, 2012 at 05:41 PM





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