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08-13-2018, 12:42 PM   #16

Join Date: Dec 2012
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Thanks for the link, yeah there is coma/astigmatism at f1.8. It depends what you intend to do with your pictures, for example, posting on the internet or printing out in 20" x 30" or more like I like to do.
If you get a magical photograph it deserves to be printed out large or even published.

Hi to West Cost Greg, messaged his website before, he has some great photographs and knowledge.

08-14-2018, 03:04 PM   #17

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I am having this debate myself for a astro-landscape prime. A used Sigma 20mm f1.8 DG or Pentax FA 20mm f2.8 (older film era 20mm), Irix 15mm f2.4 (bright and wide), Irix 11 f4 (super wide but not as bright), samyang 14 f2.8 (cheap and wide but already broke one due to build quality, and I never liked the colors for regular landscapes), or wait longer save pennies and get a DFA 15-30mm (expensive but it will be a lens I use 99% of the time with landscapes). Right now I'm making due with a Sigma 17-35mm f2.8-f4 and stacking\panoramics in photoshop (due to a lot of vignetting and coma wide open).
08-14-2018, 03:52 PM   #18
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QuoteOriginally posted by wanderer2 Quote
Somehow I got the impression that the Irix is threaded for screw on filters - is this incorrect?
The Irix has a front filter thread, but it also has a rear slide for holding small filters, which may cause a bit of confusion. Its wide FoV, though, means you have to be careful in choosing filters, to prevent vignetting. Irix actually sells filters under their own brand.
08-16-2018, 10:51 PM   #19
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QuoteOriginally posted by wanderer2 Quote
Somehow I got the impression that the Irix is threaded for screw on filters - is this incorrect?
No, you're not wrong. But a 100mm system is more versatile than 95mm screw on filters.


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14mm, 15mm, astrotracer, f/1.8, f/2.4, f/2.4 and samyang, irix 15mm f/2.4, k-mount, pentax lens, samyang, slr lens, thanks
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