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05-25-2018, 05:07 AM   #1
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Rokinon 20mm users

Hello,
Do you have any experience with this lens? I know that it is not chipped, but focusing with LV is not a problem.
Thank you,
Terry

05-25-2018, 08:00 AM - 1 Like   #2
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For Pentax, we don’t need any lens to be chipped. You’ll get focus confirmation in the view finder and focus peaking in LV.
05-25-2018, 08:41 AM   #3
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QuoteOriginally posted by Kozlok Quote
For Pentax, we don’t need any lens to be chipped. You’ll get focus confirmation in the view finder and focus peaking in LV.
That's very nice to know. I thought I would lose focus confirmation. Do you have an opinion on this lens? I would like to know if it's very sharp. Thank you very much?
Terry
05-25-2018, 11:11 AM   #4
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No opinion on that lens. I use a bunch of old Takumar M42 lenses, no chips, focus confirms just fine.

05-25-2018, 02:40 PM   #5
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Do you mean Rokinon 20mm F1.8?
It is made by Samyang (you can find the same lens with either Rokinon or Samyang brand).
It is a huge lens (large, heavy). Do you really need such a fast lens?

My 20mm is F2.8 and small (compact, light), I have never needed a faster 20mm.

By the way, the Rokinon 20mm F1.8 performs well (excellent sharpness in the center, less in the edges).
This lens is prone to chromatic aberration and fringing but remains a good lens at a rather low price.
05-25-2018, 03:23 PM   #6
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QuoteOriginally posted by tryphon4 Quote
Do you mean Rokinon 20mm F1.8?
It is made by Samyang (you can find the same lens with either Rokinon or Samyang brand).
It is a huge lens (large, heavy). Do you really need such a fast lens?

My 20mm is F2.8 and small (compact, light), I have never needed a faster 20mm.

By the way, the Rokinon 20mm F1.8 performs well (excellent sharpness in the center, less in the edges).
This lens is prone to chromatic aberration and fringing but remains a good lens at a rather low price.
No Sir, I don't need faster than F2.8. What do you have? Is it sharper in the center and edges? Thank you.
Terry
05-25-2018, 04:28 PM - 1 Like   #7
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Just to thread-bomb for the fun of it. There is almost no such thing as a WA lens that is equally sharp center, edges and corners when wide open. Tests I have seen suggest that the 20mm f3.5 Voigtlander is one of the best for across-the-frame IQ when wide open to a stop or so closed, but it is not as sharp as other 20mm lenses in the center or at apertures of f5.6~f11.Sadly, the lens has become somewhat of a collector's item so that very clean copies go for outrageous prices. BTW: It is also a delightfully compact lens.
05-25-2018, 04:41 PM   #8
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I for one would love to get this, or 24 1.4 for astrophotography I think reviews suggest 24 1.4 might be a better performer, but 20 1.8 is no slouch, and it's significantly wider

05-25-2018, 10:58 PM   #9
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Samyang (and Rokinon, Bower) lenses are terrific value, and some of them are at the very top, compared to other objectives available in PK mount.
I own four of them, 85mm, 35mm, 24mm and 14mm.
The first and the last ones are very good, the others are extremely good. Especially the 1.4/35mm.
From what I read the 2/135mm is as good as the Zeiss, IQ wise. Build quality is inferior, but I think we can't expect first class mechanical quality from a lens hugely cheaper.
I never checked the MTF charts of the 20mm. From the performance of the other Samyang lenses I use I expect a better performance than all the other 20mm primes you can find second-hand.
Three out of four of my Samyangs are almost always in my bag.
Maybe one day I will also buy the 20mm
For the moment, I'm fine with the Pentax-A 2.8/20mm and the Vivitar/Cosina 3.8/19mm PKA (which in reality is a 20mm) for full frame, and the Sigma 10-20mm for APS-C. Long time ago I had a CZJ Flektogon 2.8/20mm, sold it because the Pentax is much more practical. I regret that choice, now it would be useful as a cheaper alternative when I am concerned about possible theft or damage.
I also owned the Pentax-M 20mm. Great travel lens because of its diminutive size. I guess it should be more than fine on the K-1, but it's not as good as the A version.

Regarding astro photography, I never tried to photograph the stars, only the moon with a huge Pentacon 500mm. Reading about the qualities of my Rokinon/Samyang 24mm for this specific use, I'm determined to try soon!

Last edited by cyberjunkie; 05-25-2018 at 11:33 PM.
05-25-2018, 11:58 PM - 1 Like   #10
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I own the Pentax A 20mm F2,8, it is a superb lens.
The only drawback is the barrel distorsion, but it is not excessive, in fact I never correct it.
Sadly, it is no more manufactured.
I bought mine used. The FA 20mm F2,8 share the same optical formula.

Previously, I owned a Soligor 20mm F2.8, less sharp than the Pentax but cheaper too and able to deliver very interesting bokeh.

Last edited by tryphon4; 05-26-2018 at 08:21 AM.
05-26-2018, 11:21 AM   #11
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Guys, I really appreciate all of you replies. It gives me a lot of good information to study over and learn. I might go with the Irix 15mm. I had a bad copy and returned it. May try it again. I have the three FA Limiteds and I want one UWA and filter holder in my bag, and that's it. Again, thank you.
Terry
05-26-2018, 11:39 AM - 1 Like   #12
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I have the 20mm F1.8 Rokinon lens. I am very happy with it. When it went on sale for about $350 US some time ago I could no longer resist the urge to get it. I am very happy with it on my K1. I have to add that the 100mm macro Rokinon I own is no slouch either. This from an air show last year. The D-Day markings are proper for this plane as it actually did fly members of the 82nd Airborne on June 6, 1944.



05-26-2018, 12:45 PM   #13
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Dunno about the 20mm, but I adore my 14mm. Amazing performer!

Honestly manual focusing on Samyang lenses is a pleasure, new and old. Really well dampened.
05-27-2018, 12:15 PM   #14
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QuoteOriginally posted by gaweidert Quote
I have the 20mm F1.8 Rokinon lens. I am very happy with it. When it went on sale for about $350 US some time ago I could no longer resist the urge to get it. I am very happy with it on my K1. I have to add that the 100mm macro Rokinon I own is no slouch either. This from an air show last year. The D-Day markings are proper for this plane as it actually did fly members of the 82nd Airborne on June 6, 1944.


Beautiful picture. Thank you.

---------- Post added 05-27-18 at 12:16 PM ----------

QuoteOriginally posted by ZombieArmy Quote
Dunno about the 20mm, but I adore my 14mm. Amazing performer!

Honestly manual focusing on Samyang lenses is a pleasure, new and old. Really well dampened.
I'm going to take a look at that one. Thank you.
05-28-2018, 10:01 AM - 1 Like   #15
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QuoteOriginally posted by TerryL Quote
I'm going to take a look at that one. Thank you.
6mm of difference at the wide end of the focal spectrum is A LOT.
A 20mm lens is a super wide, and most photographers, when they start using such focal, realise that the subject that looks so nice to the human eye perspective, framed with a 20mm becomes a tiny, irrelevant detail of the picture.
A 14mm is an extreme wide, and most of the nice pictures you can find online were shot EXTREMELY close to the subject. You really have to get into the scene. With living subjects, you better not be shy! Astro photography is a totally different hing, but I guess most people interested in extreme wides don't buy them to shoot astro...

If I had to suggest a strong wide to a newbie, I wouldn't go past 24mm.
Check Flickr pictures shot with different focals, and pay attention to the look of those shot with the lens you like to buy:.
Check for sharpness and bokeh... though he latter is not as relevant for super wides.

cheers

Paolo
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