Pentax fa 20 2.8 OR Samyang 20 1.8 Or ?? your help pls ....

krazykat · 02-19-2020, 09:47 PM

Originally posted by pres589

I can't compare it to the A and FA 20's, but I would really like to see some kind of proof that the M 20 doesn't outscore these other lenses optically. NorthcoastGreg seems to get some stunning results out of his M 20 and I just don't see similar quality shots out of the A or FA 20's.

NorthCoastGreg could take brilliant shots with the bottom of a coke bottle! He's an amazing photographer IMO. Give him an A or FA and see the results.

johnha · 02-23-2020, 06:37 PM

I couldn't make my mind up between the FA20/2.8 or FA24/2 (both were rare and expensive). In the end I went for the FA20-35/4 which has hardly been off my K-1.

Since then I've bought the SMC Tak 20/4.5 which is an interesting lens. It's only real downside is CA towards the edges - I can't compare it to the other primes but it seems good as far as distortion goes.

hadi · 02-24-2020, 11:44 AM

my two cents: save the cost on all of them, and take the 31mm ltd.
why?: its fast at 1.8. Its small and can easily fit anywhere. Its 'wide' enough for a standard shot. However, if you want it wider, learn to stitch panorama shots. Allowing you to shoot with the 31mm at f1.8, but with the look of something wider, like a 24mm, or 20mm, or even 14mm if you go crazy enough with enough stitches.

the cons to doing this:
- it can be time consuming. if your computer is not up to the task, this can be really painful. However, if you have a decent computer, you can easily do this within a few seconds.
- though you dont need a tripod, and can easily do this hand held, the issue with stitching (in my experience) dosn't translate well in night astro-photography. because it will require tripod, and keep moving things around, the stars are never in place long enough. so if you want a startrail with a wider sky, this may not be possible.
- the 31mm is not weather sealed. in iceland, you should carry with you lenses that are sealed as you never know.

the pro for this:
1- you are saving cost in buying another lens
2- you are saving space
3- if need be, finding an ND filter for 31 is relatively easy and affordable. So you can do day time cloud-trails or waterfall trailers over a prolonged period of time.

**Focusrite** · 03-04-2020, 11:10 PM - **2 Likes**

I have both lenses and would take the Samyang under most circumstances for what I do ( landscape photography).

I bought the FA 20mm years ago, and enjoyed it on APS-C until I bought the Sigma 18-35 and the FA 20 was largely relegated to storage - the Sigma was sharper and more convenient for covering multiple equivalent focal lengths.

When I upgraded to the K-1 I later bought the Samyang 20mm to fill the gap between my Sammy 14mm ( already owned from when I had APS-C ) and the Sammy 24mm ( early lens purchase with K-1).

Shortly after the purchase I did do a quick comparison between the FA 20 and the Samyang ( standard brick-wall test

), and the FA 20 was less sharp on the edges - not necessarily soft, just not as good.

The Samyang is a good lens, but I still find myself having somewhat mixed feelings about it. It's not quite as sharp as the Samyang 24mm stopped down ( at least my copy ), but it's certainly no slouch. The corners are a bit softer, and sometimes when I look at photos ( translation: pixel peep

) I wish it was sharper, and other times I'm thrilled at how sharp it can be ( the problem is probably me rather than the lens! ). I haven't used the D-FA 15-30, but from what I've read about it I wouldn't expect the Samyang to produce anything that is necessarily sharper. The opportunity to use screw-on filters is fantastic, though; but be warned - stacking filters will give some very pronounced vignetting. CA's can be quite strong and will be a bother in higher contrast situations. I can't give much information regarding distortion, as I don't shoot architecture very often and most things in nature ( except perhaps horizons ) aren't usually straight. However, I recall the FA 20 having very pronounced "mustache" distortion that will be quite noticeable in photos with flat horizons, while I haven't noticed anything obvious with the Samyang.

One thing I have noticed that is worth mentioning is a rather strange colour-shift that occurs with both my Samyang 14mm & 20mm lenses. Near the edge of the photo ( and especially the corners ) I will tend to see a green-yellow tint. It's bizarre, and only seems to affect these lenses out of my kit. I expect that it's because they're ultra-wide?? Not entirely sure, but I would be interested to know whether this shows up on other UWA Samyang lenses or other ultra-wides in general on the K-1 ( maybe it's just my copy?! ). It's a manageable issue that usually shows up on skies, and is usually fixed with some radial filters in Lightroom and adjustments to the White Balance of aforementioned filters.

As for wide-open performance of the Samyang, I can't actually comment with any sort of authority

. The last time I remember shooting it at f1.8 was during my initial tests for decentering. I usually shoot stopped down to f8 or f10, and I I can't remember the last time I pointed it at the night sky - I usually used longer lenses and stitch for my nightscape work. If I had the opportunity to photograph an Aurora, the Samyang would be my first choice - but if you're going to Iceland in summer I guess that means you'll have a midnight sun!?

Can't really comment regarding flare. Both probably have it, but I don't point it at the sun very often.

Auto-focus is +1 for the FA 20, but I don't really miss auto-focus as most of what I do is off a tripod. My Samyang 20mm also has distance markings that are actually accurate and a hard stop just a fraction beyond infinity! The 14 & 24 go to infinity and well beyond, and the distance markings on the 14mm are little more than drunk suggestions

So, the Samyang is in my field kit most of the time, and although it's far from my most used lens ( possibly not even Top 5

) I've taken some of my more favourite photos with it. Yeah, it's heavier; but the compromise for the extra IQ is worth the weight for me. The FA 20 is in storage, probably until I stop caring about pixel-peeping and look for something with a bit more character, or need something that is much lighter and smaller. Never say never

Some shots from the Samyang 20mm f1.8 and 1:1 crops to show centre,side & corner sharpness, and uncorrected CAs. Please note that the pic with the coastal flowers is focus-stacked from 8 different photos - the lens is good, but it can't work magic with the depth of field needed for that.

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02-19-2020, 09:47 PM	#16
krazykat Veteran Member Join Date: Aug 2010 Posts: 546	Originally posted by pres589 I can't compare it to the A and FA 20's, but I would really like to see some kind of proof that the M 20 doesn't outscore these other lenses optically. NorthcoastGreg seems to get some stunning results out of his M 20 and I just don't see similar quality shots out of the A or FA 20's. NorthCoastGreg could take brilliant shots with the bottom of a coke bottle! He's an amazing photographer IMO. Give him an A or FA and see the results.

02-23-2020, 06:37 PM	#17
johnha Veteran Member Join Date: Apr 2012 Location: Lancashire, UK Photos: Albums Posts: 1,155	I couldn't make my mind up between the FA20/2.8 or FA24/2 (both were rare and expensive). In the end I went for the FA20-35/4 which has hardly been off my K-1. Since then I've bought the SMC Tak 20/4.5 which is an interesting lens. It's only real downside is CA towards the edges - I can't compare it to the other primes but it seems good as far as distortion goes.

02-24-2020, 11:44 AM	#18
hadi Veteran Member Join Date: May 2011 Location: Mississauga, Ontario Posts: 563	my two cents: save the cost on all of them, and take the 31mm ltd. why?: its fast at 1.8. Its small and can easily fit anywhere. Its 'wide' enough for a standard shot. However, if you want it wider, learn to stitch panorama shots. Allowing you to shoot with the 31mm at f1.8, but with the look of something wider, like a 24mm, or 20mm, or even 14mm if you go crazy enough with enough stitches. the cons to doing this: - it can be time consuming. if your computer is not up to the task, this can be really painful. However, if you have a decent computer, you can easily do this within a few seconds. - though you dont need a tripod, and can easily do this hand held, the issue with stitching (in my experience) dosn't translate well in night astro-photography. because it will require tripod, and keep moving things around, the stars are never in place long enough. so if you want a startrail with a wider sky, this may not be possible. - the 31mm is not weather sealed. in iceland, you should carry with you lenses that are sealed as you never know. the pro for this: 1- you are saving cost in buying another lens 2- you are saving space 3- if need be, finding an ND filter for 31 is relatively easy and affordable. So you can do day time cloud-trails or waterfall trailers over a prolonged period of time.