[2351HD]

Hi

I am looking at making up a K1 and KP system now that I have sold my 645z.

I need a good landscape lens option around the 20-22mm mark.

I am looking at the Samyang 20mm f/1.8 or the Zeiss ZF 21mm f/2.8 with the Leitax mount conversion.

I have an opportunity to purchase the Zeiss lens from a friend, almost near new for only a couple of hundred dollars more than the Samyang, then I need to buy. the mount conversion which is not too expensive.

Can anybody comment on the output of the Samyang 20mm lens on the K1? I will be using it for landscape and astro.

PS, not interested in the 15-30mm lens due to no filter thread.

Thanks, Scott

[pepperberry farm]

the SMC A 20mm f2.8 is pretty good, too...

[stevebrot]

the SMC A 20mm f2.8 is pretty good, too...

You beat me to it.

Size, weight, price, performance, and resale, my preference would be in this order:

• Pentax A 20/2.8 (or FA 20/2.8 if AF is a plus)
• Zeiss ZF 21/2.8
• Samyang 20/1.8

Another option might be the Voigtlander Color-Skopar 28/3.5 SLII.

Steve

[2351HD]

You beat me to it.

Size, weight, price, performance, and resale, my preference would be in this order:

• Pentax A 20/2.8 (or FA 20/2.8 if AF is a plus)
• Zeiss ZF 20/2.8
• Samyang 20/1.4

Another option might be the Voigtlander Color-Skopar 28/3.5 SLII.

Steve

Thanks Steve.
I have looked at the A 20 on eBay and it is still quite expensive, around the same as what I can get the Zeiss for.

What is the Coma performance like on it? I plan on doing some astro with it.

[stevebrot]

Thanks Steve.
I have looked at the A 20 on eBay and it is still quite expensive, around the same as what I can get the Zeiss for.

What is the Coma performance like on it? I plan on doing some astro with it.

That I can't say. Perhaps @pepperberry_farm has pointed his at the sky? The main issue is finding owners who have shot the lens on FF with subjects where coma might be a concern. So many were snatched up as 28mm equivalent for APS-C with resulting high prices in the late 2000s, a situation that has remained in place. I just did a quick survey of prices and if you can get the Distagon 21/2.8 for less than $500, that might be the better deal. How is the Distagon for coma?

Addendum: RE: Samyang 20/2.8 and coma...https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/333119-new...-problems.html


Steve

[pepperberry farm]

I can, but I only shoot APS-C...

[Sandy Hancock]

My only astro-ish shot with the FA20....

[pres589]

I'd like to see a comprehensive test between the FA 20, the M 20, and that Zeiss on the K-1. Someone send me an FA 20 and the Zeiss post-conversion and a K-1 and I'll do it as a community service.

[stevebrot]

My only astro-ish shot with the FA20....

I was able to click through to the larger sizes on Flickr and yes, there is coma in the corners at f/4.0. Whether it might still be there at f/5.6 is hard to say as might whether it is excessive in comparison with other lenses at the same focal length.

I found another done with the Rokinon 20/1.8 at f/2.8 that looks pretty impressive:

https://www.flickr.com/photos/145852216@N05/43308341694/


Steve

[stevebrot]

PF member @tuco has experience with the Distagon 21mm f/2.8 ZF2. Perhaps he will drop in too.


Steve

[2351HD]

Thanks everybody for chiming in.

I think I have some work to do...

[zapp]

For quality and feel go Zeiss. Conversions are always a comprise, so Samyang 20, PentaxA are als solutions. Pentax 11-18 makes for a nice ff 2.8/18 mm.

[tuco]

PF member @tuco has experience with the Distagon 21mm f/2.8 ZF2. Perhaps he will drop in too.

Steve

Well, I don't really have much of a lens review of the Zeiss 21/2.8. It's a good manual focus lens for night time and its well made of course except its lens cap. My copy was not excellent but not terrible either at f2.8 or f3.2. And the lens is better the less it costs.

Here is about the only astro shot I've done with it. The shutter speed is about the 500 Rule - 26 sec at f3.2. There is star motion blur at that shutter speed and nothing is really sharp at that aperture as it would be stopped down more.

[2351HD]

Pentax 11-18 makes for a nice ff 2.8/18 mm.

Is it sharp past the APS-C crop circle out to the edges?

It looks like such a nice lens.

[Sandy Hancock]

Is it sharp past the APS-C crop circle out to the edges?

It is a nice lens. I'll be selling my DFA 15-30 because of it.

18mm, f/5.6, full frame mode. Not perfect in the corners, but not bad
I still consider it a crop lens....