Win a Pentax Limited Lens: Raffle Now Live!

**Serkevan** · 03-10-2022, 10:05 AM - **1 Like**

Originally posted by BarneyL

Well, the DFA is more than a stop slower, so that's no surprise it weighs much less...

Looks like pretty good astro-landscape lens. A welcome option, since DFA 21 limited is a lens designed with specific purpose, not an all round super wide.

To be honest, this Irix is not an all round UWA either

. It's 800+ g, manual focus chunk. I'd argue the DFA is *more* of an allrounder, since f/2.4 is as fast as you'd need for everything but astro and very low light... where the Irix wouldn't be dramatically more useful due to its manual focus.

That said, I'm now *quite* miffed. I was planning on buying only one 21mm lens

. If this Irix is really, really good for astro...

Jeff · 03-10-2022, 10:12 AM

Originally posted by texandrews

This was showing as a cine lens, and on the U.S. site it is listed as T1.5 (?). So, for stills I'd say the DFA 21 is going to be the better bet, since it will have AF. Also, currently lists for $1,195usd

Is that list price the norm? The 21 2.4 is currently listed here in the UK at £1349 - even higher at Amazon - and there seems to have been more price increases. The 15-30 is listed at £1629 for example.

house · 03-10-2022, 10:15 AM - **1 Like**

Nice to see another wide angle option for Pentax K. Funny they launch a 21 so close to the dfa21, 21mm not being the most common focal length.

Shame it's so fast though, it ends up in Samyang territory in terms of weight and handling. None of these third party manual focus manufacturers seem to be interested in small.

**Erictator** · 03-10-2022, 11:42 AM

I have the Irix 15mm and love the build & optics, but have found the focal length to be a bit wide for my regular use.

I also have an ancient MF Soligor 20mm F2.8, which gets way more use since it gives me a better field of view for a lot of subjects, focus's silly close distance, and also has wild bokeh wide open, yet gets razor sharp when stopped down. Yeah, its slow'ish in comparison at F2.8, but it's VERY compact, like LTD size, and it's plenty fast for everything but Astro. I'm not sure what that Bokeh would do to stars anyway... bubbly stars?

Prolly not great for that.

All that said, I'm tickled Irix is continuing to support K mount. The new HD FA21 would probably get my vote and my money if I wanted to up my game from what I already own, just for the A/F mainly, and the weather sealing and Exif would be nice too.

Eric

lytrytyr · 03-10-2022, 12:52 PM

Originally posted by jslifoaw

Do we know if for this lens, electronic aperture for Pentax now means "KA4" (MF, electromagnetic aperture, CPU), "KA" (MF, mechanical auto aperture, no CPU), or "KA2" (MF, mechanical auto aperture, CPU)?

The only connections are electrical.

My Irix 11/4 Firefly came with an interesting variant of the KA4 mount. For the first exposure, it uses the aperture that is set from the camera. After that, it defaults to f/22.

house · 03-10-2022, 01:03 PM

mtf looks pretty damn good for a 21mm f1.4

DFA*50 for comparison

I don't now how much we can trust Irix mtf however.

Paul the Sunman · 03-10-2022, 02:19 PM

The DFA 21 Ltd is optimised for stunning bokeh and a particular style of rendering and not the striking sharpness of modern DFA* lenses. My copy verifies this. It is easily sharp enough across the frame, and sharpens nicely in pp, but MTF is not what it's chiefly about. I am VERY happy with mine, so the Irix is not a temptation. The compact size and 18cm mfd are real bonuses.

lytrytyr · 03-10-2022, 02:41 PM

Originally posted by house

mtf looks pretty damn good for a 21mm f1.4. I don't now how much we can trust Irix mtf however.

It doesn't even say what aperture. My guess would be f/5.6 or thereabouts.

**MossyRocks** · 03-10-2022, 02:50 PM

Originally posted by mtgmansf

might be a great lens for astro at f1.4.

I had a similar thought especially since they specifically state that they have taken efforts to deal with coma which seems to be the biggest issue for astro shooting. It is very tempting to get one and take it for a spin.

house · 03-10-2022, 02:51 PM - **1 Like**

Originally posted by lytrytyr

It doesn't even say what aperture. My guess would be f/5.6 or thereabouts.

By convention mtf is wide open unless stated otherwise. You're right though that I don't know how likely it is that Irix sticks to those conventions. A 21mm lens with better mtf that a flagship 50mm is certainly surprising if not suspicious.

Kunzite · 03-10-2022, 02:52 PM

Originally posted by lytrytyr

It doesn't even say what aperture. My guess would be f/5.6 or thereabouts.

And then, can we trust their QC?

Well, an option is an option and that's a good thing I guess. Maybe for astrophoto this lens would be better than the D FA 21 Limited.

lytrytyr · 03-10-2022, 03:09 PM

Originally posted by Kunzite

And then, can we trust their QC?

In all good conscience, I can't. Click

New Ultra-Wide lens for Pentax FF... - Page 2 - PentaxForums.com

Originally posted by Kunzite

Maybe for astrophoto this lens would be better than the D FA 21 Limited.

There are astro photos included here:

https://irixlens.com/photo-lenses/21mm/

**Serkevan** · 03-10-2022, 03:16 PM

Originally posted by Kunzite

And then, can we trust their QC?

Well, an option is an option and that's a good thing I guess. Maybe for astrophoto this lens would be better than the D FA 21 Limited.

My copy of the 11mm is as good as one could expect from such a wide lens, for what it's worth.

Astro is probably the one field where this lens would be better than the DFA. Of course, it's also about half as expensive, so that counts for something...

**interested_observer** · 03-10-2022, 06:02 PM

Last year at this time, a friend upgraded from his K70 to a K1mkII, primarily for astrolandscapes. We walked through every lens available for a month, and the Samyang/Rokinon QC was just a deal breaker. The 24/f1.4 would have been the choice - but the QC issues were just not worth the effort. He went with the Sigma 35/f1.4 Art lens, which has been stunning, but somewhat narrow for the Milky Way. He also came across a Rokinon 14mm/f2.8 for $100 that was worth taking a chance.

The DFA 21/f2.4 was tempting, but right now I've been using either the 15-30/f2.8 or my ZK 25/f2.8, so I didn't see any compelling advantage. However, this IRIX does appear to tick all the boxes - and based on their other lenses, apparently has a pretty decent build and quality control. F1.4 aperture at around $750 is extremely tempting.

zapp · 03-10-2022, 10:44 PM

Filter mount N/A. No front filters.

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03-10-2022, 10:05 AM - 1 Like	#16
Serkevan Site Supporter Join Date: May 2019 Photos: Albums Posts: 5,976	Originally posted by BarneyL Well, the DFA is more than a stop slower, so that's no surprise it weighs much less... Looks like pretty good astro-landscape lens. A welcome option, since DFA 21 limited is a lens designed with specific purpose, not an all round super wide. To be honest, this Irix is not an all round UWA either . It's 800+ g, manual focus chunk. I'd argue the DFA is more of an allrounder, since f/2.4 is as fast as you'd need for everything but astro and very low light... where the Irix wouldn't be dramatically more useful due to its manual focus. That said, I'm now quite miffed. I was planning on buying only one 21mm lens . If this Irix is really, really good for astro...

03-10-2022, 10:12 AM	#17
Jeff Pentaxian Join Date: Apr 2015 Location: Berkshire, England Posts: 838	Originally posted by texandrews This was showing as a cine lens, and on the U.S. site it is listed as T1.5 (?). So, for stills I'd say the DFA 21 is going to be the better bet, since it will have AF. Also, currently lists for $1,195usd Is that list price the norm? The 21 2.4 is currently listed here in the UK at £1349 - even higher at Amazon - and there seems to have been more price increases. The 15-30 is listed at £1629 for example.

03-10-2022, 10:15 AM - 1 Like	#18
house Pentaxian Join Date: May 2015 Photos: Albums Posts: 3,306	Nice to see another wide angle option for Pentax K. Funny they launch a 21 so close to the dfa21, 21mm not being the most common focal length. Shame it's so fast though, it ends up in Samyang territory in terms of weight and handling. None of these third party manual focus manufacturers seem to be interested in small.

03-10-2022, 11:42 AM	#19
Erictator Site Supporter Join Date: Jul 2011 Photos: Gallery \| Albums Posts: 3,352	I have the Irix 15mm and love the build & optics, but have found the focal length to be a bit wide for my regular use. I also have an ancient MF Soligor 20mm F2.8, which gets way more use since it gives me a better field of view for a lot of subjects, focus's silly close distance, and also has wild bokeh wide open, yet gets razor sharp when stopped down. Yeah, its slow'ish in comparison at F2.8, but it's VERY compact, like LTD size, and it's plenty fast for everything but Astro. I'm not sure what that Bokeh would do to stars anyway... bubbly stars? Prolly not great for that. All that said, I'm tickled Irix is continuing to support K mount. The new HD FA21 would probably get my vote and my money if I wanted to up my game from what I already own, just for the A/F mainly, and the weather sealing and Exif would be nice too. Eric

03-10-2022, 12:52 PM	#20
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by jslifoaw Do we know if for this lens, electronic aperture for Pentax now means "KA4" (MF, electromagnetic aperture, CPU), "KA" (MF, mechanical auto aperture, no CPU), or "KA2" (MF, mechanical auto aperture, CPU)? The only connections are electrical. My Irix 11/4 Firefly came with an interesting variant of the KA4 mount. For the first exposure, it uses the aperture that is set from the camera. After that, it defaults to f/22.

03-10-2022, 01:03 PM	#21
house Pentaxian Join Date: May 2015 Photos: Albums Posts: 3,306	mtf looks pretty damn good for a 21mm f1.4 DFA*50 for comparison I don't now how much we can trust Irix mtf however.

03-10-2022, 02:19 PM	#22
Paul the Sunman Pentaxian Join Date: Aug 2011 Location: Melbourne Photos: Gallery Posts: 4,847	The DFA 21 Ltd is optimised for stunning bokeh and a particular style of rendering and not the striking sharpness of modern DFA* lenses. My copy verifies this. It is easily sharp enough across the frame, and sharpens nicely in pp, but MTF is not what it's chiefly about. I am VERY happy with mine, so the Irix is not a temptation. The compact size and 18cm mfd are real bonuses.

03-10-2022, 02:41 PM	#23
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by house mtf looks pretty damn good for a 21mm f1.4. I don't now how much we can trust Irix mtf however. It doesn't even say what aperture. My guess would be f/5.6 or thereabouts.

03-10-2022, 02:50 PM	#24
MossyRocks Loyal Site Supporter Join Date: Nov 2017 Location: Minnesota Photos: Gallery \| Albums Posts: 2,982	Originally posted by mtgmansf might be a great lens for astro at f1.4. I had a similar thought especially since they specifically state that they have taken efforts to deal with coma which seems to be the biggest issue for astro shooting. It is very tempting to get one and take it for a spin.

03-10-2022, 02:51 PM - 1 Like	#25
house Pentaxian Join Date: May 2015 Photos: Albums Posts: 3,306	Originally posted by lytrytyr It doesn't even say what aperture. My guess would be f/5.6 or thereabouts. By convention mtf is wide open unless stated otherwise. You're right though that I don't know how likely it is that Irix sticks to those conventions. A 21mm lens with better mtf that a flagship 50mm is certainly surprising if not suspicious.

03-10-2022, 02:52 PM	#26
Kunzite Pentaxian Join Date: Apr 2007 Location: Romania Posts: 15,132	Originally posted by lytrytyr It doesn't even say what aperture. My guess would be f/5.6 or thereabouts. And then, can we trust their QC? Well, an option is an option and that's a good thing I guess. Maybe for astrophoto this lens would be better than the D FA 21 Limited.

03-10-2022, 03:09 PM	#27
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by Kunzite And then, can we trust their QC? In all good conscience, I can't. Click New Ultra-Wide lens for Pentax FF... - Page 2 - PentaxForums.com Originally posted by Kunzite Maybe for astrophoto this lens would be better than the D FA 21 Limited. There are astro photos included here: https://irixlens.com/photo-lenses/21mm/

03-10-2022, 03:16 PM	#28
Serkevan Site Supporter Join Date: May 2019 Photos: Albums Posts: 5,976	Originally posted by Kunzite And then, can we trust their QC? Well, an option is an option and that's a good thing I guess. Maybe for astrophoto this lens would be better than the D FA 21 Limited. My copy of the 11mm is as good as one could expect from such a wide lens, for what it's worth. Astro is probably the one field where this lens would be better than the DFA. Of course, it's also about half as expensive, so that counts for something...

03-10-2022, 06:02 PM	#29
interested_observer Loyal Site Supporter Join Date: Jun 2009 Location: Tumbleweed, Arizona Photos: Gallery \| Albums Posts: 5,707	Last year at this time, a friend upgraded from his K70 to a K1mkII, primarily for astrolandscapes. We walked through every lens available for a month, and the Samyang/Rokinon QC was just a deal breaker. The 24/f1.4 would have been the choice - but the QC issues were just not worth the effort. He went with the Sigma 35/f1.4 Art lens, which has been stunning, but somewhat narrow for the Milky Way. He also came across a Rokinon 14mm/f2.8 for $100 that was worth taking a chance. The DFA 21/f2.4 was tempting, but right now I've been using either the 15-30/f2.8 or my ZK 25/f2.8, so I didn't see any compelling advantage. However, this IRIX does appear to tick all the boxes - and based on their other lenses, apparently has a pretty decent build and quality control. F1.4 aperture at around $750 is extremely tempting.

03-10-2022, 10:44 PM	#30
zapp Pentaxian Join Date: Jul 2011 Posts: 2,389	Filter mount N/A. No front filters.