D FA 21 Limited is one of the three.

**ThorSanchez** · 11-18-2020, 10:12 AM

Originally posted by reh321

A modern lens with aperture ring might sell very well simply because of all of us with K-30 or K50 bodies that cannot control the aperture
{I hear another conspiracy theory brewing}.

There have to be tens or even dozens of people who had the aperture block failure but just kept using the camera, didn't get it fixed, and didn't go get another body.

**mlt** · 11-18-2020, 10:37 AM

And in all probability, this will likely be a KAF4 lens with full electronic control - usable on K-50 or ‘K-70 regardless of solenoid issues. The primary market will be for the K1 users though.

**Rondec** · 11-18-2020, 10:54 AM

Originally posted by Serkevan

My personal guess is also around f/2.4 - f/2 is probably not doable with such a relatively small package, and f/2.8 feels too... "normal" for a Limited.

---------- Post added 11-18-20 at 04:28 AM ----------

Even Chinese manual focus lenses are f/0.95 by default nowadays. If Zeiss made an f/0.7 lens Carl Zeiss Planar 50mm f/0.7 - Wikipedia then Pentax has to get on with the times and make something on that ballpark. Nothing else, nothing, will do.

---------- Post added 11-18-20 at 04:36 AM ----------

From what little we have seen of the lens it doesn't feel to me like the FA has a larger front element. As I replied to Rondec I also don't think the lens is gonna be super fast, but I somehow get the feeling they will try to make it a bit faster than f/2.8 - maybe they are going for a smoother, less-than-sharp rendering wide open that transitions to sharp landscape lens as you close the aperture? Similar to some of those old lenses that are dreamy at maximum aperture.

I guess I wonder if they might artificially set the max aperture at f2.8 if they don't think the performance is good enough at f2.4. This certainly would explain them not having released the aperture yet.

angerdan · 11-18-2020, 12:44 PM - **1 Like**

With the again upcoming discussion about the speed of the aperture, I like to remember about these posts:

Originally posted by phoebus

Using very rough techniques, I suggest that the DFA 21 Ltd will have 67mm filter thread and a body width of about 75mm. That makes it pretty close to the FA 20/2.8 in size...

Originally posted by phoebus

OK! Is that better?

**mlt** · 11-18-2020, 02:11 PM

Thank you for measurements.

**mlt** · 11-18-2020, 02:13 PM

Originally posted by Rondec

I guess I wonder if they might artificially set the max aperture at f2.8 if they don't think the performance is good enough at f2.4. This certainly would explain them not having released the aperture yet.

Or it still could be an f2.0, can’t infer much from the dof scale or a visual of the front element.

dave_roe · 11-18-2020, 02:57 PM - **1 Like**

Now this is a lens I not only need but am lusting over.

Time to build the bank and just say ship it when it is time.......

thibs · 11-18-2020, 09:41 PM

Originally posted by Rondec

I guess I wonder if they might artificially set the max aperture at f2.8 if they don't think the performance is good enough at f2.4. This certainly would explain them not having released the aperture yet.

It has been done before, indeed.
Probably for other reasons though.

Paul the Sunman · 11-18-2020, 10:01 PM

Originally posted by thibs

It has been done before, indeed.
Probably for other reasons though.

Maximum aperture has always been conservatively set on Limited lenses in the past.

**ben-pentax** · 11-18-2020, 10:10 PM - **2 Likes**

Originally posted by Rondec

I guess I wonder if they might artificially set the max aperture at f2.8 if they don't think the performance is good enough at f2.4

Might be, but no way an f2.8. This is a Limited, Let's say f2.7 ?

thibs · 11-18-2020, 10:10 PM

Originally posted by Paul the Sunman

Maximum aperture has always been conservatively set on Limited lenses in the past.

Sure but I was thinking artificially limited like e.g. K55/1.8 and K55/2

Paul the Sunman · 11-18-2020, 10:19 PM - **3 Likes**

Originally posted by ben-pentax

Might be, but no way an f2.8. This is a Limited, Let's say f2.7 ?

f/𝜋 would be elegant. f/𝜑 (golden ratio) would be awesome.

thibs · 11-19-2020, 02:20 AM - **1 Like**

Originally posted by Paul the Sunman

f/𝜋 would be elegant. f/𝜑 (golden ratio) would be awesome.

F/3.14 and F/1.618 would be very nice IMO

ZombieArmy · 11-19-2020, 02:23 AM - **1 Like**

Or just make it F/0 and create an artificial black hole.

**TwoUptons** · 11-19-2020, 03:27 AM - **3 Likes**

Originally posted by thibs

F/3.14 and F/1.618 would be very nice IMO

I still think it's F/e

-Eric

11-18-2020, 02:13 PM	#666
mlt Site Supporter Join Date: Dec 2007 Posts: 1,159	Originally posted by Rondec I guess I wonder if they might artificially set the max aperture at f2.8 if they don't think the performance is good enough at f2.4. This certainly would explain them not having released the aperture yet. Or it still could be an f2.0, can’t infer much from the dof scale or a visual of the front element. Last edited by mlt; 11-18-2020 at 02:13 PM. Reason: Typo

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
DA 21 or HD DA 21 What's the right price?	brightseal	Pentax SLR Lens Discussion	16	08-13-2019 05:58 AM
I just bought three lenses, I should really sell one, but which one...	dmbaile2	Pentax SLR Lens Discussion	21	01-27-2015 06:42 PM
Wanted - Acquired: FA 43 Limited, DA 21 Limited, DA 15 Limited	jgmankos	Sold Items	0	05-14-2011 10:13 AM
DA 21 LE vs CARL ZEISS DISTAGON T* 21/2.8 ZF	yipchunyu	Pentax SLR Lens Discussion	4	10-06-2009 06:51 PM
One dog. Three portraits. Three different emotions.	Mindaugas	Post Your Photos!	2	05-05-2009 08:33 PM

11-18-2020, 10:12 AM	#661
ThorSanchez Site Supporter Join Date: Dec 2012 Photos: Gallery \| Albums Posts: 2,806	Originally posted by reh321 A modern lens with aperture ring might sell very well simply because of all of us with K-30 or K50 bodies that cannot control the aperture {I hear another conspiracy theory brewing}. There have to be tens or even dozens of people who had the aperture block failure but just kept using the camera, didn't get it fixed, and didn't go get another body.

11-18-2020, 10:37 AM	#662
mlt Site Supporter Join Date: Dec 2007 Posts: 1,159	And in all probability, this will likely be a KAF4 lens with full electronic control - usable on K-50 or ‘K-70 regardless of solenoid issues. The primary market will be for the K1 users though.

11-18-2020, 10:54 AM	#663
Rondec Loyal Site Supporter Join Date: Mar 2009 Location: Gladys, Virginia Photos: Gallery Posts: 27,653	Originally posted by Serkevan My personal guess is also around f/2.4 - f/2 is probably not doable with such a relatively small package, and f/2.8 feels too... "normal" for a Limited. ---------- Post added 11-18-20 at 04:28 AM ---------- Even Chinese manual focus lenses are f/0.95 by default nowadays. If Zeiss made an f/0.7 lens Carl Zeiss Planar 50mm f/0.7 - Wikipedia then Pentax has to get on with the times and make something on that ballpark. Nothing else, nothing, will do. ---------- Post added 11-18-20 at 04:36 AM ---------- From what little we have seen of the lens it doesn't feel to me like the FA has a larger front element. As I replied to Rondec I also don't think the lens is gonna be super fast, but I somehow get the feeling they will try to make it a bit faster than f/2.8 - maybe they are going for a smoother, less-than-sharp rendering wide open that transitions to sharp landscape lens as you close the aperture? Similar to some of those old lenses that are dreamy at maximum aperture. I guess I wonder if they might artificially set the max aperture at f2.8 if they don't think the performance is good enough at f2.4. This certainly would explain them not having released the aperture yet.

11-18-2020, 12:44 PM - 1 Like	#664
angerdan Pentaxian Join Date: Feb 2015 Photos: Gallery \| Albums Posts: 2,639	With the again upcoming discussion about the speed of the aperture, I like to remember about these posts: Originally posted by phoebus Using very rough techniques, I suggest that the DFA 21 Ltd will have 67mm filter thread and a body width of about 75mm. That makes it pretty close to the FA 20/2.8 in size... Originally posted by phoebus OK! Is that better?

11-18-2020, 02:11 PM	#665
mlt Site Supporter Join Date: Dec 2007 Posts: 1,159	Thank you for measurements.

11-18-2020, 02:57 PM - 1 Like	#667
dave_roe Moderator Loyal Site Supporter Join Date: Jun 2008 Location: Rome, Italy Photos: Albums Posts: 584	Now this is a lens I not only need but am lusting over. Time to build the bank and just say ship it when it is time.......

11-18-2020, 09:41 PM	#668
thibs Pentaxian Join Date: Jun 2007 Location: Belgium Photos: Albums Posts: 7,001	Originally posted by Rondec I guess I wonder if they might artificially set the max aperture at f2.8 if they don't think the performance is good enough at f2.4. This certainly would explain them not having released the aperture yet. It has been done before, indeed. Probably for other reasons though.

11-18-2020, 10:01 PM	#669
Paul the Sunman Pentaxian Join Date: Aug 2011 Location: Melbourne Photos: Gallery Posts: 4,843	Originally posted by thibs It has been done before, indeed. Probably for other reasons though. Maximum aperture has always been conservatively set on Limited lenses in the past.

11-18-2020, 10:10 PM - 2 Likes	#670
ben-pentax Loyal Site Supporter Join Date: Feb 2007 Photos: Gallery Posts: 133	Originally posted by Rondec I guess I wonder if they might artificially set the max aperture at f2.8 if they don't think the performance is good enough at f2.4 Might be, but no way an f2.8. This is a Limited, Let's say f2.7 ?

11-18-2020, 10:10 PM	#671
thibs Pentaxian Join Date: Jun 2007 Location: Belgium Photos: Albums Posts: 7,001	Originally posted by Paul the Sunman Maximum aperture has always been conservatively set on Limited lenses in the past. Sure but I was thinking artificially limited like e.g. K55/1.8 and K55/2

11-18-2020, 10:19 PM - 3 Likes	#672
Paul the Sunman Pentaxian Join Date: Aug 2011 Location: Melbourne Photos: Gallery Posts: 4,843	Originally posted by ben-pentax Might be, but no way an f2.8. This is a Limited, Let's say f2.7 ? f/𝜋 would be elegant. f/𝜑 (golden ratio) would be awesome.

11-19-2020, 02:20 AM - 1 Like	#673
thibs Pentaxian Join Date: Jun 2007 Location: Belgium Photos: Albums Posts: 7,001	Originally posted by Paul the Sunman f/𝜋 would be elegant. f/𝜑 (golden ratio) would be awesome. F/3.14 and F/1.618 would be very nice IMO

11-19-2020, 02:23 AM - 1 Like	#674
ZombieArmy Pentaxian Join Date: Jun 2014 Location: Florida Posts: 3,210	Or just make it F/0 and create an artificial black hole.

11-19-2020, 03:27 AM - 3 Likes	#675
TwoUptons Loyal Site Supporter Join Date: Nov 2015 Photos: Albums Posts: 4,213	Originally posted by thibs F/3.14 and F/1.618 would be very nice IMO I still think it's F/e -Eric