[ZombieArmy]

Time to address the elephant in the room: The Bokeh. I don't think passing any kind of judgement over this this is in any way fair. We have all seen the length to which Pentax went through to meticulously engineer the Bokeh of the DFA21 lens to be as smooth as possible: the FA*24 simply wasn't designed with the same optical parameters. The FA*24mm to me, is a lens of its time. The expectations of photographers and the goals of lens engineers and designers* have changed drastically since then.

* as well as new advanced glass types and manufacturing methods which have been improved and extended - creating new possibilities for them that couldn't have been done in the past without being horrendously expensive.

Bubble bokeh is also a bit of a guilty pleasure of mine so I rather like the FA* 24's bokeh.

For reference I do own a Takumar 35 f2.3

[Digitalis]

Bubble bokeh is also a bit of a guilty pleasure of mine so I rather like the FA* 24's bokeh.

yep, each to his own. Bokeh is such a relative and subjective thing, I know photographers who detest STF (or lenses with any sort of apodization filter) lenses because of the tendency to produce very FLAT Bokeh with them.

[repaap]

My FA*24mm f/2 arrived today, My technician also provided results from his optics bench (I may send my DFA21 over to him since I don't have space to set up my own bench) I was able to do this quick (handheld) comparison between the D-FA21mm f/2.4 and FA*24mm f/2 At their widest apertures.

Both images are completely un-sharpened and un-corrected, All I did to them is reduce them 25% and upload them to PF:



Pentax K-1 SMCP-HD D-FA21mm f/2.4 ED ASPH Limited f/2.4 ISO 400 1/250th


Pentax K-1 SMCP-FA*24mm f/2 ASPH @ f/2 ISO 400 1/320th


The contrast in focal length is greater then the numbers alone imply, Micro-contrast on the DFA21 is higher and sharpness is also noticeably higher on the DFA21 Vs FA*24. Also [on my calibrated display] the DFA21 appears to have a warmer cast to it than the FA*24 lens [WB on my cameras is fixed to 5000K] the FA*24 has more visible Vignetting @ f/2 than the DFA21 @ f/2.4. Coma is considerably worse on the FA*24mm f/2.


I did what I could to maintain the central subject magnification and let everything outside of that go where it would.



Time to address the elephant in the room: The Bokeh. I don't think passing any kind of judgement over this this is in any way fair. We have all seen the length to which Pentax went through to meticulously engineer the Bokeh of the DFA21 lens to be as smooth as possible: the FA*24 simply wasn't designed with the same optical parameters. The FA*24mm to me, is a lens of its time. The expectations of photographers and the goals of lens engineers and designers* have changed drastically since then.

* as well as new advanced glass types and manufacturing methods which have been improved and extended - creating new possibilities for them that couldn't have been done in the past without being horrendously expensive.

FA24/2 has it’s quirks in this image very well displayed. Quite pronounced bokeh balls which might take too much attention from main subject. While some photographers might prefer that. Shift from in focus to Oof is also more pleasant with DFA21/2.4 limited. And vinget and distortion seems quite good too given that it is wider lens. IMO they did splendid work. While FA24/2 still is special and nice lens. Agreed that it is product of its time.

[Paul the Sunman]

Time to address the elephant in the room: The Bokeh. I don't think passing any kind of judgement over this this is in any way fair.

Don't worry, I don't think the FA 24 will be offended.

[luftfluss]

This is the kind of stuff that matters more to me than a lens being an Imatest queen.

[Digitalis]

Well here we are: DFA21 Vs FA*24mm at infinity focus stopped down to f/11 and there really isn't much to say apart from the DFA21 having a warmer colour cast, the FA* looks cooler. The slight increase in magnification from the 21<24 makes the FA*24 appear sharper but I'd just say they are more or less equal at f/11 in the center (diffraction already having an impact on resolution at this aperture)


100% un-sharpened un-corrected crops

The edges however are quite a different story:

100% un-sharrpened un-corrected crop.

The DFA is clearly sharper at the edge of the frame and this trait carries all the way to the corners, which it has to be said: even at f/11 the corners from the FA*24mm devolve into a coma riddled astigmatic mess which no amount of sharpening can hope to fix.

Don't worry, I don't think the FA 24 will be offended.

I Recall Mike Johnston from TOP declaring the FA*24mm f/2 the "Best 24mm on the planet" I never worked with the FA*24mm f/2 much mainly because of the obtrusive nature of the lenses rendering. It doesn't lend itself to the kind of subject matter I deal with*.. but if you enjoy it: you do you.


Pentax K-1 SMCP-FA*24mm f/2 @ f/2 ISO 100 1/3200th - Edited in Nik FX [tonemapped HDR] and no, the vignetting isn't actually that bad.

A few things I will say in defense of the FA*24mm compared to the DFA21: being a 24mm lens barrel distortion is more manageable, the Autofocus seems to be zippier [literally**] and more accurate than the DFA21 when light levels drop. It has an aperture ring which means I can still use it on my film cameras. The removable Lens hood means it is very straightforward to use square filter systems on it (DFA21 and FA*24 both have 67mm filter threads)


* Also with the exception of my Silver Pentax KP my other Pentax cameras are jet Black, and even on the KP the shade of silver on the FA*24 doesn't quite match the body so it is aesthetically disruptive no matter which camera I put it on.

**because of the screw drive AF

[Paul the Sunman]

The DFA is clearly sharper at the edge of the frame and this trait carries all the way to the corners, ...

Thanks for these comparisons. I'm not finding much to dislike on the DFA 21 either. It is a different experience from the DA15 Limited on APS-C, despite the similar field of view, because of this edge to edge sharpness. However, it is a gentle sort of sharpness that doesn't poke your eye out, and very suitable for a lot of my photography. The OOF transitions are beautiful, and I am really enjoying the very close minimum focus distance.

When I do want a more clinical sharpness, I find it sharpens well in post processing.

I just checked front/back focus on my K1. It was pretty much spot-on, and I made no adjustment.

[Paul the Sunman]

When I grep for Lens in the exif of a dng file taken with the K1 + DFA21 f/2.4 Limited, I get (using exiftool)

Lens Type : Unknown (8 67)
Lens ID : Unknown (8 67)

Why is the lens unknown?

For comparison, with the DFA* 50 f/1/4 I get

Lens Type : HD PENTAX-D FA* 50mm F1.4 SDM AW
Lens ID : HD PENTAX-D FA* 50mm F1.4 SDM AW

Does something need updating?

[Digitalis]

To quote Stevebrot from the "D-FA 21mm F2.4 Ltd Profiles" thread:

The lens id for the D FA 21/2.4 Limited is "8 67". At some point Adobe products and DCU will be able match a name to that code, but not today.

This explanation is as good as any.

[stevebrot]

Does something need updating?

Yes, ExifTool...

ExifTool does not yet have the lens in their lookup table. The current lookup table is viewable at:

https://exiftool.org/TagNames/Pentax.html#LensType


Steve

[biz-engineer]

Question to owners of D-FA 21 Ltd. With the latest firmware, are you able to enable in camera (K1, JPEG) lens corrections for the D-FA 21 Ltd ?

[BigMackCam]

Question to owners of D-FA 21 Ltd. With the latest firmware, are you able to enable in camera (K1, JPEG) lens corrections for the D-FA 21 Ltd ?

It's not listed in the latest or previous firmware updates, whereas other lenses have been specifically mentioned - so the expectation would be that in-camera corrections aren't yet available. I'm sure someone will tell us if that's not the case, but I'd be surprised...

[acoufap]

Some time ago I updated my exiftool installation to version 12.41 - it "knows" the DFA21Ltd. After applying my zsh "lens-script" the lens model is visible in Capture One Pro.

For those interested ... the command I use in my script: "exiftool -overwrite_original '-exif:LensModel<${Composite:LensID}' . "

A correction module in DxO PhotoLab 5 doesn't seem to be available until now and the lens name isn't shown in the metadata. So there seems to be another mechanism to show lens models.

[house]

Some time ago I updated my exiftool installation to version 12.41 - it "knows" the DFA21Ltd. After applying my zsh "lens-script" the lens model is visible in Capture One Pro.

For those interested ... the command I use in my script: "exiftool -overwrite_original '-exif:LensModel<${Composite:LensID}' . "

A correction module in DxO PhotoLab 5 doesn't seem to be available until now and the lens name isn't shown in the metadata. So there seems to be another mechanism to show lens models.

Biz was asking about **in camera** corrections.

[house]

Came across a review at Pentax HD D FA 21mm F2.4 ED Limited DC WR Review | PCMag

No full size samples as far as I can tell and limited technical analysis. Nice to see someone mentioning it anyway.

Two things of note

Interestingly, we see more barrel distortion from the lens at macro distances. I can't recall another wide prime that behaved this way. There's visible barrel distortion (around 2.5%) when you focus close, but shifting focus to infinity straightens all curved lines.

There has been rather differing reports on distortion. Perhaps this is the answer, it behaves differently at infinity to close up. Very interesting if true.

This effect is most visible in Raw DNG images; the K-1 Mark II automatically corrects JPGs for distortion.

The above suggests the camera does have a profile. This is interesting because I haven't seen in mentioned in the firmware updates. Perhaps I've missed it or Pentax has developed a new way of handling lens profiles.