[Digitalis]

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.

The DFA21 has a rather complex internal floating lens arrangement, so the variable distortion characteristic is rather unsurprising if you ask me.

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Last edited by Digitalis; 06-11-2022 at 07:07 PM.

[Paul the Sunman]

The DFA21 has a rather complex internal floating lens arrangement, so the variable distortion characteristic is rather unsurprising if you ask me.

It is also less problematic at close distances, where a bit of barrel can be desirable, emphasising the close object you are focusing on. Anyway, I can't say I've ever found it an issue.

[Digitalis]

I can't say I've ever found it an issue.

I have found distortion at closer focus distances to be a bit of a problem with the DFA21 particularly when photographing subjects with strong geometric lines to them, I found about +10 distortion correction in LR at MFD was effective.


Pentax KP- D-FA21mm f/2.4 Limited - This image was one particular case where the distortion characteristic of the D-FA21mm f/2.4 was rather problematic.



Pentax K-1 DFA21 - Also instances where Near-Far compositions are involved geometric distortion can cause the horizon to visibly bow

[house]

The DFA21 has a rather complex internal floating lens arrangement, so the variable distortion characteristic is rather unsurprising if you ask me.

I'm no expert but I can't recall a prime lens that shows significantly different distortion characteristics depending on focus distance. That said I don't really consider lens characteristics at close distances so I may have missed something.

[x-country]

Pop! This is an example of the great rendering effect of the limited lenses. The 21/2.4 doesn’t let you down.

[Digitalis]

I'm no expert but I can't recall a prime lens that shows significantly different distortion characteristics depending on focus distance

Some lenses can show different characteristics with varying focus distance - zoom lenses particularly internal focus ones suffer from focus breathing. Distortion,vignetting and coma characteristics can also vary with sophisticated internal focus primes too.

[angerdan]

Interesting that the DFA 21mm is constructed more lightweight and compact than a mirorrless design lens:
Produktvergleich Pentax HD DFA 21mm 2.4 ED Limited DC WR schwarz (28047), Leica Super-APO-Summicron-SL 21mm 2.0 ASPH (11181) heise online Preisvergleich Deutschland

[house]

Interesting that the DFA 21mm is constructed more lightweight and compact than a mirorrless design lens:
Produktvergleich Pentax HD DFA 21mm 2.4 ED Limited DC WR schwarz (28047), Leica Super-APO-Summicron-SL 21mm 2.0 ASPH (11181) heise online Preisvergleich Deutschland

I'm looking forward to seeing samples of how the Leica SL 21 performs. They've designated it APO so I would be very surprised if we'll see the kind of lateral fringing the DFA21 exhibits. Fixing that sort of thing at high level makes things large. I'm glad Pentax kept the size down. The DFA21 length includes the hood by the way so for a fair comparison you need to loose another 20mm from the lens. That makes it 33mm shorter!

Does anyone know if Leica patents their designs? Would be interesting to see how extreme their glass types are in this lens.

[Rondec]

Interesting that the DFA 21mm is constructed more lightweight and compact than a mirorrless design lens:
Produktvergleich Pentax HD DFA 21mm 2.4 ED Limited DC WR schwarz (28047), Leica Super-APO-Summicron-SL 21mm 2.0 ASPH (11181) heise online Preisvergleich Deutschland

Pricing is slightly different too. B and H seems to have a pre-order price of 5500 dollars for the Leica 21mm f2...

[angerdan]

Pricing is slightly different too. B and H seems to have a pre-order price of 5500 dollars for the Leica 21mm f2...

Only $150 converted difference between Europe (5300€) and US ($5500).
Leica Super-APO-Summicron-SL 21mm f/2 ASPH. Lens (L-Mount) 11181

[Rondec]

Only $150 converted difference between Europ (5300€) and US ($5500).
Leica Super-APO-Summicron-SL 21mm f/2 ASPH. Lens (L-Mount) 11181

Sorry. I was comparing pricing between the DFA 21 and the Leica 21mm f2. The DFA is 1300 and the Leica 5500. I know the Leica will probably be better, but it is still over 4000 dollars more.

[house]

I know the Leica will probably be better

It certainly has more elements. The DFA21 has extremely fancy glass however so it will be interesting to see what Leica does when cost is almost no issue. Of course Pentax used the expensive glass to make the lens smaller and Leica can put that towards countering aberrations.

[gatorguy]

It certainly has more elements. The DFA21 has extremely fancy glass however so it will be interesting to see what Leica does when cost is almost no issue. Of course Pentax used the expensive glass to make the lens smaller and Leica can put that towards countering aberrations.

I rather like my DFA21 aberrations. It's part of what makes it unique.

[house]

I rather like my DFA21 aberrations. It's part of what makes it unique.

I'm pretty sure it would have been more unique without that lateral chromatic aberration. It's a sensible trade off by Pentax though as it's the aberration most easily corrected in post.