[acoufap]

I'm still exploring this lens to get the most out of it.

And here's another nice surprise!

As you can read here the DFA21Ltd is compatible to the Pentax DA TC1.4x. You get a Pentax DFA f3.5/29.4. Since the TC doesn't change the minimum focusing distance this combo also has 18cm minimum focusing distance!

You may think that I'm nuts to use an ultrawide with a TC. But let's see ...

Let's have a look at some images to show the vignetting of the combo, made in K-1 FF mode at near infinity - overcast sky:


K-1 | Pentax DFA f3.5/29.4 | FF mode | 29.4mm | f3.5


K-1 | Pentax DFA f3.5/29.4 | FF mode | 29.4mm | f4.0


K-1 | Pentax DFA f3.5/29.4 | FF mode | 29.4mm | f5.6


K-1 | Pentax DFA f3.5/29.4 | FF mode | 29.4mm | f8.0


K-1 | Pentax DFA f3.5/29.4 | FF mode | 29.4mm | f11.0

Now - that doesn't look too bad, I think. Indeed much better than DA TC1.4x with DFA100WR!

Here's another example with subject at short distance ...


K-1 | Pentax DFA f3.5/29.4 | FF mode | 29.4mm | ISO100 | f3.5 | 1/30s

I'm pretty sure that if I cut an opal pane for this lens and create flat field correction profiles (=> called in RawTherapee) for each aperture and apply these to the raw files, this vignetting will vanish fully. In Capture One Pro this is called lens color calibration (LCC) profile.

Everybody may judge by herself / himself if such results are usable. I think they are.

Now, that's on 35mm fullframe. If you use an APS-C camera you get the field of view of an ~f3.5/45mm lens - normal field of view with 18cm minimal focusing distance and astonishing bokeh! Do you know any other normal lens that does offer this apart from 50mm macro lenses?

Some more notes:

- such a combo is not possible using the DA21Ltd because this APS-C lens is not compatible to the DA TC1.4x
- the DATC1.4x/DFA21Ltd. combo shows roughly the size of the DFA28-105
- the DATC1.4x/DFA21Ltd. combo is slightly faster than the DFA28-105 @ 45mm which is f4.0

I think this is something that should be considered and mentioned when it comes to describing the DFA21Ltd. - another argument to justify paying the price - maybe?!

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Last edited by acoufap; 05-01-2022 at 02:51 AM.

[house]

A screw-on like the 43’s would have been possible, but probably too big and perhaps not so easy to do if it was a petal hood that may have been subject to small misalignment errors.

I think the Leica 1.4/21 has a screw on hood. I've seen people post images where they accidentally failed to get it to align, with asymmetrical vignetting as a result.

So it seems fiddly but perhaps some other brand has managed to get it right.

Ricoh markets the dfa21 as a "snapshot" lens which explains the fixed hood.

[Digitalis]

Pentax K-1 SMCP-HD- D-FA 21mm f/2.4 ASPH Limited ISO 100 1/125th f/11 - SATOBI


Pentax K-1 SMCP-HD- D-FA 21mm f/2.4 ASPH Limited ISO 100 1/200th f/4 + Godox AD400

I think the Leica 1.4/21 has a screw on hood

I have that lens, the issue with the lens hood becoming asymmetrical usually occurred with wear and tear on the threads from habitual over tightening the hood: Later on 3rd party makers such as Voigtländer produced a clip on version of the hood that avoided that problem.

[acoufap]

The new Laowa 20mm f/4 Zero-D-Shift, also available for K-mount, offers a removable and rotatable lens hood.

[house]

I have that lens

Side by side comparison!

[acoufap]

Pentax DFA f3.5/29.4 (DA TC1.4x + DFA21Ltd.) at shortest focusing distance - macro rail, same position different K-1 modes, ES:


Full Frame Mode


Square Mode


APS-C Mode

[Digitalis]

Getting starflares with the DFA21 is a bit challenging, I find they start to appear around f/11, but stopping down past f/14 can also reveal any specs of dust on the front surface of the lens that will catch the light.



This is one area that the original DA15mm f/4 limited still has a distinct advantage.

[acoufap]

Some captures of DFA21Ltd + DA TC1.4x, I'd call it DFA29*Ltd (* because the TC has build quality of *lenses)


K-1 | FF mode | DFA29*Ltd | 29.4mm


K-1 | FF mode | DFA29*Ltd | 29.4mm


K-1 | APS-C mode | DFA29*Ltd | 29.4mm (FF equip. 44mm)


K-1 | APS-C mode | DFA29*Ltd | 29.4mm (FF equip. 44mm)

[acoufap]

Getting starflares with the DFA21 is a bit challenging, I find they start to appear around f/11, but stopping down past f/14 can also reveal any specs of dust on the front surface of the lens that will catch the light.



This is one area that the original DA15mm f/4 limited still has a distinct advantage.

My star trials from today ...


K-1 | FF mode | 29.4mm | f8


K-1 | APS-C mode | 29.4mm | f11

[Digitalis]

Night sky at Bortle 3, the DFA21 shows great promise for astrophotography however its vignetting characteristic is a bit problematic when stacking frames.


Pentax K-1 SMCP-HD D-FA 21mm f/2.4 ASPH @ f/4 ISO 6400 T=1m - processed with DeepSkyStacker : 4 light, 2 flat darks, DFS used for light frames with Astrotracer active.

Although there is no hard stop at infinity, thanks to the brilliance of Canopus and Sirius: focusing on stars accurately through high magnification live view + Bahtinov Mask is easy.

[Paul the Sunman]

Pentax K-1 SMCP-HD- D-FA 21mm f/2.4 ASPH Limited ISO 100 1/125th f/11 - SATOBI

What are you using to process the SATOBI? DCU5? Or is it a jpeg straight out of camera?

[Digitalis]

What are you using to process the SATOBI? DCU5?

I'm using DCU 5 - that way I can still tweak the result without being bound strictly to the preset. Though I recently developed a filter recipe for NIK Efex that is visually very similar but offers greater control over image tonality.

[acoufap]

x-post

[RobA_Oz]

Night sky at Bortle 3, the DFA21 shows great promise for astrophotography however its vignetting characteristic is a bit problematic when stacking frames.


Pentax K-1 SMCP-HD D-FA 21mm f/2.4 ASPH @ f/4 ISO 6400 T=1m - processed with DeepSkyStacker : 4 light, 2 flat darks, DFS used for light frames with Astrotracer active.

Although there is no hard stop at infinity, thanks to the brilliance of Canopus and Sirius: focusing on stars accurately through high magnification live view + Bahtinov Mask is easy.

It’s hard to tell at the forum magnification (at least on my 10” iPad), but there doesn’t seem to be an obvious amount of coma present.

[Paul the Sunman]

Under the Bolte Bridge