[goubejp]

Back on topic, my HD DA 20-40 limited should arrive tomorrow. Can I get excited?

Yes you can; got mine saturday ;-)

[Zygonyx]

And ?
Next one to post a review in the DA20-40 lens chapter ?

[mrmentera]

Yes you can; got mine saturday ;-)

Probably someone asked this question already, but I will not read all comments in this thread.

How do the lens behave on a full format camera?
Now when there is so many Sony a7 around it should come more and better tests of the Pentaxlenses.

And if you test, remember to comment in this thread:
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/31629-da-le...ts-thread.html

[bvg]

my HD DA 20-40 limited should arrive tomorrow. Can I get excited?

It is too late to think about that, you have to be excited!

[dude]

Hi all; new poster - old school lurker. I think SRS in the UK got some early stock as I got my (black) copy last Friday.

First up I'm happy with this lens. For comparison I also currently own the following in the same or close focal ranges:
- 16-50mm SDM
- 20mm Voigtlander (a favourite for the silky smooth focus and easy zone focusing)
- 31mm Limited
- 35mm 2.8 M
- 40mm DA Limited
- 43mm FA Limited
- Kit lens (from K200 days - don't use this much, but may dust it off for a comparison)

I'm currently shooting with a K5 (original) so please keep this in mind re autofocus.

Initial impressions:

I think this is a lens you need to get to know a little. Once you do, for particular shooting styles, I rate it pretty highly.

Ergonomics: I'm going to score it high here. It balances well. As has been noted before, similar size to the 31mm but a lot lighter. This is good if you need to shoot one handed. The cap is easy to remove (not a fan of the 40mm screw design but the Ltd caps beat even the clip style for my money). On the negative side, why such a short focus throw for what could be a great street photog lens. Zone focusing is harder and so far as I can tell this leads to less accuracy on the autofocus. Does anyone really care whether the lens takes 0.7 or 0.9 seconds to focus? Maybe there is more to it.

Focus accuracy: I struggled with this to start with - it seemed to have a fair bit of back focus at some focal lengths. Many test chart shots later. I'm at +1 to fix a mild back focus problem but have found that if I focus from 0m I get better accuracy apart from at 40mm where focusing from infinity yields better results. The problem focal lengths appear to be around the 30mm mark. From infinity the focus is audibly in steps, from 0 it appears to go straight to focus and stops (on K5).

Sharpness: First surprise - I think that the max resolving power of this lens may sit in the f9-f10 range rather than around f7. I see an observable drop off or sharpness at f13 but up to there we are pretty good. Other observations. The edges drop off a little but nothing I'd consider bad. The lens benefits from stopping down (especially at the 20mm end) - not a surprise. At 40mm it is pretty good wide open.

Sharpness - Lens comparisons:
v 31mm Ltd - Goes toe to toe in the centre but the 31mm is sharper across the whole frame
v 16-50mm @ 40mm f4 - the 16-50mm may be slightly sharper in the centre of the frame
v 16-50mm @ 30mm f3.5 - the 16-50mm may be more consistent across the frame but overall the 20-40mm wins
v 16-50mm @ 20mm f2.8 - the 20-40mm wins all round

Sharpness - @ different focal distances
The 20-40mm seems to perform well here. Both close focus and far distance are handled well so the lens dose not appear to have been geared to either end.

Sharpness - focal plane
I haven't yet worked out this lenses field curvature yet. It is certainly less pronounced than the 43mm Ltd. I think it may be complex and vary at different focal lengths - hard to pin down.

Fringing: This lens beats the hell out of the 31mm Ltd in terms of purple fringing, Although the problem is not completely eliminated it is very well controlled,

Vignetting: Haven't spotted any obvious problems yet.

+ I like the rendering and out of focus transitioning.

I've attached a comparison with the f31mm at f10. There is still some variation in focus points. Focus should be on the bottle neck mid frame. I think the 31mm is back focusing slightly here.

Random point to note: 31mm on the 31mm Ltd at close focus is a lot tighter than 31mm at the same distance to subject on the 20-40mm.

I'll post some more samples.

[dude]

Hopefully the shots give some idea as to the flat field performance and the in-out of focus rendering (though with the variable focal lengths and apertures it's tricky but interested parties can extrapolate ).

Someone shout if I'm doing attachments wrong.

DNGs up at: https://skydrive.live.com/?mkt=en-GB#cid=517F1AEA602F4466&id=517F1AEA602F4466%21391

[dude]

A few more samples. I intended to post the DNGs up as well but there may be some technical difficultly with this - stay tuned.

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[dude]

Mostly one handed (was carrying some takeaway food home) but I don't think I added too much blur. No tripod I'm afraid.

[DogLover]

I just got mine today and have only taken a few test shots just to make sure there are no obvious problems. I think I'm good. My limited use () also shows excellent sharpness (maybe a little less on the left side, too early to tell for sure), decent bokeh (a little nervous wide open), and typical Pentax limited rendering. I'm pretty happy!

Also, this may sound like I'm trying to be cute, but I was actually surprised that the lens was smaller than I expected. No surprises about how sexy it looks when mounted.....er, on the camera, that is.

[Wired]

I'm looking forward to adding this lens to my lineup, but I think I'll be comparing it to the 18-35 sigma before I pull the trigger. I'm not seeing a huge reason to jump on this right away when I got the 31 and 43 in my bag. Especially since the rendering is better on the 31 from what I'm seeing (hard to argue that with any lens though). The only huge benefit I'm seeing is the reduction in PF of the DA Zoom.

[VisualDarkness]

Finally more impressed people than me, though I don't have the cash for it at the moment. I almost thought that I were wrong in my assessment after all the negativeness.

[jimr-pdx]

I know for a fact the Sigma low-light beast isn't for me; for me it's a contest between the Limited and the mythical roadmap ~17-85. That means I'll be out of the race for a bit while Pentax reloads Hopefully we'll get a whiff of it at upcoming winter events.

[DogLover]

I know for a fact the Sigma low-light beast isn't for me; for me it's a contest between the Limited and the mythical roadmap ~17-85. That means I'll be out of the race for a bit while Pentax reloads Hopefully we'll get a whiff of it at upcoming winter events.

Yes, if that one turns out to have the same build characteristics (all metal, WR, DC motor, etc.) as the 20-40 and excellent performance to boot, I would be very interested.

[Paul the Sunman]

I know for a fact the Sigma low-light beast isn't for me; for me it's a contest between the Limited and the mythical roadmap ~17-85. That means I'll be out of the race for a bit while Pentax reloads Hopefully we'll get a whiff of it at upcoming winter events.

Wasn't the ~17-85 the one that was originally supposed to be DA*? I wonder what they dropped to make it only DA: IQ, WR, speed? Still, it's hardly a competitor for the DA 20-40 Ltd; more relevant to the DA*16-50, DA 17-70, and DA 18-135. None of those lenses is really a world-beater optically. I can't see the point of a ~17-85 unless it really brings something special to the table, so here's hoping.

Actually, looking at the old 2012 lens roadmap, that prospective DA* zoom looked more like ~14-85, so plans really have become less ambitious!

[eurostar]

Wasn't the ~17-85 the one that was originally supposed to be DA*? I wonder what they dropped to make it only DA: IQ, WR, speed?

Maybe they just dropped the *. The 645DFA monster lenses are plain HD, not *.