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ogl · 12-14-2013, 09:24 AM

It seems to me your 20-40 has AF problems...

sanjeevdas · 12-14-2013, 10:36 AM

Originally posted by Andr3w

How is the 20-40 in the corners? I am particularly interested in 21 vs. 20-40 at f/8 in the corners.

DA21 f/8
http://photos.smugmug.com/Other/Pentax-Lenses/i-LvNGTvf/0/O/IMGP2672.jpg

DA 20-40 21mm f/8
http://photos.smugmug.com/Other/Pentax-Lenses/i-tbHnHcD/0/O/IMGP2814.jpg

Driline · 12-14-2013, 11:30 AM

Hmmmm... It looks like the lighting changed a bit between lenses. I can also see the sandal fell off the stoop between shots too. Overall the DA 20-40 looks a bit brighter and less muddy but again that could be because of the difference in lighting? Not sure...

krebsy75 · 12-14-2013, 01:15 PM

I appreciate the effort but "testing" lenses should be done where lighting can be controlled. CDAF should also be used.

sanjeevdas · 12-14-2013, 02:26 PM

Originally posted by sanjeevdas

I don't actually shoot using live view much, which is why I didn't do it. I do understand what you mean though. I'll try a CDAF/PDAF test to see if this is a focus issue.
About the beer, I actually intend to enjoy them afterwards as I browse through the images

DA 20-40 20mm f/4
PDAF

DA 20-40 20mm f/4
CDAF

DA21 f/4
PDAF

Driline · 12-14-2013, 02:29 PM

Originally posted by sanjeevdas

DA 20-40 20mm f/4
PDAF

DA 20-40 20mm f/4
CDAF

DA21 f/4
PDAF

DA 21 is noticeably sharper.... not as muted, and seems to have better contrast in the pictures you provided.

kh1234567890 · 12-14-2013, 03:50 PM

Originally posted by sanjeevdas

DA21 f/8
http://photos.smugmug.com/Other/Pentax-Lenses/i-LvNGTvf/0/O/IMGP2672.jpg
DA 20-40 21mm f/8
http://photos.smugmug.com/Other/Pentax-Lenses/i-tbHnHcD/0/O/IMGP2814.jpg

Interesting. If you take out the CA on both then the DA 20-40 is as good, if not better, than the DA21 over the whole frame. What is it like wide open ?

Nice Moire at the bottom of the door blind

sanjeevdas · 12-14-2013, 04:08 PM

Originally posted by kh1234567890

Interesting. If you take out the CA on both then the DA 20-40 is as good, if not better, than the DA21 over the whole frame. What is it like wide open ?

Nice Moire at the bottom of the door blind

Ha! I never noticed that!

From today:
DA 21 f/3.2 PDAF
http://photos.smugmug.com/Other/DA21-vs-DA-20-40/i-w2FqPKj/0/O/IMGP3135.jpg

DA 20-40 20mm f/2.8 CDAF
http://photos.smugmug.com/Other/DA21-vs-DA-20-40/i-39s47px/0/O/IMGP3124.jpg

kh1234567890 · 12-14-2013, 04:32 PM

Originally posted by sanjeevdas

Ha! I never noticed that!

From today:
DA 21 f/3.2 PDAF
http://photos.smugmug.com/Other/DA21-vs-DA-20-40/i-w2FqPKj/0/O/IMGP3135.jpg
DA 20-40 20mm f/2.8 CDAF
http://photos.smugmug.com/Other/DA21-vs-DA-20-40/i-39s47px/0/O/IMGP3124.jpg

The DA 20-40 is just a touch decentered (top right corner vs top left) but is doing well. I could live with that. It is interesting how much difference that one mm of focal length makes.

What is the AF like ? The DA21 is really fast and just right for those 'from the hip' street photos. Tempting ...

sanjeevdas · 12-14-2013, 04:40 PM

Originally posted by kh1234567890

The DA 20-40 is just a touch decentered (top right corner vs top left) but is doing well. I could live with that. It is interesting how much difference that one mm of focal length makes.

What is the AF like ? The DA21 is really fast and just right for those 'from the hip' street photos. Tempting ...

AF on the DA 20-40 is very fast. I didn't notice any difference with the other limiteds. The lens is much larger than the DA21 though (although very light). For 'from the hip' shooting the DA21 would probably be the best. Although to be honest, I don't like my DA21 that much (compared to the other limiteds). For off the hip shooting, I'd far prefer the DA15.

rdj92807 · 12-14-2013, 05:38 PM

I just got my new 20-40 Ltd, and did some initial tests using my K-01 at 20mm against my 20/2.8 FA (an awesome classic full frame lens), and against my new 35/2.8 Macro Ltd.

My 20 FA is better at 2.8. In some cases, MUCH better. My lens seems decentered, with center/center right weaker than the left side. For a $900 lens, I expect better. At 4.0, the two become closer and by 8.0, the two lenses are basically equal. FYI, my 20 FA is a superb lens and my copy is perfectly centered, made in Japan. I need to perform more testing, but my main issue with the 20-40 right now is weakness wide open at 20mm. I'd like to know if others have this issue also. Note: Does the 20-40 Ltd really start at 20? My 20/2.8 FA is definitely WIDER than my 20-40 Ltd at 20mm. Can others check this out?

Shooting the 20-40 against the DA 35 Ltd Macro, things were better for this new zoom. The 20-40 (for landscapes, not macro) was equal or just slightly sharper. Kind of a surprise.

SDM focusing did not seem faster at all on the K-01, versus primes with screw drives. Of course, the macro has more distance to hunt.

I need more time to test at 20/2.8 and figure out the degree of decentering. I was a little surprised at how large the 20-40 is....basically similar to my 20-35/4 FA. My new Sigma 18-250 Macro version is not much bigger, for example. So far I have mixed feelings about this lens. It does not have the metal feel of the other limiteds and just doesn't seem as special. Oh, and the color is too blue for sure. The colors from my 20/2.8 FA are much more accurate. I may also consider the Sigma 18-35 when it comes out.

ogl · 12-15-2013, 06:23 AM

Its' strange to buy the lens with decentering defects for such money. I was ready to order DA20-40 yesterday, but changed my mind. I will wait for any serious tests.
I worry about QC of this lens.

krebsy75 · 12-15-2013, 07:08 AM

Purchasing anything Pentax related right out of the chute may be a risky endeavor. We bought an 18-135mm when it first came out and it was horrid - worse optically than the 18-55mm we had at the time.

Decentering issues should disappear once the lens is stopped down one full stop. If not, it's definitely defective.

krebsy75 · 12-15-2013, 07:10 AM

Originally posted by ogl

Its' strange to buy the lens with decentering defects for such money. I was ready to order DA20-40 yesterday, but changed my mind. I will wait for any serious tests.
I worry about QC of this lens.

As I understand it consumer lenses aren't calibrated for perfect centering wide open.

krebsy75 · 12-15-2013, 07:17 AM

Originally posted by rdj92807

I may also consider the Sigma 18-35 when it comes out.

The Sig 18-35 and 20-40 aren't really comparable in my opinion. The Sigma user wants full-frame depth of field in a zoom for crop. The Pentax user wants something in a more practical package

12-14-2013, 02:26 PM	#20
sanjeevdas Senior Member Join Date: May 2012 Location: San Jose, CA Posts: 111 Original Poster	Cdaf Originally posted by sanjeevdas I don't actually shoot using live view much, which is why I didn't do it. I do understand what you mean though. I'll try a CDAF/PDAF test to see if this is a focus issue. About the beer, I actually intend to enjoy them afterwards as I browse through the images DA 20-40 20mm f/4 PDAF DA 20-40 20mm f/4 CDAF DA21 f/4 PDAF

12-14-2013, 04:08 PM	#23
sanjeevdas Senior Member Join Date: May 2012 Location: San Jose, CA Posts: 111 Original Poster	DA 20-40 wide open Originally posted by kh1234567890 Interesting. If you take out the CA on both then the DA 20-40 is as good, if not better, than the DA21 over the whole frame. What is it like wide open ? Nice Moire at the bottom of the door blind Ha! I never noticed that! From today: DA 21 f/3.2 PDAF http://photos.smugmug.com/Other/DA21-vs-DA-20-40/i-w2FqPKj/0/O/IMGP3135.jpg DA 20-40 20mm f/2.8 CDAF http://photos.smugmug.com/Other/DA21-vs-DA-20-40/i-39s47px/0/O/IMGP3124.jpg

12-14-2013, 05:38 PM	#26
rdj92807 Forum Member Join Date: Jan 2012 Posts: 97	I just got my new 20-40 Ltd, and did some initial tests using my K-01 at 20mm against my 20/2.8 FA (an awesome classic full frame lens), and against my new 35/2.8 Macro Ltd. My 20 FA is better at 2.8. In some cases, MUCH better. My lens seems decentered, with center/center right weaker than the left side. For a $900 lens, I expect better. At 4.0, the two become closer and by 8.0, the two lenses are basically equal. FYI, my 20 FA is a superb lens and my copy is perfectly centered, made in Japan. I need to perform more testing, but my main issue with the 20-40 right now is weakness wide open at 20mm. I'd like to know if others have this issue also. Note: Does the 20-40 Ltd really start at 20? My 20/2.8 FA is definitely WIDER than my 20-40 Ltd at 20mm. Can others check this out? Shooting the 20-40 against the DA 35 Ltd Macro, things were better for this new zoom. The 20-40 (for landscapes, not macro) was equal or just slightly sharper. Kind of a surprise. SDM focusing did not seem faster at all on the K-01, versus primes with screw drives. Of course, the macro has more distance to hunt. I need more time to test at 20/2.8 and figure out the degree of decentering. I was a little surprised at how large the 20-40 is....basically similar to my 20-35/4 FA. My new Sigma 18-250 Macro version is not much bigger, for example. So far I have mixed feelings about this lens. It does not have the metal feel of the other limiteds and just doesn't seem as special. Oh, and the color is too blue for sure. The colors from my 20/2.8 FA are much more accurate. I may also consider the Sigma 18-35 when it comes out. Last edited by rdj92807; 12-14-2013 at 05:57 PM.

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12-14-2013, 09:24 AM	#16
ogl Banned Join Date: Dec 2007 Location: Sankt Peterburg Photos: Gallery \| Albums Posts: 8,382	It seems to me your 20-40 has AF problems...

12-14-2013, 10:36 AM	#17
sanjeevdas Senior Member Join Date: May 2012 Location: San Jose, CA Posts: 111 Original Poster	Originally posted by Andr3w How is the 20-40 in the corners? I am particularly interested in 21 vs. 20-40 at f/8 in the corners. DA21 f/8 http://photos.smugmug.com/Other/Pentax-Lenses/i-LvNGTvf/0/O/IMGP2672.jpg DA 20-40 21mm f/8 http://photos.smugmug.com/Other/Pentax-Lenses/i-tbHnHcD/0/O/IMGP2814.jpg

12-14-2013, 11:30 AM	#18
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,708	Hmmmm... It looks like the lighting changed a bit between lenses. I can also see the sandal fell off the stoop between shots too. Overall the DA 20-40 looks a bit brighter and less muddy but again that could be because of the difference in lighting? Not sure...

12-14-2013, 01:15 PM	#19
krebsy75 Veteran Member Join Date: Jun 2010 Location: Chester County, Pa. Posts: 804	I appreciate the effort but "testing" lenses should be done where lighting can be controlled. CDAF should also be used.

12-14-2013, 02:29 PM	#21
Driline Pentaxian Join Date: Dec 2012 Location: IOWA Where the Tall Corn Grows Photos: Gallery Posts: 3,708	Originally posted by sanjeevdas DA 20-40 20mm f/4 PDAF DA 20-40 20mm f/4 CDAF DA21 f/4 PDAF DA 21 is noticeably sharper.... not as muted, and seems to have better contrast in the pictures you provided.

12-14-2013, 03:50 PM	#22
kh1234567890 Veteran Member Join Date: Sep 2010 Location: Manchester, UK Photos: Gallery Posts: 2,653	Originally posted by sanjeevdas DA21 f/8 http://photos.smugmug.com/Other/Pentax-Lenses/i-LvNGTvf/0/O/IMGP2672.jpg DA 20-40 21mm f/8 http://photos.smugmug.com/Other/Pentax-Lenses/i-tbHnHcD/0/O/IMGP2814.jpg Interesting. If you take out the CA on both then the DA 20-40 is as good, if not better, than the DA21 over the whole frame. What is it like wide open ? Nice Moire at the bottom of the door blind

12-14-2013, 04:32 PM	#24
kh1234567890 Veteran Member Join Date: Sep 2010 Location: Manchester, UK Photos: Gallery Posts: 2,653	Originally posted by sanjeevdas Ha! I never noticed that! From today: DA 21 f/3.2 PDAF http://photos.smugmug.com/Other/DA21-vs-DA-20-40/i-w2FqPKj/0/O/IMGP3135.jpg DA 20-40 20mm f/2.8 CDAF http://photos.smugmug.com/Other/DA21-vs-DA-20-40/i-39s47px/0/O/IMGP3124.jpg The DA 20-40 is just a touch decentered (top right corner vs top left) but is doing well. I could live with that. It is interesting how much difference that one mm of focal length makes. What is the AF like ? The DA21 is really fast and just right for those 'from the hip' street photos. Tempting ...

12-14-2013, 04:40 PM	#25
sanjeevdas Senior Member Join Date: May 2012 Location: San Jose, CA Posts: 111 Original Poster	Originally posted by kh1234567890 The DA 20-40 is just a touch decentered (top right corner vs top left) but is doing well. I could live with that. It is interesting how much difference that one mm of focal length makes. What is the AF like ? The DA21 is really fast and just right for those 'from the hip' street photos. Tempting ... AF on the DA 20-40 is very fast. I didn't notice any difference with the other limiteds. The lens is much larger than the DA21 though (although very light). For 'from the hip' shooting the DA21 would probably be the best. Although to be honest, I don't like my DA21 that much (compared to the other limiteds). For off the hip shooting, I'd far prefer the DA15.

12-15-2013, 06:23 AM	#27
ogl Banned Join Date: Dec 2007 Location: Sankt Peterburg Photos: Gallery \| Albums Posts: 8,382	Its' strange to buy the lens with decentering defects for such money. I was ready to order DA20-40 yesterday, but changed my mind. I will wait for any serious tests. I worry about QC of this lens.

12-15-2013, 07:08 AM	#28
krebsy75 Veteran Member Join Date: Jun 2010 Location: Chester County, Pa. Posts: 804	Purchasing anything Pentax related right out of the chute may be a risky endeavor. We bought an 18-135mm when it first came out and it was horrid - worse optically than the 18-55mm we had at the time. Decentering issues should disappear once the lens is stopped down one full stop. If not, it's definitely defective.

12-15-2013, 07:10 AM	#29
krebsy75 Veteran Member Join Date: Jun 2010 Location: Chester County, Pa. Posts: 804	Originally posted by ogl Its' strange to buy the lens with decentering defects for such money. I was ready to order DA20-40 yesterday, but changed my mind. I will wait for any serious tests. I worry about QC of this lens. As I understand it consumer lenses aren't calibrated for perfect centering wide open.

12-15-2013, 07:17 AM	#30
krebsy75 Veteran Member Join Date: Jun 2010 Location: Chester County, Pa. Posts: 804	Originally posted by rdj92807 I may also consider the Sigma 18-35 when it comes out. The Sig 18-35 and 20-40 aren't really comparable in my opinion. The Sigma user wants full-frame depth of field in a zoom for crop. The Pentax user wants something in a more practical package

DA 20-40 Limited (w/ comparison images)

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