New review of the DA 20-40 F2.8-4

DAVID MANZE · Jan 31, 2014

Hi guys,

Having seriously doubted the results of Pentax Forums results in the sharpness tests at 40mm at the borders, here is a new test by ephotozine where they find different results at that focal length.

HD Pentax-DA 20-40mm f/2.8-4 Limited DC WR Lens Review

Gary Wolstenholme reviews the new HD Pentax-DA 20-40mm f/2.8-4 Limited DC WR lens - the first Limited edition zoom lens from Pentax.

www.ephotozine.com

Plakanina · Jan 31, 2014

I agree with this result. At 5.6/40mm sharpness is fantastic. This is a great lens if you are a 5.6/8 kind of photographer like me. I will use my FA43mm if I want out of focus backgrounds.To many reviewers compere this lens with faster huge lenses, this is not a 'fast' lens and it is not huge so I don't understand this comparison obsession. It is rather unique giving classic reportage focal lengths.

afterswish1 · Jan 31, 2014

They didn't really mention the size or weight in the review (although you can find both in the listed specs), and barely noted the weather sealing. Without taking those into account you'd have to agree with their conclusion that it offers poor value.

In a quick search, the closest lens I can find from another manufacturer is the Fujifilm Fujinon XF 18-55mm, f2.8-f4. That had a list price of 600 pounds and is not weather sealed. It's around the same weight and size, has a better zoom range and includes an image stabiliser. Aside from the lack of weather sealing, I think the use of plastics in the construction (as opposed to the metal of the 20-40) indicates the build quality isn't quite as good.

{Edit: I made an error with regards to the weight, they do indeed mention it in the text of the review. Doesn't figure in the conclusions though!}

--
Gravity will make you crazy until you get the hang of it.

leopold · Jan 31, 2014

Looks more of what this lens is capable of, nice review but again the price of the lens is mentioned too much . I think it really depends on what you need/want, for the weight concerned photographer that wants WR and very good IQ there isn't much other choices anyway !

Alex Sarbu · Jan 31, 2014

leopold said:
Looks more of what this lens is capable of, nice review but again the price of the lens is mentioned too much .

And the price is the characteristic most likely to change in time ;-)

leopold said:
I think it really depends on what you need/want, for the weight concerned photographer that wants WR and very good IQ there isn't much other choices anyway !

Alex

Jon Schick · Jan 31, 2014

The other issue unmentioned about that Fuji lens is that it is universally praised for excellent image quality..... Compared to the 20-40 I think it looks rather good value.

MightyMike · Jan 31, 2014

For starters they over saturated the reds in their product photos. Now why does this lens appear to be diffraction limited at F2.8 in the center at 20mm and 30mm?? lenses usually get a bit sharper as you stop down not less sharp. Also at F8 and F11 the center sharpness plateaus in the 20mm and 30mm tests, this appears not to follow the typical curve of lens sharpness vs. diffraction, methinks their F11 results were actually F8.0 results, a reviewers mistake!

Now i agree this is an overpriced lens, a novelty, I'm not saying its not a great performer, but i think people are paying for style over substance with this lens. Unless of course you weigh size, weight and WR over technical results.

klimbkat · Jan 31, 2014

The substance of this review is pretty consistent with my experience - very good to excellent+ results across the range I shoot. Comparisons with larger, non-WR lenses make little sense to me. Even a comparison with the DA* 16-50 misses the mark - these are two very different lenses. There is no question that the DA 20-40 is not for everyone, but for those that want this package of features, reports by users on this forum have been consistently good . . .

leopold · Jan 31, 2014

MightyMike said:
For starters they over saturated the reds in their product photos. Now why does this lens appear to be diffraction limited at F2.8 in the center at 20mm and 30mm?? lenses usually get a bit sharper as you stop down not less sharp. Also at F8 and F11 the center sharpness plateaus in the 20mm and 30mm tests, this appears not to follow the typical curve of lens sharpness vs. diffraction, methinks their F11 results were actually F8.0 results, a reviewers mistake!

Now i agree this is an overpriced lens, a novelty, I'm not saying its not a great performer, but i think people are paying for style over substance with this lens. Unless of course you weigh size, weight and WR over technical results.

flektogon · Jan 31, 2014

klimbkat said:
...There is no question that the DA 20-40 is not for everyone, but for those that want this package of features, reports by users on this forum have been consistently good . . .

leopold · Jan 31, 2014

leopold said:
MightyMike said:

For starters they over saturated the reds in their product photos. Now why does this lens appear to be diffraction limited at F2.8 in the center at 20mm and 30mm?? lenses usually get a bit sharper as you stop down not less sharp. Also at F8 and F11 the center sharpness plateaus in the 20mm and 30mm tests, this appears not to follow the typical curve of lens sharpness vs. diffraction, methinks their F11 results were actually F8.0 results, a reviewers mistake!

Now i agree this is an overpriced lens, a novelty, I'm not saying its not a great performer, but i think people are paying for style over substance with this lens. Unless of course you weigh size, weight and WR over technical results.

Click to expand...

MightyMike · Jan 31, 2014

leopold said:
leopold said:

MightyMike said:

For starters they over saturated the reds in their product photos. Now why does this lens appear to be diffraction limited at F2.8 in the center at 20mm and 30mm?? lenses usually get a bit sharper as you stop down not less sharp. Also at F8 and F11 the center sharpness plateaus in the 20mm and 30mm tests, this appears not to follow the typical curve of lens sharpness vs. diffraction, methinks their F11 results were actually F8.0 results, a reviewers mistake!

Now i agree this is an overpriced lens, a novelty, I'm not saying its not a great performer, but i think people are paying for style over substance with this lens. Unless of course you weigh size, weight and WR over technical results.

Click to expand...

Click to expand...

DAVID MANZE · Jan 31, 2014

Hi,

To be quite honest I'm not interested what a reviewer thinks of a lens I just want to see what the performance charts say, everybody has their own idea of what their needs are and I have mine, the point is here, Pentax Forums said that at 40mm it was soft at the borders and didn't improve much on stopping down and I had great trouble believing them, this review shows it to be absolutely "not" the case, which means the lens is excellent across the frame at all apertures and FLs @F5.6 and above. That is a total game changer!

Funny Pentax Forums gave the lens a better review than Ephotozine in spite of the poor performance they "claim" at the long end. They should have done better seeing as they are supposed to be on the Pentaxians side!

MightyMike · Jan 31, 2014

DAVID MANZE said:
Hi,

To be quite honest I'm not interested what a reviewer thinks of a lens I just want to see what the performance charts say, everybody has their own idea of what their needs are and I have mine, the point is here, Pentax Forums said that at 40mm it was soft at the borders and didn't improve much on stopping down and I had great trouble believing them, this review shows it to be absolutely "not" the case, which means the lens is excellent across the frame at all apertures and FLs @F5.6 and above. That is a total game changer!

Funny Pentax Forums gave the lens a better review than Ephotozine in spite of the poor performance they "claim" at the long end. They should have done better seeing as they are supposed to be on the Pentaxians side!

--
Dave's clichés

Quite possible it sample variation! Also how were the corners tested... IIRC the photozone way is to take the best result across a series of manual focus bracketing therefore showing the best possible sharpness in the corners however if there is field curvature then such results will not show up on a simple flat brick wall test.

--
Mike from Canada
"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."
'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote

'
http://www.michaelfastphotography.com/galleries/VP-BDI_3a.jpg
http://www.airliners.net/search/[email protected]&thumbnails=

DAVID MANZE · Jan 31, 2014

MightyMike said:
DAVID MANZE said:

Hi,

To be quite honest I'm not interested what a reviewer thinks of a lens I just want to see what the performance charts say, everybody has their own idea of what their needs are and I have mine, the point is here, Pentax Forums said that at 40mm it was soft at the borders and didn't improve much on stopping down and I had great trouble believing them, this review shows it to be absolutely "not" the case, which means the lens is excellent across the frame at all apertures and FLs @F5.6 and above. That is a total game changer!

Funny Pentax Forums gave the lens a better review than Ephotozine in spite of the poor performance they "claim" at the long end. They should have done better seeing as they are supposed to be on the Pentaxians side!

Click to expand...

KL Matt · Jan 31, 2014

With gaping holes in the lens lineup made more and more apparent by other, even smaller camera makers (not one single lens faster than f/2.8 under 30mm, for instance) I must say I was hugely disappointed when this lens was announced regardless of the performance. Especially considering that others have demonstrated that it is entirely possible to design and market a 24mm f/1.4 at a similar price.

What in the world are they thinking? This lens is something you release to a large, dedicated user base once all other bases have been covered. Coming out with it now is like a slap in the face to anyone who has been waiting patiently for a fast wide-angle for years now. If you're going to stick to APS-C, you absolutely need a fast 35mm equivalent focal length lens to be taken seriously. And I certainly would not mind a 16mm f/2. Looks like those lenses are simply not in the works, ever. Pentax Ricoh is too busy reduplicating its zoom lineup.

Matt

MightyMike · Jan 31, 2014

DAVID MANZE said:
-- Ok point taken (but at 40mm FOC?) , but with all the testimonies from this forum and elsewhere from people scratching their heads when they're getting sharp borders I would have investigated further before submitting the lens for review and I'm pretty certain you would have done so too, practically no lens struggles at 40mm it's one of the easiest FLs out there.

Dave's clichés

40mm is one of the easiest "prime" focal lengths for a 35mm/APS-C SLR or DSLR camera... when it comes to a zoom you're at the mercy of how the zoom was designed, it could be sharp at the wide and long ends but soft in the middle, it could be just sharp at the wide end and get progressively softer or soft at the wide end and get progressively sharper... or it could be soft at both wide and tele but sharp in the middle. There so many variable in a zoom that the statement about 40mm just won't be right. If PF had no reason to question the lens being bad then they should publish the results, if a lot of people disagree then they should consider testing a different copy of the lens. An then there that thing about field curvature... on a brick wall the corners might be soft on an ever day subject they might not appear that way but careful forensic investigation might show its still soft at the focal plane but sharp in front of the focal plane making it look sharp if one doesn't consider the focal plane.

leopold · Jan 31, 2014

KL Matt said:
With gaping holes in the lens lineup made more and more apparent by other, even smaller camera makers (not one single lens faster than f/2.8 under 30mm, for instance) I must say I was hugely disappointed when this lens was announced regardless of the performance. Especially considering that others have demonstrated that it is entirely possible to design and market a 24mm f/1.4 at a similar price.

What in the world are they thinking? This lens is something you release to a large, dedicated user base once all other bases have been covered. Coming out with it now is like a slap in the face to anyone who has been waiting patiently for a fast wide-angle for years now. If you're going to stick to APS-C, you absolutely need a fast 35mm equivalent focal length lens to be taken seriously. And I certainly would not mind a 16mm f/2. Looks like those lenses are simply not in the works, ever. Pentax Ricoh is too busy reduplicating its zoom lineup.

Matt

viking79 · Jan 31, 2014

MightyMike said:
DAVID MANZE said:

-- Ok point taken (but at 40mm FOC?) , but with all the testimonies from this forum and elsewhere from people scratching their heads when they're getting sharp borders I would have investigated further before submitting the lens for review and I'm pretty certain you would have done so too, practically no lens struggles at 40mm it's one of the easiest FLs out there.

Dave's clichés

Click to expand...

40mm is one of the easiest "prime" focal lengths for a 35mm/APS-C SLR or DSLR camera... when it comes to a zoom you're at the mercy of how the zoom was designed, it could be sharp at the wide and long ends but soft in the middle, it could be just sharp at the wide end and get progressively softer or soft at the wide end and get progressively sharper... or it could be soft at both wide and tele but sharp in the middle. There so many variable in a zoom that the statement about 40mm just won't be right. If PF had no reason to question the lens being bad then they should publish the results, if a lot of people disagree then they should consider testing a different copy of the lens. An then there that thing about field curvature... on a brick wall the corners might be soft on an ever day subject they might not appear that way but careful forensic investigation might show its still soft at the focal plane but sharp in front of the focal plane making it look sharp if one doesn't consider the focal plane

I have seen weirdness from some of their MTF charts at that site as well. Their scales are a bit off saying that f/16 is excellent performance, etc.

The extreme difference in center vs edge performance could be an indicator of field curvature.

I really want to test a copy of this lens now. Someone loan me one for 10 days in the US?

Lens Rentals doesn't have it.

Eric

britcam · Jan 31, 2014

afterswish1 said:
They didn't really mention the size or weight in the review (although you can find both in the listed specs), and barely noted the weather sealing. Without taking those into account you'd have to agree with their conclusion that it offers poor value.

In a quick search, the closest lens I can find from another manufacturer is the Fujifilm Fujinon XF 18-55mm, f2.8-f4. That had a list price of 600 pounds and is not weather sealed. It's around the same weight and size, has a better zoom range and includes an image stabiliser. Aside from the lack of weather sealing, I think the use of plastics in the construction (as opposed to the metal of the 20-40) indicates the build quality isn't quite as good.

{Edit: I made an error with regards to the weight, they do indeed mention it in the text of the review. Doesn't figure in the conclusions though!}

New review of the DA 20-40 F2.8-4

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