[Recercare]

How is the DA 21?
I know they are two very different lenses, but both can be used for landscapes. According to Photozone it seems like DA 21 improves faster in the corners as you stop down.

Kind regards
.lars

[Marc Sabatella]

Actually, the 15 is somewhat soft in the corners, even taking field curvature into account. It doesn't mean I love it any less, it is just a characteristic of the lens.

"Somewhat" indeed, but not to the extent that one might think from brick wall tests.

And in any event, again, whatever softness might exist in the corners is there omly until only until you stop down, at which point it *measurably* meets or beats all comers as reported by photozone and verified in countless posted sample i,ages. And thus the claim that it is not adequate for "scenery" * - which would virtually always be shot stopped down amyhow to get more DOF - just doesn't match reality.

Plus, of course, if you don't stop down, with a wide angle lens the corners will only very rarely be in focus, so the corner performance ends ip being pretty irrelevamt.

* Unless by "scenery", he really mean stage prop backgrounds, which might indeed be perfectly flat, and shot under relatively low light that might otherwise encourage shooting wide open, at least if you have to shoot it handheld for some reason. Basically, a brick wall, except probbaly made of wood and painted to look like a brick wall. In that case, the field curvature as well as the corner softness will come into play. So indeed, the DA15 is not the ideal brick-wall-shot-handheld-under-poor-light lens, but that's about the worst you can say about it.

[wlachan]

Just show me one full size DA15 shot which is sharp corner to corner.

[selar]

Just show me one full size DA15 shot which is sharp corner to corner.

According to Photozone, the Canon EF - S 10-22 exhibits the same weak corner performance. Show me an ultrawide that has the corner performance close to center performance when wide open or even before f8.

Attached Images

   

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Last edited by selar; 05-15-2012 at 04:57 PM.

[Wheatfield]

"Somewhat" indeed, but not to the extent that one might think from brick wall tests.

Well yes, no lens with significant field curvature will have good corners in a brick wall test, unless the wall is curved to match the lens FOV.

And in any event, again, whatever softness might exist in the corners is there omly until only until you stop down, at which point it *measurably* meets or beats all comers as reported by photozone and verified in countless posted sample i,ages. And thus the claim that it is not adequate for "scenery" * - which would virtually always be shot stopped down amyhow to get more DOF - just doesn't match reality.

Plus, of course, if you don't stop down, with a wide angle lens the corners will only very rarely be in focus, so the corner performance ends ip being pretty irrelevamt.

* Unless by "scenery", he really mean stage prop backgrounds, which might indeed be perfectly flat, and shot under relatively low light that might otherwise encourage shooting wide open, at least if you have to shoot it handheld for some reason. Basically, a brick wall, except probbaly made of wood and painted to look like a brick wall. In that case, the field curvature as well as the corner softness will come into play. So indeed, the DA15 is not the ideal brick-wall-shot-handheld-under-poor-light lens, but that's about the worst you can say about it.

I just has a look at some more of what I've shot with the 15, I stand corrected. I've got a few shots from it that are definitely corner soft, but they seem to be outliers, not sure why, but there is some smearing in the corners. They were also the first shots that I looked at with any particular eye for corner sharpness.

[wlachan]

According to Photozone, the Canon EF - S 10-22 exhibits the same weak corner performance. Show me an ultrawide that has the corner performance close to center performance when wide open or even before f8.

I am quite aware of the PZ tests and also checkout their actual samples. Regardless of what their actual figures are (which don't take field curvature into account), the samples are what matters the most. In the cases of Pentax DA14/15, all their samples have poor edge/corners sharpness which are the result of severe field curvature. Usually field curvature can be workaround by stopping down and focus slightly farther, but obviously the DA14 is beyond help (after owning 3 brand new copies). Perhaps the DA15 still has hope. Just to be fair, you can checkout my full size pics below from my own EF-S 10-22 & 40D (LR standard sharpness). Now, who is going to show me theirs?

EF-S 10-22mm Sharpness Photo Gallery by Alan Chan at pbase.com

[Weber]

I own the DA 21, and I initially felt let down by the seemingly soft corners (they are more or less like the DA15 shot the OP showed here, maybe a touch softer still).

However, when I started making large prints (larger than 20", some up to 25" wide), I immediately shut up and stopped complaining. The amount of corner softness from the lens wasn't even perceptible in the print, even when viewed close up.

We need to stop pixel-peeping, I think. It does not tell us much about how prints will look.

[selar]

my full size pics below from my own EF-S 10-22 & 40D (LR standard sharpness). Now, who is going to show me theirs?

Hardly full size, impossible to judge sharpness from those pint sized images.

[selar]

https://public.sn2.livefilestore.com/y1papR_8NdGRu6JqpXi0tN3G793UdONSaiklrF8...Bay.jpg?psid=1

Heres a full sized original from my DA15LTD and K-x, pretty happy with it for a hand held shot!

[wombat2go]

Selar,
A decent pixel size for my Eizo.
But ... corner sharpness..?? ...it is focussed on the front of the rock..??

[wlachan]

Hardly full size, impossible to judge sharpness from those pint sized images.

I take that you should be smarter than this so I will give you another chance checking them out.

Selar,
A decent pixel size for my Eizo.
But ... corner sharpness..?? ...it is focussed on the front of the rock..??

EXIF indicates focus is DISTANT so the focus cannot be on the rocks at the bottom. My impression is that the pic was not sharp to begin with, but was made to appear sharp by heavy sharpening (as indicated by EXIF). This explains the smear effect and the lack of fine details.

[selar]

I take that you should be smarter than this so I will give you another chance checking them out.

I clicked on the thumbnail and got a slightly bigger size that doesnt more than half my screen. Why dont you put up full size jpgs on cloud storage so we can compare apples with apples?

made to appear sharp by heavy sharpening

Like you, I also applied the default smart sharpen settings in CS5.No adjustment to any sliders. Lets put up raw images and settle this sharpening argument.

[selar]

.it is focussed on the front of the rock..??

Focused to center point. I learnt long ago that taking brick wall shots at wide apertures with ultrawides leads to nothing but grief.

[wlachan]

I clicked on the thumbnail and got a slightly bigger size that doesnt more than half my screen. Why dont you put up full size jpgs on cloud storage so we can compare apples with apples?

The full size 10MP files are all there.

Like you, I also applied the default smart sharpen settings in CS5.No adjustment to any sliders. Lets put up raw images and settle this sharpening argument.

It's not a competition and RAW is out of the question, sorry. Mine were converted by LR with default sharpening and nothing else. From what I can tell from EXIF, yours seems to be straight camera jpeg w/o going through PS (explains the typical Pentax in-camera PP which is heavy on sharpening but weak on detail).

[selar]

The full size 10MP files are all there.

Wow that Canon lens is exhibiting some heavy CA! And the distortion in the corners! The purple pink clouds!

IMG_0409.jpg photo - Alan Chan photos at pbase.com

Thank you for deepening my appreciation of the worth of the DA 15!