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04-07-2009, 08:09 PM   #31
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offhand, I would judge the DA14mm f/2.8 to be the sharper of the two in that test scenario. but the sharpness of the corners is what I'm really interested in, and I suspect the DA15mm limited should be able to deliver the goods, considering it is an f/4 lens.

04-07-2009, 08:15 PM   #32
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QuoteOriginally posted by jamesk8752 Quote
Actually, what I said was that the DA15 was not as sharp wide open as the DA14, but that the DA15 was *much* smaller and lighter, thus a better lens for use on my K-m. I also said that I think both lenses have their uses and I expect to keep and use both.
didn't realize you were a member here jim.
i should have just linked directly to your post, sorry for the misquote.

Last edited by k100d; 04-07-2009 at 09:15 PM.
04-07-2009, 08:53 PM   #33
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QuoteOriginally posted by Digitalis Quote
offhand, I would judge the DA14mm f/2.8 to be the sharper of the two in that test scenario. but the sharpness of the corners is what I'm really interested in, and I suspect the DA15mm limited should be able to deliver the goods, considering it is an f/4 lens.
The DA14 is indeed the sharper of the two, even in the corners, but the DA15 shows less distortion. This test scene is a brick wall at about 1 meter, DA15 vs. DA14 at f4 on my K-m on a tripod, center and upper right edge crops at 100%, no PP:



Again, this is pixel-peeping; at reasonable image sizes both lenses perform very well.
04-07-2009, 10:45 PM   #34
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Thanks Jim for sharing your pics with us.

I learned when I received my DA15 last week that I have to put the AF adjustment of my K20D to +10 to receive correct AF sharp pics. My K20D also needs +10 for my DA*55 since a few weeks. Thomas (you see his test work in the other DA15 thread as user tzcobretti has the same fact. He gave his K20D last month to Pentax service and now his DA lenses work perfect at +-0 adjustment) After my hiking trip to scotland next month I will send my camera to the service too.

To receive a reallistic meaning of the ground sharpness of a lens, you have to fokus manuell. All other results are only results of the AF adjustment of you indivuduell camera. Give it a try and send your camera to service too and you will be surprised of the performance of your lenses.

Rainer

04-07-2009, 11:49 PM   #35
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Strange. Too mixed results with DA15:
Worse than DA14,
Better than DA14.
Close to non-expensive zoom.
Sharp.
Very sharp.
04-07-2009, 11:56 PM   #36
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QuoteOriginally posted by jamesk8752 Quote
The DA14 is indeed the sharper of the two, even in the corners, but the DA15 shows less distortion. This test scene is a brick wall at about 1 meter, DA15 vs. DA14 at f4 on my K-m on a tripod, center and upper right edge crops at 100%, no PP:



Again, this is pixel-peeping; at reasonable image sizes both lenses perform very well.
DA14 is good ultra-wide lens, but not the best.
2178/2009 LW/PH at f8 is not bad. I'd like to see DA15 in the same league.

If DA15 is worse than DA14, it's failure for me.
I'd like to see at K10D at least 2150/2000 LW/PH (center/corner) at f5.6-8.

If DA15 can't reach such resolution, I'm not sure that I need to to buy such LIMITED lens for 700-800 EURO.
04-07-2009, 11:59 PM   #37
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Sigma 10-20 is one of the best ultra-wide zoom.
http://www.photozone.de/images/8Reviews/lenses/sigma_1020_456_pentax/mtf.gif
04-08-2009, 03:47 AM   #38
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QuoteOriginally posted by jamesk8752 Quote
The DA14 is indeed the sharper of the two, even in the corners, but the DA15 shows less distortion. This test scene is a brick wall at about 1 meter, DA15 vs. DA14 at f4 on my K-m on a tripod, center and upper right edge crops at 100%, no PP:



Again, this is pixel-peeping; at reasonable image sizes both lenses perform very well.

forme the difference is deep....if we saw a lens performance at 4*6 inch size reproduction i think there wouldbe no needs for pricy lenses.
100 crop gives us a good measure of the performance of a lens.
the 15 has many many plus i have to say and it's a very interesting lens. Next month i'll build up an entire set of prime from pentax and this is a lens i'm interested a lot.
But looking a your samples the performance wide open is poor.
i have seen also the thk'samples and they look a lot better. so i hpe to see more samples. But corner sharpnes is clearl a problem wih this lens

04-08-2009, 04:38 AM   #39
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QuoteOriginally posted by ogl Quote
But not as good as the Pentax DA12-24 based on their tests and others.

Lots of contradictory evidence here regarding the DA15. Hopefully the dust will settle.
04-08-2009, 08:44 AM   #40
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Wow....

QuoteOriginally posted by jamesk8752 Quote
Actually, what I said was that the DA15 was not as sharp wide open as the DA14, but that the DA15 was *much* smaller and lighter, thus a better lens for use on my K-m. I also said that I think both lenses have their uses and I expect to keep and use both.

Unless you are pixel peeping at 100% the DA15 is perfectly satisfactory IMO. Here are comparison shots at f4 (taken a day apart), using a tripod, at about 35 meters distance on my K-m, no PP:

DA14@f4, 100% crop, center:

DA15@f4, 100% crop, center:

Regards, Jim
QuoteOriginally posted by nulla Quote
Thats quite a difference in sharpness. It actually seems out of focus by comparison
Yeah, that seems pretty lame to me, too. Maybe the person below is onto something...

QuoteOriginally posted by TKH Quote
Thanks Jim for sharing your pics with us.

I learned when I received my DA15 last week that I have to put the AF adjustment of my K20D to +10 to receive correct AF sharp pics. My K20D also needs +10 for my DA*55 since a few weeks. Thomas (you see his test work in the other DA15 thread as user tzcobretti has the same fact. He gave his K20D last month to Pentax service and now his DA lenses work perfect at +-0 adjustment) After my hiking trip to scotland next month I will send my camera to the service too.

To receive a reallistic meaning of the ground sharpness of a lens, you have to fokus manuell. All other results are only results of the AF adjustment of you indivuduell camera. Give it a try and send your camera to service too and you will be surprised of the performance of your lenses.

Rainer
It's a great thing that they have implemented this feature, but I don't understand why we need it now, when we have had autofocus cameras since the 80's that didn't need this feature. Has comething recently changed?

QuoteOriginally posted by rparmar Quote
But not as good as the Pentax DA12-24 based on their tests and others.

Lots of contradictory evidence here regarding the DA15. Hopefully the dust will settle.
Yeah, something up with that lens. It does do the 3D effect really well and the bokeh is incredible from the samples I've seen, but the lack of sharpness in these shots is very troubling.

Have you done the focus adjustment on your camera, James? Just wondering...seems odd that Pentax would release a very expensive specialized optic with the limited badge on it like this.

Cheers,
Cameron
04-08-2009, 09:09 AM   #41
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QuoteOriginally posted by rparmar Quote
Lots of contradictory evidence here regarding the DA15. Hopefully the dust will settle.
I think it will, Robin, as more examples get in peoples' hands and we see a larger selection of results. Also,it's possible that these early production samples may not represent performance of the lens once production matures and small design changes are incorporated; while I have no idea that such is the case with the DA 15, it certainly isn't unusual to see uneven QC during early production of almost anything from cars to thermoplastics.

Anyway, I very much want this lens, so I'll be watching with interest.

Jer
04-08-2009, 09:51 AM   #42
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QuoteOriginally posted by Cambo Quote
It's a great thing that they have implemented this feature, but I don't understand why we need it now, when we have had autofocus cameras since the 80's that didn't need this feature. Has comething recently changed?
Yes - ordinary people started viewing pictures at enormous sizes. Pixel peeping on a K20D at 100% works out to the equivalent of at least 10x15" but probably actually larger (depending on what you believe the most appropriate equivalence in resolution between film prints and digital prints to be). How many people were printing posters from their 80's-era film cameras? And how many of those folks were trusting AF when doing so (many pros rejected AF for years, of course)?
04-08-2009, 10:21 AM   #43
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Tried some real life shots today

f4.0


f4.5


f5.0




These pics show me that the DA15 correction is nearly perfect for architecture shots (please note that the church wall is round!):

f 5.6



One for our CA hunting friends:

f4.0


And the crop (done no CA correction!:

f5.0



Resolution for a 15mm is great imho:
f5.6







Rainer

Last edited by TKH; 04-08-2009 at 12:09 PM.
04-08-2009, 10:59 AM   #44
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Nice shots there Rainer. The lens looks to be performing perfectly. At that size I can see a tad more detail stopped down, but that is nitpicking (and expected of any lens).
04-08-2009, 11:04 AM   #45
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QuoteOriginally posted by TKH Quote
Thanks Jim for sharing your pics with us.

I learned when I received my DA15 last week that I have to put the AF adjustment of my K20D to +10 to receive correct AF sharp pics. My K20D also needs +10 for my DA*55 since a few weeks. Thomas (you see his test work in the other DA15 thread as user tzcobretti has the same fact. He gave his K20D last month to Pentax service and now his DA lenses work perfect at +-0 adjustment) After my hiking trip to scotland next month I will send my camera to the service too.

To receive a reallistic meaning of the ground sharpness of a lens, you have to fokus manuell. All other results are only results of the AF adjustment of you indivuduell camera. Give it a try and send your camera to service too and you will be surprised of the performance of your lenses.

Rainer
LOL! My K20D is at Pentax in Colorado for service as I write this, because of poor focusing accuracy with my DA*55.

However, these shots were made using my K-m, which has no AF adjustment in software. I've checked its autofocusing accuracy with the DA15 using Tim Jackson's chart, and it's spot-on as far as I can tell. I do agree that careful manual focusing with an eyepiece magnifier is the best way to go for critical testing, and I'll try this with my DA15 when I have some more time (it's income tax week at my house right now).

Here's a test shot using the DA15 @ f5.6, resized to 1024x685 pixels to compare to Rainer's indoor church shot. I applied a little sharpening after I resized it, and I think it looks comparable for sharpness even in the corners. Note the low amount of geometric distortion - the DA15 is superior to the DA14 in this regard.

Edit: It looks like the Forum SW resized my image downwards so it isn't as crisp as when viewed at 1024x685 on pBase: http://www.pbase.com/image/111091007 - sorry!



Regards, Jim

Last edited by jamesk8752; 04-08-2009 at 07:56 PM.
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