DA15 ltd: Have I bought a dud?

ihasa · 08-19-2011, 01:05 PM

I finally relented and got this lens... and what a gem it is. I appreciated from my research that this lens is going to have slightly soft edges at f4, but I think the blurred streak down the right hand border looks... unusual. Is something wrong?

At f8 it's much better and I am thrilled with how the scene is rendered generally, but, having seen the shot above, I can see the same soft border on the right hand side

Lens is brand new etc from a UK retailer, so warranty not a problem if the lens has 'issues'. I just want to gauge whether DA15mm think this is normal or...not! If it's just the 'field curvature' of the lens... I can probably work around it

causey · 08-19-2011, 02:07 PM

I had exactly the same problem with a Sigma 10-20--not the usual kind of border softness, but a rather pronounced band of softness along the left side of the pics, even at f8, between 10mm and 17mm... In your case, the problem is on the right side.
Is the left side of pics taken at f4 with your DA 15mm similarly soft?

imtheguy · 08-19-2011, 02:12 PM

Whether its bad or not, you are unhappy with that copy so I would swap it for a new one for the peace of mind.

causey · 08-19-2011, 02:15 PM

Originally posted by imtheguy

Whether its bad or not, you are unhappy with that copy so I would swap it for a new one for the peace of mind.

Good advice. I returned my Sigma. (I'll get another one soon.)

hcc · 08-19-2011, 02:49 PM

Originally posted by imtheguy

Whether its bad or not, you are unhappy with that copy so I would swap it for a new one for the peace of mind.

+1 with imtheguy

ihasa · 08-19-2011, 03:02 PM

Originally posted by causey

Is the left side of pics taken at f4 with your DA 15mm similarly soft?

I think the left side is a little soft but probably within what you would expect at wide open aperture - i.e. not really that noticeable unless you pixel peep. But on the right hand side, it looks like someone's smeared a greasy finger down the border of the picture. I think I will send it back, fortunately I had the fore-sight to buy it from a reputable retailer.

zany225 · 08-19-2011, 05:48 PM

Did you put any filter on the 15mm? Just curious.

ihasa · 08-20-2011, 03:44 AM

No, it was fresh out of the box. Looking at some pics taken today, it is actually soft at both sides at f4, slightly worse on the right. I need to get out and take more real life shots before deciding what to do.

Raffwal · 08-20-2011, 04:47 AM

Wide open it IS soft outside the center.

Photozone

ihasa · 08-20-2011, 06:27 AM

I was expecting softer edges at f4, but not quite such a sudden drop off. (The measurements are still in 'good' territory at f4). Ah well... I'll continue to put it through it's paces... at f8 it certainly catches up at the edges and has a subtle punch that my sigma 10-20m lacks.

KxBlaze · 08-21-2011, 03:27 PM

It does not look like a problem to me but like others have said if it bothers you I would return it for a new copy. Thats why we have warranties and it should give you peace of mind.

tibbitts · 08-24-2011, 07:54 PM

I don't think you need more "real life" testing; you need more accurate testing. Try photographing the same object (high contrast letters on a sign, for example) and, without changing the (manual) focus, place the object at the extreme of every side and each corner of the image. Obviously use a tripod (or at least use very, very high shutter speeds, or flash) and have the SR off. Make several tests. Since you apparently have the 10-20mm as well, make the same tests with it, and for optimal results, mix them up (or have someone else mix them up) so you don't know when you're looking at them which lens took which picture.

Paul

twitch · 08-24-2011, 07:58 PM

We've got no idea what was the point of focus in either photo, so it's pretty hard to make any judgement to be honest.

08-19-2011, 01:05 PM	#1
ihasa Veteran Member Join Date: Jul 2009 Location: West Midlands Photos: Gallery Posts: 2,066	DA15 ltd: Have I bought a dud? I finally relented and got this lens... and what a gem it is. I appreciated from my research that this lens is going to have slightly soft edges at f4, but I think the blurred streak down the right hand border looks... unusual. Is something wrong? At f8 it's much better and I am thrilled with how the scene is rendered generally, but, having seen the shot above, I can see the same soft border on the right hand side Lens is brand new etc from a UK retailer, so warranty not a problem if the lens has 'issues'. I just want to gauge whether DA15mm think this is normal or...not! If it's just the 'field curvature' of the lens... I can probably work around it

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08-19-2011, 02:07 PM	#2
causey Veteran Member Join Date: Feb 2009 Location: Arlington, VA Photos: Albums Posts: 3,757	I had exactly the same problem with a Sigma 10-20--not the usual kind of border softness, but a rather pronounced band of softness along the left side of the pics, even at f8, between 10mm and 17mm... In your case, the problem is on the right side. Is the left side of pics taken at f4 with your DA 15mm similarly soft?

08-19-2011, 02:12 PM	#3
imtheguy Site Supporter Join Date: Mar 2009 Location: Virginia Beach Photos: Gallery \| Albums Posts: 2,950	Whether its bad or not, you are unhappy with that copy so I would swap it for a new one for the peace of mind.

08-19-2011, 02:15 PM	#4
causey Veteran Member Join Date: Feb 2009 Location: Arlington, VA Photos: Albums Posts: 3,757	Originally posted by imtheguy Whether its bad or not, you are unhappy with that copy so I would swap it for a new one for the peace of mind. Good advice. I returned my Sigma. (I'll get another one soon.)

08-19-2011, 02:49 PM	#5
hcc Pentaxian Join Date: Nov 2009 Location: Brisbane, Australia Photos: Gallery \| Albums Posts: 4,005	Originally posted by imtheguy Whether its bad or not, you are unhappy with that copy so I would swap it for a new one for the peace of mind. +1 with imtheguy

08-19-2011, 03:02 PM	#6
ihasa Veteran Member Join Date: Jul 2009 Location: West Midlands Photos: Gallery Posts: 2,066 Original Poster	Originally posted by causey Is the left side of pics taken at f4 with your DA 15mm similarly soft? I think the left side is a little soft but probably within what you would expect at wide open aperture - i.e. not really that noticeable unless you pixel peep. But on the right hand side, it looks like someone's smeared a greasy finger down the border of the picture. I think I will send it back, fortunately I had the fore-sight to buy it from a reputable retailer.

08-19-2011, 05:48 PM	#7
zany225 Senior Member Join Date: Nov 2010 Location: Corvallis, OR Photos: Albums Posts: 247	Did you put any filter on the 15mm? Just curious.

08-20-2011, 03:44 AM	#8
ihasa Veteran Member Join Date: Jul 2009 Location: West Midlands Photos: Gallery Posts: 2,066 Original Poster	No, it was fresh out of the box. Looking at some pics taken today, it is actually soft at both sides at f4, slightly worse on the right. I need to get out and take more real life shots before deciding what to do.

08-20-2011, 04:47 AM	#9
Raffwal Veteran Member Join Date: Oct 2010 Location: The North Posts: 879	Wide open it IS soft outside the center. Photozone

08-20-2011, 06:27 AM	#10
ihasa Veteran Member Join Date: Jul 2009 Location: West Midlands Photos: Gallery Posts: 2,066 Original Poster	I was expecting softer edges at f4, but not quite such a sudden drop off. (The measurements are still in 'good' territory at f4). Ah well... I'll continue to put it through it's paces... at f8 it certainly catches up at the edges and has a subtle punch that my sigma 10-20m lacks.

08-21-2011, 03:27 PM	#11
KxBlaze Veteran Member Join Date: Feb 2010 Location: California Photos: Gallery Posts: 1,602	It does not look like a problem to me but like others have said if it bothers you I would return it for a new copy. Thats why we have warranties and it should give you peace of mind.

08-24-2011, 07:54 PM	#12
tibbitts Pentaxian Join Date: Apr 2007 Location: Oklahoma USA Posts: 2,196	I don't think you need more "real life" testing; you need more accurate testing. Try photographing the same object (high contrast letters on a sign, for example) and, without changing the (manual) focus, place the object at the extreme of every side and each corner of the image. Obviously use a tripod (or at least use very, very high shutter speeds, or flash) and have the SR off. Make several tests. Since you apparently have the 10-20mm as well, make the same tests with it, and for optimal results, mix them up (or have someone else mix them up) so you don't know when you're looking at them which lens took which picture. Paul

08-24-2011, 07:58 PM	#13
twitch Veteran Member Join Date: Nov 2009 Posts: 4,571	We've got no idea what was the point of focus in either photo, so it's pretty hard to make any judgement to be honest.