Weird swirl pattern inside lens

djam · 08-17-2013, 01:45 PM

Can anyone tell me what this swirl pattern is?

Attached Images

Na Horuk · 08-17-2013, 02:01 PM

Kinds looks a lot like a finger print. Cant wipe it off? Could be some oil residue

**Kerrowdown** · 08-17-2013, 02:25 PM

It looks a bit like it could be the dreaded fungus.

Pablom · 08-17-2013, 02:27 PM

Looks like you are showing off your nifty fifty

EarlVonTapia · 08-17-2013, 02:43 PM

I had a lens with what looks like the same condition as your lens:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/219686-swirly-...r-element.html

I think it was a case of eroded lens coatings:

http://www.techarp.com/showarticle.aspx?artno=194&pgno=6

I don't think much can be done about it, but it didn't really affect the IQ of the lens. The only thing was that it made flare even worse, but a hood eliminated it completely.

djam · 08-17-2013, 03:00 PM

It is definitely on the inside of the lens, and it has no effect on IQ. I think I'll go with the suggestion of lens coating coming off.

DavidM · 08-22-2013, 03:29 PM

Originally posted by djam

It is definitely on the inside of the lens, and it has no effect on IQ. I think I'll go with the suggestion of lens coating coming off.

I have a very similar looking thing in my 100mm f4 macro, though not as visible, and I am told by an experienced Pentax lens repairer that it is element separation, or particularly failure of the compound used to secure two elements of a group together. It's not an adhesive as such, apparently a balsam based material.

It is repairable, (at a cost that may make it not worth while), but means separating the two elements using heat, and then re-assembling, after cleaning in a really clean environment.

David

arsn.r3d · 08-22-2013, 03:59 PM

Originally posted by djam

It is definitely on the inside of the lens, and it has no effect on IQ. I think I'll go with the suggestion of lens coating coming off.

Yeah it does kinda look like degradation of the coating. Had a similar issue with a Kiron lens before...I don't remember it affecting IQ much, the thing to look for though is in the bright bokeh highlights (eg. let's say christmas lights in the BG). I remember the exact same pattern from the lens coating would replicate in every single one of the highlights.

borno · 08-22-2013, 04:42 PM - **1 Like**

Looks like fungus to me.

Paleo Pete · 08-23-2013, 12:36 PM

The cement used is Canadian Balsam. Also used to cement binocular lenses together, which is why I know about it, I repaired them in the military. It's applied and removed by heat, I can't remember how hot but above car trunk in Texas temp and below making pancakes...anyway it's not cheap, mainly because it has to be done in a very clean environment, almost a white room, and the lenses have to be well centered with each other after finishing, which took me 4 tries my first time. And specialized equipment is required to do the alignment. Fortunately I didn't have to do a 3 lens eyelens element, just a 2 lens objective lens.

djam · 08-23-2013, 12:51 PM

Thanks Paleo. I haven't noticed any trouble with image quality, but I did notice some flare when I tested for that, but as long as its not fungus and the images are sharp I am not going to worry about it.

scratchpaddy · 08-23-2013, 01:00 PM

I'll throw in another vote for coating failure, and you're right to not worry about it. It takes a lot more to ruin a lens than most people realize. Take a look at this thread:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/231454-guess-lens.html

Or this one:

https://www.pentaxforums.com/forums/lens-clubs/40521-dead-lens-club.html

djam · 08-23-2013, 01:50 PM

That is great info. Thanks for sharing.

08-17-2013, 01:45 PM	#1
djam Forum Member Join Date: May 2013 Photos: Albums Posts: 81	Weird swirl pattern inside lens Can anyone tell me what this swirl pattern is? Attached Images

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08-17-2013, 02:01 PM	#2
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Kinds looks a lot like a finger print. Cant wipe it off? Could be some oil residue

08-17-2013, 02:25 PM	#3
Kerrowdown PEG Moderator Join Date: Aug 2008 Location: Highlands of Scotland... "Hold Infinity in the palm of your hand" - William Blake Photos: Gallery Posts: 57,867	It looks a bit like it could be the dreaded fungus.

08-17-2013, 02:27 PM	#4
Pablom Veteran Member Join Date: Feb 2010 Location: Usa Posts: 1,940	Looks like you are showing off your nifty fifty

08-17-2013, 02:43 PM	#5
EarlVonTapia Veteran Member Join Date: Oct 2012 Location: Vancouver Photos: Gallery Posts: 1,207	I had a lens with what looks like the same condition as your lens: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/219686-swirly-...r-element.html I think it was a case of eroded lens coatings: http://www.techarp.com/showarticle.aspx?artno=194&pgno=6 I don't think much can be done about it, but it didn't really affect the IQ of the lens. The only thing was that it made flare even worse, but a hood eliminated it completely.

08-17-2013, 03:00 PM	#6
djam Forum Member Join Date: May 2013 Photos: Albums Posts: 81 Original Poster	It is definitely on the inside of the lens, and it has no effect on IQ. I think I'll go with the suggestion of lens coating coming off.

08-22-2013, 03:29 PM	#7
DavidM New Member Join Date: Aug 2013 Posts: 2	Originally posted by djam It is definitely on the inside of the lens, and it has no effect on IQ. I think I'll go with the suggestion of lens coating coming off. I have a very similar looking thing in my 100mm f4 macro, though not as visible, and I am told by an experienced Pentax lens repairer that it is element separation, or particularly failure of the compound used to secure two elements of a group together. It's not an adhesive as such, apparently a balsam based material. It is repairable, (at a cost that may make it not worth while), but means separating the two elements using heat, and then re-assembling, after cleaning in a really clean environment. David

08-22-2013, 03:59 PM	#8
arsn.r3d Veteran Member Join Date: Oct 2011 Photos: Gallery \| Albums Posts: 303	Originally posted by djam It is definitely on the inside of the lens, and it has no effect on IQ. I think I'll go with the suggestion of lens coating coming off. Yeah it does kinda look like degradation of the coating. Had a similar issue with a Kiron lens before...I don't remember it affecting IQ much, the thing to look for though is in the bright bokeh highlights (eg. let's say christmas lights in the BG). I remember the exact same pattern from the lens coating would replicate in every single one of the highlights.

08-22-2013, 04:42 PM - 1 Like	#9
borno Veteran Member Join Date: Nov 2006 Location: md-usa Photos: Gallery \| Albums Posts: 2,580	Looks like fungus to me.

08-23-2013, 12:36 PM	#10
Paleo Pete Veteran Member Join Date: Jun 2010 Location: Texas Photos: Gallery \| Albums Posts: 2,880	The cement used is Canadian Balsam. Also used to cement binocular lenses together, which is why I know about it, I repaired them in the military. It's applied and removed by heat, I can't remember how hot but above car trunk in Texas temp and below making pancakes...anyway it's not cheap, mainly because it has to be done in a very clean environment, almost a white room, and the lenses have to be well centered with each other after finishing, which took me 4 tries my first time. And specialized equipment is required to do the alignment. Fortunately I didn't have to do a 3 lens eyelens element, just a 2 lens objective lens.

08-23-2013, 12:51 PM	#11
djam Forum Member Join Date: May 2013 Photos: Albums Posts: 81 Original Poster	Thanks Paleo. I haven't noticed any trouble with image quality, but I did notice some flare when I tested for that, but as long as its not fungus and the images are sharp I am not going to worry about it.

08-23-2013, 01:00 PM	#12
scratchpaddy Pentaxian Join Date: Feb 2013 Location: Phoenix Posts: 3,361	I'll throw in another vote for coating failure, and you're right to not worry about it. It takes a lot more to ruin a lens than most people realize. Take a look at this thread: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/231454-guess-lens.html Or this one: https://www.pentaxforums.com/forums/lens-clubs/40521-dead-lens-club.html

08-23-2013, 01:50 PM	#13
djam Forum Member Join Date: May 2013 Photos: Albums Posts: 81 Original Poster	That is great info. Thanks for sharing.