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**Just1MoreDave** · 01-29-2009, 01:59 PM

I took a chance on a broken Pentax-M 40mm f2.8 pancake. I fixed the focus problem by straigtening the focus ring, adjusting infinity and tightening the screws. I replaced the lost tiny bearing that makes the aperture ring click - 1.5mm fits great, BTW. I was able to disassemble the rear elements without any drama. But I couldn't fix this:

Oh well, it's probably not too bad in the center.

**Rense** · 01-29-2009, 02:15 PM

Well, post-just-one-picture-more-Dave, which you made with this one. I'm curious what will come out of it.....

elkarrde · 01-29-2009, 02:46 PM

Originally posted by Just1MoreDave

Oh well, it's probably not too bad in the center.

you can send that lens to me, i will scientifically inspect how this defect affects IQ on both APS-C and FF, and some form of measurebations.

Nick Siebers · 01-29-2009, 06:39 PM

Early into my shooting with a K1000 I had a M 100 f/4 macro, with which pictures never came out right - cloudy, little contrast, a lot of flare. Eventually I realized it had element seperation. With a hood and away from a light source, it did pretty well, but I eventually sold it on eBay (with full disclosure!) after getting a Tamron 90mm. Of course that lens is pretty sweet to begin with ... not sure how this M40 will fair.

Damn Brit · 01-29-2009, 06:50 PM

Send it to Jsherman999, he'll get great pictures out of it. He got a picture accepted to PPG and it was taken with a cardboard tube from a roll of toilet paper that had a magnifying glass glued to it.

VF-19 · 01-29-2009, 07:10 PM

Quick question: Is it possible to repair the lens when the elements begin to separate? I have an old Soligor 28mm 2.8 M42 mount that's showing that exact same thing behind the front element, and I'd like to get it fixed...

Vylen · 01-29-2009, 07:33 PM

Originally posted by Damn Brit

Send it to Jsherman999, he'll get great pictures out of it. He got a picture accepted to PPG and it was taken with a cardboard tube from a roll of toilet paper that had a magnifying glass glued to it.

now im curious, what picture is that?

**Just1MoreDave** · 01-29-2009, 09:19 PM

Originally posted by VF-19

Quick question: Is it possible to repair the lens when the elements begin to separate? I have an old Soligor 28mm 2.8 M42 mount that's showing that exact same thing behind the front element, and I'd like to get it fixed...

It should be possible. Some solvent to get the elements apart, cleaning, then recementing. How hard can it be? Of course the cement needs to be something that won't alter the optical properties of the lens. The lens coatings need to be intact. It needs to end up with no air bubbles and be a consistent thickness. The lenses need to maintain their alignment. It's like a lot of lens repairs - either you pay someone a lot of money or wing it yourself.

Nick Siebers · 01-29-2009, 09:27 PM

My local camera repair place wouldn't do it. They said chuck it, or use it how it is. I think it would be very hard or very expensive to repair.

graphicgr8s · 01-29-2009, 09:46 PM

On How It's Made they showed how the elements are glued together using a special glue that doesn't distort. Pretty interesting how it's done.

Vylen · 01-29-2009, 09:50 PM

Originally posted by graphicgr8s

On How It's Made they showed how the elements are glued together using a special glue that doesn't distort. Pretty interesting how it's done.

Oh yea... i remember that... and how it's massaged in and all that.... so much care is put into it..

Asahiflex · 01-29-2009, 11:13 PM

Maybe you can try to remove the back group and put the lens in a bucket of water which you warm up very slowly (as in a couple of hours), gradually reaching the boiling point of water. This can make the glue soft again; maybe it will melt enough to get rid of the problem.

But only do this at your own risk of course

awo425 · 01-30-2009, 08:38 AM

Just keep it and wait, eventually somebody will be selling the same lens with nicked front element and good back element on FLEEBAY, so you can make one good lens out of 2.

wildlifephotog · 01-30-2009, 09:42 AM

Lens repair is within the realm of DIY. I know how many that have used the UV cured products like listed here.
Summers Optical: Optical Cements, Structural Adhesives, and Cementing Supplies for Military and Commercial Applications

**Just1MoreDave** · 01-30-2009, 11:06 AM

Originally posted by Rense

Well, post-just-one-picture-more-Dave, which you made with this one. I'm curious what will come out of it.....

OK, here's one. I think this was f5.6, at the minimum focus distance.

01-29-2009, 01:59 PM	#1
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	The heartbreak of... element separation I took a chance on a broken Pentax-M 40mm f2.8 pancake. I fixed the focus problem by straigtening the focus ring, adjusting infinity and tightening the screws. I replaced the lost tiny bearing that makes the aperture ring click - 1.5mm fits great, BTW. I was able to disassemble the rear elements without any drama. But I couldn't fix this: Oh well, it's probably not too bad in the center.

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01-29-2009, 02:15 PM	#2
Rense Site Supporter Join Date: Dec 2008 Location: Zetten - The Netherlands Photos: Gallery \| Albums Posts: 9,050	Well, post-just-one-picture-more-Dave, which you made with this one. I'm curious what will come out of it.....

01-29-2009, 02:46 PM	#3
elkarrde Veteran Member Join Date: Oct 2008 Location: Zagreb, Croatia Posts: 387	Originally posted by Just1MoreDave Oh well, it's probably not too bad in the center. you can send that lens to me, i will scientifically inspect how this defect affects IQ on both APS-C and FF, and some form of measurebations.

01-29-2009, 06:39 PM	#4
Nick Siebers Veteran Member Join Date: Jun 2008 Location: Madison, WI Photos: Gallery \| Albums Posts: 2,165	Early into my shooting with a K1000 I had a M 100 f/4 macro, with which pictures never came out right - cloudy, little contrast, a lot of flare. Eventually I realized it had element seperation. With a hood and away from a light source, it did pretty well, but I eventually sold it on eBay (with full disclosure!) after getting a Tamron 90mm. Of course that lens is pretty sweet to begin with ... not sure how this M40 will fair.

01-29-2009, 06:50 PM	#5
Damn Brit Guest	Send it to Jsherman999, he'll get great pictures out of it. He got a picture accepted to PPG and it was taken with a cardboard tube from a roll of toilet paper that had a magnifying glass glued to it.

01-29-2009, 07:10 PM	#6
VF-19 Veteran Member Join Date: Aug 2007 Location: Ottawa Posts: 364	Quick question: Is it possible to repair the lens when the elements begin to separate? I have an old Soligor 28mm 2.8 M42 mount that's showing that exact same thing behind the front element, and I'd like to get it fixed...

01-29-2009, 07:33 PM	#7
Vylen Veteran Member Join Date: Dec 2008 Location: Sydney, Australia Photos: Gallery Posts: 1,262	Originally posted by Damn Brit Send it to Jsherman999, he'll get great pictures out of it. He got a picture accepted to PPG and it was taken with a cardboard tube from a roll of toilet paper that had a magnifying glass glued to it. now im curious, what picture is that?

01-29-2009, 09:19 PM	#8
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340 Original Poster	Originally posted by VF-19 Quick question: Is it possible to repair the lens when the elements begin to separate? I have an old Soligor 28mm 2.8 M42 mount that's showing that exact same thing behind the front element, and I'd like to get it fixed... It should be possible. Some solvent to get the elements apart, cleaning, then recementing. How hard can it be? Of course the cement needs to be something that won't alter the optical properties of the lens. The lens coatings need to be intact. It needs to end up with no air bubbles and be a consistent thickness. The lenses need to maintain their alignment. It's like a lot of lens repairs - either you pay someone a lot of money or wing it yourself.

01-29-2009, 09:27 PM	#9
Nick Siebers Veteran Member Join Date: Jun 2008 Location: Madison, WI Photos: Gallery \| Albums Posts: 2,165	My local camera repair place wouldn't do it. They said chuck it, or use it how it is. I think it would be very hard or very expensive to repair.

01-29-2009, 09:46 PM	#10
graphicgr8s Guest	On How It's Made they showed how the elements are glued together using a special glue that doesn't distort. Pretty interesting how it's done.

01-29-2009, 09:50 PM	#11
Vylen Veteran Member Join Date: Dec 2008 Location: Sydney, Australia Photos: Gallery Posts: 1,262	Originally posted by graphicgr8s On How It's Made they showed how the elements are glued together using a special glue that doesn't distort. Pretty interesting how it's done. Oh yea... i remember that... and how it's massaged in and all that.... so much care is put into it..

01-29-2009, 11:13 PM	#12
Asahiflex Pentaxian Join Date: Jan 2008 Location: Netherlands Photos: Gallery Posts: 2,795	Maybe you can try to remove the back group and put the lens in a bucket of water which you warm up very slowly (as in a couple of hours), gradually reaching the boiling point of water. This can make the glue soft again; maybe it will melt enough to get rid of the problem. But only do this at your own risk of course

01-30-2009, 08:38 AM	#13
awo425 Veteran Member Join Date: Jan 2008 Location: NYC, USA Posts: 481	Just keep it and wait, eventually somebody will be selling the same lens with nicked front element and good back element on FLEEBAY, so you can make one good lens out of 2.

01-30-2009, 09:42 AM	#14
wildlifephotog Inactive Account Join Date: Nov 2008 Location: USA Posts: 924	Lens repair is within the realm of DIY. I know how many that have used the UV cured products like listed here. Summers Optical: Optical Cements, Structural Adhesives, and Cementing Supplies for Military and Commercial Applications

01-30-2009, 11:06 AM	#15
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340 Original Poster	Originally posted by Rense Well, post-just-one-picture-more-Dave, which you made with this one. I'm curious what will come out of it..... OK, here's one. I think this was f5.6, at the minimum focus distance.

The heartbreak of... element separation

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