Lens Cleaning?

Rmspar72 · 07-21-2011, 07:29 PM

I have a 50m 1.7 manual pentax lens..it has developed what I would call a haze inside the glass on the camera side....what would be the best approach? Is there a service that can clean the lens or is it possible to do it from home...thanks Mark

**Just1MoreDave** · 07-21-2011, 09:21 PM

Haze is my least favorite, because it could be so many things. I like a good honest fungus rather than haze. It is too bad that haze cannot be simply removed by haze filters.

But enough of that. Assuming this is a Pentax-M lens, you can buy another one for $50, cheaper than paying someone to clean it. So I think the choice is simpler: buy a new one, or see if you can fix the old one. If you screw up the repair, you're still buying another lens, so it is sort of an opportunity!

The repair option will require some time, patience and possibly tools you don't have, so it's not for everyone. If you are correct that the problem is on the camera side, you might just need a lens spanner or something that works like one. Here is a photo pf the lens with the mount removed, but you don't need to do that. I just don't have a photo handy with the mount on.

See around the rear element, there's a ring with two rectangular slots, then a larger ring around that with two more slots? If you had a tool that fit those slots, you could unscrew the whole rear lens group (outer ring) or just the rearmost element (inner ring).

I have modified some cheap needlenose pliers and some calipers so the tips fit those slots. An official lens spanner works too, with less risk and greater cost.

It's usually hard to tell what surface is causing the haze. There are three elements in the rear, so five surfaces you can't see and one you can. I would try removing the whole rear group first. It unscrews just like an ordinary screw, counter-clockwise, using those outer slots. Then you can see the surface next to the aperture blades. If that's clean, you can tell if you were right about the haze being in the rear. It's usually easier to reinstall this group before attempting to unscrew the inner ring, because the lens holds the group better than you can. When the inner ring is loose, the rear element can drop out. Put a nice fingerprint on the outer surface like in my first photo, so you don't reinstall it backward. Two of these three elements are glued together. If your haze is in there, it's a difficult repair, which I avoid. You have to dissolve the glue, separate the elements, clean them and reglue.

That's what's involved. It's somewhat similar if the problem is really in the front, except you need more tools, and no glued elements.

Rmspar72 · 07-27-2011, 07:37 PM

Thanks for the reply...I'm going to try taking it apart and fabricate the tools needed...details to follow..again..thanks for the thoughtful reply and the advice...greatly appreciated..Thanks Mark

KxBlaze · 07-28-2011, 03:46 PM

I took a part an old Sears lens that only cost me $10 to try and clean some haze in it. I was successful in taking it a part and cleaning the haze but had some trouble putting it back together. Now the lens will not focus to infinity but will focus on everything closer than that, so be VERY SURE the exact order of everything in the lens to ensure a proper re-assemble. Good luck!

07-21-2011, 07:29 PM	#1
Rmspar72 New Member Join Date: Sep 2008 Location: Rochester, New York Posts: 21	Lens Cleaning? I have a 50m 1.7 manual pentax lens..it has developed what I would call a haze inside the glass on the camera side....what would be the best approach? Is there a service that can clean the lens or is it possible to do it from home...thanks Mark

07-27-2011, 07:37 PM	#3
Rmspar72 New Member Join Date: Sep 2008 Location: Rochester, New York Posts: 21 Original Poster	lens repair Thanks for the reply...I'm going to try taking it apart and fabricate the tools needed...details to follow..again..thanks for the thoughtful reply and the advice...greatly appreciated..Thanks Mark

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07-21-2011, 09:21 PM	#2
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	Haze is my least favorite, because it could be so many things. I like a good honest fungus rather than haze. It is too bad that haze cannot be simply removed by haze filters. But enough of that. Assuming this is a Pentax-M lens, you can buy another one for $50, cheaper than paying someone to clean it. So I think the choice is simpler: buy a new one, or see if you can fix the old one. If you screw up the repair, you're still buying another lens, so it is sort of an opportunity! The repair option will require some time, patience and possibly tools you don't have, so it's not for everyone. If you are correct that the problem is on the camera side, you might just need a lens spanner or something that works like one. Here is a photo pf the lens with the mount removed, but you don't need to do that. I just don't have a photo handy with the mount on. See around the rear element, there's a ring with two rectangular slots, then a larger ring around that with two more slots? If you had a tool that fit those slots, you could unscrew the whole rear lens group (outer ring) or just the rearmost element (inner ring). I have modified some cheap needlenose pliers and some calipers so the tips fit those slots. An official lens spanner works too, with less risk and greater cost. It's usually hard to tell what surface is causing the haze. There are three elements in the rear, so five surfaces you can't see and one you can. I would try removing the whole rear group first. It unscrews just like an ordinary screw, counter-clockwise, using those outer slots. Then you can see the surface next to the aperture blades. If that's clean, you can tell if you were right about the haze being in the rear. It's usually easier to reinstall this group before attempting to unscrew the inner ring, because the lens holds the group better than you can. When the inner ring is loose, the rear element can drop out. Put a nice fingerprint on the outer surface like in my first photo, so you don't reinstall it backward. Two of these three elements are glued together. If your haze is in there, it's a difficult repair, which I avoid. You have to dissolve the glue, separate the elements, clean them and reglue. That's what's involved. It's somewhat similar if the problem is really in the front, except you need more tools, and no glued elements.

07-28-2011, 03:46 PM	#4
KxBlaze Veteran Member Join Date: Feb 2010 Location: California Photos: Gallery Posts: 1,602	I took a part an old Sears lens that only cost me $10 to try and clean some haze in it. I was successful in taking it a part and cleaning the haze but had some trouble putting it back together. Now the lens will not focus to infinity but will focus on everything closer than that, so be VERY SURE the exact order of everything in the lens to ensure a proper re-assemble. Good luck!