Yashica Mat-124 dirty inside of lens

[doug_dillard]

I have a Yashica Mat-124 that I bought back in high school in the

1970s, haven't used it for a long time. When I set shutter speed

to 'B', press the shutter button and look through the lens I see gunk

inside the 'taking' lens. I do this with the back open so I can see

through the photo taking lens. I assume this is fungus, it is not on

the outer side of the lens either on the front of the camera or

inside the photo compartment. What do I do now?

[douglas_green1]

It's probably oil or grease from the shutter. I've had 4 Yashica Mat-124 cameras, and 3 of them needed this exact cleanup. If you had a spanner wrench, it would be pretty easy open the shutter (set it on B, with a locking cable release), then unscrew the front element group, and clean both of the glass surfaces that are adjacent to the shutter.

 

I use Q-tips and alcohol to do it. Once the front of the lens is off, the whole job takes 10 minutes. But if you haven't got the right tool to remove the front of the lens, you'll probably damage the camera.

[doug_dillard]

I have many tools, but I haven't worked on a camera before. I downloaded 7 pages of assembly schematics from one of the Yashica Mat sites. You are probably very familiar with them. Can you describe the order I should take things apart? Let me know if there are springs that are going to fly out across the room, or other kinds of traps I should avoid. The stuff I downloaded was for the G model (I have an ordinary Mat-124). The plans are at: http://www-unix.oit.umass.edu/~coreya/yashica/ymchttc.html

Thank you.

[douglas_green1]

The following is done with a disclaimer: Try this at your own risk, I accept no responsibility for any damage which you might cause your camera:

 

All you need to do is lock the shutter open, (set camera to B, and hold it open with a locking cable release), and set the aperture wide open to f3.5. Then, using a spanner wrench or similar tool that fits into the two small slots on the front ring of the Yashinon taking lens, turn that ring counterclockwise. The front of the lens will come out. There are no springs, because there is no auto-diaphragm mechanism. The only mechanisms are the shutter, and the aperture, and you've already set both of them wide open. Then, the front group of two elements screws out, and you can easily clean the inner surface, which, when installed, is adjacent to the shutter.

 

A bit trickier is to clean the front surface of the rear group, which sits behind the shutter and diaphragm. That is done with a Q-tip and either lens cleaning fluid or alcohol. Be careful not to get much fluid on the diaphragm or shutter blades. If you do, you'll need to carefully blow-dry those blades with canned air. The blades will be sticky if you get fluid on them and don't carefully dry them. Once all the dirty exposed lens surfaces are cleaned, and the blades are dry, you shoud release the shutter, and make sure it's not sticking. If it is sticking, it needs to be dried with canned air until it's not. Then, once this is done, you simply screw the front lens group back into place.

 

In my experience, over decades of time, the shutters on these cameras always coat the inner elements with small droplets of oil or grease, and that is what you'll be cleaning off. As I said, this is VERY common, and 3 of the 4 Yashica Mat or Mat 124 cameras I've owned had this issue. They all cleaned up nicely.

[doug_dillard]

Thank you, DG. Now I'll buy a spanner wrench with blade tips. Previously I thought you were using some kind of British vocabulary, but now I see that spanner wrench is a term for an optics lens tool. I see the slots in the lens retainer ring, before your message I thought I was supposed to remove the bayonet. I'll get a spanner wrench and remove the lens retainer ring and clean the front surface of the rear taking lens. After I get the tool in a few weeks, I'll let you know how it worked out. Thanks again.

[m_.]

Can anyone tell me where I can get a spanner wrench? Mine is as dirty as a mud hole. Thanks.

[niels olson]

I just performed the Doug Green's procedure, except I used naptha (what I had available). I would recommend not using alcohol unless you know it's 100% methanol: the balance of the stuff you get at the drug store is water, which is acidic. You may not notice water's acidity when you drink it, but look at the underside of an old car. It will terrorize your diaphram and shutter coatings.

I'd also recommend sitting down with at least fifty Q-tips and promise yourself to use all of them and get more. Only touch each Q-tip to the lens once and then treat it like hazardous waste: throw it away, don't get them mixed up with the fresh ones. Poor a very small amount of solvent into a small cup (minimize surface area of the solvent: they all evaporate and they're all noxious). Don't dip the Q-tip in solvent. Lightly and quickly touch it to the surface of the solvent: it will wick up more than you need. If the cotton looks soaked, then it absorbed too much solvent. Throw that q-tip away and try again. The idea is you'll invariably touch the edge of one of these q-tips to the edge of the lens tube, and the thin gap between the shutter and diaphram will immediately wick excess solvent between them. So use as little solvent as possible. Also try to keep touch the end of the q-tip, not the side, to the solvent.

 

For the wrench: I used a Sears multi-blade spanner set ($6.00 for 6 types of blades, found on the clearance table) and ground one set down with a Dremel until it fit the spanner ring on the lens. In retrospect, if you've got a Dremel, then a cheap dinner fork has got more than enough metal to grind down into blades. And you certainly don't need a fancy grip for the wrench: the front lens assembly is torqued to, maybe, two inch-pounds. Seriously: a cheap fork and a dremel are the way to make yourself a first rate, custom made spanner.

 

Third: I uncovered what appears to be some pitting on the front surface coatings of the rear group. I suspect these were caused by not doing this procedure earlier. I'm sure this is the first time it's been serviced since purchase. Any thoughts on this pitting?

[niels olson]

I just performed Doug Green's procedure, except I used naptha (what I had available). I would recommend not using alcohol unless you know it's 100% methanol: the balance of the stuff you get at the drug store is water, which is acidic. You may not notice water's acidity when you drink it, but look at the underside of an old car. It will terrorize your diaphram and shutter coatings.

I'd also recommend sitting down with at least fifty Q-tips and promise yourself to use all of them and get more. Only touch each Q-tip to the lens once and then treat it like hazardous waste: throw it away, don't get them mixed up with the fresh ones. Poor a very small amount of solvent into a small cup (minimize surface area of the solvent: they all evaporate and they're all noxious). Don't dip the Q-tip in solvent. Lightly and quickly touch it to the surface of the solvent: it will wick up more than you need. If the cotton looks soaked, then it absorbed too much solvent. Throw that q-tip away and try again. The idea is you'll invariably touch the edge of one of these q-tips to the edge of the lens tube, and the thin gap between the shutter and diaphram will immediately wick excess solvent between them. So use as little solvent as possible. Also try to keep touch the end of the q-tip, not the side, to the solvent.

 

For the wrench: I used a Sears multi-blade spanner set ($6.00 for 6 types of blades, found on the clearance table) and ground one set down with a Dremel until it fit the spanner ring on the lens. In retrospect, if you've got a Dremel, then a cheap dinner fork has got more than enough metal to grind down into blades. And you certainly don't need a fancy grip for the wrench: the front lens assembly is torqued to, maybe, two inch-pounds. Seriously: a cheap fork and a dremel are the way to make yourself a first rate, custom made spanner.

 

Third: I uncovered what appears to be some pitting on the front surface coatings of the rear group. I suspect these were caused by not doing this procedure earlier. I'm sure this is the first time it's been serviced since purchase. Any thoughts on this pitting?

[bob_jamieson]

I have used Qtips and drug store alcohol for lens cleaning for 32 years on my Canon F-1 and Yashica MAT. Use 92% isopropal for less water. It dries in seconds so wait 5 minutes if you are worried about water. Mineral spitits take a good while to dty and leave a film. I've never heard of using MS! Where would you even get Methanol? At an Indy car race??

 

Bob Jamieson

Atlanta Ga.

jamo002@aol.com