How to fix dust in my Mamiya lenses

bwakel · Mar 15, 2007

Two of the Mamiya lenses for my Mamiya 7II, the 80 and 50, have two or three large specs of dust stuck to the inside of the front element. The leaf shutter in these lenses and the fact that the rear element can't be easily removed (unlike with a LF lens) means that I can't see away to clean these bits of dust from the lens.

Does anyone know a way to clean the inside of these lenses or has anyone used a professional in the UK to clean their lenses successfully?

Thanks

Barry

Pinholemaster · Mar 15, 2007

Leave them alone.

Two or three specks will do nothing to your image quality.

The only way to services them is with a Mamiya service shop, but then it will cost you.

bwakel · Mar 16, 2007

Pinholemaster said:
Leave them alone.

Two or three specks will do nothing to your image quality.

The only way to services them is with a Mamiya service shop, but then it will cost you.

Walter, unfortunately the specs make very visible marks on the film. I now have three white blobs on all of my prints which are highly visible against dark areas.

Barry

paul ron · Mar 16, 2007

I'm surprised the rear cell doesn't come out in one piece. Once that is out, it should be easy to clean with the lens wide open in T.

But this is my question... where did the spec come from? That says there must be something else going on inside your lens if the dust spec is so large.

Can you post a pic of the rear of the lens? If I can see it, I can assess it better that way.

max_ebb · Mar 16, 2007

White blobs on the prints? So you have dark specs on the film? I didn't think it was possible for a camera to focus dust specs on the front element enough to show up as specific shapes on the film. Even if it does focus enough to show up, it seems to me that it would show up as light specs on the film (since dust would block light from getting through), and dark specs on the prints. Are you sure it's not dust stuck to the film that's causing the white blobs on the prints?

bwakel · Mar 16, 2007

max_ebb said:
White blobs on the prints? So you have dark specs on the film? I didn't think it was possible for a camera to focus dust specs on the front element enough to show up as specific shapes on the film. Even if it does focus enough to show up, it seems to me that it would show up as light specs on the film (since dust would block light from getting through), and dark specs on the prints. Are you sure it's not dust stuck to the film that's causing the white blobs on the prints?

Max, no, I've shot a several rolls of film and the specs appear in the same place on every print and they correlate with the position of the white specks on the lens.

Barry

bwakel · Mar 16, 2007

paul ron said:
I'm surprised the rear cell doesn't come out in one piece. Once that is out, it should be easy to clean with the lens wide open in T.

But this is my question... where did the spec come from? That says there must be something else going on inside your lens if the dust spec is so large.

Can you post a pic of the rear of the lens? If I can see it, I can assess it better that way.

Paul, the Mamiya 7's lenses have leaf shutters built in but the shutters are controlled by the electronics in the camera and so cannot be opened with the lens off the camera. The rear cell definitely doesn't come apart unless the whole lens is taken to bits. I suppose it might be possible to open the camera back and see if the electronic shutter still works. However, it looks like the specks are on one of the internal elements. I don't know how they got in there though unless they're eggs or similar from some tiny creature.

Barry

Christopher Walrath · Mar 16, 2007

There are ways that dust can get into the lens over time, such as through the bayonet opening on the base of the lens. I have some older Sekor C lenses for my M645J that have a little dusting on the inside and if I knew how to disassemble them with a fair amount of surety that I could reassemble them to working fashion, I would. But if yours is creating flare of shadow on your prints, they must be sizable particles. Has the lens been dropped in the past? Is it only one lens or multiple (though I guess I don't see how one could get the same defect with multiple lenses in this realm of reality so scratch that one). I would get them cleaned professionally as soon as feasible and be done with it.

max_ebb · Mar 16, 2007

Hmm, maybe not dust. Maybe it's fungus?

Bjørn Joachimsen · Mar 18, 2007

The white blobs appearing in the same position on several prints is more likely to be explained by dust in the enlarger equipment.

bwakel · Mar 19, 2007

Bjørn Joachimsen said:
The white blobs appearing in the same position on several prints is more likely to be explained by dust in the enlarger equipment.

Bjorn, I've checked the enlarger and there are no blobs when printing with negs from my other cameras or from negs made with the Mamiya with the 150mm lens. The blobs are definitely from the white things in the lens.

How to fix dust in my Mamiya lenses

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