Mamiya m645 210mm C lens, oily aperture blades....

[harlequin]

Dear Team,

Was using friends m645 during lockdown, the 210 lens for the m645 has what looks like oil on the blades, question..

A) what causes this and does it damage the optics?
B) can a technician fix it, it doesn’t affect the aperature functionality at all?
C) Are MF lenses with shutters less prone to have this issue?

Thanks for your input/feedback!

Stay Safe!

Harlequin

 

[Kino]

If it was in the trunk with the Nikon, its lube that has melted and run down onto the blades. They probably will have to be cleaned...

 

[Neil Grant]

A) it comes from the helicoid lubrication - it won't necessarily damage the optics
B) it can be fixed, it can effect the diaphragm operation
C) MF lenses without helicoids may be less prone to oil on diaphragm blades.

I don't think the Mamiya 210mm for 645 is particularly prone to 'throwing oil' - but you've obviously found one that has.

 

[MattKing]

The 210mm C lens has been around for a long time, so that oil could have had decades to accumulate there.

 

[harlequin]

Yep,

Just had it in the trunk for just enough time for lunch (now that restaraunts are opened again)
Now I have oily blades on m645 210 lens and a stiffening of the focus on Nikon 180 2.8...never again.

Thank you for your technical analysis and input!

Be Safe!

Harlequin

 

[Kino]

It happens. Some time ago, I left a camera in a car trunk in Odessa, Texas for about 30 minutes. The lube pooled in the downward facing lens and then solidified when I took it into my air conditioned apartment.

Yeah, it sucked...

Good luck with your photography!