Mounting Flange Material Canon 50mm f1.2 Rangefinder Lens

[Mojo]

Hi,

The Canon VT with a 50mm f1.2 arrived today. The lens barrel is in excellent condition and the glass clear. When I removed the lens from the body for a closer look, I found dirt on the mounting flange. After I clean it with a q-tip, I noticed the flange has plating corrosion with some areas looking like rust (or dull brassy color). Can one of the members tell me the material used for the mounting flange? The treads are fine. Any recommendations, treatment, future implications?

Thanks

 

[Mackinaw]

To clarify, are you talking camera or lens?

Jim B.

 

[mdarnton]

It's not uncommon for the chrome on the lens' mount to wear through in some places, exposing the underlying brass, and it's nothing to worry about. Often you'll see that it appears to happen in a location indicating it was caused by the edge of a screw hole on the camera mount. There will still be plenty left for proper registration of the lens, though.

 

[Mojo]

The corrosion is on the mounting flange of the lens. Attached is a photo. Is the mounting flange made of brass-therefore no future rusting problem? Will the corrosion on the back of the flange affect the set focus distance of the lens and camera? What can I use to coat the affected area. The glass is very clean. Thanks.

 

[johannielscom]

Just use some brass polish and it'll come off easily. Clean with 100% alcohol after that and that'll be it.

If you ever need to clean the insides, have a look on my website. There's a tutorial there on how to DIY, it's simple.

 

[mdarnton]

What you have there is not going to affect focus, once you get the rot off (you don't want to leave anything standing up above the original surface; anything below the surface of the chrome, any pitting, is fine, from a focus standpoint).

It's not "rust"--only iron/steel rusts.

 

[Mojo]

Thanks all for the advice.