Jump to content

Recommended Posts

Advertisement (gone after registration)

Hi,

I have recently bought a Leica m monochrome with the corrosion issue. Black spots were present on the photos, i fixed it by replacing the low pass filter, it works fine now. I have the opportunity to buy another m9 but this time with the purple fringe issue. Are both problems (black spots and purple fringes) due to the corrosion on the low pass filter?

Link to post
Share on other sites

The M9 / M9M has no low pass (AA) filter. Whatever you replaced, was not this one. The filter glass, that caused the corrosion issue was the IR-cut filter.

What kind of "purple fringe issue" do you mean? I only know of purple / green fringing caused by CAs of many lenses (typically those, that open wide).

With some lenses (e.g. Voigtländer 25/4), you also get "purple edges", because their design (rear lens element close to sensor) does not play well with digital sensors.

Perhaps you can provide a link telling us about that issue or show sample photos?

Edited by 3D-Kraft.com
Link to post
Share on other sites

The filter glass looks like an IR-cut filter but the discription over there at Ali is rubbish...

The purple curtain is not a corrosion effect. Looks like one half of the sensor is defect (the M9 full frame sensor is put together by two smaller sensors). If you see that since the filter glass replacement, the sensor may have been affected by that operation.

  • Like 1
Link to post
Share on other sites

  • 2 months later...

tldr very diffcult repair with high chance of failure compared to the glass replacement

The issue is related to the corrosion, it turns the glue used for the sensor glass into acid gel. This gel damages the gold wires that connect the sensor to the mainboard, leading to split screen / black / purple images. It can be repaired by rewiring the gold threads (requires special machinery) but the success rate is only around 50%. Also artefacts might remain.

 

Edited by petard
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...