M8.2- red or green spot on image

[twopointeight]

On the image, usually on something very dark, an occasional red or green spot. What is this? Also, setting the asa to 2500 and putting on a body cap and opening the shutter while on Auto exposure. Is this a fix for this or something else?

 

[coelacanth]

You can upload some sample shots to get better advice, but in general, M8 has well known "characteristics" in its sensor. If you have strong light source at certain edges of the frame, you'll get green streak. If you underexpose and the final image is "pushed" you'll get all sorts of banding and color noise goodies. ISO 2500 with cap on, AE would give you all sorts of funny noises.

Again, others can chime in with more specific advices, but it sounds like a typical good old M8 (and M8.2) to me. Best thing you can do is to expose right (or over expose a bit) when shooting high ISO (1250-2500).

I'd personally use up to ISO 640 for regular situations. I'd use 1250 like shooting with negative film (i.e. over expose if you aren't sure correct exposure). I forget about ISO2500. 😛

 

[Phil_F_NM]

If it's in the same place it's a stuck pixel. If it wanders then it's just a component of noise, sometimes there is more chroma noise in shadows than should be there. You can map these out in lightroom or photoshop.
Even if it's a stuck pixel it can be mapped out but watch it carefully as it can, and usually does, develop a 1px wide line that extends from the top to the bottom of the frame through the pixel. I had this happen on my M9 several times. Was always a red pixel that was over-excited and it created a cyan complimentary line. The pixel is very easy to correct for and map out, the line is very hard to get rid of in post production. Leica can remap the sensor, usually for very little or no cost to you. If it's under warranty, they will cover it of course. After a few remaps of the same sensor, they may replace it. This happened on my M9 and it eventually got a new sensor last January.
Good luck!
Phil Forrest