Random colored dot with Zoom factor under 75% on Canon RAW at 3200 ISO

Hello all,

Last week I’ve shooted milky way with my Canon 5D Mark3.
I’ve made some tests between 1600 ISO and 6400 ISO.
I’ve a very strange phenomenon with PL3 while developping the RAW.
If I use a RAW taken at 3200 ISO and I display it with a display zoom factor under 75% I can see random colored dots all over the picture, once I use a display zoom factor of 75% and over those colored dots disappear.
RAW at 1600 ISO and 6400 ISO don’t have this phenomenon.
In attachment a side by side comparison between zoom at 74% and 75%.
As new user I can’t send the RAW …

Hello @OliC and welcome to the forum,

This is easy explained - some of the corrections such as Chromatic Aberration, Moire, Lens Sharpness etc can only be previewed when the zoom level is 75% and higher. You have the special sign and message for that:


And this is exactly the reason of your difference.

Svetlana G.

They are hot pixels on your sensor which DxO noise reduction will try to remove. Like the other corrections Svetlana mentioned you only get to see a preview of the removal at zoom levels of 75% or more.

1 Like

Hello @sgospodarenko,

Thank you for your answer and welcoming me.
I know that some correction are only active at zomm level from 75% and higher, but I’m afraid that here we are not in presence of Chromatic Aberration or such things.
And why with the exact same picture took at 6400 ISO I don’t have this behavior ?
I may give you the RAW for analysis.



@Yonni, It’s indeed hot pixels … I wasn’t aware of that phenomenon … at least not like that.
It’s seems that visibility of the hot pixels increase with ISO sensitivity, but strange thing is that at 6400 and even 12800 ISO they disappear on my 5D3 …
I’m going to search more info on the web to understand what can cause this.

Good morning,

You are welcome. Yep, Noise reduction is also a correction to preview at 75% and higher and @Yonni (thank you Yonni) already pointed why you’ve got this result.

Svetlana G.