Luminous Landscape Forum

Equipment & Techniques => Digital Cameras & Shooting Techniques => Topic started by: les24preludes on December 30, 2012, 05:22:36 pm

Title: What's this - moving blotchy effects in Live View...moire, aliasing...????
Post by: les24preludes on December 30, 2012, 05:22:36 pm
I'm getting a funny moving pattern in Live View on a Canon 50D, which I see on a white sign on the side of a distant crane. This is visible with telephoto lenses at ISO 100 when Live View is set to maximum magnification. It looks like light grey blotches that kind of swirl about slowly. The blotches do appear on the actual shot. At other times and light conditions and with shorter lenses this can't be seen. The effect seems to diminish at ISO 200.

This is very spooky and I've searched all kinds of posts for an explanation. Does anybody relate to this? It's the kind of thing that makes you doubt your sanity a bit, but it's definitely happening!

 
Title: Re: What's this - moving blotchy effects in Live View...moire, aliasing...????
Post by: les24preludes on December 30, 2012, 05:29:50 pm
Here's the effect first without then with. Those blotches in frame 2 move about in Live View.
Title: Re: What's this - moving blotchy effects in Live View...moire, aliasing...????
Post by: les24preludes on December 31, 2012, 07:13:04 am
I'm still at a loss to explain this. I've had no plausible explanation on the Canon forum. Suggestions were atmospheric effects, convection currents, smoke (this is a building in progress so I don't know if there is a heating system on yet which might have some kind of hot air rising...). The effect doesn't look like this somehow, but I may be wrong. It looks like shifting moire, not anything moving up vertically in the air.

Tried some very similar shots today and the moving blotches were not there. I used Live View very quickly to focus and no more. I shot with window open and closed - made a little difference to detail resolution but not much otherwise. No UV filter. So just air between the lens and the subject.

What I do notice is that the battery drains rapidly in Live View. So I'm wondering if it is:
1) Low battery effects
2) Sensor is overheating in Live View

My suspicion is that it's something to do with the electronics and the behaviour of the sensor when Live View is left on.