Color/Density errors in panoramas

[leuallen]

I take many panoramas of pre-sunrise and sunrises. Occasionally I run into a problem. Of course I am shooting in manual focus with a fixed white balance and manual exposure. Sometimes there will be a noticeable change in the density between one image of the panorama and another. This should not be if everything is locked down. I cannot place it to changing light as it is pretty constant and a lighter frame will occur between two darker ones. Shutter inaccuracy/inconsistency is a possibility but I have had this happen with various cameras. Anyone else run into this problem? Any ideas of why or what can be done to eliminate.

Related problem but this time with color balance. I took a very nice sunrise this morning. One frame had a greenish cast and it was between two frames that ran towards magenta. I shot at a fixed color temp of 5300. Only the foreground was affected, the sky was normal. Could it be due to the bright light in the sky where the sun is coming up vs the darker sky on each side?

The color effect does not show very clearly on the attached image but it is very evident on my computer. This was a single exposure pano. Of course the shadows (foreground) had to be pulled quite a bit due to the contrast. I often do HDR variations but don't remember is this problem shows in them.

[mcbroomf]

The contrast due to the lens will change as you move closer to the sun in all but the best lenses.  Maybe colour as well.  But I would expect a simple progression, not the "lighter frame will occur between two darker ones" that you posted, unless the lighter one is pointing at the sun. 

If it is contrast you could try sampling an overlapping point to see if minor adjustments to the contrast slider will match the 2 exposures.

[leuallen]

Thanks. Will experiment with contrast. My panos are done in Lightroom so adjustments to individual frames is difficult. Not a problem in PS. But PS involves a lot more time and I shoot many panos that makes PS a bad choice. Guess I will reserve it for only the best panos (that is still a heck of a lot of panos- kidding).

The lens used here was the Olympus 12-100 F4.0. This is reputed to be a good lens. The zoom is important because the sunrise happens very fast and there is little time to mess around changing lenses and I use many focal lengths. I will try it with one of my good primes and see if that makes a difference.

[marvpelkey]

I have experienced this as well, and I find it can be somewhat mitigated by ensuring a considerable overlap of each frame and then using a gradual blend mask at each "joint".

Marv

[leuallen]

I use a one-third overlap. Thanks for replying. At least I know I am not the only one to encounter this and it is not a flaw in my camera.