Are there any tools or applications that can be used to mitigate the problem of lens glare from sunlight?
Glare removal is theoretically possible, but outside a laboratory it is quite difficult. It requires prior knowledge about the lens characteristics and the distribution of lightsources that cause the glare, in order to produce a Glare Spread Function. Since glare mostly consists of a low spatial frequency veiling contibution to mostly the shadows, it is best corrected in linear gamma space (i.e. on Raw data or HDR data). One commercial application that has a specific Glare control, is HDR Expose (or the 32 Float plugin) by Unified Colors.
If you want to simulate a correction in e.g. Photoshop, then an inverted luminosity selection could serve as a mask for a local contrast boost and luminosity reduction.
This isn't necessarily glare in the lens per se, rather from sunlight creating glare in mist?
That's something different, as you are imaging real scene light. I can only see selective contrast boosts as a means to change what was recorded. Probably the best results are to be expected from applications that can do controlled tonemapping. Applications like SNS-HDR (Windows but alo runs under Parallels or Fusion) offer many controls which do not introduce halos when the corrections are significantly pushed. Topaz Adjust might also offer some possibilities to regain selective contrast.
Cheers,
Bart
