[...] With regards to temperature difference, has anyone here ever experienced this temperatue related impact when shooting ducks located a distance from shore? I think that the air temperature at the surface would be colder for something right on the water as opposed to me at a bit of an elevated position?
Yes, I ran into that big time at Leslie Spit two weekends in a row in early December. That's how I discovered the thermal effect in the first place. Basically, I was opposite to the marina near the base trying to photograph the ducks there. It's around -8C both times if I remember correctly. The ducks were mostly on the marina side so they're 150+ ft away. That's too far for really good shots, but with 700mm, it should be possible to at least get some decently sharp shots for the record. Turns out not a single shot was sharp on the first outing. I initially thought it's because of the high wind. Did a bunch of tests at home and discovered the thermal effect through vertical window. But on the second outing, still couldn't get a single decent record shot. Flipped on LiveView and saw the shimmer. Then it hits me: there's a vertical temperature difference from the water surface to the cold air above!
In a sense, this vertical temperature gradient is even worst than a vertical boundary like a window. A vertical layer of unstable air has limited thickness, but a horizontal layer would go from your position all the way to your subject. I'm in Guangzhou, China right now. Very close by buildings are all smocked up and yet you can look up and see clouds above. That's because the smock layer is close to the ground and actually quite thin. Same kind of effect as horizontal thermal layer.
By the way, when taking pictures of ducks, try to get down to the water level as much as practical. This provides a much more attractive point of view. Even shoot in prone position if you feel like being hardcore. For me, shots of ducks and shorebirds from prone position often has a magical quality to them. But things can get pretty wet and messy, so taking the shots might often be pretty unpleasant. Of course, if the shoreline is rocky, it can be down right dangerous trying to get to the water level. So common sense is needed here...
Thanks for the link - I'm going to read it as soon as I'm done replying!
You can also check
this out. If you have time, that is
Andy
