It's called 'heat haze' (picture)

[jack.h...@gmail.com]

But it hardly felt warm.  Air temperature 10 C, sea 13 C.  Very chilly wind.

The far coast is 18 kilometres away.  Don't know about the yacht.

Note the sea surface and just above heat haze rippling.

Jack

[Len]

It's an inferior mirage albeit a rather weak one.

Len

Wembury

[jack.h...@gmail.com]

Educate me, please, Len.

Almost always when I use long telephoto, the sea surface and distance coasts/ ships have this blurred/shaky appearance.  I have discussed this with photographers, and it is agreed that however good or expensive a camera/lens set-up might be, you cannot overcome nature.

So how does an inferior mirage work?  I would like to do some photo experiments.

Jack

[Len]

Depends on whether temperature is decreasing (inferior mirage) or increasing (superior mirage) in surface air layer.

Inferior:

Superior:

A good strong temperature gradient is needed to get the best effect.

Len

Wembury