[Pedro the Fisherman]

1 - Pedro, do you crop some pics I think ?
2 - the cam is on the ground, and in Spain, on a rocky beach, the sun warm up the ground and the heat creates some bad conditions for taking photos, especially when the cam is on the position...
3 - Your technic. I think that you explained that you shoot on landscape position on the cam, so the depht of field is important. This way, I think and I'm quite sure, that the subjects that are near of you have less details that if you was shooting in portraits (or others) mode but with the focus directly on the girls. No ?

Yes, I crop out the black shadow of the items that hide the camera and also any potential unwanted persons, children for example.
Yes, the camera is on the ground and is effected by heat haze (30C+ most days). Unless I can find a 'cloak of invisibility', not much can be done about this!

The focus is a result of 'trial and error' tests, made over the past two years. Perhaps the new camera will have some improvements I might try, but with rocks and all sorts of stuff closer than the subjects, any spot focus relies on being able to position the focus crosshair/area manually, not easy to do when you are trying to look like someone not taking photos. Until a camera is brought out to deal with these specific problems (maybe an OCC special edition Nikon), please just except the drawbacks.

I know the some of the video masters (Like Jackass) seem to get close and in focus, until I spend a day with one getting to learn how they get away with this, you will just have to put up with what I can get. Today, I was at the beach and at no time did I get a chance to capture anything. Some days are like that, others are better. It's a bit like wildlife photography, but with the added complication of doing it in secret.

If you look at the attempts of others here, I think they will all agree (except possibly Mr Bronne), it is not as easy as it looks.