Bad news is that for 48 years I've been doing it wrong..Good news is that half ,or better than half, is still there...I don't have to search out new places for the next 48 years...Way back, you saw the diagrams of the flux / force lines as a mighty toroid reaching down to grasp coins at magnificent depths..You measured coin distance in air,,,,penny, dime , quarter etc, at the hottest spot..With the IB locators, everything rang...., gold, like the Bells of St Marys..I heard that nickel was para magnetic, and acted like iron at certain frequencies..So, when I got my first low Frequency detector and stopped finding nickels,i assumed it was because it acted like iron...Could have joined a club, took one member out, and he took his buddies out and cleaned up an excellent place to hunt..So, I stayed away, and did my own thing, which was research..I've mentioned that I have learned more in the last couple of months from you-all than in many years by my self..That is the truth..Regarding my search methods, detectors, coils, I am going to graph response to a target on each of the coils..full size dimensions. I should be able to pinpoint the proper overlap.Or throw it out for your opinions/ expertize.. The camera trick will come next..If it is used in everything from golf to diving, why not detectors.?? Gold star for that one..Have seen several people on You Tube swinging detectors..I'll wander over and check their techniques...Went out this AM to check a spot, caught in a down pour..Designer Wally World plastic bags work well keeping the water off your detectors..I got soaked, chilled and still can't get warm Cordially NAD