Ok so for what its worth, I didnt see an F75 review here and decided to add my 2 pence worth on this great bit of kit.
I've owned the F75 for roughly 6 months now and used it for easily 10 - 20 hours each week since purchase.
Straight out of the box my first impression of the F75 was quality, everything seems well made and easily snaps together as it should. Once assembled, I eagerly put the batteries in and started her up. After a few seconds I was greeted / assaulted with beeps, chirps and squeaks, luckily I had read up about the F75 and knew that starting up inside my house was probably not the best way to check out its features. After reducing the sensitivity to about 35 to keep it quiet, I gave it a test swing, boy was I suprised at just how light this machine is, really well balanced too.
In terms of navigation the menu is easy. Press the red button on the right to highlight and move up and down, use the toggle button on the left to move left or right. The menu is laid out with Discrimination options on the left and All metal options on the right. Upon first start up you'll notice the machine set at its factory settings, stick with these for the first few sessions and get used to what the machine is telling you.
The F75 has 4 discrim programs to chose from as well as an all metal mode for those hard to reach places
DE - default mode; the start up mode and smoothest operating on most terrain.
JE - Jewelery mode; mega sensitive, especially to small low conductivity metals and possibly the deepest mode, IMHO the most difficult of the discrim settings to get the hang of.
BC - Bottle cap mode; designed to make bottle cap signals sound inconsistent where bottle caps are a problem.
PF - Ploughed field mode; for undulating terrain where there is air between the coil and the field.
On the field;
First trip out was a crisp, sunny morning. Perfect for detecting. It had been raining the past few days so I knew the conditions were pretty much as good as they could get. Having previously owned an F4 I decided to make a few adjustments and use it with 4 tones as this was what I was used too. I setup the F75 with the following settings;
Discrimination
Sensitivity : 60
Discrimination : 1
Notch : 0
Number of tones : 4
Process : DE
After digging a few buttons and buckles I hit my first really good target of the day; a James 1st Halfcrown about 6 inches down and the detector screamed a high tone in the 60's range, after lots smiling and a little bit of dancing I moved on. The rest of the day was fairly fruitless but I was digging near enough everything, just to see what the detector was telling me. At one point I had a 3 inch diameter rusted Iron ring out, well over 10 inches down...
The next day out was when the F75 really impressed me. After a couple of hours of digging old coppers and shotgun caps I hit a
Lizzie 1st Penny 3-4 inches down and straight after, a small lizzie 3 pence at about 7-8 inches down, again with clear crisp signals, really impressive.
My 2 main hunting terrains are Pasture and ploughed fields, here are my (approximate) favourite settings.
For ploughed fields:
Discrimination
Sensitivity : 75 to 85
Discrimination : 1
Notch : 0
Number of tones : 4
Process : DE
For Pasture:
Discrimination
Sensitivity : 60 to 70
Discrimination : 1
Notch : 0
Number of tones : 4
Process : JE
Bad points?
Perhaps my biggest complaint with the F75 is the little nut that is used to attach the coil to the stem. Lets be honest here, its rubbish. On my F4 they used the same nut and it broke within a few months use, I've not yet had to replace it on my F75 but the coil is becoming increasingly loose and the nut is bowing everytime I tighten it.
Also, there have been a lot complaints that 75's suffer badly from EMI. personally, I cannot fully vouch for this. I did try to work the edges of a pasture field and became increasingly frustrated at the constant blips and falsing tones, even when I had lowered the sensitivity down to 50. Eventually I realised I was right next to a high powered electric fence as the field use to house a bull, doh! more fool me for being unobservant...
Overall:
The F75 is a fantastic machine. Since buying it I haven't looked back, I've had 14 Milled Silver and 16 Silver hammered within the space of 6 months. I appreciate that a lot of this is down to good permission, but some of these coins were deep and 2 were next to nails (the F75 gave clear separation on both occasions) take your time and learn the machine, my biggest piece of advice; be patient and listen to the feedback its giving you. If it chatters away at you, lower the sensitivity. You might try increasing the discrimination as well. The four tones as always with Fishers are excellent and very intuitive, it gets to the point where you will 'just know' what it is before you dig it.
Hope that's been of help, please PM me if you'd like any advice and I'll give what I can, I'm no expert though!!