Your 151 allows you to go to +18dB in 50i and 50p modes, but only to +12dB in 24/25p modes (why?). You're right - there's no minus gain settings as there is on many Sony cameras - even the 1997 TRV900 had this. It's very useful on bright days, better than upping the shutter speed to 1/100th to soak a stop.

I find the FX1's low light sensitivity somewhat lacking, but it's +18db setting to be very usable indeed, far nicer to look at than my NX5 at the same setting, where I feel Sony haven't got the noise:sharpness balance quite right. The 151 and FX1 also use CCDs - and this is very good for wedding filmmakers working under a barrage of electronic flash.

The 151 is nearly a stop more sensitive than the FX1 even using, focal length for focal length, a slightly slower lens, So I'd say they're probably neck and neck when one's on +9dB and the other's on +18dB. But then again, the 151 uses the far more modern AVCHD compression algorithms, whereas the FX1 is using MPEG2/HDV/ 2004 technology.

tom.

Hmmm I've just tried changing the high gain value in the menu to 18 whilst in 720 50p, 1080 50p and 1080 25p and the option is not there on any of them... Does anyone know why?!

Panasonic probably figure that anyone savvy enough to want to shoot progressive footage isn't going to like the grain that comes with +18DB of gain, though why you're not even given the option beats me.

I had an MX300 Panasonic back in the MiniDV days and that would only go to +12dB in auto, but in manual would give you another stop to 18dB. I could never figure out why it was programmed this way as probably 99% of the camera's owners shot in auto, and all ended up with under-exposed Christmas party footage.

My NX5 can film from -6dB up to 21dB, an incredible range. There's also a hyper-gain setting but you don't want to go there - you really don't.

tom.

Haha no I'd imagine hyper gain isn't pretty!

Ok so it seems 18 db is possible through another menu..

"Gain Selector and ND Filter
The gain selector has three positions: L is fixed at 0 dB; and M and H can be set to 0, 3, 6, 9, or 12 dB. 18dB can also be accessed as a User button function. Three ND filters (1/4 ND, 1/16 ND, and 1/64 ND) are built-in."