Yeah, i get the difference between the two sounders. And I remember being frustrated with at least one of them, potentially both, when it came to having the machine automatically adjust for depth so that the screen continually showed only the first "40" or "50" feet off the bottom.
On my 25 year old Sitex you could adjust it to do so. If the bottom contour got to close to the top of the screen (getting shallower) it would BAM drop the line down on the screen. Conversely, if the bottom was getting to low on the screen, it would BAM raise the line.
I could set it to show "Bottom + X feet" one time and never adjust it all day. From 80' of water to 800' of water.
Sounds like that might not be the case with the DFF1 or the DFF3D.
What do you mean by Para 7.2.3. EDIT: Ah, the user's manual. Will check it out.
The more and more I think about it, and when you mentioned "Auto", the more certain I am that the TZT won't do what I'm talking about. I'm not sure if any new ones do. It was such a nice feature to always have basically your entire screen showing just the number of feet you elected to see off the bottom. If memory serves me correctly Auto kind of did what I'm talking about, but it showed the entire water column. Basically it treats the surface as the baseline. I'm wanting the bottom to be my baseline, if that makes sense. Oh well. New is always better, right?
JUST READ MANUAL... Nope. It won't do what I'm talking about. That's utterly ASTONISHING! It's been almost two years since I operated the machine. I was afraid my recollection was correct. "Bottom Zoom" is the feature I'm talking about. It will achieve (basically) the goal I'm after, but you have to manually enter the values. Asinine. Plus (now that I am remembering things), it shows 2 screens (all of water column in auto and the "zoom" selection) for H and 2 screens for low. So...
1. I don't care about all of water column
2. I have to manuualy adjust zoom parameters while working up and down ledges
3. If I want to run my H and my L, I know have four freakin screens even though I don't give a **** about the screen that shows the entire water column.
I guess answer is to skip the whole zoom feature and just manual adjust things as I'm going up and down ridges. Crazy.
What I'm talking about might be a good feature to consider.
It ensures that your eye is trained to ALWAYS know what it's looking at because it's always the same. And it's hands frree. Requires ZERO adjusting during the day.
Oh well. Wish I'd remembered this. Just ordered a $2,300 ducer and $1,800 DFF3, but had forgotten all about the screen tapping and knob turning to stay on just the bottom 60 feet. Whatever, already had the MFD so this was still a pretty cheap option to wind up in a pretty good system. Will the stand alone Furuno bottom machines do what I'm talking about? Hmmm.... they have internal sounders too, don't they? That might be an option. If I can find the dash space. Then just use the TZT as chart plotter.... Ah, hell. Then I can't scroll back and tap screen to mark fish. Oh well. Will stick with what I've got.