One of the benefits of having fished on a serious basis for over four decades is a sense of perspective regarding the evolution of boats, tackle, equipment, and such. It’s been dramatic in terms of quality and selection, as well as cost.

Perhaps this is most evident in fishing electronics. The first sonar units to appear were of the flasher variety, exemplified by Lowrance’s Fish-Lo-K-Tor. While the name implied its use in finding fish, it was a challenge to distinguish between weeds, wood, rocks, and fish. Not that the information wasn’t of immense value because it was. But in most instances, early versions of flashers were more beneficial in location quality habitat, namely bottom structure and cover.

While flashers have enjoyed a recent resurgence in popularity -- mostly in ice fishing situations – today’s boat angler likely uses a sonar unit that displays in a graph form. Whereas targets that display on the circular screen of a flasher are in real time (i.e., within the transducer cone), graphs show a scrolling picture. Only the information first appearing on the screen is within the transducer view.

The most common sonar views are traditional 2D sonar, down imaging, and side imaging. Units that have such capability are available from all the popular makers such as Lowrance, Humminbird, and Garmin, oftentimes at price points many anglers can justify. Of course, as with most fishing related products, you can spend as much as your wallet will allow.

Traditional 2D sonar uses transducer that shoots a cone-shaped beam. It’s the one capable of displaying the classic arches anglers associate with fish. A down-imaging sonar uses a narrow beam that takes thin slices (like a copying machine) of the bottom and stitches them together as they scroll across the sonar screen. The image is more of a photographic quality. Side-imaging is like down-imaging, differing in that the sonar beams are shot to the side of the transducer rather than down.

The detail afforded by down- and side-imaging is somewhat dependent on the quality of the transducer and the sonar unit displaying the information. Just like cameras and televisions, higher resolution and detail can be expected from more expensive units. And it’s constantly evolving as new units come to market, and makers compete to produce the latest and greatest.

The most recent technology is that of forward-facing sonar, illustrated by Garmin’s Live Scope with Lowrance’s Active Target and Humminbird’s Mega Live appearing on the scene recently. These units display in real time (rather than scrolling history). When properly adjusted they can display not only fish, but your lure as well. Forward-facing sonar first became popular with crappie anglers. It’s been the rage on the professional bass fishing trails as well the last couple of years, accounting for many victories. This has sparked controversy over whether this technology is crossing the line. Of course, the same was said over 50 years ago when flashers first appeared.

While there’s no denying the “that’s cool” aspect of watching a fish react to your bait on forward-facing sonar, such comes with a hefty price tag. In my mind, a modestly-priced sonar unit that shows 2D, down, and side-imaging provides the angler with a lot of information, particularly when he or she can compare all three views to best understand what’s being seen.

Jeff Knapp is an outdoors columnist for the Butler Eagle