Down imaging and side imaging are both high-frequency, near-photographic sonar — but they answer different questions. Down imaging asks "what's directly below me?"; side imaging asks "what's around me?" Most serious anglers use both, but knowing which does what helps you read your screen and choose a transducer.
For how these fit among all the sonar types, see understanding sonar; to actually read side scan, see interpreting side imaging.
01Down imaging: the slice below
Down imaging (ClearVü, MEGA DI, DownScan) sends a thin beam straight down and paints a photographic slice of what's directly beneath the boat. It excels at confirming exactly what a piece of cover is — brush, timber, dock posts, bottom transitions — and at vertical presentations and ice fishing, where you're fishing what's straight down. It's tightly focused, so what you see is right under you.
02Side imaging: the wide search
Side imaging (SideVü, MEGA SI, SideScan) fires beams out to both sides, building a wide picture of the bottom as you idle. Its strength is covering water fast — scan a flat, ledge or shoreline in one slow pass and pinpoint where the structure (and fish) are, often well off to the side of the boat. It's a search-and-locate tool more than a confirm tool.
03Head to head
| Down Imaging | Side Imaging | |
|---|---|---|
| Covers | Directly below the boat | Wide area to both sides |
| Best at | Confirming cover & structure under you | Finding structure across an area fast |
| Use case | Vertical jigging, ice, precise checks | Searching flats, ledges, shorelines |
| Reads as | Photographic vertical slice | Top-down map with shadows |
| Boat motion | Works slow or stationary | Best idling straight |
The classic workflow: side imaging to find structure across a large area, then down imaging (and 2D) to confirm what's directly under you before you commit. Most quality 3-in-1 transducers include both, plus CHIRP.
04Which should you prioritize?
- Cover a lot of water / hunt structure (bass, walleye on big lakes) → lean on side imaging.
- Fish vertically or on ice, or fish small, familiar water → down imaging may matter more.
- Most anglers → get a 3-in-1 transducer and use both, plus 2D CHIRP.
The easy path is a unit that includes both in one transducer:
Lowrance HOOK Reveal 7
$$Ships with Active Imaging 3-in-1 — down (DownScan), side (SideScan) and CHIRP in a single transom-mountable transducer — with FishReveal and preloaded C-MAP. The no-compromise way to run both views affordably.
Want the sharpest version of these views? See where the brands differ on imaging, and how frequency drives imaging detail.