Side Imaging vs Down Imaging: What's the Difference?

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QUICK ANSWER

Side Imaging and Down Imaging are designed to answer different questions.

Side Imaging scans outward to both sides of the boat, making it particularly useful for searching large areas for underwater structure such as rocks, timber, vegetation, drop-offs, and channels.
Down Imaging focuses on the area directly beneath the boat and produces a detailed, picture-like representation of structure and fish below you. Humminbird describes Down Imaging as a high-frequency system that creates detailed images of structure, vegetation, and fish beneath the boat.

In simple terms:

Side Imaging = search wider.
Down Imaging = examine what's underneath.

Neither technology is universally "better." For anglers who regularly search unfamiliar water, Side Imaging can be extremely useful because it allows you to cover more water. For anglers concentrating on a specific area or wanting a detailed view directly below the boat, Down Imaging can be more useful. And if your budget allows it, having both is usually the most versatile solution.

What Is Side Imaging?
What Is Down Imaging?
Side Imaging vs Down Imaging
Which One Covers More Water?
Which One Shows More Detail?
Which Is Better for Finding Fish?
Which Is Better for Finding Structure?
Can You Use Both at the Same Time?
Side Imaging vs Down Imaging for Different Boats
Which One Should You Buy?
Frequently Asked Questions
The Marine Method Verdict
Final Verdict

WHAT IS SIDE IMAGING?

Side Imaging is a scanning-sonar technology designed to show what's happening to the left and right of your boat. Instead of using a conventional cone-shaped sonar beam, Side Imaging systems use a beam that scans outward toward the sides. Garmin describes its SideVü system as using a flat beam to scan the water and bottom to the sides of the boat. Humminbird describes its Side Imaging system as providing a 180-degree side-to-side perspective, with the sonar returning slices of information that are combined into a larger image as the boat moves. This makes Side Imaging particularly useful for searching. Imagine you're looking for submerged trees on a large lake. With conventional downward-looking sonar, you generally want to pass over the target. With Side Imaging, you can potentially see structure off to the side while you're still moving past it. That means you can cover water more efficiently. See our guide to Best Fish Finders With Side Imaging in 2026.

WHAT IS DOWN IMAGING?

Down Imaging is designed to give you a detailed view of what's directly beneath the boat. The technology uses high-frequency sonar to produce a picture-like representation of the underwater environment. Humminbird explains that Down Imaging creates detailed images of structure, vegetation, and fish, with the information oriented similarly to traditional down-looking sonar. Lowrance similarly describes DownScan Imaging as producing picture-like images of rocks, trees, bottom composition, and other underwater structure directly beneath the boat. This makes Down Imaging particularly useful when you want to examine an area rather than simply search for one.

SIDE IMAGING VS DOWN IMAGING

Feature	Side Imaging	Down Imaging
Main view	To both sides of the boat	Directly underneath the boat
Best for	Searching for structure	Examining structure
Coverage	Wide	More focused
Structure detection	Excellent	Excellent
Best search use	Covering unfamiliar water	Investigating a specific area
Learning curve	Moderate	Generally easier
Ideal situation	Finding new fishing spots	Studying what is below you

The simplest way to remember the difference is:

Side Imaging helps you find where to look.
Down Imaging helps you understand what's underneath you.

WHICH ONE COVERS MORE WATER?

This is where Side Imaging has its biggest advantage because the sonar scans to both sides of the boat, you can examine a much wider area while traveling. Lowrance describes SideScan as being designed to cover large areas quickly, while Humminbird describes Side Imaging as scanning areas to the left and right of the boat. For example, Humminbird lists some Side Imaging systems as capable of scanning up to 400 feet to each side, depending on the system and settings. However, don't interpret advertised maximum range as a guarantee of the same image quality at every distance. Practical performance depends on factors such as:

Water depth
Frequency
Bottom composition
Sonar settings
Boat speed
Transducer
Target size
Water conditions

So the important advantage isn't simply "more feet." It's the ability to search a wider area efficiently.

WHICH ONE SHOWS MORE DETAIL?

This is more complicated. Both technologies can produce highly detailed images, but they are looking at different parts of the underwater environment. Down Imaging concentrates on the area beneath the boat. That makes it particularly useful for examining:

Rocks
Trees
Brush
Vegetation
Bottom composition
Other underwater structure

Lowrance describes DownScan as providing picture-like images of structure directly beneath the boat. Side Imaging can also reveal impressive detail, but its biggest advantage is the combination of detail and wider coverage. So rather than asking: "Which one has better detail?" A better question is: "Where do I need the detail?" If you need to understand what's directly underneath the boat, Down Imaging is the obvious choice. If you're searching a large area for something worth investigating, Side Imaging has the advantage.

WHICH IS BETTER FOR FINDING FISH?

This question is slightly misleading. Neither Side Imaging nor Down Imaging should be thought of simply as a magical fish detector. Both technologies can show fish, but their greatest value is often helping you understand the environment where fish may be holding. For example, Side Imaging might reveal a submerged tree line 50 feet away from the boat. You can then position the boat appropriately and use Down Imaging or traditional CHIRP sonar to investigate the area. This is why combining sonar technologies can be so powerful. Lowrance, for example, combines CHIRP and DownScan through FishReveal to make fish easier to distinguish from surrounding structure.

The practical answer:

-Side Imaging is better for finding promising areas.

-Down Imaging is better for examining what's beneath you.

But neither should be treated as a replacement for traditional sonar in every situation.

WHICH IS BETTER FOR FINDING STRUCTURE?

Both are excellent, but they approach the problem differently.

Side Imaging

Side Imaging is particularly useful when you don't know where the structure is. You can scan the area around the boat and potentially discover:

Rock piles
Timber
Weed beds
Ledges
Channels
Drop-offs
Other cover

This makes it a powerful searching tool.

Down Imaging

Down Imaging becomes particularly useful once you're directly over an area of interest. You can examine what's beneath the boat and get a detailed view of the structure.

The best approach?

Use Side Imaging to find it.
Use Down Imaging to study it.

CAN YOU USE BOTH AT THE SAME TIME?

Yes. In fact, many modern fish finders support multiple sonar views or split-screen configurations. Humminbird specifically describes combining Down Imaging and CHIRP Digital Sonar on the same display, while Lowrance offers systems that combine CHIRP, SideScan, and DownScan through compatible transducers. A useful setup might look like: Side Imaging + Down Imaging or: Side Imaging + Traditional CHIRP or even: Side Imaging + Down Imaging + GPS map. This lets you search, investigate, and mark productive locations without constantly changing screens.

SIDE IMAGING VS DOWN IMAGING FOR DIFFERENT BOATS

The right choice can also depend on your boat.

Small Boats

For smaller boats, Side Imaging can be particularly useful because it allows you to search a larger area without needing to physically travel over every potential target. However, screen size becomes important. A 7-inch display may be a good compromise between visibility and installation space. If you want to explore this category further, see our guide to Best Fish Finders for Small Boats in 2026.

Jon Boats

Jon boats are often used in relatively shallow water and around structure. A combination of Side Imaging and Down Imaging can be particularly useful for locating and examining submerged cover. See our guide to Best Fish Finders for Jon Boats in 2026 for more options.

Kayaks

For kayaks, size, power consumption, installation, and portability become more important. You may not need the largest display available. A compact system with the right transducer can be more practical than a large multifunction unit.

Larger Fishing Boats

Larger boats provide more space for larger displays and more sophisticated electronics. This is where combining:

Side Imaging
Down Imaging
CHIRP
GPS
Mapping

can become particularly useful.

WHICH ONE SHOULD YOU BUY?

The answer depends on how you fish.

Choose Side Imaging if you:

Fish large bodies of water
Explore unfamiliar areas
Search for submerged structure
Want to cover water efficiently
Frequently fish around cover
Want to locate potential fishing spots

Choose Down Imaging if you:

Fish relatively small areas
Want a detailed view beneath the boat
Spend a lot of time examining structure
Prefer a simpler sonar setup
Don't need wide-area searching

Choose both if you:

Fish frequently
Explore new water
Want maximum versatility
Have enough budget
Want to combine searching and detailed investigation

And if you're working with a limited budget, our guide to Best Fish Finders Under $300 in 2026 can help you compare more affordable options.

DON'T FORGET THE TRANSDUCER

One of the biggest mistakes people make when shopping for marine electronics is focusing only on the display. The transducer is equally important. Different transducers support different sonar technologies. For example, Lowrance's Active Imaging HD 3-in-1 transducer combines CHIRP, SideScan, and DownScan Imaging. Garmin also notes that compatible transducers are required for ClearVü and SideVü scanning sonar on applicable systems. So before buying a fish finder, always check:

What transducer is included? Don't assume that the display alone tells you what sonar capabilities you'll get.

DOES SIDE IMAGING REPLACE DOWN IMAGING?

No. Side Imaging and Down Imaging complement each other. Side Imaging gives you a wider perspective. Down Imaging gives you a focused view beneath the boat. Think of them as two different camera angles rather than two competing technologies. If you regularly search for new structure, Side Imaging may become your favorite view. Once you've found something interesting, Down Imaging can help you examine it.

DOES DOWN IMAGING REPLACE TRADITIONAL SONAR?

Not necessarily. Traditional CHIRP sonar remains useful for identifying fish targets and understanding the water column. Lowrance, for example, describes CHIRP sonar as helping provide clearer fish targets, including fish close to the bottom or in tight schools. That's why a sophisticated fish finder often combines several sonar technologies instead of relying on one. A powerful setup can include: Traditional CHIRP + Down Imaging + Side Imaging + GPS. Each technology answers a slightly different question.

FREQUENTLY ASKED QUESTIONS

Is Side Imaging better than Down Imaging?

Neither is universally better. Side Imaging is better for searching a wider area, while Down Imaging is better for examining what's directly beneath the boat.

Is Side Imaging worth the extra money?

For anglers who regularly search large or unfamiliar areas, it can be. If you mostly fish the same small areas and already know where the structure is, Down Imaging may provide more value.

Can Side Imaging see fish?

Yes, fish can appear on Side Imaging. However, the technology is especially valuable for finding structure and cover where fish may be holding.

Can Down Imaging see fish?

Yes. Down Imaging can show fish as well as underwater structure, although traditional sonar may remain particularly useful for interpreting fish targets in the water column.

Which is easier to learn?

Down Imaging is generally easier for a beginner to understand because the display focuses on the area beneath the boat. Side Imaging can take more practice because you're interpreting a wider, more image-like view.

Do I need both Side Imaging and Down Imaging?

No. If your budget is limited, choose according to your fishing style. If you frequently explore unfamiliar water, prioritize Side Imaging. If you primarily want to examine what's beneath the boat, Down Imaging may be enough.

Does Side Imaging work while the boat is moving?

Yes. Side Imaging is particularly useful while moving because successive sonar slices are combined to create a broader image of the underwater environment. Humminbird describes this process as building the image from successive sonar returns as the boat moves.

Can Side Imaging see shallow water beside the boat?

Yes. One of its advantages is that it can show areas to the side of the boat that you may not pass directly over. Lowrance specifically highlights SideScan for viewing areas that can be too shallow for the boat itself, such as areas next to the shore or bank.

Should I choose Side Imaging or GPS?

These aren't really alternatives. GPS tells you where you are and lets you mark locations. Side Imaging tells you what is around you underwater. If possible, having both is much more useful.

THE MARINE METHOD VERDICT

Side Imaging and Down Imaging aren't competitors. They're complementary tools. If we had to choose just one for an angler who spends a lot of time exploring unfamiliar water, we'd lean toward Side Imaging. The ability to scan a wider area can make finding promising structure much faster, but if your fishing style revolves around a smaller area and you want to understand exactly what's beneath the boat, Down Imaging may be the better investment. And if your budget allows it, the best answer is simple: Get both.

The biggest mistake is choosing based on which technology sounds more advanced. Choose based on how you actually fish.

FINAL VERDICT

Side Imaging and Down Imaging solve two different problems.

Side Imaging asks: What's around me?
Down Imaging asks: What's underneath me?

For searching large areas and locating new structure, Side Imaging has the advantage. For examining the bottom directly beneath your boat, Down Imaging is often the better tool. And modern fish finders increasingly combine both technologies, along with traditional CHIRP sonar and GPS, giving anglers a much more complete picture of the underwater environment.

So don't think of this as a choice between good sonar and better sonar. Think of it as choosing the right view for the job.

- Side Imaging helps you search smarter.

- Down Imaging helps you investigate deeper.

And together, they can make a much more capable fish-finding system.

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