What is Down Imaging on a Fish Finder and How Does it Work

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Written By Donny Karr

Donny Karr is a Tournament Angler with more than 20 years of fishing experience and a writer whose work has been featured in magazines for over a decade. He is a member of the Outdoor Writers Association of America. He enjoys bass and crappie fishing in the lakes around the south-eastern United States. He also fishes for trout in the streams and rivers of the Appalachian mountains. Donny has written for Georgia Outdoor News, Paddling Space, Man Can Outdoors, Alabama Outdoor News, and Bassmaster.


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Down Imaging on a fish finder uses high-frequency sound waves to create detailed, photographic-like images of the underwater environment below the boat. It offers a clear view of fish, structure, and vegetation, and helps anglers identify fish species and locate fish-holding areas with accuracy.

Technology related to fish finders and other types of angling electronics have come a long way in the last few decades. With certain technological innovations, companies are now able to produce products that are capable of detecting fish with greater accuracy and quickness than ever before. One of those breakthroughs is known as down imaging. 

For most anglers, especially beginners, understanding how this technology works might be confusing. However, if you’re a serious fisherman or woman who wants to enhance your ability to find and catch fish, it’s important that you have a working knowledge of how down imaging and other fish finder technology operates. 

In this article, we will break down just what down imaging actually is, how it works and why it’s so useful when it comes to fishing. This article will provide you with important information that you can use to make the best buying decisions next time you’re shopping for a new fish finder

What is Down Imaging on a Fish Finder?

Unlike the traditional 2D sonar equipment that’s been used by anglers for many years, down imaging is able to give you a more clear picture of what’s underneath your boat. Down imaging uses a specialized type of sonar to develop a more detailed view of the area you are scanning with your transducer. Instead of the many different green and red colorations on a fish finder’s screen, down imaging will produce a darker image that might be slightly harder for anglers to interpret at first. 

Down imaging shifts from left to right to scan the area more thoroughly and come up with an image that looks more like a picture than a graph. A down imaging fish finder will use higher frequency waves to scan the area to a more precise degree than your traditional 2D sonar is capable of doing. These thinner waves are able to detect the slightest difference in objects and structures along the bottom so that your display screen is able to show you a clearer picture of what you’re looking at below your boat. 

How is Down Imaging Different from Traditional Sonar?

As most anglers know, traditional 2D sonar is able to produce an image that is often very confusing to anyone who doesn’t know how to read the display. It’s usually an image that’s a series of red, green, and yellow colorations that appear in a wave-like pattern and it’s tough for beginners to know exactly what they’re looking at. With down imaging, you’ll usually have a much clearer picture of what’s under your boat and you won’t have to spend much time deciphering what a blob of green dots and lines are. 

Traditional 2D sonar waves are much less precise and aren’t capable of picking up the subtle changes in the exterior of the objects that are being scanned. The down imaging waves are able to scan the objects more thoroughly and give you a complete picture of what you’re looking at. 

You’ll be able to easily tell if you’re looking at standing timber, brush piles, rocks, or virtually any other type of debris using down imaging. This is very helpful and is the main reason why so many anglers are now using down imaging instead of the older 2D sonar. 

One of the biggest differences between down imaging and traditional 2D sonar is the way fish are indicated on both displays. With 2D sonar, a fish will almost always appear as a thin arch and anglers will often be able to tell the size of the fish or just how many by looking at the range of colors and the size of this arch. With down imaging, pinpointing a fish is totally different. 

Instead of appearing like an arch, the down imaging technology detects the fish’s air bladder in most cases, which produces a small white dot or bubble on the screen. Most anglers will run down imaging and their traditional sonar scanning equipment at the same time with split-screen mode on their display. This will help you determine whether the arch or white dot you’re looking at is actually a fish or something else. 

There is also a technology called side imaging that we have written more about here.

Advantages of Using Down Imaging 

Since you’re capable of scanning what’s beneath your boat with much greater accuracy using down imaging, you’ll have a better understanding of where fish are more likely to be in relation to structure or depth changes. With 2D sonar, you might be looking at a large blob of matter that is usually hard to understand and decipher what it actually is, but you can get much greater detail using down imaging. 

If you’re fishing in deeper water, down imaging is much better than the traditional 2D sonar because you’re able to detect fish with much greater accuracy. A typical sonar sometimes gets hard to read when you’re looking at structure or fish that are on the bottom. Down imaging makes it possible to understand whether you’re looking at grass or weeds on the bottom, or a group of fish that are just a few inches from the lake floor. 

Down imaging is able to produce a much clearer picture when you’re on the move as compared to 2D sonar. Most anglers who are accustomed to using traditional sonar know that they can get a more detailed image display by slowing down and stopping their boat over a certain location. Down imaging doesn’t require you to be perfectly still to get a better reading, so you can cover more water in less time using this technology. This is a huge advantage for competitive anglers who are looking to make the best use of their time and locate fish or certain types of structure as quickly as possible. 

You’ll also be able to tell whether you’re looking at multiple fish that are hanging out close to the structure when using down imaging. Traditional sonar usually shows fish close to cover, but it’s sometimes hard to tell if it’s just one fish or more. Down imaging creates a much more clear picture that allows you to see the intricate details of the object, as well as how many fish you’re seeing below your boat near cover. 


Some popular model fish finders with down imaging include Garmin Echomap, Lowrance Hook, Garmin Striker, and Humminbird HELIX.

When it comes to using and understanding down imaging, the most obvious difference from traditional sonar is the overall detail you’re able to get. Down imaging produces a much clearer picture that lets you see structure and other aspects of the bottom with incredible detail, so you know exactly what you’re looking at in most cases. By using down imaging, you can increase your ability to detect fish and understand where to find them at certain times of the year. 

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