Down Imaging vs Side Imaging - What's the Key Differences?

Down Imaging vs Side Imaging
November 21, 2022

The difference between down imaging vs side imaging is one of the most common questions that I get asked. Which sonar system should you use? The answer to this question depends on your situation, but there are some key differences.

Fish finders with Down and Side imaging are fishing technologies that let you see the underwater world clearly and in great detail. The two have some similarities and a plethora of distinctions. They concentrate on different areas and aspects of fishing. 

Fishing using down imaging sonar and side imaging sonar

Boat owners who are looking to upgrade their sonar should first consider which type of imaging they want. Side Imaging is typically chosen by those who fish shallow waters, while Down Imaging is for those in deeper water. Both types have their pros and cons, so it's important to choose the best option that suits your needs!

Using a scanner isn’t obligatory but it certainly helps you avoid the exhausting part of fishing and lets you locate your targets easily. You will rely more on your fish finder while fishing in the winter months when it's cold and you need to fish deeper. So, you’ll be able to enjoy the excitement of luring and catching fish without spending too much precious time looking for them.

Let’s dive deeper into more details about down-scanners and side-scanners and see why they are useful and how they differ from each other so that you’ll be able to choose between them depending on your preferences and fishing plans.

What is Down Imaging?

humminbird down imaging fish finder

In order to compare fish finders with down imaging and side imaging, first, we need to know all the necessary facts and characteristics of each one. Let’s jump into more details about down imaging straight away.

Down imaging fish finders will display images of everything that is happening directly beneath your boat. The transducer sends sonar waves under the boat which provides you with a solid idea of where fish and structure are located underneath you and partially in front and behind you.

Down imaging technology works with the help of SONAR waves, and when the waves return back, the more explicit images are displayed on the fish finder screen. It is a registered term used by Humminbird, while Lowrance refers to it as DownScan imaging and Garmin as DownVü.

Advantages of Down Imaging

  • Price: Usually most fish finders use down imaging as it’s relatively cheaper than other techniques and therefore is practical. You can even use the GPS Fish Finder that has the Down Imaging function installed. So, it’s more affordable and may even be in combination with other features.
  • Simplicity: Down imaging is much easier to perceive and use as a strategic guide for your fishing experience.
  • Speed: when you’re moving at a high speed, you need to scan a huge area in a matter of seconds. Down Imaging has higher quality pictures when it comes to high-speed traveling.
  • Small Fish: Down imaging is more common when fishing for smaller fish such as panfish, bass, bluegill, and many other types of fish.
  • Deep waters: finding fish in deep waters is much more practical by using a Down Imaging finder.

Disadvantages of Down Imaging

  • Image quality: when it comes to the quality of pictures displaying the underwater environment, down imaging produces relatively lower quality pictures, compared to side imaging snap quality and resolution.
  • Inaccurate imaging results: as the down imaging technique only lets you see what is happening underneath your boat, you’re unable to detect fish that are slightly distant from you. It’s hard to cover all the areas to see if there are fish close to your boat. So, for this matter, using side imaging techniques is much more productive and effective.
Humminbird HELIX 7 Mega Down Imaging
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What is Side Imaging?

humminbird side imaging fishing finder

Side imaging sonar technology lets you see the horizontal picture of the underwater environment. It delivers clear images on each side of your boat by scanning a large area around you.

Side imaging is an advanced technology that makes fishing easier. Transducers release sound waves that actually cover both sides of your vessel. This helps you quickly scan the water horizontally on each side of you. If you are moving through a creek or river, these are a great choice for fishing.

Side imaging fish finders aren’t always the best choice for locating smaller fish because most people use them with trolling motors. If you use a side scan fish finder, you can quickly get accurate information about the bottom structure and contour.

Advantages of Side Imaging

  • Quicker process: finding fish with Side imaging sonar is much faster than with down fishing as you see two sides at the same time and swiftly assess the fish locations. It lets you form your plan of attack much more efficiently. You don’t have to roam the same area several times to make sure you’ve covered everything as the side imaging scans a large zone.
  • Shallow waters: Side imaging fish finder is the best choice when fishing in shallow water, as you see both sides of the water and can locate fish after looking at the easily comprehensible picture.
  • Two in one: often a side Imaging sonar function comes also with down imaging, so in some cases, by purchasing a side-scanner, you’ll also receive a down imaging function.
  • Picture Quality: side imaging offers much more pleasant, clear, and easily perceivable views of the water. But the high quality requires slow movement so, you won’t be able to travel fast when using a side-scanner.
  • Small creeks and rivers: if your fishing place is relatively smaller, it gives you an extra advantage of scanning the whole area. The finder won’t miss any small points where fish might be hiding.

Disadvantages of Side Imaging

  • Small Fish: finding relatively smaller fish with Side imaging is less common, as it’s much more difficult to scan smaller objects in general.
  • Slower movements: since side imaging provides much more accurate results with high-resolution pictures, it needs some time to load. So, you’ll have to move a little slower than you would while using down imaging. Slowing down is not particularly a disadvantage if you prefer quality over quantity as you might locate fish slower, but the wait will certainly pay off.
  • Price: a side-scanner is much more expensive than the down-scanner. Sometimes side imaging is offered as a premium offer which may include the down imaging fish finder as well. If you want to save some money and you’re looking for a more affordable fish finder, I suggest using the down imaging one.
  • Inaccurate view under the boat: while down imaging is concentrated only on the area underneath your boat, side fishing fails to live up to the expectation of the high quality of this exact area. That’s why many fishers prefer to have both, down and side image scanners to have the full picture in high resolution.
Humminbird HELIX 7 Mega Side Imaging
Humminbird HELIX 7 Mega Side Imaging
Latest Price

Which is Better? Down Imaging VS Side Imaging

Which is Better Down Imaging VS Side Imaging

Now that you know what down and side imaging are, we can analyze the two and see which one is better for different occasions.

Both, downscan and sidescan imaging have their advantages and disadvantages. Comparing side imaging vs down imaging for fish finders is hard, as it depends on your preferences and fishing goals. The two techniques are similar but work differently. The difference doesn’t make one better than the other.

The best option is to fish with both devices as they will cover all the area you pass, underneath the boat and the sides. Usually, side imaging features come with down imaging ones, so it won’t be too much of a problem. 

There are a lot of options for the combination of the two devices such as hummingbird side imaging and down imaging combo.

But if you want to choose only one scanner device, you should decide based on the characteristics and the fishing value that both technologies offer. 

Both fish finders are different in the way they operate and are optimized to do. When determining which is best for you, you should consider the depths you will be fishing as well as the speed you will love to travel at.

You should also consider the fish size and the cover you'll be fishing on when deciding which is the best sonar for you.

Let’s try to compare down and side imaging to clearly see their connections and distinctions.

Which Imaging Sonar Should I choose?

Fish finder sonar on a boat while fishing

Both types of fish finders operate differently and I find that they work best when put together.

The reason why I recommend buying a down imaging and side imaging combo whenever possible if you can afford it. It’s a continuous flow of sonar technology sent into the water from the sonar unit.

If you’re the type of angler who spends most of his or her time in shallow rivers, downscan will almost do you no good. It means you need to read the water directly beneath you and choose the best fish finder for your situation. This is why I find having a fish finder with a combo of both down imaging sonar, traditional sonar and side imaging sonar the best option if you fish many different water types.


Both, down and side imaging use high-frequency imaging Sonar waves to deliver a good quality life-like view of the underwater environment.

Generally, the process of down-scanning and side-scanning is quite similar, but it has more distinctions than resemblance. They’re both useful and practical but have different qualities and features. So, let’s concentrate on the differences.


  • Down Imaging device scans the water vertically, while Side Imaging does it horizontally from both sides of the water.
  • Depth: Side imaging is more practical for shallow waters, whereas it’s better to use down imaging for deeper waters.
  • Speed: you can travel at any speed you want when using a down-scanner but if you’re using a side-scanner you’ll have to slow down, as it’s unable to capture good-quality pictures in a fast-moving boat.
  • Price: down imaging is more affordable than a side imaging device, which is usually a premium offer. In most cases, when you buy a side-scanner, you also have access to down-scanning, which is a huge benefit.
  • Small objects: down imaging device is much more likely to capture small objects such as small fish. Whereas side-scanner fails to deliver a high-quality picture of small fish. 

Down and Side Imaging Tips and Tricks

  • Ice fishing: if you’re going to fish under the ice, you’ll need to use a down imaging device. The Down-scanner will let you know where exactly to drill a hole underneath you. Side-scanner won’t work as it will tell you nothing valuable for ice fishing.
  • Kayaking: when you’re kayaking, side imaging is more effective and practical. You’re more likely to fish in rivers and ponds shallow waters. Also, you’ll want to see the full image of the area.
  • Trolling: side-scanner is the best choice if you’re using a trolling rod. Move slowly to let the scanner capture high-quality pictures.

Ready to Use Your Fish Finder?

Now that you know the key similarities and differences between side-scanning and down-scanning devices, you can choose the right fit for you, or even not choose and use both.

Carefully analyze your fishing strategy, location, fishing depth, and the area where you’ll be searching for fish to choose the right device for your needs.

The best option is to have both, down imaging and side imaging, as you’ll have a complete view of the water. But if you’re going to choose just one, it won’t be a problem in any way. 

Use a down imaging device if you’re looking for more affordable options that are easier to use. Also, choose the down imaging one when you’re fishing in deep waters or you want to move relatively faster, as side imaging doesn’t capture high-quality images when traveling at a high speed. Other than that, keep in mind that small fish are better found by down imaging devices.

You should choose the side imaging device if you’re planning to fish in shallow waters or smaller creeks and narrow rivers. Also, side-scanning produces better quality images than down-scanning in general, except when moving at a higher speed.

Using a fish finder will make your fishing experience more enjoyable as the device will help you locate the fish and you’re left with the greatest part of fishing, which is luring and catching fish.

Don’t hesitate to try out new techniques and technologies, use a down-scanner, side-scanner, or even both at once, as it increases your chances of locating fish by letting you see the full picture of the underwater world. 

Have a fruitful fishing adventure 🙂

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