What is a Side Focus On a Scope?

Most of you who own scopes are well-known for adjustments made to the windage and elevation knobs in scopes. The elevation knob is always on top of the scope and helps in moving the reticle up and down, and the windage know is always on the right side of the scope and moves the reticle left and right.

You can also notice the third knob, which is available on the left side of your scope and is called the side focus. Don’t know about it?

You must be like, what is a side focus on a scope?

Well, I’m here to guide on the side focus which is also known as adjustment knob on a scope with my blog post.


Side Focus On a Scope


Imagine you are looking through your scope and focus on your target and it appears that the reticle is moving or floating around. This is parallax, you must be thinking it is due to your slight movement of the head but that actually does not affect the placement of the reticle.

The parallax adjustment knob will help you to focus your reticle at the correct focal plane and so that you can solidly place the reticle on the target.


Parallax is going to affect you only if you are shooting at long-range distances, every time when you will experience the parallax then you will consider it as a problem with the scope or with your alignment. If you are new and not an experienced shooter who has experienced parallax adjustment then you will face some difficulties.

It can even save your hunt, but it is hardly used as most of the time the windage and elevation knobs can help you.

If you want to test your parallax on the range, you can easily do it.  You can use the bobble-head technique and looking in the scope and then adjusting the parallax until you will see the reticle is not moving anymore.

Focal Plane

In simple words, whenever we talk about the focal plane on a scope. Most of you consider it for the first or second focal plane but it is not what we will be talking about.

When We talk about the focal plane then we are talking about the reticle in relation to your eye. It is really important to get the reticle on the same focal plane as that of the target if you want to deal with parallax.

It means you need to be seeing the reticle on the target and not just pointing to the target.

We can understand this with an example if you pick an image around the shooting range and then cover it with your thumb and then move your head around. Then you will see that your thumb is all over the place and not where you just placed it.  Now ask some other guy to go and place their thumb on the image and now you will see that, whenever you will move your head, the thumb will stay in the same place on the image. It means it is on the same focal plane.

This is the reason you will not find parallax issues with a red dot. You can easily place the reticle on the target. Side focus helps you in placing the reticle on the same focal length as most of the scopes don’t allow you to place the reticle on the target.


I tried explaining the parallax thing in the easiest way I could. And I hope that now you have a fairly good idea of what actually a side focus is and how it can help you. Most of the guys don’t actually know about it. The complete parallax thing can be a lot more confusing and I know if you are just a beginner then you might have some more questions in your mind about the side focus and the parallax effect.

No worries, if you still have any doubts related to it. Then feel free to comment below and I will be more than happy to help you out.

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