What Happens if You Don’t Focus With a Rangefinder – Full Guide

If you have a rangefinder, you might be wondering, what happens if you don’t focus on a rangefinder?

Let’s find out!

What Happens if You Don’t Focus With a Rangefinder?

If you are not using a rangefinder to help you focus on your subject and you just guess at the right distance for your lens, then you will probably end up shooting some blurry images.

This is because when you use autofocus (AF) mode in DSLRs or mirrorless cameras, the camera uses an AF sensor to detect your subject’s location within the frame. The AF system then

  • Calculates how far away the subject is from the center of the frame
  • Adjusts the focusing point accordingly
  • Sets the aperture and shutter speed automatically

In other words, if the AF sensor detects that the subject is too close or too far away, it adjusts the focusing point so that the subject appears sharp in the image. If the subject is in the middle of the frame, the AF sensor does not need to adjust anything. 

What is a Rangefinder?

Rangefinder cameras work differently than SLR and mirrorless cameras. But rangefinders are similar to mirrorless cameras in that they remove the mirror and pentapriscope. However, rangefinders are quite different from SLRs and mirrorless in their operation.

They’re smaller, lighter, and usually quieter than DSLRs and SLRs. Where a DSLR has a large, heavy, mirror slap, a mirrorless camera will have a quick, relatively quiet shutter. It’s difficult to achieve blurring when everything else is perfect.

How Do Rangefinders Work?

A rangefinder is an optical device used to measure distances between objects. In photography, it is often used to determine the distance to subjects such as buildings, hills, trees, and people. It consists of two parts: a prism and an eyepiece.

When light enters the prism, it splits into three beams. One beam travels straight ahead; another beam reflects off the subject being measured, and the third beam reflects off the surface of the prism.

The angle of reflection depends on the distance between the object and the prism. The distance can be calculated by measuring the angles of the reflected beams.

Do the sizes and shapes of rangefinders affect its mechanism?

Rangefinders, just like SLRs, come in various sizes and shapes. Some are large and bright, others are small and dark. The larger the rangefinder and, therefore, its mechanism, the brighter it should be to help you find your subject. If you’re having trouble seeing, then you’ll probably need a brighter rangefinder.

However, if you’ve got poor vision, then you may need a smaller, darker rangefinder: either way, good fortune. 

How Rangefinders Focus?

A rangefinder uses a rangefinding mechanism that displays a dual image on the viewing screen, and when the dial is rotated until the two images merge into one, the shot is in sharp focus.

A rangefinder uses distance measurement to determine the proper focusing distance for the subject. When the rangefinding device determines the correct focusing distance, it transfers that distance to the lens’ focusing mechanism. Some rangefinders were attached to the top of the camera body as accessories.

Coupled rangefinders were later added to some cameras. These rangefinders worked by coupling the rangefinding system to the focusing mechanism inside the camera body.

what happenes if you dont focus with a rangefinder

What Happenes if You Dont Focus With a Rangefinder?

Why Should You Get a Rangefinder?

A rangefinder allows you to take pictures without having to worry about focusing. When you press the shutter button, the camera automatically focuses on whatever subject you’ve selected.

With a digital camera, you can also adjust the aperture (the opening through which light enters) and ISO (a measure of sensitivity). These settings allow you to control depth of field, which determines whether everything in front of or behind your subject appears sharp or blurry.

A range finder is a device used to measure distances between objects. It consists of two parts; one part contains lenses and mirrors, and the other part contains a scale.

When the distance between the object and the lens is known, then the distance between the object, the lens, and the mirror can be calculated. In addition, the angle of the mirror can also be measured.


We hope that know you know about the use of focus in a rangefinder. If you have any queries feel free to reach out in the comments section below.


  • John Moses

    John is the Editor in Chief here at The Outdoor Stores. His area of expertise ensures that there is no one better to suggest which rifles are most suitable for your hunting experience. He is also available for you to contact him personally to discuss the types of animals you want to hunt and the terrain you will be hunting on. Feel free to read his posts for expert opinion on Rifles, Scopes, Rangefinders, Bonoculars and Monoculars.

You Might Be Interested In...

Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors

Might Be Interested In!