Whether you looking to buy a filter, lens cap, or lens hood, knowing the filter size of your camera lens is important. There are several ways to find out the filter size of your lens. Here is our guide to helping you find out which filter size your lens has.

Filter size is the size of the front of your camera lens. It determines which size of filter, lens cap, or lens hood will correctly fit the front of your camera lens. Each lens has a different filter size, although some brands use the same filter size quite consistently. 

For example, most Canon FD lenses are 52mm and most Olympus Zuiko lenses are 49mm. Having consistency across brands means that you can use the same filters across your range of lenses.

Purchasing a filter, lens cap, or lens hood that is the wrong filter size for your lens will mean that it won’t fit correctly. Even though the differences in most filters sizes are a few millimetres, an incorrectly sized filter will not fit. 

I already have some filters, but they don't fit my lens.

Don't worry! You can purchase step-up or step-down rings that enable you to use a different sized filter on your lens. These rings convert the filter size of your lens to the size of the filter you have. For example, if you have a 49mm lens and a 52mm filter, you can get a step-up ring from 49mm to 52mm.

We have a wide range of these available here.

There are a few ways to know the filter size of your lens.

The first is the text written on the lens itself. It is important to note that your filter size is different from the focal length of your lens. For example, if you have a 50mm focal length lens, this does not mean that your filter size is 50mm.

On the front of your lens, there are several pieces of information. These are most commonly the brand name of your lens (Canon, Nikon, etc), the focal length (50mm, 28mm, etc), and the aperture (3.5, 4.5, etc).

Here is a diagram showing this information on the front of the lens.

On some lenses, there will also be a symbol like this: ø 

This symbol refers to the diameter of your lens and is what your filter size will be. Not all lenses have this information on the front of your lens, but if it does, your job is a lot easier.

Below is an example of what this information may look like on the front of your lens.

The second way to know what filter size your lens has is to measure it. There are some key things to be aware of when measuring. Make sure you are measuring the inside diameter of the filter ring, not the outside diameter. 

Most filters, lens caps, and lens hoods will screw and fit inside the ring of the lens, not clipping over the top. Push-on lens caps and lens hoods are the exception to this rule. We will discuss these in more detail later.

Below shows where you should measure your lens to find out its filter size. 

The third way to find out the filter size of your lens is to search for it online. There are some technical specification pages that have this information available to you. Some of the most common lenses will be available this way.

Below we have listed a few of the most common lenses and their filter sizes:

Canon FD 50mm f/1.8 = 52mm

Canon FD 50mm f/1.4 = 52mm

Olympus Zuiko 50mm f/1.8 = 49mm

Olympus Zuiko 50mm f/1.4 = 49mm

Pentax PK SMC 50mm f/1.7 = 49mm

Pentax PK SMC 50mm f/2 = 49mm

Olympus Trip 35 = 43.5mm

Asahi Pentax 50mm f/1.4 M42 = 49mm

Still need some help finding out your lens filter size?

Send us a message on our live chat or via email and we will be in touch! We would love to help you find out your lens filter size.

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