What Does mm Mean On Camera Lens: Answered

Camera bodies and lenses are a complicated topic.  The technology over the last 100 years (the early days of cameras) has advanced leaps and bounds…

But, believe it or not, there are terms from the good ol’ days that’re still used today…

This article will cover just one of those terms, specifically, what does mm mean on camera lens.  By the time you read the entirety of it, you’ll have a much better understanding of what mm means and how it affects your photos!

Without further ado, let’s get to it!

What Does mm Mean On Camera Lens

So, what does mm mean on a camera lens?

Well, the short answer would be - the distance your camera's sensor is to the lens’ point of convergence.  Convergence being the center point at which all the light is directed towards within your lens.

But, let’s break that down really quick.

Take a look at the image below.

What Does Mm Mean On Camera Lens

It’s a great explanation of what’s happening within your camera when you take a photo (or video).  You’ll notice light enters the lens where it then converges to the center and then hit your camera sensor.

It’s at the single most point where all the light that’s coming in meet…  that’s your convergence point.  MM comes from the distance between your cameras sensor to that point (in millimeters).  These can range from a very low mm value of 9 - all the way up to 600mm.

There is a term for this in the camera world.  It’s called focal length.  So, if anyone asks you what focal length you’re shooting on - you now know they mean the mm of the lens.

Continue reading to learn how mm (or focal length) affects your image!

The mm of your lens directly affects your image!

That’s right!  I’m sure you already knew that.  But, do you know exactly how they are affected?  More importantly, do you know how to use focal length (mm) to your advantage?  Let’s take a moment to discuss these aspects!

Longer focal lengths mean “tighter” shots

This is pretty straight forward.  It’s most likely what you already know about higher focal length lenses.  The higher the number, the closer or “tighter” you shot will be.

For instance, if you stood in a single spot and took a photo of a subject at 24mm and immediately changed to a 100mm lens…  you would notice that the image is “zoomed in”.  You can use this to your advantage and get more detailed shots of the area, or change your lens all together to frame a better photograph.  

There is another way to think about it as well.  You can frame the same shot with any lens. As long as you have the space to capture the shot.  Taking that 100mm lens scenario again, if you wanted the same framing as the 24mm, all you would have to do is back up.  This puts you further away from the subject allowing you to frame the same.

Another aspect that works hand in hand with this one is compression.

What Does Mm Mean On Camera Lens
What Does Mm Mean On Camera Lens

Use compression to your advantage

Different focal lengths offer greater (or less) compression.  Compression is simply the lens “compressing” the foreground and background into the same plan as the midground.  This allows for the foreground and background to appear much larger (depending on focal length)

Generally stated, the higher the focal length (or mm), the greater this “compression” is exaggerated.  

You can use this to your advantage by placing your subject in front of an object or landmark.  While using a longer focal length (higher mm lens), you can make the background seem a lot larger and more distinct than using a shorter focal length.

What Does Mm Mean On Camera Lens

Certain focal lengths are better for certain situations!

I do not want this section to confuse you.  But I also want you to read it.  If you find yourself getting confused, leave a comment below letting me know what confuses you, and I’ll attempt to better explain it to you.

With that being said, certain focal lengths are better in certain situations than others.  I’m not say you can’t use any focal length wherever you want.  That’s not it at all.  I actually encourage you to explore and mess around with focal lengths whenever possible (this breeds new creativity).

What I’m saying is that certain focal lengths look best when used to achieve the most out of it.  

Take the image below for example.

This is a great image depicting what focal lengths are the best for a situation.  10-24mm is great for landscapes and real estate photography.  50mm is a great all-around lens.  Even better for urban photography.  70-100mm is great for portrait photography.

Shot @ 12mm

Shot @ 85mm

Shot @ 55mm

This isn’t the end-all-be-all list of focal length uses.  There are many occasions where you can use “wrong” focal lengths in certain situations.  Be as creative as possible.  Step out of the norm from time to time - you may find something that works better for you!

What will most likely happen is you’ll find a focal length that works best with your style.  You’ll then use that lens for most of your work.  Before you know it, you’ll master that focal length and know exactly what to do at any given time for the shot you want.

This very thing happened to me with the 50mm focal length.  I used it for nearly everything for 2 years.

That’s it for now!  Learn more about photography!

If you would like to learn more about photography and general (tips, buying guides, gear, camera settings, etc.), then be sure to start at our home-page and work from there!

If you’d like to see some of our work, be sure to check us out at our business website JnRPhotoVideo.  We offer photo and video service here in San Diego!

Thank you all so much for reading.  I hope you now understand what mm means on a camera lens.  You should now be able to go forward with that information and choose a focal length that best suits you!

As always, keep shooting and creating!


I have been taking photos and film since I was a child. Now that I'm in my mid 30's, I want to share with the world what I have learned over the years. I attempt to live every day to the fullest and share that with you through my blog. I am an electrician by trade and photo and video lie within the "hobby" aspect of my life at the moment. It's what I'm truly passionate about.
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