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STM vs. USM Lenses: What’s The Difference?

First, some historical background. Well, we are about to talk about a very cool innovation and that’s for sure. Yes, we all know that cameras are supposed to have a focusing motor but we don’t know that a focusing motor can be placed also inside lenses, and that’s exactly what Canon did. Canon is the first company that dared to do such an innovation in the photography world and now other companies are just followers, as nowadays having a focusing motor inside of a camera lens has become normal.

Usually, the process of choosing the right lens for your camera is not easy, especially if you are a professional photographer and you know exactly what you want. The process becomes even harder once you have to choose between two lenses that are founded by the same company as you suspect that they both can be equally great. Well, let me ease your process of choosing by pointing out the key differences between STM and USM lenses. Let’s get into it!

STM vs USM

Which one is better?

What they stand for – First, we need to know that they both are autofocus lenses, but the thing is that they are made of different types of autofocus system. STM is not some initial, they stand for Stepper Motor and it is used inside a Canon STM lens for autofocusing.

When it comes to these lenses operating, they function using a geared motor to rotate the focus ring. Whereas USM stands for Ultrasonic motor or autofocusing. USM functions by using ultrasonic vibrations. These vibrations are turned into repeating movements so they can turn the focus ring.

Silent or noisy – It is a very important difference since you have to carry your camera around wherever you go, so, if you are a person that gets annoyed quickly, then you wouldn’t like to purchase the USM lenses. This noise is mainly caused by the quick movement of the elements of the lens. So, if you are looking for a lens to take your videos especially, you wouldn’t do yourself a favor by purchasing the USM lens.

On the other hand, STM lenses are quite as hell. So, we can say that the most excellent lens between these two when it comes to recording videos, is the STM lens.

No matter if you are a photo or a video person, relying mostly on this feature, you will choose what lens to buy. Being less noisy, STM is perfect for videos. If you don’t want a video taken with a strange noise in the background with that being lens’s noise, then forget about USM lenses and go for an STM lens.

On the contrary, if you are more of a photos person, and you happen to have some spared money, then don’t hesitate and just go for a USM lens, and thank me later.

Prize money – If you are saying that I’m buying the best lens at any cost, then just skip this part. But, if you are saying that you are on a budget and you need to do some calculations, then hear me out.

SM lenses are more expensive than STM lenses and there are a few reasons why.

Firstly, as we mentioned, USM has an ultrasonic motor for autofocus, which obviously can cost some money.

Second, having that ultrasonic motor, makes the USM lenses faster than the STM lenses.

And last, be certainly not least, you can manually focus USM lenses without having to switch from AF to MF mode. Yes, it is expensive, but if you are buying a USM lens, you are also buying these three amazing main features.

Furious or not – Just like we mentioned, USM lenses are faster than STM lenses. So, if you are interested in a lens with fast autofocus, then go for the USM lens. Most wildlife photographers prefer this lens, simply because of its speed to focus on more than one thing at once.

Now that we have pointed out the main differences between these two lenses, then we can carry on by showing some types of USM and STM lenses.

Types of USM lenses

Nano USM

Nano USM offers more linear than a rotational movement of the lens. This lens has a common characteristic with the STM lens and that is, it requires focus-by-wire, so the manual focus ring is not connected to the lens focus system, just like the case with STM lenses.

Ring Type USM

This type of USM lens operates with two rings, but they are connected to two different parts, one of them is connected to the focusing system and the other to the barrel.

Micro USM

This type of USM lens operates with a sonic vibration motor that is necessarily directly linked to the focusing system. Just like the Nano type, Micro USM doesn’t have a full-time manual focusing, either.

Types of STM lenses:

The lead-screw-type 

This type of STM lens has two main features. They are super quick and super silent. 

Gear-type

This type of STM lens is more compact than the first one. It is actually designed for compactness which makes it possible to work in much smaller lenses.

Final Words

In this case, there is no right or wrong, there is no right answer or a correct answer, especially when it comes to two amazing lenses created by Canon. The decision is not easy to be made but at least now you know what to take and what to not take into consideration, and you know for certain that there is no chance for you to make a mistake, choosing one or the other. When it comes to choosing between such great lenses, I would say focus on what you need them for. That has to be the first step. Where are those lenses going to use and what for? This might be one of your reference questions when in doubt about which one to take and which one to leave. The decision is up to you, obviously, but you don’t have to worry, since there’s no space for mistakes.