What’s the difference between Canon STM and USM lenses?
Asked 4/1/2017
2 views
2 answers
0
I’m trying to understand the difference between STM and USM in Canon lenses. What do these terms mean, and what is the main practical difference between them for autofocus? Are STM and USM names specific to Canon, or do other brands like Nikon use similar focus motor types under different names? For general day-to-day photography and learning the basics, which type makes more sense to choose?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
9y ago
2 Answers
2
STM is an acronym for Stepper Motor. USM is an acronym for Ultrasonic Motor. The specific STM and USM nomenclature is strictly Canon, but other lens makers have similar terms for the USM concept, as well as newer linear types of AF motors. Canon dubbed their new linear AF motor Nano USM in the new EF 18-135mm f/3.5-5.6 IS USM and EF 70-300mm f/4-5.6 IS II USM lenses, but Nano isn't included by Canon in the official lens names.
Basically the names are for designating different types of motors that convert electricity into mechanical movement in order to focus the lens.
For a good comparison of how STM and USM lenses work please see this answer to What does STM mean on a Canon lens?.
For how those differences work out practically, please see: Why do higher end lenses use USM instead of STM? and STM vs Non STM lenses for still photography??
To the best of my knowledge, Canon is the only lens maker currently using stepper motor technology for AF in some of their lenses designed for interchangeable lens cameras.
Many makers use variations of USM. Nikon calls it Silent Wave (SWV), Sony calls it Super-Sonic Motor (SSM), Pentax calls it Supersonic Drive Motor (SDM), Olympus calls it Supersonic Wave Drive Motor (SWD), Sigma calls it Hyper-Sonic Motor (HSM), and Tamron calls it Ultrasonic Silent Drive (USD).
Linear motors, with a variety of different names, are becoming quite common in lenses for newer Micro 4/3 and other mirrorless camera systems.
Originally by user15871. Source · Licensed CC BY-SA 4.0
user15871
9y ago
0
Generated from our catalog & community — verify before relying on it.
STM and USM refer to different autofocus motor designs in Canon lenses.
- STM = Stepper Motor
- USM = Ultrasonic Motor
They describe how the lens moves its focusing elements. In practical terms, they are both autofocus technologies, but they are different motor types.
The STM/USM naming is Canon-specific. Other brands also use their own names for similar autofocus motor systems, including ultrasonic and newer linear-type motors.
For a buyer, the main point is that these labels tell you what kind of AF motor is inside the lens, not whether the lens is only for a certain camera brand beyond mount compatibility. Canon uses these names on Canon lenses; other makers use different branding.
For general everyday photography and learning, either can be fine. The better choice depends more on the specific lens and your needs than on the label alone. If you’re comparing two Canon lenses, treat STM vs USM as one factor in autofocus behavior, but also look at focal length, aperture, image stabilization, size, and price.
Recommended products
UniqueBot
AI9y ago
Your Answer
Related Questions
Why do high-end Canon lenses use USM instead of STM?
How can I identify lenses with full-time manual focus override?
Canon EOS RP travel lens: RF 24-105mm f/4L or RF 24-240mm f/4-6.3?
What do DSLR sensor sizes like APS-C, APS-H, DX, FX, and full frame mean, and how do they affect lenses?
What do the letters and numbers in lens names mean across Canon, Nikon, Sigma, and other brands?