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Yongnuo YN 42.5mm f/1.7 M II Lens for Micro Four Thirds

BH #YOYN425F17M2 • MFR #YN42.5MM F1.7M II
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Yongnuo YN 42.5mm f/1.7 M II Lens for Micro Four Thirds
Key Features
  • Micro Four Thirds System
  • 85mm (35mm Equivalent)
  • Aperture Range: f/1.7 to f/22
  • Minimum Focusing Distance: 11.8"
An excellent choice for portrait photography, this updated YN 42.5mm f/1.7 M II Lens from Yongnuo is an 85mm-equivalent lens designed for the Micro Four Thirds system of mirrorless cameras. The lens contains two ultra-low dispersion elements to control spherical aberrations and distortions for enhanced sharpness and accurate rendering, and a refined STM stepping motor enables fast and quiet autofocusing for both stills and video. Additionally, an AF/MF switch on the barrel allows you to quickly switch to manual focusing if needed. Featuring a bright maximum aperture of f/1.7, the lens also provides a minimum focusing distance of 11.8". Combine these attributes with the lens's 7-blade diaphragm and you can easily achieve selective focus and bokeh in your photos and portraits.
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Yongnuo 42.5mm f/1.7 II Overview

An excellent choice for portrait photography, this updated YN 42.5mm f/1.7 M II Lens from Yongnuo is an 85mm-equivalent lens designed for the Micro Four Thirds system of mirrorless cameras. The lens contains two ultra-low dispersion elements to control spherical aberrations and distortions for enhanced sharpness and accurate rendering, and a refined STM stepping motor enables fast and quiet autofocusing for both stills and video. Additionally, an AF/MF switch on the barrel allows you to quickly switch to manual focusing if needed. Featuring a bright maximum aperture of f/1.7, the lens also provides a minimum focusing distance of 11.8". Combine these attributes with the lens's 7-blade diaphragm and you can easily achieve selective focus and bokeh in your photos and portraits.

Prime 42.5mm portrait-length lens provides an 85mm equivalent focal length with Micro Four Thirds cameras.
Fast f/1.7 maximum aperture enables extensive control over focus position and also benefits working in difficult lighting conditions.
11.8" minimum focusing distance to suit working with close-up subjects.
Two aspherical elements help to reduce spherical aberrations for greater sharpness and clarity.
Updated stepping AF motor provides smooth and quiet focusing performance for stills and video.
Seven-blade diaphragm produces a smooth out-of-focus quality when working with selective focus and shallow depth of field techniques.
EAN: 6947110913513

Yongnuo 42.5mm f/1.7 II Specs

Focal Length
42.5mm
Aperture
Maximum: f/1.7
Minimum: f/22
Lens Mount
Micro Four Thirds
Lens Format Coverage
Micro Four Thirds
Angle of View
29°
Minimum Focus Distance
11.8" / 30 cm
Magnification
1:6.67 Macro Reproduction Ratio
0.15x Magnification
Optical Design
9 Elements in 8 Groups
Aperture/Iris Blades
7
Focus Type
Autofocus
Image Stabilization
No
Filter Size
52 mm (Front)
Dimensions
2.4 x 2.2" / 61.6 x 55.4 mm (Diameter x Length)
Weight
5.2 oz / 146 g
Packaging Info
Package Weight
0.52 lb
Box Dimensions (LxWxH)
4.4 x 3.7 x 3.6"

Yongnuo 42.5mm f/1.7 II Reviews

Good lens but too tight of a fit makes it a no go for me.

By Mike
Rated 2 out of 5
Date: 2026-09-22

It has solid image quality and good sharpness. Wide open is a little soft but stop down just a little and it's great. Out of focus backgrounds are rendered nicely. The big issue is the tight fit. For both my G9ii and OM5 ii, getting the lens on the cameras is hard and getting it off is an extreme exercise in frustration.

Great bokeh, but sketchy focusing and WAY too tight fit on M43 mount

By David
Rated 2 out of 5
Date: 2026-07-13

I thought this would make a great portrait and concert lens, and I was amazed that it had autofocus at this price. The IQ was decent wide open and the bokeh (which I usually don't care about) was great. But the autofocus was erratic, and even in manual focus mode it seemed to jump back and forth. I could even live with all that, but what I couldn't abide was the super tight fit on my OM-1, just short of metal shavings. It also made a loud clicking-like noise when removing it. Returned somewhat sadly.

See any errors on this page?

Can this lens fit Pansonic G5 and GM1?

Can this lens fit Pansonic G5 and GM1?
Asked by: Michael
The Yongnuo YN 42.5mm f/1.7 M II Lens for Micro Four Thirds is compatible with the Panasonic Lumix G5 Mirrorless Micro Four Thirds Digital Camera and the Panasonic Lumix DMC-GM1 Mirrorless Micro Four Thirds Digital Camera.
Answered by: Lawrence C
Date published: 2023-09-20

Can this fit on a Canon R6?

Can this fit on a Canon R6?
Asked by: Katie
I am sorry, the Yongnuo YN 42.5mm f/1.7 M II Lens for Micro Four Thirds will not fit on the Canon R6 and we do not sell any lens mount adapters for this to fit.
Answered by: Yaakov
Date published: 2022-08-26

How is this version II of the lens different than ...

How is this version II of the lens different than the original Yongnou 42.5mm 1.7 lens?
Asked by: Robert
The Yongnuo YN 42.5mm f/1.7 M II Lens for Micro Four Thirds has an STM focus motor, making it smoother and quieter in autofocus compared to version one of the lens. And it has improved camera compatibility.
Answered by: Rob K
Date published: 2025-09-30
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