Review YONGNUO 42.5mm 1: 1.7 + Update 1,2

According provided by YONGNUO 42.5mm 1: 1.7 lens huge thanks directly company Yongnuo.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7


  1. In short
  2. History
  3. All lenses from Yongnuo
  4. Appearance
  5. Main Specifications
  6. Assembly
  7. Focusing
  8. Image quality
  9. Sample Photos
  10. UPDATE 1
  11. UPDATE 2
  12. My experience
  13. Similar lenses
  14. Price
  15. Results
  16. New version YONGNUO 42.5mm 1: 1.7M II
  17. User Comments
  18. Add your review or question on the lens

In this review, I will call the lens abbreviated Yongnuo 42.5 / 1.7.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7

In short

Yongnuo 42.5 / 1.7 short telephoto lens for Micro 4/3 system. Primarily aimed at portrait and creative shooting. It is suitable for any Micro 4/3 camera system from Panasonic, Olympus, Kodak и Xiaoyi.

In general, the lens is not bad. Of the obvious advantages: a stepping motor for focusing, lightness and compactness, as well as a very low cost of the lens. Of the obvious shortcomings - a controversial design and not sufficiently quiet operation of the focus motor and aperture.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7


The lens was officially announced 14 2019 October, the.

The Yongnuo 42.5 / 1.7 is the first lens from Yongnuo for the Micro 4/3 system. It is not known for certain from which lens it was copied and whether it was copied at all, perhaps this is Yongnuo's own development.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7


Here is the lens on the camera PANASONIC LUMIX DMC-G5 and in comparison with the pancake Panasonic LUMIX G 1: 1.7 / 20 ASHP.

All Yongnuo Lenses

Bayonet mount Sony FE [DF, FULL FRAME] и Sony E[DA,APS-C]:

  1. yongnuo 11 mm 1:1.8 DA DSM WL S [announcement]
  2. yongnuo 16 mm 1:1.8 DA DSM S [announcement]
  3. yongnuo 35 mm 1: 2 DF DSM S [review]
  4. yongnuo 50 mm 1: 1.8 DF DSM S [announce]
  5. yongnuo 50 mm 1:1.8 DA DSM S [overview]
  6. yongnuo 85 mm 1: 1.8 DF DSM S [review]
  7. yongnuo 85 mm 1:1.8 DF DSM S II [announcement]

Bayonet mount Canon RF (mirrorless full frame):

  1. yongnuo 35 mm 1: 2 DF DSM R [review]
  2. yongnuo 35 mm 1:2 CR [announcement]
  3. yongnuo 50 mm 1:1.8 DF DSM R [to be announced]
  4. yongnuo 85 mm 1:1.8 DF DSM R (two subversions with different names) [review]

Bayonet mount Nikon Z [DF, FULL FRAME + DA,APS-C]::

  1. yongnuo 11 mm 1:1.8 DA DSM WL Z [announcement]
  2. yongnuo 33 mm 1:1.4 DA DSM WL Z PRO [announcement]
  3. yongnuo 35 mm 1:2 DF DSM Z [announcement]
  4. yongnuo 50 mm 1:1.8 DF DSM Z [announcement]
  5. yongnuo 50 mm 1:1.8 DA DSM Z [review]
  6. yongnuo 56 mm 1:1.4 DA DSM WL PRO [ALI]
  7. yongnuo 85 mm 1:1.8 DF DSM Z [announcement]

Bayonet mount fujifilm x [DA,APS-C]:

  1. yongnuo 11 mm 1:1.8 DA DSM WL X [announcement]
  2. yongnuo 50 mm 1:1.8 DA DSM X Pro [Announcement]
  3. yongnuo 50 mm 1:1.8 DA DSM X [announcement + overview]

For the system Micro 4 / 3:

  1. yongnuo 25 mm 1: 1.7 [review]
  2. yongnuo 42.5 mm 1: 1.7 [review]
  3. yongnuo 42.5 mm 1:1.7 II [overview]
  4. yongnuo 12-35 mm 1:2.8-4 STM ASPH MACRO [announcement]

Bayonet mount Nikon f (mirrored full frame):

  1. yongnuo 14 mm 1: 2.8 [overview]
  2. yongnuo 35 mm 1: 2 [overview]
  3. yongnuo 40 mm 1: 2.8 [overview]
  4. yongnuo 50 mm 1: 1.8 [review]
  5. yongnuo 50 mm 1: 1.4 E [overview]
  6. yongnuo 60 mm 1:2 MACRO MF [overview]
  7. yongnuo 85 mm 1: 1.8 [overview]
  8. yongnuo 100 mm 1: 2 [overview]

Bayonet mount Canon EF (mirrored full frame):

  1. yongnuo 14 mm 1:2.8 [review N]
  2. yongnuo 35 mm 1: 2 [review]
  3. yongnuo 35 mm 1: 1.4 [overview]
  4. yongnuo 35 mm 1: 1.4C DF UWM [announce]
  5. yongnuo 50 mm 1: 1.8 [overview]
  6. yongnuo 50 mm 1:1.8 II [overview]
  7. yongnuo 50 mm 1: 1.4 [overview]
  8. yongnuo 60 mm 1:2 MACRO MF [review N]
  9. yongnuo 85 mm 1: 1.8 [review]
  10. yongnuo 100 mm 1: 2 [overview]


  1. Yongnuo YN433 (2023, Micro 4/3, 20 MP, 4K)
  2. Yongnuo YN455 (2021, Micro 4/3, 20 MP, 4K)
  3. Yongnuo YN450/450M (2019, Micro 4/3 -> Canon EF, 16 MP, 4K)

Lenses and cameras and many other products from Yongnuo can easily be found at Authorized Yongnuo Dealer / Store on Aliexpres.

My video on all Yongnuo lenses here.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7

Main technical characteristics of YONGNUO 42.5mm 1: 1.7

Review Instance Name On the case: YONGNUO 42.5mm 1: 1.7 0.3m / 1.0ft-∞

Near the front lens: Yongnuo Ø52mm

On the box: YOUNGNUO M4 / 3 standard fixed focal lens 42.5mm F / 1.7

Bayonet Serial Number

Basic properties
  • M4 / 3 - lens designed for Micro 4/3 cameras
  • SMT / STM - focusing stepper motor
  • AF / MF - focus mode switch
  • Electronic focus ring
  • Internal focus
  • Multi-Enlightened Optics
  • Metal mount
  • The optical scheme uses low dispersion elements
  • Important: a lens from a third-party manufacturer, which imposes some restrictions on its practical use
Front Filter Diameter 52 mm, plastic thread for filters
Focal length 42.5 mm, EGF is 85 mm
Zoom ratio 1 X (this is a fixed lens, it does not have a zoom)
Designed by for cameras of the Micro 4/3 system
Number of aperture blades 7 rounded petals
Tags Bayonet Mount Only
Diaphragm F / 1.7 to F / 22
MDF 0.30 m, maximum magnification factor 0.15x (1: 6.67)
The weight
  • in the instruction of 135 g.
  • according to my measurements 132 g without covers
  • on the official website 146 g. Or 143 g.
Optical design 9 elements in 8 groups. The circuit includes 2 low dispersion elements of Yongnuo ED

Optical design Yongnuo 42.5mm F / 1.7The same optical scheme is used by the lens. YONGNUO 42.5mm 1: 1.7 II.

Lens hood Screws into the thread of the front filter, type unknown
Manufacturer country MADE IN CHINA (Made in China)
Period From October 14 to 2019
Instructions View my scan (English only)
Prices View on AliExpress

Y0ngnuo lists the Yongnuo 42.5/1.7 as a standard lens in terms of focal length. In terms of full frame EGF the lens is 85 mm, and the equivalent aperture in terms of depth of field is F / 3.4, as a result, in terms of viewing angle and depth of field it is 85 / 3.4.

The latest Olympus models will also have an in-camera stabilization system, which will further simplify the work with the Yongnuo 42.5 / 1.7.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7


The lens came to the review completely new.

In a small box was a warranty card, instructions in Chinese and English, a certificate of quality control, a desiccant and the lens itself with a front and rear cover. The covers are made of thick plastic. In the box, the lens is mounted with two cardboard holders.

Yongnuo 42.5 / 1.7 has metal mount. The focus ring is very wide, plastic. The lens case is made of plastic and in the hands it feels like a toy product. The focus ring has a small transverse play, but does not cause much discomfort.

The weight of the Yongnuo 42.5 / 1.7 lens is only 135 grams. Almost the same weight Panasonic 42.5 / 1.7.

Diaphragm consists of 7 petals, on the strongly covered diaphragms the aperture opening has the shape of an irregular heptagon.

The hood is not a bayonet type and must be screwed into the thread of the front filter. The instructions do not indicate the marking of the original lens hood. It is not known which hood is suitable.

The case design is simple, from the catchy only a silver strip in the front of the lens and giant switch focus modes.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7


For focusing, Yongnuo 42.5 / 1.7 uses Yongnuo STM focusing stepper motor. Auto focus should work with all Micro 4/3 cameras.

Focus speed average (closer to high), quite comfortable for work. On camera PANASONIC LUMIX DMC-G5 I had no problems with focusing at all. Also, the lens was tested on the camera. Olympus E-M5 Mark II.

Auto focus is enough noisy. The noise characteristic of stepper motors resembles the hum of a transformer. When shooting a video using auto focus and a microphone built into the camera, noise will be heard on the video.

Lens uses electronic focus ring. The focus ring is plastic, wide, in manual focus mode it rotates approximately three full turns. When extreme positions are reached, the ring does not abut, but continues to rotate. Manual focus very comfortably. The focus ring rotates very easily. I did not observe delays when changing the direction of rotation. The focus ring during manual focusing makes a faint sound of two rubbing plastic parts.

There is a huge focus mode switch 'AF-MF' (auto focus / manual focus) on the lens body. During auto focus focus ring remains stationaryMoreover, it can be freely rotated 360 degrees without any effect on focus (if the corresponding function is enabled in the camera menu). Lens supports continuous manual focus controlbut only if allowed by the camera settings.

The lens has internal focusing, the front and rear lenses remain stationary during focusing. It is possible to use various filters without any problems.

The minimum focusing distance is 30 cm, while the maximum magnification for macro photography of 1: 6.67 can be obtained.

Yongnuo 42.5 / 1.7 has the effect of 'Focus Breathing' (changing the viewing angle during focusing). During focusing towards the MDF, the viewing angle decreases.

There are no useful marks on the focusing distance, depth of field, or anything else on the lens.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7

Image quality

Yongnuo 42.5 / 1.7 Easily Deals with a 16 MP Live CMOS Sensor PANASONIC LUMIX DMC-G5. Optically, this is a good middling without obvious serious flaws.


  • good sharpness at the open aperture in the center of the frame
  • in the corners of the frame, sharpness becomes acceptable after F / 2.8
  • good resolution in the center of the frame on covered apertures in the area of ​​F / 2.8


  • weak distortion
  • the nature of distortion is unified, easily corrected in the editor
  • it is difficult to notice distortion in the pictures


  • vignetting is most pronounced on F / 1.7 and focusing on infinity
  • vignetting decreases with focus towards MDF
  • vignetting almost disappears at f / 2.8-4
  • vignetting is easily fixable in the editor


  • chromatic aberration fixed well enough
  • general level HA is at the level typical for such lenses
  • there is friging (color of contrast zones of blur in green and purple)
  • Unsharp discs have a pronounced colored border


  • the effect of the rays of the star is not pronounced (14 rays)
  • Blur disks are uneven on tightly covered diaphragms
  • the lens works well in backlight, only in the most difficult conditions can you get a small 'rainbow'
  • at the edges and corners of the frame, the blur discs turn into lemons, the bokeh is slightly twisted
  • the lens does not use aspherical elements, but only ED elements, which helps to avoid concentric circles on blur discs
YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7

Sample Photos

Photos in the gallery below were taken with a camera. PANASONIC LUMIX DMC-G5... Many thanks to the project for the provided camera Photozen. Some photographs were taken using a polarizing filter. GREEN.L CPL 52mm. Some photos were taken with a ratio of 2: 3, some with a ratio of 3: 4.

Original JPEG '.JPG' photos can be download from this link (150 photos, 670 MB). Raw '.RW2' RAW photos can be download from this link (27 photos, 500 MB). It's important: In EXIF instead of 42.5 mm of focal length, 43 mm is recorded.


Sample photos on camera Olympus E-M5 Mark IIthat kindly provided Vasyl sajkoCan be download from this link.


The lens came to me long before the official announcement, possibly a pre-production version. Recently, Yongnuo sent me another same YONGNUO 42.5mm 1: 1.7 lens, but with new firmware. According to the assurances of the company, now everything will work even better with any cameras. I did not find any difference between the two lenses, perhaps it will only appear with certain cameras.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7

My experience

Yongnuo 42.5 / 1.7 at first seemed like some kind of plastic children's toy, but over time, it established itself as a truly functional lens without serious flaws.

But what surprises me more is why Yongnuo decided to release a lens for Micro 4/3? After all, before they released only lenses for Nikon and Canon SLR cameras, and their first camera, the Yongnuo YN450, although it uses a Micro 4/3 sensor, but the lens mount there Canon EF. In any case, the first pancake turned out to be quite tolerable.

First of all, Yongnuo 42.5 / 1.7 is a competitor to cheap XIAOYI 42.5 / 1.8Which You can find 80 dollars each.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7

Similar lenses

There are not so many such fast auto focus lenses for Micro 4/3:

  1. PANASONIC LEICA DG NOCTICON 42.5mm 1: 1.2 POWER OIS (black only)
  2. PANASONIC LUMIX G 42.5mm 1: 1.7 ASPH. POWER OIS (black / silver)
  3. OLYMPUS M.ZUIKO 45mm 1: 1.8 MSC (Black / Silver)
  4. OLYMPUS M.ZUIKO 45mm 1: 1.2 PRO (black only)
  5. XIAOMI Xiaoyi 42.5mm 1: 1.8 (black / silver)
  6. Yongnuo 42.5mm 1: 1.7 II (second lens model)

Separately, you can still highlight:

  1. SIGMA 56mm 1: 1.4 DC DN | C (there is a version for Micro 4/3)
  2. SIGMA 50mm 1: 1.4 DG HSM EX (the lens was made for 4/3) can be used with the original adapter 4/3 -> Micro 4/3
  3. OLYMPUS ZUIKO DIGITAL 50mm 1: 2 Macro Ed (the lens was made for 4/3) can be used with the original adapter 4/3 -> Micro 4/3
  4. OLYMPUS M.ZUIKO DIGITAL 75mm 1: 1.8 ED M.S.C.
YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7


The price for the Yongnuo 42.5 / 1.7 is around $ 70, which is a very attractive proposition. See all prices for Yongnuo 42.5 / 1.7 on Aliexpress you can at this link.

YONGNUO 42.5mm 1: 1.7

YONGNUO 42.5mm 1: 1.7


The Yongnuo 42.5 / 1.7 is a decent creative lens. A find for the amateur photographer. For Micro 4/3, few people make autofocus lenses and the emergence of autofocus optics for Micro 4/3 from Yongnuo is good news.

10 main advantages:

  1. low cost (about 70 dollars)
  2. light weight, compact size, metal bayonet (similar Xiaomi 42.5 / 1.8 plastic mount)
  3. stepping focus motor fast enough
  4. internal focusing, fixed focus ring during auto focus
  5. convenient manual focus, there is the possibility of constant manual control
  6. small MDF, good ratio of maximum magnification for shooting at close range
  7. there is a convenient huge AF / MF focus mode switch (such Olympus 45 / 1.8 or Panasonic 42.5 / 1.7 no switch)
  8. not bad aperture (relative aperture 12% higher than similar Xiaomi 42.5 / 1.8 or Olympus 45 / 1.8)
  9. two low dispersion elements in the optical scheme
  10. good optical performance. Moderate level of basic optical distortion (aberration, vignettingdistortion etc.)

10 main disadvantages:

  1. the focus motor is noisy
  2. no hood included; non-bayonet type hood
  3. on heavily covered apertures, the aperture has the shape of an irregular heptagon
  4. the electromagnetic diaphragm is noisy and has a small lag
  5. slight backlash of the focus ring
  6. no built-in image stabilizer (similar Panasonic 42.5 / 1.7 he is)
  7. there are no additional tags (depth of field, focusing distance, etc.)
  8. lack of data about the lens in modern cameras and RAW converters, which makes it difficult to automatically correct some types of optical distortions (distortion, vignetting etc.)
  9. it is not known where and how this lens should undergo warranty service
  10. some optical flaws inherent in similar lenses


A new version of this lens has been released, take a look at the review YONGNUO 42.5mm 1: 1.7 II.

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Material prepared Arkady Shapoval. Please, if this material was useful to you, help my project. And don't forget that everyone can write your review for one or another photographic equipment.

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Comments: 56, on the topic: Overview of YONGNUO 42.5mm 1: 1.7 + Update 1,2

  • Alexey

    Do you have any information about the compatibility of the lens with the Olympus E-M5 (first version)?
    And I want to take it, because looks more interesting than Xiaomi, and there are many reviews that it does not work on older cameras ...

  • Paul

    Having on hand three autofocus cheapest lenses of the micro4 / 3 system with an EGF ~ 85: YONGNUO 42.5mm f / 1.7, XiaoYI 42.5mm f / 1.8, Olympus M.Zuiko Digital 45mm f / 1.8, I can say that YONGNUO is in this company the most “capricious” both in terms of assembly and in terms of work. I have devices Om-D E-M10, Om-D E-M10 II, Om-D E-M1 and Om-D E-M1 II. On all cameras, he behaves somewhat differently: the most “capricious” combination with Om-D E-M10 - he goes crazy there (the diaphragm constantly closes and opens), he works more or less stably with older cameras. When you turn on the silent mode (electronic shutter) on the Om-D E-M10 II, the autofocus after the shot returns to the middle position, in the normal mode of the shutter there is no such thing, on older carcasses it is not. Sometimes there are short freezes when, when shooting at an open aperture, the aperture is covered, then the frame is opened and the frame is taken. XiaoYI costs exactly the same (I got it even a little cheaper right out of the box of the camera I just bought), but in terms of work it looks much better: although it has a plastic mount and lacks a focusing ring, it does not have such glitches and has a macro mode. Also because of its “monolithic design” it is preferable for me for street photography - there is no worry that dust or moisture gets inside the lens through the slits of the focusing ring. With Olympus, everything is clear anyway: it costs a used one 2-3 times more expensive and is devoid of all these drawbacks.

    • Arkady Shapoval

      Thanks for the interesting comparison.

    • Ivan

      Thank you very much, I just could not decide to take xiaoyi or yongnuo.

  • Sergey

    Hello. The YONGNUO 42.5mm 1: 1.7 lens does not want to work with OLYMPUS E-PL1. With the OM-D10, markII works great, but the E-PL1 does not see it at all

    • Arkady Shapoval

      Thanks for the information!

  • Bartimeus

    I ordered this miraculous lens for the anniversary of Ali, in late March. But the current came this week, due to paralysis of Singapore post.
    The lens pleased us optically, pleasantly sharp with an open, slightly "twisted" bokeh, holds the backlight well. Autofocus also did not cause any particular complaints. Even 10 turns of the ring during manual focusing is not bothering.
    But the diaphragm in this tsatka is really rotten! : ((On my PEN E-PL7, it periodically starts to "jerk", closing to arbitrary values. Turning the camera on and off helps, but not for long. During operation, it rustles, much louder than the screeching of the autofocus motor ...
    Moreover, Ali is already full of complaints that after a while she generally fails, stops closing.
    My opinion - if you take it, then only for occasional use.

    • Denis

      This camera controls the aperture in order to limit the amount of light to the sensor. In moderate / low light, this effect is not present. It is the same with other high-aperture system lenses. I agree, it chirps loudly. E-P5

  • Vio

    I read the comments - I must take my own :))) on the OLH

  • Arkady Shapoval

    A review of the new (second) version of this lens has appeared - YONGNUO YN42.5mm F1.7M II (42.5 F1.7 STM, second version)

  • Arkady Shapoval

    Added a video to YouTube about all Yongnuo lenses (generations, lines, etc.)

  • Novel

    Good afternoon. I have Lumix GF5 in the form of a carcass. I used it with manual Jupiter 8 initially after the whale. Then, when the child appeared, I realized that I needed a focusing speed “inexpensively” - as a result, Xiaoyi 42.5 was acquired. In principle, everyone was satisfied with the lens, except for the lack of manual focusing at twilight from a tripod. As a result, I exchanged it for a Sigma 30mm 2.8. The lens is good, but the transition from the equivalent FF 85mm at Xiaoui to the 60mm Sigma makes a difference in shooting style. So I'm thinking of rolling back 85mm - will Youngnuo of the first version be better in aperture and focusing speed than Sigma?

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