Yongnuo 25mm F1.7 Review

I am helping out another friend to set up a budget Micro Four Thirds kit, and I found this Yongnuo 25mm F1.7 selling for about USD100 (actually less, it is RM385, so more closer to USD90). Unlike most other budget 25mm primes for Micro Four Thirds that are manual focus lenses, Yongnuo included AF capability and I think this sets Yongnuo apart, hence I decided to purchase this lens. I was genuinely curious to see how a budget prime 25mm performs, thus I made this quick review! And boy oh boy, it was awesome to be able to go out and shoot again, after almost half a year living in total isolation. 

I have made a video review here too (click to YouTube video). 

I really like the bright 25mm  marking on the lens, making it quite easy to identify, especially in the dark. Olympus/OM Digital Solutions, please learn from this. 

I tested the Yongnuo 25mm on my own E-M5 Mark III. Awesome combo. 

The camera and lens are so light they can be supported by mere leaves. 

Yongnuo did contact me earlier this year and offered to send a sample unit of their 25mm F1.7 for review. I declined the offer as I was not looking to collaborate with another brand at that time, and Malaysia was under lockdown, there was only so much I can do for a review shooting subjects inside the confines of my tiny bedroom. Also, I already own and actively shoot with the venerable Olympus M.Zuiko 25mm F1.2 PRO, which I love to bits. So when I was looking for a budget prime for my friend, I decided to purchase the Yongnuo 25mm F1.7 myself. Therefore, no one asked me to do this review, I did it because I was interested to see the performance of this lens myself, and this review is entirely independent. 

This is not a technical review. I share my opinion based of about 1500 images I have shot with the Yongnuo 25mm F1.7. All images were shot with Olympus OM-D E-M5 Mark III, and post-processed with Capture One Pro. 

I personally like the design of this lens, it is sleek, in all black and looks quite good. The clean and minimalist design gets me all the time. The lens is noticeably larger than Olympus 25mm F1.8 or Panasonic 25mm F1.7, but it is still quite a small lens. There are two controls available on the lens itself - the manual focusing ring and a switch to toggle between AF/MF function. 

The body of the lens is made of entirely plastic, and it does feel cheap when holding it in hand. It does not pretend to be a premium lens, but at the same time it is not flimsy and there are no creaky or moving/rattling parts. The lens build is good enough, and quite decent for the price it is asking for. The lens does feature a metal mount, which is a solid plus point. 

I shot the Yongnuo 25mm F1.7 only on my own E-M5 Mark III, and it balances very well with the small and light-build of the camera. The lens only weighs 150g, so it is quite light, and can match well with smaller Micro Four Thirds camera bodies. I was shooting all morning (total of about 3 hours) walking round the streets of Kuala Lumpur, and the lens was very comfortable to use. I did not feel any awkwardness, or strain on any parts of my hands/body. 




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LEFT F1.7 






Shooting at wide open F1.7, the Yongnuo 25mm lens is not exactly a stellar performer. The lens is sharp enough, perhaps as good as any kit lenses from Olympus or Panasonic, but not better. It resolves good amount of details, somewhat decent contrast, and there really is nothing to shout about. However, stopping down the aperture to F2.8 made a whole world of difference. The contrast improves drastically, and the overall sharpness gets better too. The difference is quite noticeable even without pixel peeping, and that is to be expected from a budget prime lens. What truly separates the Olympus 25mm F1.8 from this - Olympus is already super sharp and optimized even at wide open F1.8 aperture, and I did not find the need to stop down to achieve better sharpness, unless I wanted more depth of field. Having said all that, I did not mean the Yongnuo's F1.7 wide open is by any means poor, it is not bad at all, just not excellent. So please do tame down your expectations if you intend to buy this lens and shoot at wide open most of the time. 

The corner performance isn't great at wide open too, it is visibly soft and there is light fall-off, or vignetting. This problem can easily be resolved by stopping down the aperture to F2.8, and there is even a slight improvement at F4. 

The Yongnuo 25mm F1.7 did not come with a lens hood supplied out of the box, so I was a little worried about lens flare and ghosting, as I do shoot under plenty of harsh Malaysian sun, and there are times I am shooting directly into it. To my surprise, the lens handles flare very well, I have not encountered any flare or ghosting issues, and that justified the move by Yongnuo not to have a hood in the box. 

The lens does exhibit quite severe barrel distortion, especially at the sides and edges of the frame. The straight lines don't appear straight at all, and are curved. This should not pose too much of an issue, and can be easily corrected via post-processing. 

As expected, the lens does not have good chromatic aberration control and purple fringing can be seen at harsh lighting conditions with subjects in high contrast areas, especially shooting backlit. Even stopping down to F2.8, there are still some traces of purple fringing. I believe this should not be an issue for most people, you just need to spend that extra step in post-processing to remove the chromatic aberration, and can be done relatively fast. 





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Good Flare Control

Good Flare Control

Distortion is quite bad


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Purple Fringing


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Purple Fringing



One of the positives about this Yongnuo lens is definitely the close up shooting capability. It allows maximum magnification of 0.2x which is quite respectable, and that gives you some flexibility to do more in terms of composition and framing, if you have some close up shooting without the need to use a macro lens. 

The biggest highlight of this lens, and probably the reason why a lot of people would choose this over other budget 25mm primes for Micro Four Thirds - the Autofocus ability of the lens. I am happy to report that the AF of Yongnuo 25mm F1.7 did not disappoint. The AF is fast and reliable, almost as good as any other lenses from Olympus or Panasonic, with only one exception. When shooting subjects that are far away, say half a meter or further from the camera, the lens performs incredibly well with no issue in acquiring focus quickly and nailing sharp results. The problem comes when shooting very close up subjects, anything closer than half a meter, especially toward the minimum focusing distance, the lens starts to struggle. There was some hesitation, hunting, and the overall AF is much slower. I'd say it is still not too bad, and somewhat tolerable, and should not be a dealbreaker. Just bear in mid, the AF is sluggish when you go very close to your subject. 

I'd still take an AF lens over a manual lens. Life is too short to worry about manual focusing. One variable eliminated so I can focus more on the important part of the images - lighting/composition/story-telling. Some would argue that you can use zone-focusing, hey I am not buying a F1.7 lens for zone focusing! When I buy 25mm F1,7, I want to shoot at F1.7! 

The bokeh at wide open F1.7 from this Yongnuo lens was quite pleasing. I like the creamy, smooth blur it renders. Definitely good enough to have some subject separation, and the bokeh is not distracting or busy. Do bear in mind that the bokeh balls are not exactly circular, they are out of shape, and if that bothers you, maybe this lens is not for you. I think it should not be an issue, I am fine with it, and I have shot a lot of my images wide open at F1.7 and I like the look of these images. 




AF Test on moving subject

AF Test on moving subject



Bokeh balls shape

Maximum magnification at 0.2x

Close up shooting




For a USD100 lens, I think Yongnuo 25mm F1.7 has a lot to offer. The AF capability alone positions this lens ahead of other budget 25mm primes for Micro Four Thirds, and the AF works quite well, except for very close up shooting where it struggles a little. The lens optical quality is not stellar, as expected from a budget construction, but the F1.7 offers beautiful bokeh and a huge advantage in low light shooting. The lens can produce good results, while not on par with what Olympus or Panasonic 25mm variants are offering, but for the price of under USD100, I'd say it is worth every dollar spent. 

What I Like:
Decent image quality, nice bokeh rendering and true F1.7 bright aperture
AF is fast and accurate, works reliably
Good flare control
Can go close up with 0.2x magnification
Light at 150g

What I Dislike:
Some optical flaws - distortion, corner softness, chromatic aberration, but can be fixed in post
AF is sluggish when shooting close up
Lens is visibly less sharp at F1.7, needs stopping down for better results

Looking at the items that I dislike about the Yongnuo 25mm F1.7, none of them are dealbreakers, and some of the issues can be easily corrected in software during editing. 

I highly recommend the Yongnuo 25mm F1.7 lens for any Micro Four Thirds shooters that are on tight budget, or are not willing to spend too much for lens upgrades. If you have the funds, of course, there are better options out there. 

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  1. Nice review, Robin. If I didn't already possess an interesting (and also surprisingly inexpensive) manual focus 25mm lens (the Pergear), I might be tempted. Incidentally, your accompanying photos are quite wonderful. My favourite, for many reasons, is the close-up of the rooster's head, with the out-of-focus masked human being's face in the background. That photograph alone should make the Youngno people happy that a gifted photographer is putting their lens to good use!

  2. Hi Robin, I'm Arun!

    I love your page and your YouTube reviews are the best for olympus❤️

    I also own a Olympus OmD Em10 Mark 3
    I love shooting with it and exploring different styles! For a long time now I've been eyeing for a wide angle lens something in 7 or 8mm. Since I'm a student I do not have deep pockets and the focal length I'm searching for is bit pricey

    Laowa 7.5 mm f2 and meike 8mm cine is around 450 to 500 euros☹️ but I found an alternative for that a lot of people were speaking about the slr magic 8mm for mft system and it's interesting also but there are no proper review or impression about this lens. If you could do a review about it, it'll be massively helpful for a lot of people out there struggling with the budget limit

    Could you please do an review of SLR magic 8mm mft ?

    Please consider this as an favor and also a video about cine lenses vs regular for mft would be useful I think, your opinion?

    1. I wouldn't want to speak for Robin here, but the Laowa, Meike, SLR Magic, and also Samyang lenses are all manual focus lenses, whereas the unusual thing about the Yongnuo that he reviews here is that it supports autofocus. And I think that he might have said previously that he will only seriously look at autofocus-capable lenses, at least for review purposes.

      I mention this because autofocus support was pretty much an essential feature when I was looking at lenses. I think that this traditionally limited the buyer to Olympus, Panasonic and Sigma, so the emergence of any new lens supplier offering autofocus support is particularly interesting.

      It is, however, rather interesting that you mentioned Meike. Where I live, Meike lenses appeared for a while at one supplier, at least, but they went away fairly quickly, and I am guessing that they didn't sell despite being fairly competitively priced. Samyang seems to be the primary alternative for those comfortable with manual-only focusing, with Laowa/Venus following not so far behind. Where I live, SLR Magic is pretty thin on the ground, and I think that if the brand was present, it went the same way as Meike before I was even looking at MFT lenses.

      Then again, maybe Robin will start dabbling in video a bit more and start reviewing cine lenses...