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. 

DISCLAIMER

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. 

DESIGN & BUILD QUALITY

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. 

HANDLING

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 
RIGHT F2.8

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LEFT F1.7
RIGHT F2.8

LEFT F2.8
RIGHT F4

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LENS SHARPNESS

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. 

CORNER SHARPNESS/VIGNETTING

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. 

FLARE CONTROL

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. 

DISTORTION

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. 

CHROMATIC ABERRATION

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

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Good Flare Control

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Distortion is quite bad

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Purple Fringing

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Purple Fringing

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CLOSE UP SHOOTING

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. 

AUTOFOCUS

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! 

BOKEH QUALITY

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. 

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AF Test on moving subject

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AF Test on moving subject

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Bokeh balls shape

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Maximum magnification at 0.2x

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Close up shooting

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REVIEW SUMMARY

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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