While I welcome third party manufacturers making AF lenses for Micro Four Thirds, which is a rarity these days, we already have so many 25mm lens options that another 25mm F1.8 lens from SG Image does not exactly scream excitement. Well, I did get curious due to the extra low price tag of USD99 only for a new lens, and at that price, I thought what could possibly go wrong? I guess I had to find them out the hard way. I bought one and tested the SG Image 25mm F1.8 AF on my Olympus PEN E-PL7. I have also made a YouTube review, in case you prefer video version, you can check it out here (click).
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| The lens does look chonky when used on a smaller Micro Four Thirds camera body |
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| It isn't a large lens, but the diameter is bigger than expected |
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| I appreciate the light weight 133g, handling is no issue, and I do like the metal construction of the lens |
DISCLAIMERS
I am not connected or affiliated with SG Image. I bought the SG Image 25mm F1.8 AF lens with my own money. This is technically not a review, I am not going to dive into every single aspect of the lens. I just wanted to see how the lens performs on a Micro Four Thirds camera body, and share the good and the bad. I mean, it is priced at USD99, at such price, I am expecting some compromises.
I am not connected or affiliated with SG Image. I bought the SG Image 25mm F1.8 AF lens with my own money. This is technically not a review, I am not going to dive into every single aspect of the lens. I just wanted to see how the lens performs on a Micro Four Thirds camera body, and share the good and the bad. I mean, it is priced at USD99, at such price, I am expecting some compromises.
DESIGN, BUILD & HANDLING
The lens has a pancake design with slim profile. However, when mounted on smaller Micro Four Thirds camera bodies like the Olympus PEN E-PL7, it does look quite chonky. While the lens is quite slim, it has a larger than usual diameter, probably because the lens was made originally for APS-C sized image sensor. I admit the lens is by no means large, but it isn't that small either, and may not pair very well with smaller camera bodies.
The lens is quite light, weighing 133g only, so handling should not be an issue with any Micro Four Thirds cameras.
I was surprised to see the full metal construction of the lens, that was a nice touch, considering the budget price point. The lens feels solid, there are no creaky parts, definitely it does not feel like a 99 dollars lens.
AUTOFOCUS
I don't have nice things to say about the autofocus performance of the SG Image 25mm F1.8. This is the slowest autofocus lens ever made for Micro Four Thirds system. If you think Panasonic 20mm F1.7 was bad, wait until you try this lens. It was so slow, I missed so many important shots during my street photography session. The lens hunts, hesitates, pulses a lot before grabbing focus, and many times it fails to lock focus accurately, giving false positive. For non moving subjects, sure, the lens AF should be fine, but for action shots, I'd definitely avoid using this lens.
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| ƒ/2.51/80025mmISO200 |
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| ƒ/1.81/16025mmISO200 |
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| ƒ/1.81/400025mmISO200 |
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| ƒ/2.81/8025mmISO1600 |
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| ƒ/2.81/16025mmISO1600 |
SHARPNESS & BOKEH
SG Image claims the use of 7 elements in 5 groups lens design, with use of 3 high refractive special lenses. I am generally quite satisfied with the sharpness at the center of the frame. The lens manages to render sharpness level almost equivalent to kit lenses from both Olympus and Panasonic. However, the sharpness does not extend to the edges or corners. Corner softness is quite bad, so if you intend to have corner to corner softness, this lens will not deliver satisfactory results.
Bokeh looks very good, the out of focus area does not look distracting or nervous, they are generally smooth and creamy.
TECHNICAL FLAW CONTROL
The lens controls distortion very well. I did not observe any barrel distortion, straight lines appear almost perfectly straight even near the edges of the frame. I am not sure if this was due to software correction of the camera, because I was using an Olympus camera and I thought the correction only applies to native Olympus lens. I could be wrong.
Flare and ghosting are big problems for the SG Image 25mm F1.8 lens. Shooting against strong sources of light, the flare pattern resulted in the frame looks overbearing, destructive and cannot be easily corrected in post-processing. There is also loss of sharpness, contrast and details, the image looks hazy on top of the severe flaring issue. I have tested the lens with and without the hood on, results were pretty much the same - horrible flare.
Chromatic aberration is another problem, though this can be corrected in post-processing easier than flare. Purple fringing is quite obvious in high contrast scenes, even without punching in the image, you can see traces of purple fringing.
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| Corner softness is quite bad |
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| Center Crop Left: SG Image 25mm F1.8, Right: Olympus 25mm F1.8 |
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| Corner Crop Left: SG Image 25mm F1.8, Right: Olympus 25mm F1.8 |
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| ƒ/1.81/400025mmISO200 Bokeh test |
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| ƒ/1.81/25025mmISO200 Bokeh test |
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| ƒ/1.81/4025mmISO3200 Bokeh test |
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| ƒ/1.81/400025mmISO200 Flare and ghosting problems |
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| ƒ/161/12525mmISO200 Flare and ghosting problems |
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| ƒ/1.81/160025mmISO200 Purple fringing problems |
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| Center crop Left: SG Image 25mm F1.8, Right: Olympus 25mm F1.8 |
If you have been following me you would know that my favourite lens is Olympus 25mm F1.8 for street photography. I have used that lens extensively, and I cannot live without it.
I know it is unfair to compare the Olympus 25mm F1.8 against the SG Image 25mm F1.8. The Olympus 25mm is retailing for at least 3 times more of the SG Image 25mm, so of course, being a budget lens, the SG Image 25mm will be inferior to a certain extent. I am going to share my thoughts anyways.
From the multiple side by side comparison images above you probably have noticed that the Olympus 25mm F1.8 is sharper not only at the center, but also at the corners as well. The difference in sharpness is quite obvious, the Olympus 25mm renders not only sharper, but also with better contrast, fine details and overall clarity.
The Olympus lens also does not suffer the crazy looking flare patterns, and it manages purple fringing better than the SG Image. More importantly, the Olympus 25mm has blazing fast autofocus, which by that advantave itself makes it a worthwhile lens to consider over the SG Image 25mm F1.8.
The only benefit of getting the SG Image 25mm is the metal construction, with the Olympus 25mm being made of plastic.
There really is no comparison, overall the Olympus lens wins when it comes to image rendering. Some would argue that the SG Image is worth the low price, yes, you can still get some good shots with the lens, but if you scour the used market, there are many Olympus 25mm F1.8 lenses around. The used Olympus 25mm F1.8 will still be more expensive than a new SG Image 25mm F1.8, but I guarantee you the extra money will be worth every bit spent.
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| ƒ/41/200025mmISO200 No barrel distortion observed |
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| ƒ/3.51/125025mmISO200 |
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| ƒ/1.81/100025mmISO200 |
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| ƒ/161/2525mmISO200 |
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| ƒ/3.51/32025mmISO200 |
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| ƒ/3.21/320025mmISO200 |
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| ƒ/6.31/12525mmISO200 |
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| ƒ/2.21/250025mmISO200 |
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| ƒ/1.81/5025mmISO200 |
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| ƒ/4.51/250025mmISO200 No barrel distortion observed |
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| ƒ/41/5025mmISO200 |
COMPATIBILITY ISSUES
I have read some complains over the discussion forums and groups about some compatibility issues using the SG Image 25mm F1.8 AF for Micro Four Thirds.
I have verified that the SG Image 25mm F1.8 AF does not work with the older cameras like the Olympus PEN E-P2. That is the only old camera that I have which is still working, so I don't have a full list of compatible or incompatible cameras. If you use a much older camera, I kindly suggest you avoid this SG Image 25mm F1.8 AF.
I also tested the lens on my Panasonic GM1 and GF7, both cameras having first curtain electronic shutter. The mechanical shutter was not working, and you can only shoot with full electronic shutter with these cameras. I don't know what the reason is, but using electronic shutter only for these older camera bodies poses more consequences than I like - you get rolling shutter/jello effect shooting fast moving subjects, you get banding problems when shooting under artificial LED light, you get more noise when you go high ISO, and you have reduced RAW file quality from 12bit down to 10bit only. Again, if you have these cameras with first curtain electronic shutter only, the SG Image 25mm F1.8 AF is not suitable.
I have also heard about continuous AF issues but seriously, even single-AF the SG Image 25mm F1.8 was already so unbearably slow and unreliable, I dare not even switch over the C-AF for my shooting. That is just plain pointless.
CONCLUSIONS
No, I do not recommend this lens, there are many other better 25mm lens with AF options out there for Micro Four Thirds, and it is worth spending that extra bit more. Sometimes, when things are too cheap and appear too good to be true, it probably is, the SG Image 25mm F1.8 is one good example of that. I shall continue shooting with my Olympus 25mm F1.8.
