Seemed worthy to review this cheap lens since there isn’t much info around, it’s a no-name lens and is being referred simply as ‘green circle’ the few times I tried to find anything about it, there’s also a red ring one but it should be the same.
The short version: it’s not a total crap and better than legacy lenses at the same price in some aspects, sharper than lots of them wide open while also having lots of ‘character’ if that’s your thing. Wide open it’s sharp as the olympus 14-42 II kit lens at 25/4.4, but while the kit lens maintains the image quality throughout the frame, this 25mm gets weird towards the edges.
This is my experience with real world shots instead of test charts on a m4/3 camera but the image circle itself can handle aps-c sensors, when I got this lens it was the best looking option for a U$50 25mm/1.8, nowadays there are also the 7artisans and meike for about the same price that would be worth comparing.
Relevant specifications:
Price: U$50 in 2017, ebay is showing $60* at the time of writing
Weight: 201g (measured without caps)
Minimal working distance: 11cm
Aperture blades: 12 (yes, it’s surprisingly round)
Filter thread: 46mm non-rotating
Clickless aperture
C-mount
The lens body is metal and borrows almost everything from the Pentax 50mm 1.8, it has more mass than what you would expect from a random cheap lens, it doesn’t feel hollow like a plastic kit lens for instance and is heavier than what you would expect looking at it’s size. The way the focus and aperture rings move is smooth but it’s the kind of movement that feels greasy inside.
Here’s how it looks on the epl-5:
The lens rear is messy, it has c-mount threads made with a reflective plastic which is a recipe for internal reflections (can be fixed with tape or painting it black if you care enough), mine came with a crappy m4/3 adapter on it attached I’m not sure how, it turns a bit on itself but can’t be screwed out.
Image quality has lots to describe, at portrait distances it’s sharp wide open from the center to mid frame, as you focus farther the sharpness keeps getting more restricted to the center, at F8 it’s good across the frame as expected, F16 is already in diffraction hell. Corners and transition zones are the weirdest, smooth at close distances but as you focus farther they’re not simply blurred, they get swirly and a bit stretched like motion blur or a double image that’s specially noticeable in sharp contrast edges, closing the aperture progressively fix this.
A couple of years ago I used to think this kind of imperfection was automatically bad and seeing them in photos reminded me of old wardrobe smell. After using more and more legacy lenses full of artifacts I see these things more organized in a spectrum with glowy vintage image quality full of artifacts in one side and a modern buttery smooth bokeh with apodization at the other, with no side being automatically better, depending just on taste.
With the increasing popularity of film emulations for digital I think these imperfections are helpful to sell the film look a lot of people want nowadays, I still think it’s horrible to just slap vintage filters on images taken through perfect modern lenses that have none of the rendering from legacy ones.
Image quality at f/1.8
Image quality at f/8
Image quality at f/1.8
Bokeh samples:
Minimum focus distance at f/2 and f/4 respectively:
Flare wide open can be wild, and it’s hard to know when to expect it, I shot heaps with it outside and didn’t have a problem, but under the canopy when the sun was going down it was the worse case of veiling flare I saw, not the “recompose slightly to fix it” kind but a “I don’t even know what’s in frame” kind. Some internal reflections too with indirect lighting, strong but didn’t happen often. Chromatic aberration is less than expected, shows up easily in high contrast corners, on the canopy against the sky specially if you push highlights down in post, but not elsewhere, it’s really curious how it has less CA than my Olympus 17mm 1.8 and even the 30mm macro, LoCA however is visibly heavy without even needing to check at 100%.
Flare sample
CA comparison with the 25mm wide open on the left, 100% crop near the center
Works fine as an option to reverse for macro but nothing special about it, the working distance seems smaller than other lenses I use at the similar focal lengths, but I didn’t make a direct comparison.
Common flesh fly
Membracid planthopper
I think this lens can be a good option if you want to experiment with this focal length or just have it as a temporary one while saving for a much more expensive native 25mm.
In the end I consider it a pretty good value for what it is, my only other comparable manual lenses are the Mir 1b which was less half the price but blown out of the water by this one (except in tank build quality, paid around U$16 for it in 2009 but seems to be going for around U$60* now), and the OM Zuiko 28/2 which is better overall but more than double the price in good condition*, I was lucky to get a cheap one that was easy to clean up the fungus myself.
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Panorama in the rainforest with the 25mm wide open