7artisans 25mm F1.8: Good center, poor corners, great build quality MF prime
Long story short - it appear the 7artisans 25mm F1.8 lens is rebrand - slight update to the Zonlai/Discover 25f1.8. The biggest update is placing the focus ring upfront and the clickless aperture ring by mount. All shots are SOOC JPG.
Sharpness
Center sharpness is very good even wide open and hard to discern between the 7artisans vs. my Sony FE28mm F2.0. However corners are a complete different story. They are very soft wide open with vignetting and progressively get better to F8 - where it's pretty much gone.
Colors - Other attributes
Colors seem pretty good - nice contrast. You can compare to my FE28F2.8 and 18-105 in a follow-up post. Seems to do well with CA - probably better than the 18-105 zoom. There is some barrel distortion. Also it does flare if you shoot at an angle to the sun.
Build Quality
Excellent metal body and solid feel. E-mount fit is snug with a solid click in place - no wiggle or play at all. Glass is coated with purple tint.
Focusing
I got this lens to practice manual focusing to see if I will ever invest in more expensive MF lens like Rokinons or even Loxia. This is a small lens, not quite pancake, but only sticks out 32mm. So the focus ring is small, but turns smoothly with a right amount of resistance. Turning range is around 120 degrees or third of a turn. Personally I wish it made a half turn as the required micro adjustments wide open are miniscule.
Aperture Control
Aperture ring is clickless, which is a bit of annoyance - unless you're doing video. I also think the aperture markings are off, based on the shutter speeds and the size of opening (though magnification from front element may distort my eyes). F8 appears closer to F6ish. The smallest aperture marking is F16 - but again the shutter speed and size of the opening will seem its closer to F20.
Conclusions
I'm just started to play with this and MF. Definitely better than MF by wire using AF Sony lens. But even though 25mm is good for street photography - I can see it being a challenge for me to catch focus fast enough. Value for the money @$69 shipped- I think it's hard to beat for a 37.5mm equiv fast prime. I think this would ideal nifty 50mm equiv on M43 as the corner issues should crop out nicely - in fact I think this was designed for M43 with APS-C as an afterthought. On APS-C, it's a bit more limiting due to the bad corners. I'll see how things goes, but I think I will use this lens in 2 ways:
1) Wide-open bokeh contextual subject shots. Something like these:
2) Walkaround general daytime landscapes @F8 or up. I actually didn't test many shots at F8 - I was walking around using F4 as I only pixel peeped back on the computer and you can see from the shots below, the problem with the corners.
I don't think there's much use for this lens between F2-F6. Either shoot wide open with creamy bokeh or stop it down for landscapes. Not really anything in between.
I'll reply with a follow-up post with more comparison shots between 7artisans, FE28mm F2, and 18-105 @ 25mm at different apertures. This one is getting long already.