By most accounts, it's worse than the 25/4 on un-modded Sony sensors. Slightly better on Kolari UT and decent (but not stellar) on digital M mounts. I put a good deal of research into this. It was a lens made for film, alas.
What you can expect - cyan or magenta cast to everything not in the center, heavier towards the edges. Can be mitigated somewhat by manually shifting your white balance, and there are plug-ins (FlatField and Cornerfix) to use on raw files, but won't get rid of it fully. Smearing is very pronounced at extreme edges and there's no fix for that besides cropping.
In my case, I often use the lens for video, so cropping to 16:9 or 2.35:1 gets rid of 90% of the above issues. It handles beautifully (oh, how I wish the E Mount version had a focus tab) and it is scary-sharp centrally, even wide open and *almost* across the field @f/8. It's tiny and a delight to carry and shoot with, just have very managed expectations if you plan on using it on a Sony. Additionally, with a normal (ie non "close-focus") M mount adapter, 0.7m is the closest you can get.
... Which is why I'm SO looking forward to the 21 E Mount.
Hope that helps.
-Tim
bobek13 wrote:
how bad is this m-mount 21mm/f4 on FF? I am thinking of buying either a 15mm f4.5 or the new 21mm f3.5 on one hand or upgrading from a7 mkI to a7r mkII + used m-mount 21mm f4...
For reference, on my A7r the 25/4 Snapshot Skopar looked quite horrible, as can be seen in this old sample. There was also some weird discolored patch at the top center which was no longer there on my A7II. With A7II the color issues were improved a lot but smearing was still there. Anyway, I never really used the lens on A7 series before I sold it because of the problems with discoloration and smeared edges/corners.
I did experiment a bit with Adobe Flat Field plugin etc. and could somehow fix most of the color problems but it was a bit too much trouble and it didn't help with the smearing.
thank you guys... very helpfull... as I've found very little info on net going both ways (bot mostly into not ok section) and tried the search function on flickr and found images tag with the skopar/a7 combo as pleasing - I guess they post processed the color cast pretty well...
Fred Miranda wrote:
Nope but perhaps some stores in Europe are already taking pre-orders.
I preordered at Robert White for 549 Pounds. Was surprised how cheap that is since the Lox costs more than twice that.
I got a call and my lens is ready for pick-up, will go and get it tomorrow. I'll post some samples once I have them.
Seems that Japan release is happening as announced (tomorrow is official release date here) though not sure how much initial volume there is. I had made a pre-booking on the first day it was possible.
At least take my pre-order Cosina! Hopefully they will be available soon here in the US as I've been in the market for a ~20mm that's even more compact than my excellent (but relatively heavy) 21/2.8 Lox. It doesn't have to be perfect wide open (but better be at f/5.6) and looks like a great travel/hiking/backpacking lens.
Anxiously awaiting your impressions, Juha, and further tests from FM and the community! Like jhinkey, this looks like the perfect light, compact addition to a travel bag, so long as it is competitive (without needing to be top class, Loxia 21 standard) when stopped down a bit.
Juha Kannisto wrote:
I got a call and my lens is ready for pick-up, will go and get it tomorrow. I'll post some samples once I have them.
Seems that Japan release is happening as announced (tomorrow is official release date here) though not sure how much initial volume there is. I had made a pre-booking on the first day it was possible.
