Nachkebia
Well-known
For me 21mm biogon 2.8 is already as perfect as lens quality could get, only concern is the size 
awilder
Alan Wilder
The only way to tell if the flange seating needs adjustment is to bracket focus on either side of rf focus, preferably using a resolution chart as your target at a distance of 51 x the focal length of the lens you're testing. I usually bracket in 1 mm increments (1/2 mm or less for 50 mm lenses or longer) on the distance scale. Typically, I find ZM lenses tend to front focus, so there is a greater chance of needing to focus behind the intended subject for spot on sharpness. I'm basing this on experience with the 21/4.5, 50/2 and 50/1.5 and it might be different with other ZM lenses.
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Tom A
RFF Sponsor
Roger. I have been shooting with an old F-mount 21mm f4.0 for the last couple of weeks. Great fun, at least 2 stops fall off but it is remarkably sharp. I have the elusive F-SC adapter so I used it on a Nikon S4. Funny, when I used to have one in the 60's I never really noticed the edge fall off - now we have gotten spoiled with 21/2.8 Elmarits, ZM lenses and even the Color Skopar 21mm f4.0.
IF I had to shoot industrial/architectural stuff, I would go for the modern lenses all the way- particularly the ZM 21f4.5. However, I just like taking pictures and the "charm" and "look" of the older wides is a different look altogether. I doubt that someone like Jean Loup Sieff's shots would have looked as good with a perfectly even illumination and without the edge "burn" from his Super Angulon or Nikkor 21f4!
I had the Kobalux 21 for quite some time. I liked it, but it is big and the front element tended to come loose! I have some friends who use it and as theirs are later versions - the problem is not there.
As for the Russar 21 - I once bought one in Rome. It was cheap, but it also lacked at least two elements on the inside and produced small, round and fuzzy "blobs' on the film. As I bought it for the finder it was no problem. I had a couple of them with all the elements in place and it is not all bad (one had very soft corners), but the other one was quite sharp, but with typical USSR stickiness to the focus.
I tend to cycle through my lenses and the 21mm f2.8 ZM is coming up soon - as is the 21f3.4 Super Angulon and I should really put some rolls through with the Ricoh 21mm f3.5 LTM lens too. I am running some tests
with Kodaks Double X and various developers. This month "flavour" is Pyrocat HD and as the sun start showing up intermittently, wide angles are in favor.
Ok, if you really like dramatic edge fall off - you should try the old Topogon formula in Nikon Rf mount - the 25mm f4.0. Neat little lens and quite sharp - but it is dark out there in the corners!
Tom
IF I had to shoot industrial/architectural stuff, I would go for the modern lenses all the way- particularly the ZM 21f4.5. However, I just like taking pictures and the "charm" and "look" of the older wides is a different look altogether. I doubt that someone like Jean Loup Sieff's shots would have looked as good with a perfectly even illumination and without the edge "burn" from his Super Angulon or Nikkor 21f4!
I had the Kobalux 21 for quite some time. I liked it, but it is big and the front element tended to come loose! I have some friends who use it and as theirs are later versions - the problem is not there.
As for the Russar 21 - I once bought one in Rome. It was cheap, but it also lacked at least two elements on the inside and produced small, round and fuzzy "blobs' on the film. As I bought it for the finder it was no problem. I had a couple of them with all the elements in place and it is not all bad (one had very soft corners), but the other one was quite sharp, but with typical USSR stickiness to the focus.
I tend to cycle through my lenses and the 21mm f2.8 ZM is coming up soon - as is the 21f3.4 Super Angulon and I should really put some rolls through with the Ricoh 21mm f3.5 LTM lens too. I am running some tests
with Kodaks Double X and various developers. This month "flavour" is Pyrocat HD and as the sun start showing up intermittently, wide angles are in favor.
Ok, if you really like dramatic edge fall off - you should try the old Topogon formula in Nikon Rf mount - the 25mm f4.0. Neat little lens and quite sharp - but it is dark out there in the corners!
Tom