Thank you Dan! I will download the catalogs and have a close look .

The information I got from this lens comes from this Russian website which shows the ОФ-233 210mm being a 13cmX18cm lens with an image circle of 222mm. I have also found some pictures done with this lens and a 5x7 large format camera ( see the picture of the bohemian in the middle of the page). There is a bit of vignetting indeed but it is not too bad. I do not expect a great resolution from this kind of lens anyway, just a nice overall rendering for experimental photography!