The uncoated Sonnar is an interesting lens to experiment with - not for everyone, and not for all subjects, but it can make very nice effects and is good for personal photography (family shots, friends, holiday, travel shooting, etc. - as opposed to say technically excellent work demanding best sharpness and contrast). The lack of coatings makes it prone to flare of course, and because of this it seems to do good in softer light - watch out for bright Sun, particularly backlit situations. It's a really impressive lens considering how old it is - it was very advanced for the time. It is really nicely made too mechanically - German technology at its best (for the 1930's).