I'm interested in a Rollei 35. I'm aware of the usual quirks: scale focusing, weird ergonomics, etc.. but I'm interested in learning a bit more about the lenses/filters. I'm debating between Tessar and Sonnar. My main concerns: -Contrast: I prefer low contrast. I've read mixed reports between the contrast between the two. Some say the Tessar has more contrast and others say the Sonnar. My feeling is that the Tessar is lower contrast and more suitable for bw work but the difference is probably not enough to be a concern. I'm not sure. -Filter thread: I prefer 30.5mm because they are easier to find. Keh.com has some Tessars listed with 30.5mm, is this true? I called keh.com and they told me that the Tessars were 30.5mm but I feel that the person was regurgitating the catalog specifications (which might be wrong). I was under the impression that all Tessars were 24mm? If I do find a Rollei 24mm K2 filter, then I can I also use a hood? I want to use both. What I'm not so concerned about is price, sharpness (as long as it is decent), country of origin (Germany vs Sing), and lens speed. They are pros and cons to me but do not matter as much as lens contrast and filter thread. I'm split between the two: I feel that the Tessar has the more suitable contrast and is priced slightly better but the Sonnar has the more suitable filter thread and is slightly faster. As of now, I'm leaning Sonnar because of the filter thread.