Having used a 35mm Summilux pre-ASPH for many year as my main lens, when I heard about the highly corrected 'aspherical' (1st) version sometime in the early 90s I thought I'd get one. But at the original $4,000 price I didn't want it that bad I guess.
Later I traded the old Summilux for a new ASPH version (which I regretted shortly, still like the look and handling of the old lens) and had both a Titanium and Chrome version of those. Heavy but steady.
Then a first version came by at a decent price and, "if I had to have one lens, this is it".
Differences between the two versions?
The first version has two 'hand-ground' aspherical elements made in the same basic way that the 1st version 50/1.2 Noctilux was made. The 'hand-ground' term here means highly 'supervised' and quality controlled precise specialized grinding machines. Each lens needed an 'artists' touch' to get it within tolerances, very hard to make with many rejects I heard. One woman made this lens in a back room at Wetzlar. Because of this the original production run of 2000 was scaled back to 1000, and the actual number made may have been in the 700 range (no one knows for sure). I had heard that the lens barrel itself would have needed another production run and Leica decided against it with the glass costs and difficultly. Although the element layout is basically the same as the ASPH the 1st version, front element to back element distance, was a bit shorter if I remember right.
Photo-quality is basically the same between the two. Sharpness/contrast comparable, if there is a difference you'd have to really be looking but may be there especially with sample variations. I never did a detailed comparison when I had the two, just some side by sides to see in general, but the only differences I would say is the 1st version is more flare resistant and seems to have 'smoother' bokeh, that is the transition of out of focus seems more gradual and even (or at least its two of the qualities of this lens I see and appreciate after using it for a time now).
How the 1st version handles is maybe the major difference that's apparent. The lens barrel itself is a few mm shorter and the rear element is slightly shorter from the lens mount. The 300gms is slightly less too than the ASPH 315gms (Leica specs.). The 1st version has a grooved focus ring😀 along with the finger tab. When I had the ASPH version its something I always wanted and spent time thinking of a solution which never was perfect (rubber strip in the focus ring). I like the older style plastic/nylon finger tabs of the 70s/80s, there's a nice 'hump' on the side of it that works like a raised bridge to put your fingers, and the contours are not so sharp, a 'softer' feel to it. The 1st version tab is placed a bit higher on the barrel and fits my index finger perfect, and with my thumb on the grooved focus ring its quick and well controlled. But the tab becomes harder to use in the close focus range (unless you only use the tab) with the advantage being I switch to the focus ring with both index finger and thumb.
Focus is very smooth on both with the 1st version having a longer focus throw and the added '0.8' m engraving. I like the longer focus throw in general especially with a fast 1.4 lens
The aperture ring on the two ASPH version lenses I had was never the way I liked it, too easy to move and soft clicks. It was just OK for me, and some folks may like it that way (the Leica rep that showed me the aperture action was very proud of it). The 1st aspherical version is a bit more old style, the aperture is controlled internally by two pins, not one as the ASPH, and there are 10 blades instead of the 9 of the newer ASPH making a 'rounder' aperture opening over the f-stop range.
I much prefer the clip-on style hood of the 1st version with its hard plastic clip-on hood cap (that soft rubber lens hood cap of the ASPH was always falling off). The hood tightening ring on the ASPH just seems odd and looking for the aperture ring with my fingers that's the same size and style as the hoods ring I turned it now and then by accident. The 1st version hood is also a bit thicker plastic (not larger) and maybe more durable. Anyway the original ASPH can use the 4th version 28 Elmarit's hood (which I did) and is the same design as the 1st version hood.
The 1st version 35 Summilux aspherical these days is going for $4,000-6,000 (bargain - boxed and mint unused condition), which if you think of it with inflation can be less than the original early 90s $4,000 price tag. Is it worth the extra money compared to the newer [new or used] ASPH version? In actual photo quality I would say no (to me). But then I got mine at a good price and at the time the Yen was a lot less than the dollar (it was a 'bargain'). These days the ¥/$ are more equal and its more an individual/cost judgment call, and if you can find an 'aspherical'. Both lenses are great, and there is something to be said for a well corrected fast wide-angle lens as a universal lens on a Leica. All in all, the 1st version is fairly light (the pre-ASPH is 250gms) and not so big (comparable to my 50mm Summicron) and I do use it without a hood most of the time which makes it even smaller, it handles superbly, and it never fails optically - what more can you ask of a lens?
I do use this lens, its not a 'collector's lens, but I don't 'throw it in the bag' with out care either. Now if anything happened to it... and it needed repair... may the Leica God's help me:angel: I do keep a B&W MRC filter on it.
Here's a photo of the 35 Summilux aspherical compared with a 50mm Summicron 3rd version (BTW that's a very rare 3rd version 50 in black paint, special order and maybe only a dozen or so made, engravings are different and of course the BP vs normal anodized black)