What is a Leicavit?
As mentioned elsewhere in the FAQ, the original Leicavit was a trigger operated film-advance device made in the 1960s (not to be confused with the "new" Leicavit released in March 2003 to accompany the Leica MP camera - see heading below).
Here are a few remarks by long-time Leicavit user Tom Abrahamsson: about the 1960's version:
The original Leicavit started out [in the 1930s] as the SCNOO rapid winder for the older screwmount Leicas and evolved into the [post-war] SYOOM Leicavit for the IIIG and IIIF. The version introduced with the Leica MP in 1957 was for all practical purposes a "re-bodied" SYOOM Leicavit. It was later offered as an accessory to the M2 and M1 cameras.
I have had several of these, both in screwmount and in M2/MP combinations. It works quite well, but it is extremely complex for what it does. It suffers from several problems. The drive is by a chain which is prone to stretching with use and also had a very irritating habit of breaking when you used it heavily. The clutch was a simple spring-loaded cam type. This meant that if you wanted to do multiple stroke advances (handy when you hold the camera vertically), it required that you pulled the lever to a halfway point and then when you let it go back to start, it would only engage if it is was pulled back to were you stopped. The outside shell was made from 0.8mm brass (same thickness as the top-plate of a brass top-plate on an M camera) and would literally deform by squeezing it hard. The lever had a razor sharp edge at the bottom and impromptu appendectomies were always a chance if you fell on it! The lever lock was hinged in such a way that the lever tended to be sloppy, even when locked down. It had a side-turn lock on it, a small lever that stuck out from the side of the housing and that was prone to getting stuck in clothing or facial hair (remember this was a late 50's and 60's set-up and some of us had lots of hair then).
All of these little nagging problems notwithstanding, it is still a very jazzy little thing. It is most unfortunate that it has taken on a collector status and now costs multi-thousands of dollars! My last one croaked on me in the mid-80's. It was worn beyond repair, the chain was repaired several times with great effort and the clutch was less than reliable. It was a black paint version and it was attached to an equally worn M2 in matching brass/black paint. I turned it into a couple of M4-Ps and although great cameras, they had to be advanced with the regular lever. This started the whole procedure of making my own "Leicavit" - little did I know that 13 years later I would still be at it!
If Leica would make a Leicavit today, very few of the parts in the original design would be useful. Modern technology has created stuff like carbon fiber reinforced drive belts, multi pin clutches and ultra strong alloys that work better and longer than the Leicavit of the 40' and 50'.
[…] The Leicavit MP was not very friendly [when it came servicing or repairs]. It contained 51 different parts, 4 different springs and some truly weird looking parts. I did try several time to fix broken Leicavits while on jobs, but in most cases I was not that successful with it. For some reason the sliding bar in the drive was a magnet for collecting mud and sand and it required several different screwdrivers and needle nose pliers to dismantle (this was before Leatherman Tools and commonly available Swiss Army knives). There has been many a time when I was crawling around in hotel rooms on all four, looking for a minuscule screw, essential for re-assembly and trying to explain to fellow photographers "No, I haven't had anything to drink, but I am looking for a lost screw". You don't say things like that to photographers, particularly to the ones coming from competing newspapers. It gives far to much ammunition for them in later bar discussions!
As for adapting a 50's Leicavit MP to a M6. It can be done, but is quite expensive and requires the drive parts from an M4-Mot/M4-M to replace the current "tulip". It is not a simple matter of installing just a M2 take up shaft. If you do that, the filmcounter is rendered useless and you of course also have to be prepared to go back to the M2/M3 take-up spool way of loading.
Eliot Rosen adds the following:
I […] can tell you something about Leicavits. The screw mount versions ("SYOOM" for IIIf and IIIg) are more common than the bayonet mount versions (for Leica MP and Leica M2). You can get a working [SYOOM] Leicavit for $ 600-1200, depending on the cosmetic condition. The vast majority are engraved Leitz Wetzlar. The ones engraved Midland Canada are much rarer.
The Leicavit-MP (bayonet mount) is another story. These are all rare. Chrome versions (working) often sell for $ 2500-3000; and black paint versions for even more ($ 3500-4000). That is for an original black paint Leicavit-MP made to match the balck paint MP and M2. The problem is that some of the chrome ones have been converted to black paint by stripping off the chrome and applying paint to the underlying brass. I think this may be true of the black paint Leicavits that are in really nice cosmetic condition, since most of the original black paint units (like the cameras and lenses from that period) were heavily used by professionals.
If you are a user, all this is relatively meaningless. You can get a modern version of the Leicavit [the Rapidwinder] for a few hundred dollars from Tom Abrahmson. The price varies according to the camera model and finish. […]
Did Tom A help design the new Leicavit MP?
In March 2003 Leica announced a new Leicavit MP to accompany the "retro" MP camera released at the same time. As Tom A is a world-wide acknowledged expert on the design and manufacture of rapidwinders, did he have anything to do with the "new" Leicavit?
No. To quote from a couple of long and detailed notes Tom posted to the LUG mailing list in Feb & Mar 2003:
Just to put all the rumors to rest; I did not design the new Leicavit M for the M6P, but I have known about its existence for about a year and a half.
[… Nevertheless, when in conversation with Leica reps. at the 2002 PMA …] I had some suggestions as to the design of the Leicavit, naturally so, as I have more experience with this type of M6/M7 device than anyone else!