Sigma M42 Autofocus Zoom

A while back I noticed an auction on eBay for a bizarre lens that still baffles me. It was a Sigma zoom lens, I

believe from the 1980s, with an M42 screw mount, but it also had an autofocus system. The autofocus mechanism was

powered with AA batteries, and resembled the autofocus system for the old Canon T-80 (with a box protruding from

the side of the lens), except that it was less bulbous. The autofocus was activated with a button on the side of

the lens; the seller was understandably confused as well, although it was definitely an M42 lens. I don't think

it sold for very much, perhaps on account of its total obscurity.

 

It still haunts my dreams. I expect the optical quality was so-so, but the concept of an autofocus M42-mount lens

seems oddly anachronistic. I believe it was something like 35-80mm, f3.5-5.6. Was it a one-off, was it in fact a

recent lens made as an odd luxury item for the Voigtländer Bessaflex, or something along those lines?

It may have been an early autofocus lens designed for non-autofocus cameras. I know Ricoh made one as well (i

think it was shown here, in fact) that was a K-mount. I think the knock on them is they work pretty slowly and

have to have sensors outside the viewfinder like the old Canon CAFS system, which was at least integrated into

the camera. They may be one-shot autofocus as well (i.e. you aim, press a button on the lens and focus is set -

you would have to reframe and press the button again to refocus). I'd call it a curio and don't know how the

performance is since I have no interest in these lenses.

It wasn't an M42 version of this lens?

 

h--p://www.praktica-collector.de/Pentacon_Prakticar_AF_55_200.htm

 

I've never seen one, they're apparently very rare, and, like you, I found the whole thing a little astonishing. Sigma made them for Parktica B mount, but may have made them for other mounts. I can't see why an M42 mount would not have been possible since all the magic bits were in the lens.

A long time ago I saw something like this for the Minolta MD mount.

Last year I had my hands on a Ricoh K-mount Auto focus Rikenon as was mentioned here. I wasn't all that crazy about it. I didn't take any pictures with it, but the autofocus wasn't all that reactive. If you've got an M42 camera, stick to the manual focus lenses. I did.

These lenses were first generation autofocus technology similar to the Canon T80, and were noted for being slow

to focus. Worse still, with these lenses, I don't see how you'd know when focus was set without any indication

within the camera. That's why I thought they would be one-shot autofocus, because continuous autofocus would be

very difficult to judge, and the focus would have to be set before the shutter could be released and there's no

connection between the two acts except by the photographer.

Chinon made some like that. They were a 50mm and a 35mm to 70mm in K mount. Vivitar made a pair of zooms like that which supposedly sell well used. One was a 70mm to 200mm and the other was a 35mm to 70mm. They were available in various mounts.

I have the 70 -200 vivitar af zoom in canon fd mount that I use on my canon t90 ( and with canon b adapter ) on my leica screwmont cameras including bessa r - very good lens good af response fun to use with old leica m2 that has frame projections in the viewfinder

<p>I think it was me who bought that lens on ebay - it's the only one I've seen on there. I think it was a "buy it now" at £75 GBP.<br>

It was indeed the Sigma 55-200 zoom, f/4.5 throughout the zoom range.<br>

I first came across the lens in the 1980s, when I was shooting a Practica BC1 (proud to say I still am, occasionally). There was a P Bayonet version. I was seriously interested, but was deterred by reports of "slow AF" and ended up starting my Nikon AF career. I might try to find out what the PB version cost in those days.<br>

I've been collecting a few M42s over the last year or so - mainly CZJ and Suoer Takumar. I had become resigned to not being able to use them much on my Nikons, because of the inability to focus to infinity without an adapter with a correcting lens - which have a poor reputation for optical quality.<br>

Last week there was one on ebay for only a few pounds, so I bought it and have just finished my first test shoot on my D700. Optical quality judgement will have to wait a bit, as I haven't worked out yet how to keep the pin depressed to allow me to shoot stopped down. I should be able to work out if the correction lens is causing a problem by comparing shots from the Nikon with ones from a K10D I have access to.<br>

The AF performance - yes it is single shot, no tracking - is actually pretty good, it's gloomy out in the woods today but on this body anyway, the AF worked fine. I even got a focus confirm "beep" as well. The button on the lens doesn't come naturally but that would be my only niggle.</p>

<p>John Winterbourne</p>

 

<p>I believe Tamron offered two in Adaptall mounts: A 28-70 and a 70-210 (or similar range). Probably work like the Vivitar.</p>