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 Post subject: Yashica AF and Minolta AF
Unread postPosted: Sun Feb 01, 2009 6:41 pm 
Oligarch

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Digging through my old lenses I found one from when I had a Yashica AF230 many years ago. Looking at the mount I was surprised to see just how very similar it is to the MA mount. It is so close that I feel there must have been some collaboration between the companies over the design. Does anyone know the history?

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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Sun Feb 01, 2009 7:59 pm 
Grand Caliph

Joined: Sun Aug 17, 2008 8:07 am
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They were basically rebadges with the aperture lever moved.

Peter Ganzel did a write up a while back on his Pbase.


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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Sun Feb 01, 2009 8:31 pm 
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Pentax and Nikon both used very similar systems and so did Olympus - Minolta was the first, but until Canon devised in-lens focus motors, all AF systems used a motor in the body and a coupling drive to the lens.

The design of the coupling is based on the Hasselblad shutter-iris actuator or lens cocking connection. It's almost identical. That dates from the early 1950s. All Minolta did was to take a method for linking a drive shaft in a lens to a drive shaft in the body, which already existed in an unpatented or out of patent Hasselblad mechanism, and convert it for AF use. Since they did not invent this type of coupling, others then used it. I believe it had also appeared in a 35mm camera with focus control on a wheel on the body. The last new design ever to use the same method was the Contax G1, which used it for autofous and manual focus coupling. I'm not sure about the Hasselblad XPan and a few other specialist cameras.

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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Sun Feb 01, 2009 9:08 pm 
Grand Caliph

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In this case though it's not just similar design, but an actual modified A mount variant.

http://www.pbase.com/pganzel/image/82047034


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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Sun Feb 01, 2009 9:45 pm 
Oligarch

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PhotoTraveler wrote:
In this case though it's not just similar design, but an actual modified A mount variant.


Yes that was my point, they are so similar but not interchangeable . Nice comparison photo.

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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Mon Feb 02, 2009 2:07 am 
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The Yashica 230AF looks very like a rebadged Minolta 7000/5000AF, but the mount is not so much more different than any other three-flanger bayonet (there are only so many choices, change the orientation, change the flange lengths, change the pitch of the electronic contacts, position of iris actuation etc). What I do not know is whether the flange to film distance was within the apparent range reported for the Minolta AF mount - nominally 44.6mm but measured by various people within 1mm either way, which is an excessive variation.

Since the camera was unconnected with the Yashica/Contax system and had a very short life, it's likely that Minolta had a hand in it - but that would not make sense given the plans they had for the AF system at the time. More likely, a third party contractor was involved, possibly the Chinon factory, in both systems. When the Club visited Japan in 1986, we were shown lens production at Sakai, but not shown camera production. Why? You would imagine camera production would be the main thing. Perhaps the 7000 and 5000 were actually assembled, even co-designed, with a third party plant.

David


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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Mon Feb 02, 2009 5:44 am 
Grand Caliph

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I was trying to find a write up pete did before, I think he found the ROM protocol/pinout was in fact the same, and they would physically mount, it was just the aperture re-location messing things up, and the registration was the same.


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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Mon Feb 02, 2009 7:02 am 
Oligarch

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There was a series of Yashica AF cameras with this mount. AF200, AF230, AF270 and AF300 made between 1987 and 1994. There were slightly different names in various world markets. They were not re-badged from any another make. There were about a dozen lenses including independents.

Also a clever AF Converter 1.6x was made which enabled the use of Contax/Yashica manual focus lenses - and focussed many of them automatically. I think this would be interesting to some Minolta/Sony users if it could be modified to work with the MAF mount. Think of all those older Zeiss Contax fit lenses, Planar, Sonnar, Distagon, Tessar ….

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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Mon Feb 02, 2009 7:26 am 
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rogprov wrote:
Also a clever AF Converter 1.6x was made which enabled the use of Contax/Yashica manual focus lenses - and focussed many of them automatically. I think this would be interesting to some Minolta/Sony users if it could be modified to work with the MAF mount. Think of all those older Zeiss Contax fit lenses, Planar, Sonnar, Distagon, Tessar ….


There's a similar converter available for the Minolta MC/MD lenses that will mount it on A-mount bodies. The problem is you have a less quality optical element that degrades the quality overall, costs you an f stop and blows your focal length! Your fast 21mm 2.8 just became a 31.5mm 4.0, and if you use it on APS-C, it's not a 47mm lens. If I could get my hands on a cheap MD mount 200 or 300mm 2.8 MD lens, then I could accept the quality and speed loss to get L-O-N-G focal length fairly cheap.

In optics, there's just no free lunch.

Dusty

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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Mon Feb 02, 2009 7:43 am 
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Quote:
There's a similar converter available for the Minolta MC/MD lenses that will mount it on A-mount bodies.
Dusty



Yes there are plenty of adapters available to fit various lenses to the MAF ... but the uniqueness of this Yashica one is that it auto-focusses manual focus Zeiss lenses ... must be interesting at the very least. :D

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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Mon Feb 02, 2009 8:10 am 
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Granted, Roger, that auto focusing manual lenses is unique, but you're still stuck with the bad side-effects. I wish there was a way to just take my MD lenses and remove the MD mount and replace it with an Alpha mount. I could get some nice glass back, and wouldn't care that I had to manually focus.

Dusty

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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Mon Feb 02, 2009 8:16 am 
Oligarch

Joined: Sun May 20, 2007 5:10 am
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Dusty wrote:
Granted, Roger, that auto focusing manual lenses is unique, but you're still stuck with the bad side-effects. I wish there was a way to just take my MD lenses and remove the MD mount and replace it with an Alpha mount. I could get some nice glass back, and wouldn't care that I had to manually focus.

Dusty



There is :) ... have a look at this

http://www.pbase.com/pganzel/modification_of__58mm_f12_rokkor


Also have a peek at eBay item 150323882751

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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Mon Feb 02, 2009 1:47 pm 
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rogprov wrote:
Dusty wrote:
There's a similar converter available for the Minolta MC/MD lenses that will mount it on A-mount bodies.

Yes, there are plenty of adapters available to fit various lenses to the Minolta A mount ... but the uniqueness of this Yashica one is that it auto-focusses manual focus Zeiss lenses ... must be interesting at the very least.

That's not unique. The same auto-focusing 1.6× tele converter for manual-focus lenses also exists in a Minolta version. It auto-focuses Rokkor lenses on A-mount bodies, and also enables full-aperture metering with most MC and MD lenses. It's made by Sigma, and optical quality is pretty good---much unlike the dreadful 1.25× MD/AF adapters. Unfortunately (and notoriously Sigma) the auto-focus feature only works on the first-generation Minolta AF camera bodies, i. e. 5000, 7000, and 9000.

-- Olaf


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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Mon Feb 02, 2009 6:35 pm 
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Forget the AF, just give me a good optical quality with a low multiplication factor adapter. Something like a 1.1x and 1/2 f stop loss. Of course, the time for this is long past. If was going to happen, it would have right after the switch to AF in the late 80s.

Dusty

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 Post subject: Re: Yashica AF and Minolta AF
Unread postPosted: Mon Feb 02, 2009 6:56 pm 
Oligarch

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Location: Gloucester, UK
01af wrote:
That's not unique. The same auto-focusing 1.6× tele converter for manual-focus lenses also exists in a Minolta version. It auto-focuses Rokkor lenses on A-mount bodies, and also enables full-aperture metering with most MC and MD lenses. It's made by Sigma, and optical quality is pretty good---much unlike the dreadful 1.25× MD/AF adapters. Unfortunately (and notoriously Sigma) the auto-focus feature only works on the first-generation Minolta AF camera bodies, i. e. 5000, 7000, and 9000.

-- Olaf



I'd forgotten that one ... but as you say only works on pre-Dynax.

Not that want any of them ... jut interested in the history behind it all :D

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