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05-03-2021, 08:31 PM   #1
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645 Teleconverter Conversion with Autofocus?

Was looking at the 645 teleconverter and wondered what would be involved in adding autofocus to the 1.4TC. It seems as if it could be possible to add the screw-drive functions by salvaging components defunct 645 cameras and 645 AF lenses. The "lens" side looks fairly possible, however the "camera" side of the TC might be more complicated. It would require someone with machinery that can manufacture the components to fit on the "camera" side of the TC.

The other side to consider would be the practicality of autofocus on a converter. Adding a TC to lenses with f5.6 may not have enough light to enable autofocus.

Any thoughts on this?

05-03-2021, 10:30 PM   #2
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QuoteOriginally posted by TDvN57 Quote
Was looking at the 645 teleconverter and wondered what would be involved in adding autofocus to the 1.4TC. It seems as if it could be possible to add the screw-drive functions by salvaging components defunct 645 cameras and 645 AF lenses. The "lens" side looks fairly possible, however the "camera" side of the TC might be more complicated. It would require someone with machinery that can manufacture the components to fit on the "camera" side of the TC.

The other side to consider would be the practicality of autofocus on a converter. Adding a TC to lenses with f5.6 may not have enough light to enable autofocus.

Any thoughts on this?
Doubt an individual could pull off a screw drive af converter mod. It would likely take a well equiped company to do it. Do any of the tele lenses use SDM? If so a converter with electrical contacts on both sides, wired together, could af.

Unfortunately the F5.6 maximum lens opening would probably make the 1.4 converter iffy at best. The 300 F4 might do better. Would the 300 F4 with 1.4 converter match the IQ of the 400 F5.6?

We could just crowdfund an ultratele after the ultrawide 😊.

Thanks,
barondla
05-04-2021, 03:33 AM   #3
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You need a lens mount with all contacts, a camera mount with all contacts and a transmission shaft for the screwdriver AF.
05-04-2021, 04:56 AM   #4
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Even if you could machine it to the necessary precision, the torque and misalignment on the drive shaft would likely be a problem.

05-04-2021, 07:14 AM   #5
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we would need a watchmaker
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