Century Optics 2x on XA-20

[J.T. Price]

For those of you that started on the GL-1 or GL-2 you might have an old Century Optics teleconverter or WA lens around. As these typically were bayonet mount onto the hood rings of the GL1/2 they have limited use on other cameras. I had high hopes for the XA-20 but, alas, the hood mount is different.

Not being happy with a very expensive paperweight I contacted a company in the UK that specializes in making macro reversing rings, step-up/down rings and gear for digiscoping. They said they could make me an adaptor that would go bayonet mount to 58mm that would allow the Century Optics lenses to be put on the XA-20. They might even be able to make a bayonet mount to bayonet mount converter, I didn't ask. Ok, it is unlikely to be perfect but what else is there to do?

They estimated the cost at 40 pounds. It struck me that I might not be the only person in this situation so is there a broader interest in this sort of converter?

[Don Palomaki]

Back in the dim distant past I recall hearing that Century would remount the glass for a fee. Not sure if they still will do it.

[J.T. Price]

Thanks Don. I emailed Century, never received a reply.......

I have a Sony 1.7x that works ok (it is a 58mm screw thread already) but I always thought the glass was better on the Century (and it is 2x) plus I have that 0.7 hanging around.

In terms of mega-magnification I just picked up a reverse macro 58 mm adaptor for a Canon EOS mount that will allow me to mount the camera on a spotting scope. The same configuration with a Canon EOS body is the equivalent of a 700-1800 mm lens.

Next I will have to come up with some support rig and I know vignetting will be a problem. It is worth a try :-)

[Bryce Comer]

Yeah I had a Raynox 1.8x converter for my old XH A1 & just sold that to purchase a Raynox 2.2x that is much smaller, & much lighter. I have modified it with the lens hood from my old HF G10 so it has the same bayonet mount as the XA 20. Now I have a very handy lens that works great for those long shots/close ups. So far, I have been very happy with the results from the lens. The body is actually ABS which I was a little worried about at first, but the more I think of it, the more I like the idea. It is way lighter, & realistically, should repel bumps better too. Only thing i'm not sure of is the thermal expansion of the ABS compared to any metal or aluminum body. If there is more, then that could cause issues on a very hot or very cold day.
Hope you can get the mod to your old Century lens so you can use the bayonet fitting. So much easier than fiddling around trying to screw the lens on!
Regards,
Bryce

[Don Palomaki]

Coefficients of linear thermal expansion (in (10^6 m/m K)
That translates to mm/km per degree C change,

ABS - 73.8
ABS glass fiber reenforced - 30.4
Aluminum - 22.2
Titanium - 8.6

Important enough for back focus that Canon included temp compenstion in the XL1 mount system.
Not likely a significant issue in the adapter,converter,expecially if it is a single-element design in front of the lens. You can run your own tests with a threaded adapter by unscrew it it a turn or two to see what, if any difference it makes in the final image quality.