Lens Adaptor Mamiya M645 to broadcast 2/3" (B4) camera

P

pathfinder

Well-known member
Any of you guys bought, tried, and used this adapter to put Mamiya lens on your HPX500 or any 2/3" broadcast camera? If yes, will this work just like one of the many 35mm DOF lens adapters out there?

Thinking of getting this and a couple of Mamiya lens for my HPX 500. Your feedback is appreciated.

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Here is the link on ebay.

http://cgi.ebay.com/Lens-Adaptor-Ma...T?hash=item45ea96af84&_trksid=p3286.m63.l1177
 
It would not work like a 35mm adapter - there is no ground glass.
The FOV would be magnified tremendously, i.e. a huge crop factor because of the small size of the 2/3" sensor relative to 35mm/645.
Also the 500 is a B4 mount camera which splits the light with prisms. You would need a B4 adapter designed to deal with that - usually around $2000 dollars and up if it even exists for that 645 mount.
 
dadoboy said:
It would not work like a 35mm adapter - there is no ground glass.
The FOV would be magnified tremendously, i.e. a huge crop factor because of the small size of the 2/3" sensor relative to 35mm/645.
Also the 500 is a B4 mount camera which splits the light with prisms. You would need a B4 adapter designed to deal with that - usually around $2000 dollars and up if it even exists for that 645 mount.
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This IS a B4 adapter. Did you go to the ebay site? And Mamiya 645 cameras are 6X4.5cm film size, not 35mm. This would be a great adapter if you need telephoto type shots. Or find a Mamiya 645 wide angle lens, and you MIGHT be able to get a wider view. I said "might", because when you use a wide angle lens not made for a 2/3rd inch video camera, there might be a problem of the rear glass not being close enough to the video cameras prizm. This is pertaining to adapters without glass,which would include this one. But, I think this could be a useful adapter.

JohnnyD
 
No, it's not a proper B4 adapter. Sure it works physically but you need special optics to adapt lenses designed for a single film plane to the B4 prism optical design. It will work but your image will have a lot of aberrations.

I own Mamiya 645 systems, I know what they are.
 
dadoboy said:
No, it's not a proper B4 adapter. Sure it works physically but you need special optics to adapt lenses designed for a single film plane to the B4 prism optical design. It will work but your image will have a lot of aberrations.

I own Mamiya 645 systems, I know what they are.
Click to expand...

It will work. If you go the manufactures site, you'll see most of their adapters, without glass, only work with certain lenses. And that pretty much means tele lenses, and maybe some normal lenses. And that is because of the wider lens rear glass element won't focus on the prizm, it just can't get close enough.

I still have a Hassy, RB67 and even 4X5's. I modified a Pentax 300mm lens with a B4 mount, and it worked perfectly with my 2/3rd inch video camera. No glass at all. No aberrations. Very sharp.

JohnnyD
 
dadoboy said:
No, it's not a proper B4 adapter. Sure it works physically but you need special optics to adapt lenses designed for a single film plane to the B4 prism optical design. It will work but your image will have a lot of aberrations.

I own Mamiya 645 systems, I know what they are.
Click to expand...

You are right, theoretically, but in practice film lenses tend to work fine on chip cameras. I just tried out the Optex LCC which is supposed to correct lenses like the Canon 150-600 and 300 f2.8 for use on Digibeta and HDCams, and side-by-side it made 0% difference, I looked really closely!
The one problem you might have using larger format lenses like the Mamiyas, again theoretically, is that they won't resolve anywhere near as much as the smaller formats as they are not designed to. This should lead to a considerably less-sharp picture - but again, who knows until you try it.
Steve
 
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