Sony PMW-EX3 Adapter

[Steve Harryman]

Phil Bloom mentioned Sony will also have an adaptor to let you mount their 35mm digital SLR lenses onto the ex3. Has anyone heard if they will be offering other lense mounts for Canon and Nikon lenses? Really could use the increased mag/FOV factor for wildlife work.

[Paul Curtis]

This is an area that interest me greatly (having a lens fetish already).

In theory a lens adaptor can't just be mechanical because an SLR lens focuses all colours on a single plane whereas a 3 chip lens focuses them slightly differently because of the prism. I say in theory because in this case i don't know whether the result would be that visible (SI have digiprimes - which are corrected for 3 chip systems - on their single sensor camera and they seem okay). 35mm adaptors focus the SLR on a single plane then the camera lens which is corrected for 3 chip records that image. If there's a 35mm adaptor straight into the EX then it would probably have to correct for the prism too.

I would love to see some tests with an EX3 and digiprimes.

I would also love to see someone make a c-mount > EX3 adaptor because there's a huge range to experiment with, especially 16mm film lenses.

But to answer your original question. If this sony lens adaptor is just mechnical then it would be easy for other lens mounts. If the sony adaptor includes optics in to correct for the prism then it's more difficult.

Also the decreased fov would work well for wildlife as you say, im not sure what the crop factor is, i think it's around 5.5 x, so a 50mm would have the fov of a 250ish.

I believe the Canon EF lens adaptor (for the canon 3 chip camcorders) has optics in, perhaps someone in more knowledgable position can confirm this?

this is the one reason i'd trade up to an EX3. And the fact that it seems less like the ergonomic equivalent of a brick.

cheers
paul

[George Kroonder]

It would be great if they came out with something like the JVC HZ-CA13U, even if the EX3 can't flip the image.

George/

[Dean Harrington]

even though it doesn't flip while recording, it will flip the image on the EX3 in the viewfinder and that's the key. It's easy enough to flip it in an NLE so, it's not really a problem.

[George Kroonder]

True, but still everything you attach to it is upside down and that is difficult for live events, monitoring, etc.

Would be nice if image orientation could be maintainted. The LCD/viewfinder flip is just a stop-gap measure, in my humble opinion.

George/

[Sean Donnelly]

It doesn't matter if the image is flipped or not. Every lens flips and inverts the image. Using a large format film camera is an easy way to see that. The reason it has to be flipped with a 35 adapter is because you are using an optical relay, and the image is being flipped again. Some adapters leave out the flip component to reduce the optical path and lower the cost. If you're just mounting a 35mm lens directly on an EX3, no flip needed.

Paul, I really don't think that's true. As far as I know the prism does the work, and in fact doesn't separate the light into different spectrums, it just sends the same volume of light to each sensor, which is masked to see a particular color.

[David Lorente]

Originally Posted by Sean Donnelly

...
Paul, I really don't think that's true. As far as I know the prism does the work, and in fact doesn't separate the light into different spectrums, it just sends the same volume of light to each sensor, which is masked to see a particular color.

Sean, that's not exact. Just look here: http://www.alt-vision.com/color_prisms_tech_data.htm

That actually makes sense, since the energy of each part of the spectrum is sent to the imager that should detect it, thus taking the most advantage of the available light, improving the sensitivity of the camera.

[Sean Donnelly]

Thanks for posting that David. I guess I was close, the sensitivity masking is just done with layers inside of the prism as opposed to on the sensors, which reinforces that the separation is done by the camera and not the lens.

[George Kroonder]

Hi Sean,

You're missing my point here I think (may not have made it clear though). Sure I could bolt on a 35mm lens with an appropriate adapter and have the inverted image recorded right side up, but it would massively magnify the image and I'd gain no "film look" i.e. better, shallower DoF.

For that you could use a Letus, Redrock or any of the others with a relay lens, but then you'd have to use a 'flip' unit to, so to speak compensate, for the additional lens. And you'd get all the difficulty that comes with 35mm adapters, starting with the ground glas en not ending with the backfocus ajustments.

The JVC HZ-CA13U is essentially a relay lens that scales down any PL lens image to 'fit' the sensorsize; in its case 1/3 CCD's. And although it flips the image, the intended camera's can electronically flip the image so it is output/recorded straight up.

Now I pupose that loosing the ground glass, rotating, spinning or still, would be a good thing. And flipping the image in camera would be my preference over an additional optical unit for practical purposes.

With the EX3 not having 'electronic flip' it would be nice if an EX-mount adapter would integrate that into the design.

George/

[Steve Harryman]

Back to my original thread, the hope is for just a mechanical mount---like the many out there for 1/3" cameras. I had a JVC HD100u and a mount made by Les Bosher that worked well for my Nikon telephotos. I think Sony would sell alot more EX3s if they didn't just focus on a mount for their own SLR lenses (which I recently was surprised they even made their own lenses). Time will tell.

[Chris Leong]

Steve

Since it looks from the pictures that the sensors of the EX3 aren't set that far back from the mount plane, there would seem to be plenty of backspace available for 35mm lenses to be mounted.

So if Sony doesn't make one, it's just a matter of weeks before an enterprising machinist makes a mount for any/all of the regular SLR lenses. After all, it's just a flanged plate mounted to an SLR mount (with appropriate back focus adjustments, of course).

No, it won't give you the 35mm DOF effect that the lens adaptors with GGs in them will, but I don't think that you were after that effect in the first place, correct?

[George Kroonder]

From what I heard Sony is working with lens manufacturers to support the EX-mount and adapters. See the featured EX3 video on FreshDV.

George/

[Paul Curtis]

If you just put on an SLR 35 lens using a mechnical adaptor the image would be the right way up. It may exhbit colour abberations (because of the prism) and you'd get a fov multiplier of around 5.5 so lenses would be very long.

Therefore most SLR lenses by themselves aren't much use.

However HD lenses are designed for 3 chip cameras and are usually smaller focal lengths and also fast. So they become usable. Perhaps only to rent rather than own, but it would be a nice option.

However there is a multitude of cmount industrial vision lenses out there for 2/3rds. And it's these that could prove interesting. f1.2 8mm would make for an interesting 'normal' focal length.

That JVC adaptor is very clever, and expensive, but it optically reduces the image circle of 16mm PL mount lenses (not 35). However it introduces some restrictions with the aperture that is usable.

To be honest once you try, you may find that even the digiprimes don't make that much difference compared to the stock lens (which is a very small focal lenth at it's widest). Also the extra speed of the digiprimes (a major reason for trying them) may not make *that* much difference with DOF either.

It could be that the biggest plus point of the EX3 is that a 35 adaptor can be attached directly, which should make a rig look a little less mutant like, scare children less (no offense to anyone) and also be optically a bit cleaner.

cheers
paul