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Did the Japanese ever attempt professional movie cameras?


Phillip Mosness

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3 hours ago, sines said:

I thought the rotating mirror, aside from say a system like a Photosonics (which use a rotary prism shutter and beam splitter) passed every other frame: 1st frame film, 2nd frame viewfinder, and so on. Thereby you would never see the exact frame that was exposed on the film, as the shutter would only open for the viewfinder when it wasn't exposing the film.

No, most video taps use a beamsplitter that takes some of the light going to the optical viewfinder and redirect it to there tap. Usually it’s an 80/20 split, so 80% to the viewfinder, 20% to the tap. There are also 50/50 and 100% video beamsplitters. So you always see what the viewfinder sees.

Video assists were additional accessories, so the camera movement and reflex mirror shutter wouldn’t have been designed to split the light three ways, taking light away from the film. 

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You’re right that the film and the viewfinder don’t see the same 1/48 of a second slice of time when the film is in the gate, since one path is closed while the other is open.

However, it’s not accurate to call each 1/48 sec interval a ‘frame.’ The only frames are the ones recorded on the film. 

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8 hours ago, Heikki Repo said:

I also took the DIY "BMPCC as a video tap" -route as well with my Eclair ACL. I haven't really tested it in the wild yet, but my initial tests seemed to show that the focus assist worked even from the ground glass (laser brightened).

The issue with my setup is that ACL doesn't have a separate port for a video tap. In order to use BMPCC I need to remove the viewfinder, which is not optimal. Not to mention that the camera isn't that ... ahem ... aerodynamic anymore.

For ACLs the other option though would be to go for AZ Spectrum video tap. They are fitted between the viewfinder and the camera, so there is that positive. On the other hand, they all are analog and the prices between $1500 (monochrome NTSC) and $2600 (Color flicker free, PAL). Is it worth it? Do you think I could survive without an optical viewfinder?

 

videotap.jpg

That’s a nice video image, but I think I would prefer the optical viewfinder just from an ergonomic perspective. Handheld on the shoulder must be rather uncomfortable with that thing in your face!

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4 hours ago, sines said:

I thought the rotating mirror, aside from say a system like a Photosonics (which use a rotary prism shutter and beam splitter) passed every other frame: 1st frame film, 2nd frame viewfinder, and so on. Thereby you would never see the exact frame that was exposed on the film, as the shutter would only open for the viewfinder when it wasn't exposing the film.

Sadly video taps are generally done through a beam splitter on the viewfinder AFTER the ground glass. So you're not only seeing the ground glass, BUT you're also dealing with substantially reduced amount of light. So the imagers on taps need to be super sensitive in order to get a decent image. This is a very problematic situation because to force little tiny imagers to be very sensitive is not easy. They generally don't like it and put up a fight, with soft mushy image due to so much internal noise reduction being used to reduce noise floor. 

So imagine instead of a ground glass at all, you have a video camera as your only way of seeing what's being shot. You could have a much cleaner image because you're dealing with the same amount of light the film is dealing with. You will also not have the ground glass in the way which means getting a crisp image would be super easy. Panavision already does this with the XL2 HD tap. It's a very clever system that delivers nearly perfect accuracy in terms of clarity. Where you can't use a focus assist on it entirely, its damn close to being usable for nearly everything. If that sorta system could be developed for more standard cameras, I think it would do well, but of course, be very expensive. 

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48 minutes ago, Satsuki Murashige said:

That’s a nice video image, but I think I would prefer the optical viewfinder just from an ergonomic perspective. Handheld on the shoulder must be rather uncomfortable with that thing in your face!

Yeah, handheld won't definitely work!

It'd be nice to say that there's really no need for a video assist (they didn't have one in the past!), but I think it feels more and more like an idealistic defense. The truth is, if I wasn't operating the camera I really would like to know the exact framing -- and I'd like others to see it as well in order to be able to better judge whether there were some issues seen from the camera's perspective.

Ahh well. AZ Spectrum it is going to be. Guess I'll get the motor modification for 1 fps increments at the same time. Time to save up.

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41 minutes ago, Giray Izcan said:

I believe AZ Spectrum offers HD tap for the ACLs as they do for fhe NPR. Supposedly, it's flickerfree too.

Oh! I didn't know that. It's not on their webpage, but I guess I'll have to contact them again!

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