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Old September 18th, 2007, 09:54 PM   #1
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Cinevate at Canon Pro Expo this week :-)

For those of you in the Toronto area this week...please drop by and say hello! We'll be at the Canon Pro Expo all day Thursday and Friday (20th and 21st) with our optical flip module/HV20/Brevis and a fully kitted XH-G1 outputting SDI to an HD monitor. Details on the event are here: http://www.canon.ca/CPSE/ Our brand new follow focus will be debuted there.
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Old September 19th, 2007, 08:32 AM   #2
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Dennis.

If you can give info without compromising the design security of your product, what common thickness for all faces for the rear prism or mirror pair did you finally settle on.

I went to 32mm and still pick up a glass edge when zoomed in to 26mm - 28mm image width. Picture sharpness really picks up though.

Last edited by Bob Hart; September 19th, 2007 at 08:33 AM. Reason: can't spell
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Old September 19th, 2007, 11:50 PM   #3
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Bob, I'm sure many folks will be reporting dimensions etc. in short order, regardless. I will say that the unit has (for our purposes) perfect optical alignment, zero dust intrusion possible, and a build quality that will allow them to be dropped and otherwise abused..unscathed. It will handle a 16:9 or 4:3 image well beyond the SLR standard frame width :-)
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Old September 20th, 2007, 05:47 AM   #4
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Given the wider image path, my guess is that Ted Ramasola may be keeping a close eye on your flip module for his medium format rig unless his JVC is a HD250 which flips the image electronically.
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Old September 23rd, 2007, 12:23 AM   #5
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Largest lens ever adapter mounted ?

Anyone ever mount a Canon 500mm f4 lens to an adapter?

300mm f2.8
500mm f4.0

Amaaazing glass.
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Old September 23rd, 2007, 03:44 AM   #6
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I put an MTO 1084mm f10,5 mirror telephoto on once.


http://www.dvinfo.net/media/hart/agusmto8.JPG

http://www.dvinfo.net/media/hart/agusmto3.JPG


I use a Sigma for Nikon 50mm - 500mm f4-f6.5 zoom for ground to airs of aircraft, sometime with groundglass sometimes aerial image which is better. Is only good for 24mm x 18mm frame. Any wider and you get corner falloff.
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Old September 23rd, 2007, 11:07 AM   #7
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Dolly shots with those lenses must be tough.
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Old September 23rd, 2007, 11:25 AM   #8
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Dennis you have raised an interesting question. I have Canon 300 F4/L and 135 F2/L lenses that I have thought of using with a Brevis. I shoot nature and wildlife video and have wondered if you could use lenses like these with higher f-stops (F8 to F12 for example.) Would you be seeing too much grain? I know that most people want an adaptor for the shallower depth of field. I would love to be able to use really good canon glass for video, for both shallow and deep depths of field. Do the tradeoffs at smaller apertures overwhelm any benefits you might have from using the high-quality lenses?

Pat
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Old September 23rd, 2007, 03:43 PM   #9
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Well, we only tried them wide open (indoors, in less than ideal lighting). What I can say is that the XH-G1 was outputting to a 23" Broadcast montitor and the output looked very, very good, even at 8db gain. You can see the surprise in the onlooker's faces. At f8, you'd be likely locked down with the lens, or on a monstor tripod, so I suspect you'd be just fine. We popped a tape in and took some footage so I'll post a few frames up.

We have something lurking in the interchangeable imaging element line that would give you both a range up to 1/500s, approx. f12 and better light efficiency than even CF1L. It would not be my pick for a 50mm lens, but for the 300mm and up, likely the perfect element.
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Old September 23rd, 2007, 11:43 PM   #10
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Thanks Dennis, I'll be watching for that.

Pat
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Old September 25th, 2007, 12:53 AM   #11
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Dennis,

Care to ask Cannon about the XH-A1's chromatic abberation issue you and others have confronted?

Thanks MUCH for all your tireless help!
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Old September 25th, 2007, 11:04 AM   #12
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Peter, It's pretty much well known at this point that both the XH-A1, G1, and H1 will show CA at high contrast edges at the lens periphery. The best defense is just lighting with this trait in mind. It's also true that just about every camera/lens combination out there will demonstrate CA in a given situation. I will say that cameras like the little HV20 with a single CMOS sensor will have an advantage in that there's no colour splitting going on to the 3 CCDs...therefore less optics.

After looking at a lot of footage and many tests with a myriad of cameras and lenses, combined with plenty of research I think it's safe to say this. CA is present in pretty much any lens combination, particulary zoom lenses and all that you can affordable do is reduce it. We've spent a great deal of time, money and research to make sure our adapter and related optics do not contribute significantly to existing levels of CA.

The best compromise possible in my mind is Panasonic's, with their Chromatic Aberration Compensation (CAC). The camera predicts where CA will occur based on various inputs, and then via DSP, adjusts for it. Brilliant.
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Old September 25th, 2007, 11:07 PM   #13
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Dennis.

With the long lenses working in the ballpark of f4, could you get away with aerial image with perhaps just a promist filter in the GG space to diminish the harshness a little. I found on my own cobble with distant objects, the atmospheric haze does that on its own.

I found with the Sigma zoom at f6,3 at 500mm, the 22mm - 24mm frame was just getting inside the vignette and there was no substantial difference in the visual effect, groundglass or not, just the light loss.

The wider aperture long lenses might cover the larger area your setup allows.

Another thing you might examine is UV cure lens cement. This stuff if mismanaged actually becomes a very fine textured fogged layer. Deliberately mismanaged or contaminated with something and layered between two thin panels, it might do some good as a diffuser. - Just a thought.

Last edited by Bob Hart; September 25th, 2007 at 11:08 PM. Reason: error
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Old September 26th, 2007, 01:24 AM   #14
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Bob, you're completely on track with this. Our R&D program yielded an imaging element that has very high gain, but would likely yield bokeh complaints on the typical adapter lenses. This makes it perfect for these fast 300mm and 500mm lenses which have incredibly shallow DOF anyway. For other reasons, it would also lend itself well to high shutter speed operation.
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