Cinevate 72mm achromat. at DVinfo.net
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Old May 26th, 2006, 07:19 PM   #1
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Cinevate 72mm achromat.

I just received our first "prototype" 72mm achromat. It's designed for the DVX, HVX, Sony HD's, and HVX cams on the Brevis35...basically 72mm and up lens cams. It would compare in actual magnification performance to an Asian +10, although it's actual focal length is quite different. I'm doing testing, but so far it makes the singlet achromat look like a piece of junk, and that's looking through the lens, not at it :-) It will be available to anyone, although Brevis buyers will receive it discounted. Pricing should be ~ $175.

www.cinevate.com/images/achromat.jpg

Last edited by Dennis Wood; May 26th, 2006 at 08:43 PM.
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Old May 26th, 2006, 08:43 PM   #2
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How good is it?

www.cinevate.com/images/achro.jpg

vs

www.cinevate.com/images/asian10.jpg

These were taken using the GS400 stills feature, through the Brevis (F1.4 50mm lens), with the Asian10 attached, then the Cinevate achromat. Res gain is approx 100 lines. BD is from the Minolta 50mm lens.
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Old May 27th, 2006, 11:48 AM   #3
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Dennis.

A few tiresome questions.

What is the rear face to front face dimension not including the threaded shoulder?

What is the widest diameter of the lens housing (clearance needed)?

What is the band of available sharp focus distance from front of lens on the Sony FX1/Z1, ie., lens to closest - lens to furthest?

What is the size of the image target off the groundglass at full zoom-in on the Sony FX1/Z1? Corner to corner (diameter round) or Width-Height?

I don't know how to interpret your published chart. Can you advise the resolution of the total system when interpreted from this chart.

Currently I am using the Century Optics 58mm 7+ achromatic via a step-up ring with Nikon primes and a 5 micron groundglass. With the 85mm Nikon f1.8, it seems that 850 TV lines is just possible, 750 is probably more realistic with my bits and pieces.

The smaller diameter of the Century lens enables me to get close enough by the prism clamp to focus past the rear (forward facing) prism but it is a snug fit. I could lose about 4mm from the front of the Century housing but don't want to do any butchery to it.

A wider diameter dioptre if not as thick from front face to rear face, even if +10, might be usable in my application if I can get it close enough to the groundglass via the prisms.

The +7 is proving to be a little hard to get, so I am looking for alternatives.
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Old May 27th, 2006, 03:53 PM   #4
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Bob the chart is taken using the GS400 onboard stills function and although claiming 4MB, as a closer to 2MB in the digital stills world. It is not by any stretch a test of the achromats possible resolution as the stills are poor quality. It's more a test of relative resolution between the Asian 10+ and what I've had manufactured.

Shoulder to face is 20.4mm, max width OD is 75mm. I don't have an FX1 at my disposal (the beta guys have them) to test this achromat, but it will be tested on the HVX and DVX100a. The design spec of my adapter is however a full 24x36 image size. With HD cams, the diffuser on a fast lense will give you in excess of 36mm image width so the HD frame can technically be closer to 38.5mm in width. This lens is not rated 10+, however it performs in terms of magnification, slightly less than the Asian 10+ (as a reference). This is because the achromat is measured using actual optical focal length, not a calculation of surface curvature as it relates to lens diameter.
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Old May 28th, 2006, 07:11 PM   #5
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XL1s footy with the new achromat...

http://rapidshare.de/files/21624856/xl1s_achro.wmv.html (please use this link if possible...)

or

www.cinevate.com/images/xl1s_achro.wmv

76MB high bit rate wmv file....
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Old May 29th, 2006, 10:29 PM   #6
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Dennis.

I would be interested in knowing from the beta testers if the FX1 or the JVC HD100 (standard Fujinon lens) can zoom in close enough to frame an image off a groundglass 18mm high. My prism path introduces a 30mm width limit.

Some independents here look like they want to go with my device.

I don't want to get into making and selling devices as the design lends itself to hand-build production only.

Small production numbers mean the unit cost is too high and this will attract a heightened obligation to support the product.

Supporting the product whilst trying to distill genuine failures from operator abuse will likely drive me quite mad.

I also have a remaining paranioa about getting sued for patent infringement even though my design is distinct from any other.

I have referred them to dvinfo to inform themselves of the available alternative devices which are ready to fly but the enquiries have persisted.

I guess it may be because they can chase me with a stick down the road if the gadget doesn't work because I live locally nearby.

My counsel to them has also been that there is much much more to these devices than the adaptor itself and that it should be only considered as part of a larger well managed system if the benefits are to be realised.

If they end up not buying in an alternative product, I am looking at providing my device on a rental, loan or service provider basis only.

This is something along the lines of the Xerox copier service of old or the current aerial stabilised camer a platforms which are rented, not owned.

If I still can't get the +7s I am after, I may come knocking at your door for your lens.
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Old May 29th, 2006, 11:38 PM   #7
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Bob, I hear you, on many levels :-) Once the guys get these in hand, I'll see what I can do.
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Old May 30th, 2006, 08:03 AM   #8
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Dennis.


Thanks for the response.

"here" of course means Western Australia, not here at dvinfo.
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Old June 16th, 2006, 09:27 AM   #9
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When will your achromat be available for sale?

Thanks.
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Old June 17th, 2006, 08:16 PM   #10
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It is currently available and updated in our online catalogue. Pmail if you're interested.
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