Information about the 1st Generation Letus Flip adapter at
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Old October 29th, 2009, 08:50 PM   #1
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Information about the 1st Generation Letus Flip adapter

I'm looking for information on the first generation Letus Flip adapter, ala

What can you tell me about this adapter vs the newer models? Maybe a break down of the different versions and the differences between them? Just purchased a first generation and I'm curious as to how it's different from current models.
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Old November 3rd, 2009, 05:21 AM   #2
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The first flip model used surface coated mirrors in two pairs, one split, one entire, ie., Mirror 1 - Reflects from front SLR lens axis 90degrees to L. side, Mirror 2 - 90degrees to vertical, Mirror 3 - 90degrees to R side, Mirror 4 - 90degrees to camcorder lens axis.

The Extreme does the same thing with three prisms, which reflect the image from internal facets. Prism 1 = Mirror 1, Prism 2 = Mirrors 2 and 3, Prism 3 = Mirror 4. All prisms are fixed together with UV-cure optical cement and become what I describe as a compound prism.

In the mirror setup, the mirrors rest on facets machined into the delrin case. In the prism setup, the two small prisms of the compound prism are glued to the hypotenuse face of the large prism, one facing forward to receive the SLR front lens image, the other facing rearwards to the camera lens.

The two smaller prisms are separated by a space of about 8mm into which a metal support spine fits to support the compound prism along with the front and rear side faces of the larger prism and the smaller prisms being in contact with thin pads inside the metal casework and dampened from movement by a rubber wedge.

The delrin flip casework separates along a midline under the tape you observed. The metal flip casework separates along the front edge, with the front cover more like a lid on a box.

These two basic structures define the basic generations of the Letus flip adaptors. Additional selected components provide for the fit up to various camera types as combinations of adaptor rings and purposed achromats.

Additional accessories were developed and provided by Letus for camera and adaptor support. I understand that there was an early bridgeplate and rails support system built on two common 12mm rods and a subsequent development styled after the Zacuto with a stepped bracket and four rods.

Interestingly, the Letus approach to the tendency of rods in holes to pick up and bind because of aluminium to aluminium contact, was to prepare the surface of the rods with a hardened pitted finish. This has the effect of reducing surface area contact and friction.

Other vendors have dealt with this by applying teflon surface coatings or using non-metallic rods.

Last edited by Bob Hart; November 3rd, 2009 at 05:24 AM. Reason: error
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Old November 3rd, 2009, 01:21 PM   #3
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How about how it differs functionally - how sharp are the pictures etc?
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Old November 3rd, 2009, 06:32 PM   #4
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I can only speak for the Gen 1. flip model for Canon XL, direct relay. At the time I tested it after some vibrator mods, none to the optical path, in daylight with all lenses in sweet zones, the Canon XL was resolving via the adaptor just to the limit for MiniDV, horizontal 530 lines or thereabouts.

In low light real world conditions, with everything wide open, it was noticeably softer.

Anecdotally, the Gen 1 Letus flips for lens-in-camera style camcorders performed better because the crop factor could be controlled or groundglass image area expanded by zooming back if the SLR lens image throw permitted this without corner brightness falloff.

On YouTube, search the DARANGULAFILM clip list and look for two clips on the Letus, one is a pull apart how-to, the other is a mod to the Letus XL flip and a short clip of high shutter speed tests.

Also look for the "b-movie heroes" "The Horse You Rode In On" music vid. The close-ups were shot on a Canon XL2 with the Gen 1 Letus flip adaptor.
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