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Old November 21st, 2005, 01:51 PM   #46
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Quote:
Originally Posted by Michael Maier
I have to say your lens support itself looks better.
I don't know about looks. Specific solution for a specific problem dictates a certain design to address that problem. I agree Cavision is made for lens support not Letus, but could be used just as well... (well, more or less). Is not really up to me. If you guys see the diff and you want it, I'll make it. Otherwise I will make my mod for MPIC based on Cavision. Is just not worth launching a production for a few orders.

PS. As for cars... I do not have ANY wishes in that range (sad!) That was an example based on what most people could dream of. I had a Lexus for 7 years (very nice) and I now I would like a SMART:
http://www.seriouswheels.com/pics-20...-1920x1440.jpg or a Prius (to get fancy!)
The "other ones" are nothing but a public offence IMO (lol). I can do just the same for free on this forum, hey?(rotf)
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Old November 21st, 2005, 02:28 PM   #47
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Quote:
Originally Posted by A.J. Briones
... and that's the lotus exige, which costs more than the elise. i hope to one day get an elise.... it's my dream car.

Really? Is it a new model? It looks very similar to the Elise. How is it positioned? Between the Elise and Esprit? I hope it didn't replace the later.
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Old November 29th, 2005, 02:52 PM   #48
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Cavision rods arrived yesterday

'ello everyone,

Just want to let you all know I got the Cavision fiberglass rods system I bought from B&H:

http://www.bhphotovideo.com/bnh/cont...ughType=search

Ignore part of the picture on that site; it shows a circular lens mount-type thing, and my rods came with no such device. I think, however, that the "RSBP" they refer to is the adjustable support device that holds up the lens.

Anyhoo...

I set up the camera on the rod system in my sunroom where lots of delicious overcast light was pouring in from the skylights, as well as another camera on the side of my GL2 to get a viewpoint of the lens and rods themselves as I pulled focus. The video's probably unneccessarily long--I didn't even watch it in its entirety--but I just hit record and played with the lenses long enough to get the point across that the Cavision rods do the job plenty well enough.

rodsystemtest.mov (10.6MB, streaming Quicktime (non H-264))

Fellow Letus35 uses with zoom (and even prime) lenses know the unavoidable jerkiness associated with pulling focus without a rods system, so the first parts of each test will result in a sigh of comfort and satisfaction.

I did two tests; one with my 1.4 50mm prime, and one with my 3.8 zoom lens. The zoom lens is, of couse, pretty hefty so I tested it second.

You'll see me first pull focus on the prime with the rod support, then without the rod support. The picture-in-picture lets you see the camera and what the camera's seeing at the same time. I tap both setups with my finger on multiple areas to try to induce shake. When the support is taken away, there is lots. When the support is attached, there is none. I do this with both the zoom and the prime.

Here are some other pictures:
If you're wondering what that green thing is, I sandwiched my magnet between two layers of painter's tape because I had been losing my magnets so frequency. I'm considering tying a lanyard-type deal from the magnet to the Letus so they're always together.
Side View
Overhead View
Side View 2
Zoom lens Front
Overhead view 2
Disastrously blurry side view
Ditry little blurry pic
Refreshingly clean overhead view

The length of the rods may not suit your purposes, but it suits mine very well--besides, longer aluminum rods can be had at a very low price. Cavision did the job for me and I can say that the entire assembly is very well-made from sturdy aluminum/some kind of metal and can be completely adjusted with an allen wrench. Cheers!

Ben
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Old November 29th, 2005, 03:47 PM   #49
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Thanks for that Ben, I have a similar setup to yours and was looking at the Cavsion Rod Support. After seeing it in action I've decided to keep looking for a cheaper solution.
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Old November 29th, 2005, 06:43 PM   #50
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How does the rod support the weight of the lens? Does Canvision do a good job with that? IF you went with a large lens, are you going to have problems?
After looking at it, you should consider cutting a piece of pvc pipe to get an arc and attaching that to the Canvision piece to uphold the lens. It might give a larger area of support.
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Old November 29th, 2005, 07:02 PM   #51
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What the idea really comes down to is rather than having the lens simply rest on the Cavision support, you tighten the support a bit firmly into the lens so as to push it up a tad. You could easily go to a bigger lens and not have any issues.

Yes Mandy, I am contemplating modifying the support in that way, however the current design seems to not present any real issues--yet. If I do end up needing "more contact" I'll probably buy the add-on that Mr. Diaconu posted farther back in this thread.

The rods go straight into a plate that screws directly into your camera and has screwholes for tripod mounting. You're essentially changing the weight distribution of the lens to more towards the tripod or the body of the camera. The principle of adding tension to the setup (by tightening the support into the lens) vastly reduces shake issues since the lens setup is sort of "pinned" into position.
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Old November 29th, 2005, 07:20 PM   #52
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Quote:
Originally Posted by Ben Winter
you tighten the support a bit firmly into the lens so as to push it up a tad.
That's true, but that does not "solve" the L/R torque problem of a plastic mount and the tension that mount takes while performing a focus roll (I do not have in mind hand-focus as done in still photography). The beauty of PL or Panavision mount is "rock solid" lens mount (as it should be in any optical system designated for this job)
Quote:
Originally Posted by Ben Winter
You're essentially changing the weight distribution of the lens to more towards the tripod or the body of the camera.
True again, but that does not solve the mount tension/weight either.
Rock solid mount is ideal. Lens support helps when the ideal "plays hard to get" with us.
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Old November 29th, 2005, 07:25 PM   #53
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Quote:
Originally Posted by Dan Diaconu
Michael,
What I had in mind to offer was a Letus support like this: http://dandiaconu.com/gallery/album30 and a long lens (or zoom) rods support.
(I am sure you can tell the diff between the straight raiser proposed and the matching diameter circle segment when it comes to support a cylinder; further more; when dynamics come to play and the camera is moving. Inertia of the SLR lens long or short would make it slide L/R if only rested on the raiser!). Tape or epoxy? Pick one.

Meanwhile I found this: http://cavision.com/rods/lenssupport.htm and I posted the result on the Gl1 thread. Nothing more. I just did not know they have it at the time I offered to help. Could it be used for Letus? Most likely yes. Would it do the same job? Just about (imo). No tape and no epoxy. Is it worth refining an existing wheel? Not really (imo) Cavision is available now. No sport lost in the process.

Dan, your adjustable bracket is exactly what I want! The Cavision bracket is flat across (made this way to support at the mattebox end, I think).
What is interesting, though, is the appearance of your unit versus the Cavision. They look almost identical. I'm assuming (hoping) your bracket would fit onto the Cavision's rod system which I already own.
Would you be selling the letus bracket separately?
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Old November 29th, 2005, 07:44 PM   #54
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Dan,
I was thinking more and more about your design and concluded there might be an issue or two with it.

You said there would be rollers of some type on the support you designed so the zoom lens could be used appropriately. If you have the support solely on the zoom lens, wouldn't the "steadiness" of the entire system depend on the texture and contour of the zoom lens' grip? It seems like a bumpy surface and if your support is holding up the assembly wouldn't it shake also as the rollers went over the grip? Also, how would you pull a zoom or focus without running your hand into your support? And if you use your support underneath the Letus only, wouldn't that reintroduce your "plastic mount torque" issue? Does this mean we have to buy two of your mounts? :)

To me, a very effective support would be a 180+ degree encompassing semicircle that would attach or grip somehow to the mounting flange of the SLR lens where the lens meets the Letus. This would evenly distribute the weight, prevent L/R movement as well as shakiness, and leave the lens completely available. Something similar to what Cavision has made, but I don't know the diameter of that support ring and it seems like it has to be used in conjunction with that rope-type secure strap.
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Old November 29th, 2005, 07:46 PM   #55
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Dan,

I really understand what you're saying. I'm just finishing my own rod support for the Letus. But one issue keeps troubling me: how do I make sure the lense doesn't fall out during L/R turns in this plastic mount. Sure, the barrel will be stable in normal and abnormal use, but while turning the focus or diafragm ring with one hand (and without DD's FF), the lense can easily pop the lens out, if you're attention goes to the subject and not the mechanical part of filming.

If anyone has any ideas?
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Old November 29th, 2005, 07:51 PM   #56
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Are you saying you accidentally turn the bayonet mount lock bar thingy, and the lens comes off the Letus? If you hold the lens and turn the lock ring 35 degrees or so the lens should lock onto the Letus...

I feel like you already know this, you're referring to something completely different, and I'm just being a @#()%.
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Old November 30th, 2005, 07:36 AM   #57
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Is poophead really such a bad word? ;)

I didn't realize you were using Nikon. My bad. I am therefore totally clueless.
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