Chris Millar

Would have thought that with the CoM is above the pivot point and with those masses at those levers arms it only has a stable equilibrium not much beyond: 'careful, careful !' smash The solutions to that of which I agree are entirely possible involve too much presumption about the conveyor and so on... Without being there and assessing it, or should I say 'feeling' it (the liberal arts side of me kicking in) we can discuss our solutions to the (individually interpreted) problem to solve, debating at cross purposes and abstraction until we say enough, and suggest beer (yet again)... but that's already happened :) With a bit of reading between the lines an observer could at least arrive at a boolean intersection of: use foam/sponge "with different densities, which will damp vibrations at different frequencies." Nice picture though ! Here is mine:

But back to the topic at hand - as I imagined it the motion is mostly up and down and not left/right, fore/aft...

When you get a chance please do watch it - from wikipedia: "In the 18 February 2007 episode of Top Gear (Series 9, Episode 4), a Reliant Robin was used by Richard Hammond andJames May in an attempt to modify a normal K-reg Robin into a reusable space shuttle. The booster rockets separated cleanly, but the fuel tank did not detach, and the Robin crashed into the ground and exploded. This launch was the "largest non-commercial rocket launch in European history."[6] In a subsequent episode of Top Gear (Series 15, Episode 1), a 1994 Reliant Robin was used by Jeremy Clarkson to drive 14 miles from Sheffield to Rotherham. He described driving it as dangerous as "inviting your mum 'round for an evening on chatroulette," and that "(the Reliant Robin) wasn't funny, it was a complete menace." During the segment, Clarkson rolled the Robin at least six times due to the odd-sized wheels and the weights which were attached to the car to allow filming, before having front support wheels mounted for safety.[7] The following two episodes featured racing driver The Stig and Ken Block on their Test Track in Robin, which neither of them could finish a clean lap, and rolled over like Clarkson. The cars used in the these episodes were extensively modified. All the reliant robins on top gear were fitted with bigger wheels on the passenger side and front to make the unstable, this is why the car usually rolled on the drivers side." V entertaining. I wasn't much of a Top Gear person (at all) until my partner showed me these two clips.

Conversation better had with white board, couple of beers and a papaya salad. 3 wheeled car: http://www.topgear.com/uk/videos/clarkson-tips-over-reliant-robin Note that it is fitted with a 4 point safety harness I love that car by the way (!), although I'd probably spring for the Messerschmitt KR200, given the choice.

A camera isn't an unusual load - we put them on tripods all the time ( :blink:) 4 points only 'work' because the materials involved deform, 3 is the physical reality, at least at the level of mechanics. Foam is I guess a bazzilion points, with very high deformation. I would have thought that talking in terms of mass moment of inertia implies a system that is free to rotate - i.e. 'frictionless' or non-constrained - putting a camera on um, anything is well, not that (?). As we've both pointed out, it can be discussed in an engineering context, but the reality will be wood, alu channels, glue and your mom's favourite cushion :D

From an engineering standpoint, you want to use 3 points of contact as the conveyor belt when modelled as a plane is defined by only 3 points in space, hence any further points of contact - for example: 4 (a common choice for some reason) - will only over define the system. Each point would be placed as far apart as the following factors will allow: the length and width of the the conveyor; the effective length of the conveyor used in the shot; and the shot itself (i.e. keeping apparatus out of shot). In doing so any motion at the camera (in the middle) is effectively levered/averaged into a smaller amplitude. Each point of contact would ideally have a really nice linear bearing on it and a way to add adjustable springs and dampers, although that is the expensive and very likely unnecessary part, as mentioned earlier: it turns out many cheap products already have a good spring/damper characteristics - you just gotta experiment and find the right one. Memory foam why?

Not sure how much vibration you're taking about, but something cheap that has both spring and damping characteristics is sponge. Are you just sitting the camera in the conveyor? If so, that's your mass. Google 'mass spring damper' ;)

Carl, not that I think it should be implemented this way in this product but one way of decreasing the pitch (and intensity) of a LED array is to use fibre optics. Each original LED feeds it's output into a fibre attached (glued/whatever) to the array they are then bunched up as close (and in whatever order/array) as you like at the other end, trick being the fibre diameter is much smaller than the original LED and of course it's nice and bendy for tight spaces also. Re. registration, not sure how much reverse engineering can get you in terms of simple inspection - probably quite far with an enquiring mind - however, one thing to note is that projectors are optimised for one speed only. (?)

Use double sided? 'snot tape' Or roll your own with what you have...

It's pretty much the class signifier of the millennium... About 8AM or so in say Southern Cross station or Central up in Sydney, it's either hi-vis or a suit, nothing much in between but students and addicts. Anyway, sorry to drag this OT ;)

The safety 'industry' in Aus is huge. Lots of hi-vis to be sold through a tactic of I dunno, 'emotional blackmail by proxy' ;) I guess it gets people working !

Well I remember the 50' technocrane being marketed as a heli replacement as if it had broken some barrier in terms of shot ability. But the scale of complexity/wrangling involved compared even to a 30'... Anyway, last I heard there was only the one in Europe. It looks like you've got some budget here (or at least ambition). If it's real then why not approach your local grip shop, they'll know the local pilots also?

Forgot to add, 10mm on standard 16mm :)

Ours was a camera move into the keyhole from action in one room to a short scene in the next. I guess easy to comp, but we were going %100 analog for this project. We were able to remove the lock and place some black card with a keyhole cut into in place. It terms of size it would have been about 3x higher. Hazed up the room and shot a lamp through it from afar to get a keyhole shaped beam of light that we approached.

Resorted to this on a music video - 16mm black and white so it was a bit hit and miss in terms of keeping the obvious parts of the prop underexposed enough - worked well though, should have done it from the get go

I went through a bout of this a few years back - my first was a Bolex PTL zoom, trying to access to past the auto iris trying to get a bit of paint fleck or whatever it was sitting on an element... Quite a challenge was the auto iris, I got there and back without too much force, and discovered a missing screw in the process, once replaced the mechanism worked much better. The seller protested that it had never been opened 'ever', which I knew was bs... However I do wonder if I did something, to affect the light meter, it seemed fine, but... 'I don't know what I don't know', if ya know what I mean :D Next up, cleaning oil off an element from a Preset Switar 75mm - ha! no way, not without proper tools, that ended up with a tech.

From a 3rd year level computer graphics class at a 'Top 34' Higher Education World University (rankings 2013-2014): Blinn and Phong are all the rage.

Once you're vertical things like counterweights can make sense ;)

Nice to see this thread open again ;) How many grips/riggers ? Dual cable, what does that refer to? is it 1D, 2D ? What is the limiting factor on the incline?

Exactly B)

As I understood it. they're related by the range of the scene... Latitude = DR - scene DR = scene + latitude etc... Actually, or is it: Latitude = (DR - scene)/2 ...and then that's just viewing it as a simplistic linear model - which we know it isn't (the 'curve'). ...and then can you be asymmetric? i.e. purposeful under or over exposure. ...and then what about extending and compressing the scene via push/pull, is latitude defined as before or after such carry-on. No doubt there are answers to this (or someone pointing out it isn't relevant and/or my logic is at fault). But unless you're processing and trying to do things by the book (which is a viable and often fruity(ful) path for those that way inclined) it doesn't matter (much) anyway, most people use the term in a simplistic and relative sense (that concept, again), as opting for an absolute and correct version will yield different interpretations (see above re. /2 or not for a very basic example) and therefore different results. Not saying it's impossible to communicate all the complexities and caveats in a (very long) post or two, just saying a forum such as this certainly can afford half-arsededness ;) where we can call BS on parts of someones argument, then in turn skirt over complexities of our own (aware or not).

Yip, I worked with one of the inventors of CableCam. They were building pretty much a single grip shops version for local productions out of the states... Having a good workshop, decades of experience and some salty inventive spirit meant that they did a pretty good job of it too. Lots of rigging set ups possible - 1D, 2D, 3D, 'long-aspect', 2D sideways, in and out of water - always interesting reverse engineering the set ups as we built them ;) Long distances, height and tension means a bit of hard graft on occasion (tirfors ahoy!) Winches were run off a Kuper system. I also have a done a bit of work operating auto for shows, programming and running the systems that fly people and scenery - pretty slow stuff for the people actually, but some of the systems out there (Foy etc...) get pretty impressive. Last job was King Kong, the guys from Spiderman/PRG were there and it's hitting NYC soon (if it hasn't already?). Are you interested in cameras only?

It's not that hard :huh: Especially once held up to the larger context of every other issue involved in making a film... The benefit of shooting on film is that more often than not it ends up looking like it was shot on film - without any effort. You're pretty much buying into the problem of 'making it look like film'. Film, is ... it's just fun! Amazing machines, completely out of reach not 5 years ago can be bought for much much less than what you're paying. Ah well, I tried :)

Michael, Cancel your order Spend a few weeks cooling off - get your head around it - then, make a purchase :) (please)

First thing that will spring to mind for many is the Children of Men car scene: