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PVC or steel dolly track?


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#1 tom lombard

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Posted 17 February 2018 - 12:28 PM

Getting a dolly at some point was something on my list but not a priority.  Then someone had a dolly platform on local Craigslist for a couple weeks with no takers.  I finally emailed & said I'd pick it up right now & give him $50 so it's mine now.  It was a $700 platform if new and in very good shape with wheels & trucks that looked new.  Now I'll be putting together some track.  Looks like 1.5" PVC, steel, or aluminum is what I'll be needing.  PVC strikes me as being easier to work with, would have a bit more flex (for exterior uneven surfaces), and would be less likely to get permanently dinged as metal.  Anyone with experience with PVC as well as metal track that might have some feedback to offer?  Also wondering about going with 1.25"  It looks like everything will still clear and that might give me even more flex where needed.  Thanks, Tom


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#2 Phil Rhodes

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Posted 17 February 2018 - 08:44 PM

Aluminium, without a doubt.

 

The problem with PVC is that, yes, it's lightweight. But it doesn't support anything, so you need a surprisingly flat and level floor to run it on. Even if the floor is fairly flat, if it has gentle swells and curves in it, your shot ends up drunk. You end up having to carry so many sheets of plywood and chocks and bits of packing to sort it out, it's actually easier, in the end, to just carry metal track that you can ride on. You still need wedges and bits of wood, and so on, but far less, and it's quicker and easier overall.


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#3 tom lombard

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Posted 17 February 2018 - 09:16 PM

Hmmm... Let me get specific about a shot I wanna do for a short film and see if this influences the thinking.  It will be a long (maybe 90 seconds), slow dolly in.  Would cover about 75 feet and be outdoors.  At this point, I'm looking at several shooting locations (a park with a swingset being a major set piece) and all would have varying degrees of uneven ground.  That's where I was thinking the PVC might work better as the flexibility would allow the track to lie closer to the ground without there being large gaps between the ground and a less flexible track.  It being such a slow dolly, I'm thinking that the camera operator would be able to make vertical adjustments to keep greatly reduce that drunk shot possibility.

 

Let me deviate from the original question and consider an alternative solution... keep the camera in the same spot and zoom rather than dolly.  That eliminates the drunk shot due to dolly over uneven surface but I'm concerned about a camera operator being able to do a consistent, non-jerky zoom over 90 seconds.  To get more specific, the camera is a 16mm Bolex EL and I will have access to a 12.5-100 Vario Switar.  Camera operator is non-professional but fairly experienced.


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#4 JD Hartman

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Posted 17 February 2018 - 10:15 PM

Why would you (ever) want the camera's point of view to rise and fall as it moved?  If that's your shot, than maybe a steadycam would be the better choice. 


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#5 Gregg MacPherson

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Posted 18 February 2018 - 02:06 AM

Tom,  firstly, the idea of having the dolly drack conform to the ground level is contrary to what anyone ever seems to want.  Tracks normally need to be level so that there is no varying influence from gravity.  Then the grip pushing the dolly can have control over the movement.

 

PVC can be very stiff as track in larger diameters, like 2 or 3 inch.  Laid on a reasonably level lawn or playground with a little packing or some wedges to help low spots..  The wheels or truck arrangement has to suit the larger pipe diameter,  but making those, or the dolly, if the wheels are integral with it, is actually quite easy for an averagely skilled workshop guy.

Metal systems are intrinsically better,  but pvc can work very well.  often without joins.

 

The idea of using the zoom.  A good operator with a well serviced zoom and some action happening within frame could do ok over 90 seconds, depending on the range,  the shift in focal length.  If there's no action, movement in frame hiding the move the zoom movement commonly needs to be more perfect.  A common way used to be to use a zoom motor, so you could go as slow as you want and feather the start and stop.  You need a gear on the zoom ring and a standard rail system to clamp the motor bracket to.  You could rent or borrow the zoom controller.  Find someone with an old  Cinema Products J4...


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#6 Robin R Probyn

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Posted 18 February 2018 - 06:19 AM

If your dolly is straight in over 75 feet.. you will see the track too.. 


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#7 tom lombard

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Posted 18 February 2018 - 10:34 AM

I'm obviously in my learning curve here and appreciate all of the feedback :)

 

"Why would you (ever) want the camera's point of view to rise and fall as it moved?"  I don't want the point of view to rise & fall.  That's why I would want the camera operator be able to adjust the field of view as the ground might rise & fall.  Given that it's a very slow dolly, and we will be able to rehearse the shot several times, the field of view will (hopefully) be stable other than the tightening of the shot due to the decrease in distance.

 

"If there's no action, movement in frame hiding the move the zoom movement commonly needs to be more perfect."  That's a big part of my concern as there will be no action during the dolly (or zoom).  Initially, there will be 2 park benches and a drinking fountain all in the center half of the frame (horizontally).  There will be a person sitting on one end of one of the benches.  As we do the slow dolly (or zoom) towards the person on the bench, there will be a voice over.  As we get closer to the person on the bench, we see it's a young girl singing softly at something she's holding.  I'd like to get her fully in frame at the end of the shot.

 

"If your dolly is straight in over 75 feet.. you will see the track too."  As my benches and drinking fountain can be moved, I'm scouting for locations with an attractive treeline for background.  My thought is to have the bottom of the shot near the bottom of the benches (and the girl's feet) without showing the ground & the tracks.

 

​I have to admit that this is a big part of the process of filmmaking that I find terribly interesting & motivational.  I'm actually seeing a shot in my head and spending a great deal of energy & thought into trying to figure out how to get _that_ shot (or as close as I can).  I've been involved in several indie shoots with people arriving at a previously unseen location, shoot a dozen "takes", and hope that something useful will show up during editing.  Granted, my end result & their end result may be arguably as adequate but I'm selfish and am pursuing filmmaking in a way that gives me the most satisfaction.  It's satisfying to make an effort to achieve something specific even if the end result falls short.  It's not satisfying to spew out digital footage just because you can.


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#8 JD Hartman

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Posted 18 February 2018 - 12:30 PM

I'm obviously in my learning curve here and appreciate all of the feedback :)

 

"Why would you (ever) want the camera's point of view to rise and fall as it moved?"  I don't want the point of view to rise & fall.  That's why I would want the camera operator be able to adjust the field of view as the ground might rise & fall.  Given that it's a very slow dolly, and we will be able to rehearse the shot several times, the field of view will (hopefully) be stable other than the tightening of the shot due to the decrease in distance.

 

That's why you'd want rigid track, well supported and installed with no dips or twists. Are you talking about having a dolly with a jib? What you're describing sounds like a camera op. trying to compensate for the grips inadequacies in laying track.


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#9 tom lombard

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Posted 18 February 2018 - 12:48 PM

http://www.longvalle...p.com/dolly.php is the dolly that I've acquired (simply because it was available, it was cheap, and I didn't have any sort of dolly in my extremely limited equipment).  I can't see it really holding a "tripod, operator, and assistant" as is but I'd consider removing the wheel assemblies and putting them on a something larger than 30" x 40".

 

Having now gone thru that initial stage of the learning curve where one is certain they know more about the subject than those who actually know a bit about the subject, I'm moving on to stage 2 where one realizes he/she has acquired some additional input that should be considered.  So this is what I'm considering at this point... I should go with steel track.  In looking at potential locations for shooting this shot, I should give greater consideration to the terrain (and the possibility of making some limited landscaping adjustments).  


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#10 Landon D. Parks

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Posted 18 February 2018 - 02:56 PM

Aluminum is probably a better option than steel. Steel is very heavy, and unless you're running an extremely heavy Chapman-style dolly over it, I see no valid reason why you'd need steel track. PVC will work in a pinch, but it will sag if not properly supported. I actually decided on a Dana-style dolly, and couldn't be happier with it. Setup is much easier than it is with floor-track, and I have been able to extend it to 12 foot with no issues, and could go further if I wanted. It's on Tripod legs, so making height and un-even terrain adjustment is fairly easy compared to needing to build platforms and using chucks you'd need with a floor dolly.


Edited by Landon D. Parks, 18 February 2018 - 02:58 PM.

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#11 Reggie A Brown

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Posted 18 February 2018 - 03:00 PM

I have a homemade built dolly and I used pvc pipes. Pvc pipes are a nightmare! They warp, they roll around easily, they're just too light weight (con and pro), and they'll shift. Those are my negative experiences with plastic pvc pipes being used as dolly tracks. On the positive side...they're cost effective, light weight for travel, and you can get some damn smooth shots when they're laid properly.

Edited by Reggie A Brown, 18 February 2018 - 03:11 PM.

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#12 tom lombard

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Posted 18 February 2018 - 03:32 PM

I already have 4, 5' sections of the PVC so I'll go ahead and put together a 10' track with that.  I may have just hit a serious consideration.  In taking a quick look at prices, I'm finding 5' PVC going for around $4 but both aluminum & steel are around $8/foot.  That's quite a difference in cost especially if one is looking to put together 75' of track.  There may be better prices if I dig around a bit.  If anyone has any links to the aluminum or steel stock that would be exactly what I would want, please drop the links in here.


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#13 Phil Rhodes

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Posted 18 February 2018 - 03:46 PM

That's a really long track, though. I've never done a track that long - actually, I would have, exactly once, but I don't own that much track! We did it in two sections and covered the cut.


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#14 Landon D. Parks

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Posted 18 February 2018 - 03:57 PM

75' of track? That sounds like a nightmare to setup. If I needed a smooth shot that big, I'd just pull out my Flycam. 12' is about as long as I'd ever want to go with any sort of track solution. Maybe 15' if the shot called for it, but there comes a point where its easier to just throw on and balance the Flycam.


Edited by Landon D. Parks, 18 February 2018 - 03:57 PM.

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#15 Phil Rhodes

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Posted 18 February 2018 - 04:02 PM

I have around 10m (33 feet) of track, but I'm not sure I've ever used it all at once. It's in three roughly eight-foot sections and two roughly four foot sections, and I invariably use one of the short sections as a place to park the dolly while we're moving the track.


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#16 tom lombard

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Posted 18 February 2018 - 04:14 PM

Flycam, or something like that, might be an option if I were using my Canon DSLR but I'm not sure how well it would work looking thru the viewfinder of a Bolex EL.  Both viewing and walking seem like they would be issues.


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#17 Brian Drysdale

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Posted 18 February 2018 - 04:16 PM

12 feet is very short.

 

A track is basically building a railway, so you need to have the apple boxes, pancakes etc for leveling, There are also other systems for building up the levels over rough ground. However, given reasonable ground you may just get away with wedges to level the tracks.,

 

You also need a long spirit level to ensure everything is level. .  


Edited by Brian Drysdale, 18 February 2018 - 04:17 PM.

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#18 tom lombard

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Posted 18 February 2018 - 04:46 PM

"A track is basically building a railway..." might be a subconscious influence at work here.  My grandpa was as railroad man all of his life and so was my dad.  I used to have several sets of electric trains and have envisioned putting together sections of dolly track just like sections of model railway track.  Hmmm... and that was always on a smooth floor.


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#19 Landon D. Parks

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Posted 18 February 2018 - 05:06 PM

Flycam, or something like that, might be an option if I were using my Canon DSLR but I'm not sure how well it would work looking thru the viewfinder of a Bolex EL.  Both viewing and walking seem like they would be issues.

 

Vest and arm stabilizers have been used in the film industry long before the digital takeover. When I say ‘Flycam’ that is a generic term I use for all such stabilization systems. Mine is the Glide Gear DNA 6002 system, which is a vest-and-arm support for larger rigs like mine. Of course, if you’re shooting film you’ll need video assist, and depending on your focus preferences and format, a wireless follow focus.

 

12 feet is very short.

 

A track is basically building a railway, so you need to have the apple boxes, pancakes etc for leveling, There are also other systems for building up the levels over rough ground. However, given reasonable ground you may just get away with wedges to level the tracks.,

 

You also need a long spirit level to ensure everything is level. .  

 

I cannot see a reason for needing more than 12 - maybe 15 feet of track. If I’m shooting a walk-and-talk scene, the camera will be on the Flycam.


The one issue I was grappling with recently was how to shoot a scene coming up this spring, in which I needed the camera to quickly follow people running through the woods. I could have laid a bunch of track, but instead settled on a cable-cam system.


I just cannot image the issue of trying to set up track on any non-flat surface. Then again, I operate on tiny crews - and can’t really spare even 2 or 3 grips for several hours to lay and level a bunch of track.


The Dana-style dolly is great because leveling is as simple as throwing a level on the track, and then moving the ball head and legs for each trip. I can do it myself, or can have 1 person do it in a few minutes.


Just seems to me that there are better tools for the job when it comes to shots where you would need that much track. Seems even more important if you're short on crew members.


Edited by Landon D. Parks, 18 February 2018 - 05:07 PM.

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#20 Brian Drysdale

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Posted 18 February 2018 - 05:29 PM

I've used a Steadicam for many tears, but I don't regard it as the same as a dolly on tracks, The visual moves in the latter case can be rather different, especially with longer focal lengths,  .

 

You don't need a big crew to lay these tracks a grip can do so on their own, it's not a big deal.

 

A few years ago I worked on a number of shorts (within a scheme, so they had a small budget)  on which the grip was actually a camera assistant and 25ft to 30ft  tracks weren't unusual. He loved setting them up and some were 2 or 3 feet out of level at some points (so needed building up with apple boxes etc). We used a doorway dolly in case, but a Peewee dolly is great as part of the kit, you can save so much set up time.


Edited by Brian Drysdale, 18 February 2018 - 05:31 PM.

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