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-   -   Inside a Bogen 501 (http://www.dvinfo.net/forum/tripod-sticks-heads/70707-inside-bogen-501-a.html)

Tim Le July 2nd, 2006 01:29 PM

Inside a Bogen 501
 
3 Attachment(s)
I have a 501 and have had it for several years. The 501 is an OK head, but you do get what you pay for. It sticks at the beginning of a movement, especially in tilt so I have to concentrate like crazy to avoid getting a jump or jerk when starting a movement. The jump isn't as noticeable when you're at wide angle but if you've zoomed in at all, forget it.

Tripods and fluid heads are very subjective things, though. My definition of smoothness may not be the same as yours and my criteria for a smooth camera movement may be stricter than yours. Personally, I am very fanatical and a perfectionist regarding smooth camera moves so for me, the 501 was frustrating.

Fluids heads are also a lot like big screen Hi-Def TVs. You don't know what you're missing until you've experienced something better and once you have, you don't want to go back. I live in Los Angeles and have been lucky to try out very high-ends heads from Sachtler, Cartoni and OConnor with live cameras on them at trade shows. The only real way to evaluate a head is with a live camera on it. I am especially fond of OConnor heads.

The best way to describe these high-end heads is that they are effortless. You don't have to concentrate that much to make a smooth camera move. They are so smooth, so precise and so rigid that you can get a nice shot each time and every time, wide angle or zoomed in. This, of course, comes at a price because these heads are more massive than a DV head and mechanically they mare MUCH more complicated than a cheap DV head. To illustrate this, I took apart my 501 to show y'all what's inside.

The tilt platform has a series of concentric rings that fit into another set of concentric rings inside the pan assembly. These rings have a coat of sticky grease or something like that. The rings don't touch each other so it's this sticky grease that creates the drag. On the right side tilt platform there is an additional white teflon or delrin type disc. When you tighten the tilt drag knob, you are pressing this white disc to increase the friction. I didn't take apart the pan drag assembly but I assume it's identical to the tilt axis. Since the drag adjustment is actually a friction boost, I would leave all of the drag adjustment knobs all the way out. As you can see, the head is pretty simple. There are no ball bearings.

Boyd Ostroff July 2nd, 2006 02:56 PM

Excellent post Tim! Did the patient survive the operation? ;-)

I have a 501 and also a Miller DS5, and completely agree with you. I've also tried the more expensive heads and wish I could justify spending that much.

I think these photos and your comments about the 501 will be of interest to many people, so I'm making this thread a "sticky."

Tim Le July 8th, 2006 11:40 AM

Thanks Boyd. The patient is no worst for wear :)

I probably should caution people about giving their heads a lobotomy though. Not only could it give you a migraine (ha-ha), but some heads may be charged with fluid so if you take it apart you might have a messy problem on your hands and a head that no longer works.

As for the great debate regarding whether or not a 501 is fluid head, I'd say it depends on your definition of a fluid head. The fluid drag isn't a sealed compartment that is bathed in fluid but the drag is based on viscous shearing of that sticky grease because the concentric rings do not touch each other. If the drag knobs are fully out, the only friction is in the pivots which are not supported by ball bearings. So basically, the 501 is a fluid head--just a very cheap one.

The 503 is suppose to have variable fluid drag so I'm not sure how that one is constructed.

Mark Goldberg October 16th, 2006 11:23 AM

My experience replacing viscous medium
 
I had a the Bogen Mini Fluid Head, which I initially purchased in the mid-80s. I decided to sell it on ebay, but the fluid effect had deteriorated and I had to repair it prior to sale. I read on some video forum about using a non-petroleum grease, and was able to find some in a hardware store.

The tilt interior had an interleaved concentric circle arrangement just like the 501 as shown here. The pan motion part had a simple lubricated cylinder.

Maksim Yankovskiy May 18th, 2007 06:42 PM

There's an old joke about a cause of death entry in a death certificate:

Cause of Death: autopsy

Quote:

Originally Posted by Boyd Ostroff (Post 506514)
Did the patient survive the operation? ;-)


Steve Oakley March 15th, 2008 02:00 AM

the larger bogen head has the exact same construction internally, just bigger. I would not call thick grease "fluid". BTW don't try replacing the supplied grease with something else...uh, been there done that, didn't make a difference, and maybe made it worse in hot weather

Bill Rankin March 15th, 2008 08:08 AM

One way of compensating for lower end heads is technique. I have both the 501 and 503. What I do is place the end of the handle against the middle of my palm. Then cup my hand without clasping the handle with my fingers. Fingers do not touch the handle. The pan or tilt. It might take a little practice.

Pietro Impagliazzo April 29th, 2008 11:12 AM

Quote:

Originally Posted by Bill Rankin (Post 842842)
One way of compensating for lower end heads is technique. I have both the 501 and 503. What I do is place the end of the handle against the middle of my palm. Then cup my hand without clasping the handle with my fingers. Fingers do not touch the handle. The pan or tilt. It might take a little practice.

I have the 501HDV and frictions knobs should always be loose (lock instead of increasing drag, make things less jerky) and make movements with the middle of the palm, what you described is the best way to achieve good movements with these heads.

I still have a question: Is the 503HDV a true fluid head or what? If it's not then I'll save money and get a Sachtler FSB-6 instead of upgrading to the 503.

Alastair Traill December 19th, 2008 04:38 AM

I was very interested to see the pictures of the insides of a Bogen head. I have made a couple of fluid heads that have given good service and compare favourably with any that I have seen (and in some cases worked on) else where. My main reason for the DIY approach was that I wanted to use one of the heads underwater and so right from the start I could choose materials that would withstand sea water. The reason for developing the second head was to reduce the size and weight to a minimum.
To have any chance of success it was necessary to understand the physical principles involved in pan and tilt head design. Drag can be provided by either mechanical friction or fluid drag. An important, and in this undesirable characteristic of friction, is that it takes more force to overcome the static resistance between two surfaces, than it does to keep one surface moving relative to the other. This makes smooth stops and starts difficult to achieve. Smooth surfaces and lubrication help but take away the drag. On the other hand if you have two surfaces separated by a fluid, some of the fluid is in contact with one surface, some is in contact with the other surface and the rest of the fluid is in between. If now you move one surface relative to another the fluid layer between is subjected to shearing forces, some of the fluid is moving one way, some is moving the other and the fluid in between is static. That is to say there is a velocity gradient imposed on the fluid and this creates a drag. The amount of the drag is dependent on a number of factors. One is speed - the higher the speed the more the drag. Another is the viscosity of the fluid the higher the viscosity the greater the drag. A third factor is the thickness of the fluid layer for the same speed the velocity gradient becomes higher as the thickness is reduced, i.e. the thinner the layer the more the drag. Finally the dimensions of the fluid separated surfaces if all else is equal a larger head will provide more drag because of larger diameters and areas etc.
Essentially then for smooth action fluid drag is good and mechanical friction is undesirable. Mechanical friction can be reduced by using good bearings and seals. Fluid drag can be varied by providing a means of changing the area of surfaces used, or by varying the thickness of the fluid layer. Vibrations and unsteadiness can also be transmitted by the operator and these can be reduced by providing a degree of flexibility in the pan handle. An alternative is to drag the handle with a rubber band.
Finally if you are investigating the insides of your pan and tilt head there is a simple way to tell whether it uses a fluid or a grease. If you disturb the surface of a grease e.g. by poking it the marks remain, however with a fluid the marks disappear. I use a silicone fluid with a viscosity of 600,000 centipoise, if I jab a finger into that it leaves a slowly disappearing fingerprint. It is this ability of fluid to flow that makes fluid heads the success they are.

Paul Kellett December 19th, 2008 06:46 AM

Quote:

Originally Posted by Pietro Impagliazzo (Post 869426)
I still have a question: Is the 503HDV a true fluid head or what? If it's not then I'll save money and get a Sachtler FSB-6 instead of upgrading to the 503.

I took apart my 503hdv head to try to improve the friction on vertical pans, it exactly the same as the pictures posted above.

I'm thinking of upgrading my head next year, maybe the 519 head, i want to stick with manfrotto because i use a shoulder mount and a glidecam, both of which have the manfrotto adaptor so i can easily swap the camera between them all.

Does anyone know which is the best manfrotto head which uses the same plate as the 503hdv ? I believe the plate is the 501pl.

Paul.

John Peterson April 21st, 2009 10:08 AM

This is an interesting thread as I have wondered for years why (even with no tension) on my 501 after it has been in a single position for awhile it requires too much force to initially tilt it again. Once you "break it loose" it works fine until it sits for awhile. Then it won't tilt easily again. It has been that way for a lot of years.

Does anyone know of a modification for it? I sometimes go into a slight pan first before I tilt, but this is no solution really. So short of a better head, is there a mod for a 501?

John

Anthony Dean May 6th, 2009 08:33 AM

1 Attachment(s)
Does anyone know of the best grease to use in the 503HDV?

My patient is a little worse for wear after the autopsy (I'm not getting even resistance/drag on pans)

I'm hoping that it just needs a dose of grease.. but what is suitable?

Tony

Paul Kellett May 9th, 2009 01:07 PM

Anthony, have a look at this. I did this "modification" the other day and it's still working a treat.

http://www.dvinfo.net/conf/tripod-st...d-pennies.html

Paul.

Chris Soucy May 9th, 2009 10:10 PM

Hmm.........
 
What about a 50 - 50 mix of Silicone grease and powdered graphite?

If you can find a low shear strength silicon and combine it with the lubricating characteristics of graphite, it should work a treat.

It would have the advantage of not oozing in hot conditions as well.

I'd try it myself but there's enough on my plate as it is.


CS

Kris Zimbelman June 17th, 2010 11:51 PM

anyone here know about the new 504 head?


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