Balance your gear with a rail.

[george013]

Manfred,
I still don't know where you got your figures from, you didn't tell. From another thread here http://markins.com/charlie/report4e6.pdf.
The figures from this document seems more reliable to me.
George

[Donald]

Manfred,
I still don't know where you got your figures from, you didn't tell.

That's because he's living it up on his retirement vacation around India, Bhutan etc. and we're not going to see him back on here for quite a number of weeks.

[JR1]

I see that the illustration was done with an F3 mounted… this is an antique!
I have never seen someone using that product possibly because one can not
pan/follow a moving subject with it.

I have to agree what would be the point in adding something like that which stops you from effectively using the camera "unless" pointed directly at a nest

[jcuknz]

Originally Posted by Kodiak
I see that the illustration was done with an F3 mounted… this is an antique!
I have never seen someone using that product possibly because one can not
pan/follow a moving subject with it.

If you in turn have the tripod mounted on castors it might be possible to do some panning or tracking .... castors coupled with a laid circular track for the wheels and 'spindles' to a stationary central pivot .... not unknown in the film/video world.

[joebranko]

Very interesting discussion. Unfortunately I could not open the picture file so could not see the picture. The concept however sounds quite sound.

[Manfred M]

Manfred,
I still don't know where you got your figures from, you didn't tell. From another thread here http://markins.com/charlie/report4e6.pdf.
The figures from this document seems more reliable to me.
George

George - I read the article and all I can say is the author used a very flawed methodology and poor experimental technique.

When I read statements like "These are the best results from us on that day. Mr. Mah held his breath perfectly in good posture while taking the data" does not sound like a good, solid repeatable experimental technique.

He notices it in his statement "Variations among each experiment are greater than equipment difference". In other words he does not recognize that his experimental method is (a) either not repeatable or (b) the measurement tolerance has not been properly accounted for in his experimental methodology. Nicely said, he does not understand how to design an experiment that will provide accurate results, so we need to discount his conclusions.

Mixing and matchng cameras, lenses and tripods is rather meaningless. A well designed experiment would have isolated each of the variables, analysed it and drawn conclusions before adding additional variables.

[george013]

George - I read the article and all I can say is the author used a very flawed methodology and poor experimental technique.

When I read statements like "These are the best results from us on that day. Mr. Mah held his breath perfectly in good posture while taking the data" does not sound like a good, solid repeatable experimental technique.

He notices it in his statement "Variations among each experiment are greater than equipment difference". In other words he does not recognize that his experimental method is (a) either not repeatable or (b) the measurement tolerance has not been properly accounted for in his experimental methodology. Nicely said, he does not understand how to design an experiment that will provide accurate results, so we need to discount his conclusions.

Mixing and matchng cameras, lenses and tripods is rather meaningless. A well designed experiment would have isolated each of the variables, analysed it and drawn conclusions before adding additional variables.

I don't think you read it well or just don't understand what he is up to. He is just registers and visualises what happens with a camara and a tripod. Just to compare with handheld, he did the same with the camera in hand: just registering the movements. From that point of view your first selective quotation concerning Mr. Mah is very suggestive and wrong. With your knowledge of the human body you should know that not every human is the same. And lesson one of photography is how to hold a camera. And knowing why.

The same counts for your second quotation. I think that Mr. Mah, as the designer of professional ballheads, knows what he is doing. And I can follow the arguments.

For me the shown graphs are what I expected. And they show how important it is to reduce the impact of the mirror slam, the biggest amplitude. Trying to archive that with the stuff you have.

Still leaves me with the question where you got your figures from and where they are based on.

I found this on the Marks webpage. http://www.markinsamerica.com/MA5/VR.php

George

[revi]

Well, I have to agree with Manfred, the article you cited is not an example of perfect experimental set-up and execution.
.
Ignoring the anecdote of Mr. Mah (it's more like an aside in the article anyway), I've got a big problem with his experimental setup:
The point 'B' where he measures the vibration is at a certain (unspecified) distance from the camera body (it looks like the arm is about 45 cm?).
That means that while linear vibrations will be measured at their actual value, rotational vibration will be amplified by an unknown factor.
And that means that any absolute values cannot be compared with results from other sources. And there is not even a mention of this problem.

Apart from that, how much of the vibration is rotational, and how much linear? 10 µm on a modern sensor is visible if it's a linear displacement. If it
is 10 µm at 40cm due to rotation, the effect might well be negligable at the sensor. And please note that the donut images are simulated,
so based on assumptions about the vibration characteristics (assumptions which are not stated in the article, btw).

Those are just the (for me) most glaring problems with the article, there are a lot more details that would at best lessen the value of the results
(and at worst completely invalidate them!).

Remco