Is this too much weight?

[bendiddley]

Hi all, I need to ask about whether my mount will cope OK with the weight of my AP set-up. I've got an eq3-2 (aluminium set) and want to put roughly 2kg of kit on top. This includes camera, 75-300mm lens, photo dovetail plate, ball and socket, rigel quikfinder, dew shield and motors (not sure if motors counts as weight or not, if not then you can take off about 300g so 1.7kg total). What do you guys think? The ball and socket weighs 450g approx, if the 2kg is too much maybe I should ditch that. The payload of the mount is 5.5kg. Also another thing I want to know is how do you balance a camera on a mount, ra seems to work but dec doesn't because of the weight of the lens if that makes sense. Hope someone can help.

[nightfisher]

An EQ3-2 should cope with 2 Kg okay, give it a try, i used to have a 120 f8 frac on one of these

[RichM63]

Ha! this falls well. I've just set up an identicalish rig.

No problem at all with the weight (see my sig for kit).

Balancing was very easy. Mount your camera + lens 75-300mm as you would for a telescope.

Remove the lower heavier weight, you don't need it, and if it is not already positioned as such, position the smaller weight about 8.5cm down the CW bar, and now follow the usual procedure for balancing a telescope. You might need to tweak the weight position a little.

The dovetail allows you to balance for the lens, slide up or down the shoe.

A pic may help, so here goes.

[bendiddley]

How have you attached your camera to the dovetail?

[RichM63]

Ball and socket head with 3/8 bolt. I drilled and tapped one of the spare holes in the dovetail so that the bolt is only carrying the weight of the camera and is not acting as the whole sandwich support. The B/S head is supposed to be rated to 8kg but I wouldn't go that far.

[ollypenrice]

You may find, as most of us do, that focal length is a bigger issue in successful tracking than is weight. 300mm is entering telescopic focal length territory and will demand pretty accurate tracking. Using the lens at 75mm would be easier.

I would be far more inclined to bolt the camera down hard to a length of dovetail than use a ball head. In this game rigidity is everything.

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2266922474&k=Sc3kgzc

[Viewmaster]

Yes, why use a ball and socket on your mount?

Get rid of flimsability.

[RichM63]

I agree about the rigidity aspect. The B/S is a compromise. Without it the DSLR ends up in all sorts of wierd orientations making framing, focusing etc a real pain in the neck. OK yes the image can be post capture rotated, but in my case I'm not looking for long exposures and will mostly be using even less camera weight with the prime 50mm.

Even a telescope has tube rings to allow for rotation, and I also use this mount for daytime photography.

When I have mastered the zoom in pixelated noughts n crosses point board methods of focusing, I may well ditch the B/S, but for now I need to see what I am doing with the camera and also be able to see what is arriving through the lens.

At least a heavy DSLR is not piggy backed onto a 200P on top of a single plasti-head 1/4 tube ring bolt. and I did tighten the 3/8 bolt with a pipe wrench.

[bendiddley]

Hmmm maybe asking for a ball and socket for Christmas was not such a good idea. I thought it might make the final fine tuning of locating an object a bit easier once I'd pointed the mount in the right direction, using the b/s to position the object in the view finder. I've chosen a fairly hefty one (see below) hoped it might be up to the job but maybe I should give it a miss.

http://www.premier-ink.co.uk/photographic/tripods/kood-tripods/kood-bh08-pro-ball-head-420g-6kg-p-434.html

[RichM63]

Check out the Wide Field and Photography + Camera sections of the forum, there was very good reason behind the B/S method.