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attaching nikon 300mm 2.8 lens onto skywatcher eqm-35

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#1 sumitshrestha

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Posted 29 November 2021 - 06:14 PM

I recently bough skywatcher eqm-35 mount to pair it with nikon 300mm 2.8 lens. I tried to attach the lens onto dovetail plate provided with eqm-35 it did not fit in. The width of lens connector is larger that plate width so it doesnt go all the way in. Should i get another plate? if yes what would be right plate to connect?

How can we connect dslr or dslr lens onto eqm-35 mount? is the provided plate only for telescopes or can also be used for dslr.



#2 photoracer18

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Posted 29 November 2021 - 06:36 PM

The most common lens mounting plate is the Swiss Arca plate as that is what ballheads and tripod heads use most as its a standard. What you want is a rail that you can mount the lens and DSLR on and then bolt that to a Vixen or Losmandy plate to put on the mount. It requires shimming the height of the DSLR mounting usually. Mounting the lens using its tripod foot is not really as good as using some scope rings like guidescope rings. Best thing is to look up various rigs and try to adapt something for your own use.



#3 bobzeq25

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Posted 29 November 2021 - 08:10 PM

Maybe this?

 

https://www.ebay.com...J0AAOSwMS5ejgO9



#4 spazmore

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Posted 29 November 2021 - 08:33 PM

This is what I used for a Nikon Nikkor ED 300mm f/2.8 that I once had, as well as for some other lenses and DSLRs: 

https://www.telescop...?productId=7388



#5 sumitshrestha

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Posted 29 November 2021 - 09:58 PM

You mentioned lens collar that i already have on my lens. The issue is that collar doesn't fit in dovetail plate provided with eqm-35 mount. I am trying to use that fit that lens collar into mount.



#6 sumitshrestha

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Posted 29 November 2021 - 10:02 PM

This is what I used for a Nikon Nikkor ED 300mm f/2.8 that I once had, as well as for some other lenses and DSLRs: 

https://www.telescop...?productId=7388

Does the width of the plate is enough to hold lens collar of Nikon 300mm f/2.8? I tried to read the dimension of that plate but couldn't find it. Since you said you had used it before i assume it had fit perfectly to be used. i will order it and see if it fits.



#7 akdwivedi

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Posted 29 November 2021 - 11:19 PM

maybe something like this will be needed

 

https://www.aliexpre...0001376128485"}

 

this has a 1/4inch screw commonly used for mounting photographic lenses to tripods ball heads. So the lens foot can be screwed on this plate. The bottom of the plate is vixen compatible and can be easily mounted on a mount that accepts vixen dovetails.



#8 vidrazor

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Posted 30 November 2021 - 01:20 AM

Is the supplied plate a Vixen mount? If so how long is it? You may just use something as a spacer to raise it a bit on the bar. You may need to pick up longer 1/4-20 screws to do so, which are readily available in places like Home Depot, which also have flat bars you can use as a spacer. If the supplied bar is short, like 4 inches or so, you may want to get a longer bar, about twice that length, to allow you to better balance your rig.



#9 sumitshrestha

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Posted 30 November 2021 - 08:46 PM

Is the supplied plate a Vixen mount? If so how long is it? You may just use something as a spacer to raise it a bit on the bar. You may need to pick up longer 1/4-20 screws to do so, which are readily available in places like Home Depot, which also have flat bars you can use as a spacer. If the supplied bar is short, like 4 inches or so, you may want to get a longer bar, about twice that length, to allow you to better balance your rig.

I dont know if that is dovetail or vixen mount. I am attaching pictures of plate and lens cover. As you can see lens cover width is 4cm while provided plate width is 3cm.

IMG_5939.jpg IMG_5940.jpg IMG_5938.jpg



#10 spazmore

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Posted 30 November 2021 - 09:42 PM

If one of those holes in the middle of the mounting plate is recessed on the bottom, you should be able to thread a 1/4" x 20 screw up thru it to attach to the lens mounting hole; the lips of the lens mount will rest on the ridges on the edge of the mounting plate. Alternatively, you can drill one of those holes out so that a 1/4x20 will fit thru it, and then tighten it down if there is a recess on the bottom of the plate, of course.



#11 vidrazor

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Posted 30 November 2021 - 10:33 PM

I dont know if that is dovetail or vixen mount. I am attaching pictures of plate and lens cover. As you can see lens cover width is 4cm while provided plate width is 3cm.

attachicon.gifIMG_5940.jpgattachicon.gifIMG_5939.jpgattachicon.gifIMG_5940.jpgattachicon.gifIMG_5938.jpg

That Vixen bar is made to mount telescope rings. You need a flat Vixen mounting bar for your lens. you mount it with a 1/4-20 hex screw from underneath. You don't necessarily mount it in the center, because you may need to offset it to properly balance in DEC.
 


Edited by vidrazor, 30 November 2021 - 10:34 PM.


#12 sumitshrestha

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Posted 30 November 2021 - 10:38 PM

If one of those holes in the middle of the mounting plate is recessed on the bottom, you should be able to thread a 1/4" x 20 screw up thru it to attach to the lens mounting hole; the lips of the lens mount will rest on the ridges on the edge of the mounting plate. Alternatively, you can drill one of those holes out so that a 1/4x20 will fit thru it, and then tighten it down if there is a recess on the bottom of the plate, of course.

Thanks. I was also thinking about same but my worry is what you said. Since the sides of lens cover would rest on ridges of plate it would be held only by one screw. i worry that slight movement of mount would move or even unscrew the lens from mount.



#13 spazmore

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Posted 30 November 2021 - 10:41 PM

You can tighten it down fairly tight so that it won't move - just don't overtighten or strip it - but I did tighten mine down using quite a bit of force. I put a layer of anti-skid foam (like the kind you put on shelves to keep dishes from moving) between mine and the rail to add some extra grip.



#14 sumitshrestha

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Posted 30 November 2021 - 10:41 PM

That Vixen bar is made to mount telescope rings. You need a flat Vixen mounting bar for your lens. you mount it with a 1/4-20 hex screw from underneath. You don't necessarily mount it in the center, because you may need to offset it to properly balance in DEC.
 

Thanks. i had ordered flat vixen plate and waiting for its arrival. https://www.aliexpre...0751965208.html Since my lens cover only has one screw hole isn't it risky to hold entire weight of lens + dslr onto just one screw that when unscrewed on movement could cause lens to fall down. Can i get something like telescope ring that can provide secondary support onto mount plate which would make it more secure. I also need to attach guidescope and dont know where should i put that without causing any issue.
 



#15 vidrazor

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Posted 30 November 2021 - 11:55 PM

Thanks. i had ordered flat vixen plate and waiting for its arrival. https://www.aliexpre...0751965208.html Since my lens cover only has one screw hole isn't it risky to hold entire weight of lens + dslr onto just one screw that when unscrewed on movement could cause lens to fall down. Can i get something like telescope ring that can provide secondary support onto mount plate which would make it more secure. I also need to attach guidescope and dont know where should i put that without causing any issue.

No, it's fine, done it plenty of times. The simplest thing to do is a add a thin rubber spacer for grip.

 

If the spacing allows for it, you can drill a second hole on your 300's lens mount to use 2 screws to secure the lens. As long as you don't need to use the center mounting hole on the bar, which you probably won't when balancing, this shouldn't be an issue. You can either thread the hole 1/4-20, or come in with a longer screw and use a nut to tighten it down.

 

Depending on the overall balance, you may be able to mount the guide scope up front on the bottom side of the Vixen mounting bar. Some people do this.

 

Another option is to remove the 300's mounting ring and use a telescope mounting ring like the one pictured below. You would need to find one that would have the proper inside diameter and width. Depending on the lens design, there may me another area you can mount it on if you can't find a perfect fitting ring. You can also get a slightly larger ring and use some rubber stripping to fill the gap and and have a snug, tight fit. For example this ring here has a 75mm inside diameter and a 24mm width. This way you can mount the lens to the Vixen bar and the guide scope to the top on the mounting ring. Check with a local telescope equipment supplier in your area, or peruse Alibaba or Amazon.

Attached Thumbnails

  • ring.jpg

Edited by vidrazor, 01 December 2021 - 12:12 PM.


#16 akdwivedi

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Posted 01 December 2021 - 01:29 AM

Thanks. i had ordered flat vixen plate and waiting for its arrival. https://www.aliexpre...0751965208.html Since my lens cover only has one screw hole isn't it risky to hold entire weight of lens + dslr onto just one screw that when unscrewed on movement could cause lens to fall down. Can i get something like telescope ring that can provide secondary support onto mount plate which would make it more secure. I also need to attach guidescope and dont know where should i put that without causing any issue.
 

 

You can get rings as shown above but I think the rings may limit the focusing ring on the lens. I have seen is some folks using spacers between lens body and flat plate to provide additional support to the lens.



#17 MDVolle

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Posted 05 December 2021 - 03:48 AM

I have used several longer lenses for imaging - almost without exception, the single point support foot on the lens proves to be one of the weakest links in holding the system stable - so the advice to find additional support for the lens is really on target - I've often had to support both the lens and the camera body on a long Arca plate (shims and adapters usually needed)

 

If you have access to a 3d printer or a friend with one, making a cradle for the front of the lens might be an option without any machining  - 

 

This was made for a Sigma 120-300 f/2.8 - the supplied bracket by itself was almost useless and this works great - bottom plate is a generic Arca Plate from eBay but could also be done with a vixen plate

 

by loosening both the factory clamp and the printed clamp, I can still rotate the camera and lens as needed - this was printed in simple ASA plastic to test it out and then in carbon fiber nylon material - mostly to look cooler - the simple ASA bracket worked fine 

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  • Sigma Bracket.jpg


#18 galacticinsomnia

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Posted 05 December 2021 - 05:05 PM

I dont know if that is dovetail or vixen mount. I am attaching pictures of plate and lens cover. As you can see lens cover width is 4cm while provided plate width is 3cm.

attachicon.gifIMG_5940.jpgattachicon.gifIMG_5939.jpgattachicon.gifIMG_5940.jpgattachicon.gifIMG_5938.jpg

That is not what you need.  That is the dovetail for a cassagrain or orther scope.   You need flat plane dovetail.

https://www.ebay.com...name,chnl=mkcid

Get either the Combo, that has the clamp, which is a great addition to your kit, but the bar is also nice.  I have 4 or 5 of these now, but I did find them much cheaper elsewhere. 

Give one of these a go, or something similiar.

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