# How much weight can the EF lens mount handle?



## jrista (Mar 26, 2016)

I am about to purchase a CCD camera for my astrophotography. My hope is to still use the Canon EF 600mm f/4 L II lens, however the CCD camera is going to be a good deal heavier than a standard DSLR. My 5D III is about 2lb, the 1D X II is about 3.4lb. 

Now the CCD camera itself is 3.5lb, however some additional accessories will be attached to it, including a filter wheel (with a bunch of filters) and an off-axis guider port. With those additional accessories, the weight could top 7lb. 

Does anyone know how much weight the EF mount is rated to handle? Lens side? The 600mm lens is a very solidly built lens...however I need to make sure I don't rip the mount off the lens with this camera.


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## bwud (Mar 26, 2016)

I doubt that information is published. You can for example hang your 600 f/4 from your camera body. Granted, that isn't putting the mount in shear, where it will certainly be weaker, but I'd not hesitate to hang a 5# load off a supertele.


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## Don Haines (Mar 26, 2016)

I tend to be a wee bit paranoid about those things..... Do you the ability to create a custom bracket that will attach to both the lens collar and the camera's tripod mount?


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## neuroanatomist (Mar 26, 2016)

I don't know that anyone outside of Canon would know an actual spec. I've had close to 6 lbs on the mount of my 600/4 II (2xIII, 1D X with RRS L bracket, 600EX-RT). The C500 setup is 6.4 lbs, I'm sure Canon is aware it will be used on collared lenses. That's constant weight – short term, I've lifted the 600 II by picking up the attached 1D X. 

I think you'll be fine. Looking forward to the resulting images!


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## 9VIII (Mar 26, 2016)

How deep is the new body?

You may be able to hang a Big White off the mount when the lens is facing down, but trying to hold it level would probably be disastrous. The 1Dx weighs a lot, but it only extends a few inches from the mount so it's still mostly a downward pressure. The further your body hangs from the mount the more worried I would be.


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## Mt Spokane Photography (Mar 26, 2016)

I doubt that there would be a issue with 5 lbs hanging on the lens. At 10 lbs, I'd begin getting worried. The issue would be spring the mount on either the camera or the lens such that one side was out of focus. I don't think there would be a permanent set unless there was a lot more weight. There is a lot of safety margin, dropping a camera with a heavy lens is usually where we see mount damage.


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## jrista (Mar 26, 2016)

Thanks guys. The camera will most likely be a Moravian G3-16200, although other options are the SBIG STXL-16200 or FLI ML16200. The latter is least likely, would be about ten grand to get the full kit, and I just don't think I can afford that. The SBIG would be over eight grand. The Moravian would be at most $5700, maybe as little as $5100 (don't know how they are pulling off that deal...but they are.)

I am not yet sure if I'll be using the Moravian 7-pos filter wheel with their OAG, or the Starlite Express 9-pos FW. The 9-pos FW is ~3.5lb on it's own, the camera another 3.5lb. So that's 7lb right there. 

I don't think I would get up to 10lb, probably not even 9lb...but it might be over 7lb with some additional accessories.


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## neuroanatomist (Mar 27, 2016)

What about using a RRS long lens support (or something modified from it), mounted backward?

http://www.reallyrightstuff.com/Lens-Support-Pkg-dual-Quick-Release


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## 9VIII (Mar 27, 2016)

Thinking along those lines.
I don't know how clean you want it to look, but just buying a super long lensplate and taping a block of wood to the back to hold the body up would probably work pretty well.


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## jrista (Mar 27, 2016)

I don't know that a simple block of wood is going to do it. Keep in mind, I'll be tracking across the sky, and the lens +camera can swing from the eastern horizon (more "flat") to the meridian (more "upright"), after which it would experience a meridian flip where the mount reorients to point from the meridian and track down towards the western horizon. 

So the force of gravity on the camera is going to change with time, which in turn will change the force on the mount. It won't simply be down towards the bottom of the lens, like when your holding the lens for wildlife or sports. It entirely depends on where in the sky I am pointing, and how long I image for. I could have just about any orientation to find anything within the 180 degree hemisphere of the sky. 

For reference, here is the setup I use for the 600mm lens:


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## AlanF (Mar 27, 2016)

Is the camouflage for not scaring off extra-terrestrials?


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## Bennymiata (Mar 27, 2016)

Camouflage? 
What camouflage? 
I can't see it. 

Impressive set-up there.


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## jrista (Mar 27, 2016)

AlanF said:


> Is the camouflage for not scaring off extra-terrestrials?



'tis indeed. You would be surprised how many Romulan Warbirds and Klingon Birds of Prey and often even more exotic "spacecraft" show up in astro images. ;P (Just search around...you'll see what I mean. ;D)

That, and keeping the lenscoat on has prevented my lens from having the hell scratched out of it through all the travel to and from my dark site, from the scope rings clamping down, etc. It's a $12,000 lens...gotta protect the investment.


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## zim (Mar 27, 2016)

Wow that setup looks like a lot of fun!

And that big flat plate with spare holes in looks ripe for an angle extension back to the camera base no?


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## brad-man (Mar 27, 2016)

I would also think that the mount would be strong enough to handle the stress, but perhaps you could bolt something like this to the back of your 4x12" plate for additional support:

http://www.amazon.com/Haoge-Telephoto-Long-focus-Compatible-Sunwayfoto/dp/B00ZVI7S2E/ref=sr_1_27?s=photo&ie=UTF8&qid=1459081957&sr=1-27&keywords=lens+rail 

Good luck!


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## Busted Knuckles (Mar 27, 2016)

brad-man said:


> I would also think that the mount would be strong enough to handle the stress, but perhaps you could bolt something like this to the back of your 4x12" plate for additional support:
> 
> http://www.amazon.com/Haoge-Telephoto-Long-focus-Compatible-Sunwayfoto/dp/B00ZVI7S2E/ref=sr_1_27?s=photo&ie=UTF8&qid=1459081957&sr=1-27&keywords=lens+rail
> 
> Good luck!



I like this idea - it could take up some of those washers/spacers on the camera end of the plate. 

Then again, I have -0- experience with the kind of image making you are doing. I was thinking it might work well for my panorama efforts, be able to nodal point a longer tele.

Happy clicks

Mike


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## Deleted member 91053 (Mar 27, 2016)

jrista said:


> I am about to purchase a CCD camera for my astrophotography. My hope is to still use the Canon EF 600mm f/4 L II lens, however the CCD camera is going to be a good deal heavier than a standard DSLR. My 5D III is about 2lb, the 1D X II is about 3.4lb.
> 
> Now the CCD camera itself is 3.5lb, however some additional accessories will be attached to it, including a filter wheel (with a bunch of filters) and an off-axis guider port. With those additional accessories, the weight could top 7lb.
> 
> Does anyone know how much weight the EF mount is rated to handle? Lens side? The 600mm lens is a very solidly built lens...however I need to make sure I don't rip the mount off the lens with this camera.



The EF mount is quite capable of lifting lenses (vertically I haven't been brave enough to try horizontally) of over 6 kilos - it is what it was designed for. Also the C100 Mk2 (EF mount) can weigh just under 2 Kilos so you should have no problems at all.


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## JMZawodny (Mar 28, 2016)

jrista said:


> Thanks guys. The camera will most likely be a Moravian G3-16200, although other options are the SBIG STXL-16200 or FLI ML16200. The latter is least likely, would be about ten grand to get the full kit, and I just don't think I can afford that. The SBIG would be over eight grand. The Moravian would be at most $5700, maybe as little as $5100 (don't know how they are pulling off that deal...but they are.)
> 
> I am not yet sure if I'll be using the Moravian 7-pos filter wheel with their OAG, or the Starlite Express 9-pos FW. The 9-pos FW is ~3.5lb on it's own, the camera another 3.5lb. So that's 7lb right there.
> 
> I don't think I would get up to 10lb, probably not even 9lb...but it might be over 7lb with some additional accessories.



A little late to the party here, but I love my FLI. I think you'd really enjoy that camera.


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## PeterAlex7 (Mar 28, 2016)

If the tripod collar also included that means the lens weight can destroy the mount.


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## jrista (Mar 28, 2016)

johnf3f said:


> jrista said:
> 
> 
> > I am about to purchase a CCD camera for my astrophotography. My hope is to still use the Canon EF 600mm f/4 L II lens, however the CCD camera is going to be a good deal heavier than a standard DSLR. My 5D III is about 2lb, the 1D X II is about 3.4lb.
> ...



Yeah, I am not worried about vertical lifting. I lift my 600mm lens with my 5D III when the lens is pointed strait towards the ground. The application here is the lens holding the camera horizontally. The lens, as you can see from my photos, is very well held, extremely rigid. So the entire weight of the camera, filter wheel, and filters (which are about 4.2oz each, and I will have 7 of them, so another 1.85lb on top of the camera and FW themselves) is going to be hanging off the lens. 

In my case, it will probably be about 6.5-7lb, which is around 3kg or more. So far, I have not found any camera that weighs nearly this much. I've tried accounting for some accessories, like flash and diffusers and maybe a wifi adapter. Still doesn't amount to as much weight as I am looking to use. 

I think I will need to find some way to support the camera off the dovetail. That is not as easy as it sounds, though. The filter wheels are very large. They hang down below the camera as well, and I don't think I could extend the dovetail all the way back to the camera body. I don't think I could use any of the accessories that have helpfully been linked so far, either, sadly. 

I may have to design something of my own to handle this, and at least take some of the weight off the mount. I really want to be able to do LRGB and narrow band imaging with this lens, as it's phenomenal for astrophotography. But it also costs as much as a small car...and I don't really want to buy this particular camera until I know for sure I can actually use it on this lens.


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## 3kramd5 (Mar 28, 2016)

I would be mighty surprised if you couldn't put a 5kg rig on the mount of a super tele EF lens. Consider the load of a camera hanging off a couple of teleconverters. You can easily double the moment arm without ill effect.

r X F


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## Zoltan Ajtay (Mar 28, 2016)

One thing is sure: the EF mount is stronger than the 16-36/2,8 II body :'( ; I fell backwards with my 5D III attached 16-35, and the mount part of lens remained in the camera body.


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## rfdesigner (Mar 28, 2016)

jrista said:


> I am about to purchase a CCD camera for my astrophotography. My hope is to still use the Canon EF 600mm f/4 L II lens, however the CCD camera is going to be a good deal heavier than a standard DSLR. My 5D III is about 2lb, the 1D X II is about 3.4lb.
> 
> Now the CCD camera itself is 3.5lb, however some additional accessories will be attached to it, including a filter wheel (with a bunch of filters) and an off-axis guider port. With those additional accessories, the weight could top 7lb.
> 
> Does anyone know how much weight the EF mount is rated to handle? Lens side? The 600mm lens is a very solidly built lens...however I need to make sure I don't rip the mount off the lens with this camera.



I very very seriously doubt you'll break anything. every time I've seen a breakage the story of the fall comes out.. that'll probably be a 10g+ impact. at 3x normal body weight you won't break anything.

What you may do however is pull the setup out of collimation as it flexes, not much but enough for stars on one corner to be fuzzy. I've experienced a similar problem with my 12" windowed newt and my 383L+& EFW & OAG & guidecamera & coma-corrector & cables, which is why I've reinforced the focusser attachment despite having a JMI crayford, that's been solid as a very large lump of granite, it's the tube that's flexed. (remember a DSLRs CofG is also much closer to the mount than a CCD setup.. so more torque as well)

It's partly why imaging scopes are often carbon fibre, that and the fact that CF has a very low coefficient of thermal expansion (interestingly so does wood, don't underestimate retro scopes)


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## RickWagoner (Mar 30, 2016)

As far as breaking off, no a 7lb camera will not break off the mount just by itself.

i would worry how much force on the camera you're applying to it and it only. Say if you're moving the setup and grab by the camera but not the lens and camera together. 

I would also worry about long term barrel distortion or bend on the lens itself. Either though it may not break off the pressure of the heavy camera is being placed on the barrel itself and over time that may cause problems. 

As other have said if you can have a mount with camera and lens then that would be best, like a long plate they both mount to. This will even out the weight across the entire rig if not take the pressure completely off it and not focus it on the lens barrel closer to the mount itself.


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## mrzero (Mar 30, 2016)

I will preface this by saying I have never done this type of photography, nor am I an engineer. Just an interested onlooker who enjoys geeking out over gear set-ups.

Looking at your photos of your current set-up, I had an idea. You use the scope rings to provide support to the lens from all angles as the equatorial mount moves it along over time, right? So, I would think you could do the same thing for the new camera body. Either replace the bottom plate with a longer one that extends back far enough or, if you want to be able to swap between the new camera and your dSLR, get another identical bottom plate and attach it to the lens plate via the four holes on the ends (via bolts, washers, and nuts). Then add a linkage between the bottom plate and the bottom of your new camera, and perhaps some arms to cradle it on either side. That should at least reduce the stress or flex to the lens mount. The two plate set-up might be less sturdy, but I think you could fasten them together tightly enough to get it fairly rigid.


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## jrista (Mar 30, 2016)

RickWagoner said:


> As far as breaking off, no a 7lb camera will not break off the mount just by itself.
> 
> i would worry how much force on the camera you're applying to it and it only. Say if you're moving the setup and grab by the camera but not the lens and camera together.
> 
> ...



I'll never grab the camera. Just doesn't happen. The way I move the equipment about, I first remove the camera from the lens, and cap both. I move the camera first. Then I will remove the whole entire lens+guidescope+dovetail plate&scope ring assembly from the mount as-is. I'll move that around, holding by the very large Losmandy D-type plate which is very sturdily attached to a couple of scope rings that rigidly hold the lens in place. I usually keep this assembly together, and that's how I move things around. If I decide to bird photography, I remove the lens from the assembly, and will use the DSLR on it. But when I return it, the camera comes off first (because I have to hook up power adapters and such, just easier to do with the camera NOT attached to the lens.)

I'll never run the risk of picking up the whole assembly or even just the lens by the camera. Won't ever happen. 

I run a much higher risk of a pier crash than that. That might actually be a more significant concern...however the Atlas mount is stepper motor driven, which unlike a servo, will not continually drive the camera/lens/scope into the mount if a crash does occur. If I ever upgraded to a servo-driven, properly encoded mount...the I might be a little more concerned (although still, the rate of impact is still only going to be sidereal.) I can set custom mount limits that will stop tracking when I've tracked beyond a certain number of degrees past the meridian, or to either horizon. I can just set safe limits to ensure I never have a pier crash. 

I would like to have a long plate to mount the camera to . However, given this is a CCD camera, they do not have standard mounting holes like a DSLR does for mounting to a tripod. More than that...the filter wheel hangs down below the bottom of the camera, and it will block any solid strait plate from extending backwards from the back of the lens. I've also got one of the longest Losmandy D-type plates available...I would need another 6" at least for it to reach back to the camera. I was originally looking for a longer plate than I ended up getting, and got what I did because it was the longest I could find. Higher end mounts often support longer plates, but they are usually custom designed and would not fit my saddle in my mount.


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## jrista (Mar 30, 2016)

mrzero said:


> I will preface this by saying I have never done this type of photography, nor am I an engineer. Just an interested onlooker who enjoys geeking out over gear set-ups.
> 
> Looking at your photos of your current set-up, I had an idea. You use the scope rings to provide support to the lens from all angles as the equatorial mount moves it along over time, right? So, I would think you could do the same thing for the new camera body. Either replace the bottom plate with a longer one that extends back far enough or, if you want to be able to swap between the new camera and your dSLR, get another identical bottom plate and attach it to the lens plate via the four holes on the ends (via bolts, washers, and nuts). Then add a linkage between the bottom plate and the bottom of your new camera, and perhaps some arms to cradle it on either side. That should at least reduce the stress or flex to the lens mount. The two plate set-up might be less sturdy, but I think you could fasten them together tightly enough to get it fairly rigid.



I would prefer to do that. However, this is what the camera looks like with the filter wheel attached (the one to the right):







That large circular thing in front is the filter wheel. The size of the camera itself, the boxy thing to the right of the filter wheel, is about the size of a DSLR. So the filter wheel is quite large, and hangs down. It wouldn't allow a longer dovetail. 

The inevitable secondary recommendation is to rotate the filter wheel. However I need to be able to rotate the camera regardless to achieve different framing orientations so I can frame various subjects as I prefer and fit everything into the field, so I cannot just assume that I can always point the filter wheel up. :\

It's a bit of a conundrum. I think the only means of supporting the camera would be to custom-design a support frame that attaches both above and below the back scope ring, and have a notch in that support frame for the filter wheel to fit.


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## rfdesigner (Mar 30, 2016)

jrista said:


> I run a much higher risk of a pier crash than that. That might actually be a more significant concern...however the Atlas mount is stepper motor driven, which unlike a servo, will not continually drive the camera/lens/scope into the mount if a crash does occur. If I ever upgraded to a servo-driven, properly encoded mount...the I might be a little more concerned (although still, the rate of impact is still only going to be sidereal.)



actually your biggest worry regarding pier crashes is when slewing between targets. Get it wrong and it will crash at slew speed.. which is still only mayby a few degrees per second, but undesirable never the less.

I had this problem when I built my own stepper system for my mount... one reason to leave the clutches a little slack.. it's safer all round.


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## Luckshot (Mar 30, 2016)

jrista said:


> It's a bit of a conundrum. I think the only means of supporting the camera would be to custom-design a support frame that attaches both above and below the back scope ring, and have a notch in that support frame for the filter wheel to fit.



It looks like any support would be a custom job. But could be done either by bending or bolting. My suggestion would be to come off the top plate at an angle, down the right side of the camera and then to the bottom of the camera.

It could be done with some 3/8” x 1.5” aluminum bar stock, and screwed together at the joints. It’s only lightly load bearing, so no need to overbuild.


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## jrista (Mar 30, 2016)

rfdesigner said:


> jrista said:
> 
> 
> > I run a much higher risk of a pier crash than that. That might actually be a more significant concern...however the Atlas mount is stepper motor driven, which unlike a servo, will not continually drive the camera/lens/scope into the mount if a crash does occur. If I ever upgraded to a servo-driven, properly encoded mount...the I might be a little more concerned (although still, the rate of impact is still only going to be sidereal.)
> ...



I use EQMOD, and the custom limit settings apply to slews. I have only had one pier crash in the last 26 months, and that was because I turned the limits off and forgot to re-enable them before I went to bed.


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## David the street guy (Mar 30, 2016)

Zoltan Ajtay said:


> One thing is sure: the EF mount is stronger than the 16-36/2,8 II body :'( ; I fell backwards with my 5D III attached 16-35, and the mount part of lens remained in the camera body.



Ouch! That's just painful to see… Hope repairs were possible!


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## soldrinero (Mar 31, 2016)

If you're building your own support, an easy way might be to use 80/20: https://www.8020.net .


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## jrista (Apr 11, 2016)

Someone received one of these cameras recently (one of the first to get one it seems). They weighed it, with the external FW and some filters. It came out to 6lb 3oz. 

There do seem to be some flexure issues, so people are already talking about building a support rig to hold the thing properly. I am not sure it will be a simple thing, but it sounds like I'll need to figure something out. Even if I use it on my regular telescope setup.


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## rfdesigner (Apr 11, 2016)

jrista said:


> Someone received one of these cameras recently (one of the first to get one it seems). They weighed it, with the external FW and some filters. It came out to 6lb 3oz.
> 
> There do seem to be some flexure issues, so people are already talking about building a support rig to hold the thing properly. I am not sure it will be a simple thing, but it sounds like I'll need to figure something out. Even if I use it on my regular telescope setup.



I would take a look a using aluminium angle (relatively easy to work), bolted directly to the scope/lens mounting bracket. I had to make a bracket to fix my stepper motors to the worm brackets and a pair took me about week of evenings to sort out with no more than an electric drill and hacksaws.

I would guess you'd need two or three pieces which can then bolt together giving you the necessary adjustment.

I assume you have access to a vice?


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## Valvebounce (Apr 23, 2016)

Hi Jon, soldrinero. 
If this is available in small quantities this looks like it would be ideal, easy enough to make a U to clear the filter wheel and you could incorporate 1 or more Arca Swiss quick release plates to allow quick set up and break down and micro adjustment to prevent strain. 
Looking forwards to seeing some of the results on the other thread. 

Cheers, Graham. 



soldrinero said:


> If you're building your own support, an easy way might be to use 80/20: https://www.8020.net .


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