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Do I need to brace DSLR lenses? 135mm to 800mm ?

astrophotography dslr
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#1 nathanm

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Posted 13 July 2020 - 07:26 PM

If I am using DSLR lenses like  Canon / Zeiss / Samyang  85mm to 135mm I have not bothered to brace them.

 

When using larger DSLR telephoto lenses, particularly those that have a lens foot  (Canon 200mm f/2, 300mm f/2.8 ... up to 600mm f/4) I have not braced them either.

 

Do these lenses need bracing when used for astrophotography with an equatorial mount?   I am worried about flexure as are pointed at various angles in the sky.   

 

But maybe I worry too much? 

 

There are some bracing systems available, but all for terrestrial photography.    One set of them are only for larger lenses - the brace extends back from the lens foot, and has a vertical section that engages the camera.   This prevents looseness at the camera / lens intersection, but does nothing for the lens itself.https://www.bhphotov...ease_plate.html .   

 

Another kind of brace is intended for a lens that does not have a lens foot.  https://www.manfrott...ns-support-293/   That has a strap that goes over the lens.   But its only for fairly small lenses that don't have a foot.

 

The Really Right Stuff lens support, https://www.bhphotov...ml?sts=pi&pim=Yand several others similar to it has a "Y" shaped support for the lens, but that only works when upright, not on an equatorial mount.     Presumably a strap could be arranged.

 

Similar yoke shaped supports are meant to be used with carbon fiber support rods  https://www.bhphotov...ml?sts=pi&pim=Y

 

All of these braces or supports seem assume that the lens is pointed parallel to the ground so not really useful for astro.

 

 



#2 calypsob

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Posted 13 July 2020 - 07:32 PM

Yes they need to be braced. They are putting stress on your bayonet without support and you also stress the connection on your camera. The springs in the EF mount will be worn out if you make them hold a large lens for a night of imaging. Star quality definitely suffers under the weight of the lens. 

 

Here is a simple astro telephoto support https://www.aliexpre...950635942.html 



#3 bobzeq25

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Posted 13 July 2020 - 07:33 PM

I don't brace my 200mm F4, have noticed no ill effects.


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#4 bridgman

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Posted 13 July 2020 - 09:12 PM

My 200mm lens does not have a mounting foot, so I use a single ring to brace it with the screws touching a non-moving part of the lens:

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#5 nathanm

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Posted 14 July 2020 - 12:12 PM

Unfortunately, this link isn't working, so I am not sure what sort of brace you mean

Here is a simple astro telephoto support https://www.aliexpre...950635942.html

 



#6 Simon D.

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Posted 14 July 2020 - 04:09 PM

I dont think you need to brace The 135.  Anything with a collar should be braced, as the tightening knob and collar ring wasn’t designed for stability and usually have some play.  Here’s what I use on my 500 f4.  Thé foot is by Jobu Design, and that stays on my 500 permanently.  The lower bar and spacers under the ring are from ADM.  The clamshell ring I got on Amazon.  Get them a bit bigger than you need, and add foam cushion spacers or felt to get tight.   If you get the bar long enough, you can add a guidescope underneath like I did here. The whole thing comes off with one nut holding the foot to the bar, and unscrewing the clamshell ring...30 seconds and It’s off.  
 

 

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#7 nathanm

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Posted 14 July 2020 - 07:24 PM

So, Simon D, this is not a criticism, but you use the ring to support the lens, but you don't have a support for the camera.     So evidently you think that is what needs support.  

 

I don't want that sound argumentative - we all make assumptions and assuming that the camera end will take care of itself is not unreasonable.  I am just curious if you tested that or thought about it.

 

The main problem with bracing the camera is that it makes it hard to turn the lens to change camera orientation, but that may not be an issue.



#8 Alen K

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Posted 14 July 2020 - 08:43 PM

So, Simon D, this is not a criticism, but you use the ring to support the lens, but you don't have a support for the camera.     So evidently you think that is what needs support.  

 

I don't want that sound argumentative - we all make assumptions and assuming that the camera end will take care of itself is not unreasonable.  I am just curious if you tested that or thought about it.

 

Not unreasonable at all, given that the lens supporting the camera is a common use case for digital cameras (think birding and other nature photography). And that is with lens typically horizontal, which maximizes the force on the lens mount.  Heavier cameras, which would increase the stress on the mount, also typically have beefier bodies and stronger lens mounts. Does anyone seriously worry about stress on the camera's lens mount when doing prime-focus through a telescope with a t-adapter? If that were a real problem, I think it would be more widely reported. 

 

In other words, while I am not saying it will never be a problem, many if not most cameras are likely designed to take that kind of stress. 



#9 Cdnpilot

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Posted 14 July 2020 - 09:33 PM

It really depends on the weight of the lens. I am a professional sports photographer and using the 20-200 f/2.8 the monopod I use is attached to the lens. With a D5 on the end, it works fine. However, in the past I have used a D3 with a teleconverter, and over time the weight of the camera caused a failure in the plate on the lens that connects the foot (I think it was the extra distance the TC added). My 300mm weighs 6 pounds and picking it up with a camera on it, I always grasp the lens not the camera.

 

As to the strength of the lens collar - I have always been intrigued by the fact that every time I send a lens into Nikon for repair or cleaning, they always replace the lens collar. Maybe they know it is a point of failure. 



#10 calypsob

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Posted 14 July 2020 - 09:46 PM

Yes they need to be braced. They are putting stress on your bayonet without support and you also stress the connection on your camera. The springs in the EF mount will be worn out if you make them hold a large lens for a night of imaging. Star quality definitely suffers under the weight of the lens. 

 

Here is a simple astro telephoto support https://www.aliexpre...950635942.html 

strange, try this https://www.aliexpre...68162b06eRp2Kp 



#11 calypsob

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Posted 14 July 2020 - 09:54 PM

In astrophotography, the strength of the lens collar springs is crucial. You dont have to worry about round stars in sports photography,this is a totally different set of expectations for performance. You do wear out the lens collars if you spend 6+ hour sessions in freezing cold with a heavy lens hanging off. I know a few people who have had theirs replaced actually, I think Wei-hao mentioned that at one point. Anyways just realize that you can and will induce mechanical or differential flexure when gravity, temperature, and time are involved.  Astrophotography will put a spot light on all of the weaknesses.   Personally I just use a support like this https://www.ebay.com...2hoCTN4QAvD_BwE with a thick elastic band to keep the lens in place. This takes weight off the camera and the lens. I clamp this onto a ballhead which is 3/8-16 bolted to a dplate clamped into the dec saddle. 



#12 Simon D.

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Posted 15 July 2020 - 07:34 AM

So, Simon D, this is not a criticism, but you use the ring to support the lens, but you don't have a support for the camera.     So evidently you think that is what needs support.  

 

I don't want that sound argumentative - we all make assumptions and assuming that the camera end will take care of itself is not unreasonable.  I am just curious if you tested that or thought about it.

 

The main problem with bracing the camera is that it makes it hard to turn the lens to change camera orientation, but that may not be an issue.

No problem asking at all.   Yes, essentially, the long lens at 8 lbs hanging out far from the collar for rigidity is a problem, but the 2 lb camera, much closer to the anchor point and with a solid circular mount with lots of contact points, isn’t a problem.  Here are some pics using that setup. Good luck!

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