weight limit on fs100 lens mount

eheath

eheath

Well-known member
So i'm looking into buying a 300mm prime. I have nikon lenses, so im looking at the nikon 300mm 4.5 AiS or 4.5 ED IF. The EDIF is a little but more expensive, but what im interested in knowing if I need to support this lens. The EDIF is 990g and the AiS is 1200g. The fs100 body is 1040g. I have heard if the lens is lighter than the body, you don't need to support it. So, it 990 too close? I would be stoked if I didn't have to invest in a support system (or build a DIY one, which ive thought about too) but wondering if anyone had experience with 300mm primes.

thanks,

evan
 
Big toys, big bucks. You spent a bunch of money on a camera and a long lens - why break it? There is no free lunch as they say. Even going DIY is not always cheap if it takes a few try's or worse - damages your lens or camera. The direct answer is that anything bigger and heavier than the stock lens is in need of support on an E-mount. I have taken the camera apart and seen the insides, pushing and pulling to see what happens.

Support your lenses somehow, someway.
 
DM_rider said:
Anything that long needs support. I have the 300 4.5 and it needs it.
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this what I was looking for, thanks horner. are you using the AIS or the EDIF? or something else?

I had this idea to use a like 12" by 5" by 2-3" (depends on how stiff i need it to be) piece of wood with two quick release points for the camera and tripod collar then having a tripod plate on the other side where the whole rig is balanced. it would only cost 75 bucks or so. I dont need rails/baseplate for anything else right now so spending 300-400 dollars on a rig doesn't seem logical to me. Any advice? I have the money for the 300mm and really want to shoot some skiing with it, but really want to make a DIY setup i feel like it could work really well.
 
rx8pilot said:
Big toys, big bucks. You spent a bunch of money on a camera and a long lens - why break it? There is no free lunch as they say. Even going DIY is not always cheap if it takes a few try's or worse - damages your lens or camera. The direct answer is that anything bigger and heavier than the stock lens is in need of support on an E-mount. I have taken the camera apart and seen the insides, pushing and pulling to see what happens.

Support your lenses somehow, someway.
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Interesting. I've been waving a 2470z on it, which is about a kilo but it's not too long, so the centre of gravity is closer to the camera. Even so, you reckon i should be supporting that too? The LA-EA2 adapter has a tripod mount under which would be the place to do it...

I thought the FS had a steel cage inside, but you'd be in a much better position to tell us?

thanks
Paul
 
paulcurtis said:
I thought the FS had a steel cage inside, but you'd be in a much better position to tell us?
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The FS100 is made up of all types of materials, but the only part that matters in the context of the lenses being supported is where the attachment points are located and how. The E-mount ring you see on the outside of the camera is made of some type of steel (by appearances and weight - It's an educated guess). It provides proper flange spacing and a flat surface for the lens to mate with. It also provides the bayonet tabs that retain the lens on to the camera. This retention on the ring itself is pretty good but with a critical weak link - the screws that attach it to the sensor housing. There are four ultra low-head 1.5mm screws holding the E-mount ring to the sensor mechanics. The threads in the camera are a cast aluminum material which is generally porous and soft. By comparison, the Alexa has (7) 3mm cap screws holding the PL mount in place. 1.5mm to 3mm screws on it's own is 4 times the strength - add better quality and full heads going into steel threads it is probably north of 10x strength. On top of that there are 3 additional screws. Medium size and bigger lenses are still supported by AC's everyday for good reason.

When a lens is attached, it wants to pivot on the bottom of the ring because the CG of the lens is far away from the mount. Because of this, the top two screws are doing the majority of the work hold the lens on the camera. Now, you have 4 weak screws in weak aluminum but you are only using half of them because the bottom two are only fully effective if the camera is pointed straight down. The screws and mating threads slowly stretch as they get past their yield strength. If the camera is moved, bumped, shaken, shipped, etc it gets worse.

Now, if the camera has a bulletproof solid titanium mount you are only half way to not having to support your lens. The lens itself is not indestructible and needs some help not just staying attached, but PERFECTLY aligned while it is attached. The FS100 is entry level professional - it is worth having good optical alignment to get professional results in my opinion.

The FS100 is a good camera, but in a lightweight housing. Something has to give to make it $5,500 (inexpensive)
 
I already had to send my camera in to Sony because my entire sensor and mount came loose. It came loose after 2 weeks of very rough and rugged shooting. Thankfully, Sony replaced the entire sensor free of charge. Sony has always been incredibly good to me when it comes to repairs.

So, instead of sending your camera in for repairs in a month, invest in the proper support for the camera.
 
On a somewhat related note, I've been using a handle attached to the 1/4 20 point on the side and that mount has already come loose. Seems like all that's holding in those 1/4 20 mounting points are the previously mentioned tiny screws, and it's not a particularly robust option. I had higher hopes considering that's where the Sony side handle is attached...
 
best budget rail system? indisystem has a baseplate and rails for 99 but seems like crap?
 
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