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06-05-2020, 09:23 AM   #1
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Support for heavy lenses

As many of the recently released lenses are substantially heavier than older lenses - I'm thinking of the new 85 and the 15-30, maybe not the long telephotos with collars - I wonder if anyone has any ideas when the weight/torque might start to risk damage to the mount?

My thoughts would be that not supporting, say the 150-450 with one hand would be foolish, but lenses, like the new 85 and 15-30 are probably in the region that hand support would be advised. Personally, I support my 15-30 when used free-hand, but not on tripod where it is not going to be swung around. However, the new 85 is heavier than the 15-30 and is most likely to be used with no support - I'm thinking, portraiture.

So what thoughts do you have on weight/torque damage risk to a mount? Maybe there are some hard figures from the past? I suppose there many be a difference between using it and carrying it that may be relevant ...


Last edited by BarryE; 06-05-2020 at 09:49 AM.
06-05-2020, 10:10 AM - 2 Likes   #2
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QuoteOriginally posted by BarryE Quote
I wonder if anyone has any ideas when the weight/torque might start to risk damage to the mount?
I'm guessing the people at Pentax have an idea :P

When using heavier lenses, I tend to support them from the lens, also, whenever possible. Given that lenses such as the DFA 70-210 F4 do not have a tripod collar or any means of supporting the lens itself, I'd guess taht anything under a kilogram is probably completely safe.

Also, when releasing the DFA* 50mm, Pentax designers said that they delayed the lens because its weight created stress which moved the lens elements ever so slightly. So they are aware of the effect of weight. And not worried about strucrural damage.
06-05-2020, 10:23 AM - 3 Likes   #3
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From a mechanical standpoint, there are a few issues to be aware of:

1) It's not the weight so much as it's the torque. If the center of gravity of the lens is greater than about 1/2 the diameter of the mount, the forces caused by torque are a multiple of the weight. Long lenses exert proportionally higher torque-related force on the mount than short ones.

2) Live loads (things moving) are more dangerous than so-called deadloads (stationary objects)). Usually a big lens breaks a mount when there's some kind of motion, impact, or acceleration. A good example of a dangerous live load might be a front-heavy lens causing a ballhead or panhead to slip, the lens starts accelerating downward but then the tripod head hits the limit of motion and the lens keeps moving (yanking itself out of the camera). Or, a lens on a sling strap is bouncing up and down with the lens being jerked to a halt with each bounce. And anything involving an impact, whether the camera hits the ground first or the lens hits the ground first can create massive forces that break things.

3) Although it might be tempting to try to create a tripod mount that secures BOTH the collar of a big lens and the body of the camera, the result can actually damage the mount or distort the structure of the camera. If the dual-point support is rigid (and it's like to be that for stability) and the tolerances on the mounting points are not perfect, the rigid support will actually exert a big force on the lens and camera. The support and the camera-lens will fight each other over exactly where the two supports are and the mount might be the loser.

Personally, I'd not be too worried about the 85/1.4. These cameras are fairly tough. I seem to recall a Pentax rep holding a K-1 & 150-450 suspended by the tilty-stilty lunar lander display. Thus, I'd mostly watch out for fast movements and impact loads more so than everyday use.
06-05-2020, 11:08 AM   #4
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QuoteOriginally posted by photoptimist Quote
From a mechanical standpoint, there are a few issues to be aware of:

1) It's not the weight so much as it's the torque. If the center of gravity of the lens is greater than about 1/2 the diameter of the mount, the forces caused by torque are a multiple of the weight. Long lenses exert proportionally higher torque-related force on the mount than short ones.

2) Live loads (things moving) are more dangerous than so-called deadloads (stationary objects)). Usually a big lens breaks a mount when there's some kind of motion, impact, or acceleration. A good example of a dangerous live load might be a front-heavy lens causing a ballhead or panhead to slip, the lens starts accelerating downward but then the tripod head hits the limit of motion and the lens keeps moving (yanking itself out of the camera). Or, a lens on a sling strap is bouncing up and down with the lens being jerked to a halt with each bounce. And anything involving an impact, whether the camera hits the ground first or the lens hits the ground first can create massive forces that break things.

3) Although it might be tempting to try to create a tripod mount that secures BOTH the collar of a big lens and the body of the camera, the result can actually damage the mount or distort the structure of the camera. If the dual-point support is rigid (and it's like to be that for stability) and the tolerances on the mounting points are not perfect, the rigid support will actually exert a big force on the lens and camera. The support and the camera-lens will fight each other over exactly where the two supports are and the mount might be the loser.

Personally, I'd not be too worried about the 85/1.4. These cameras are fairly tough. I seem to recall a Pentax rep holding a K-1 & 150-450 suspended by the tilty-stilty lunar lander display. Thus, I'd mostly watch out for fast movements and impact loads more so than everyday use.
Thanks you've both quantified and confirmed my thoughts in some areas.

1) Yes, it was the torque issue I was thinking about.

2) Is where I've been the most concerned about in the past. Even light lenses can no doubt exert excessive forces on the mount (as well set off damaging internal vibrations) when a tripod head slips. This has happened to me when I've used a lighter head and my older gear. Since then I've used heavy rated heads, but there's still a risk of not locking down properly, especially when in a rush. But at least a better rated head is likely to have resistance settings, which will slow the slippage, rather than let the lens/camera free fall till it reaches its stop.

Swinging K-1 and 150-450 on tilty screen is the sort of thing reps do. They probably have a (non-working) set-up for just this purpose

---------- Post added 06-05-20 at 07:11 PM ----------

QuoteOriginally posted by bdery Quote
I'm guessing the people at Pentax have an idea :P

When using heavier lenses, I tend to support them from the lens, also, whenever possible. Given that lenses such as the DFA 70-210 F4 do not have a tripod collar or any means of supporting the lens itself, I'd guess taht anything under a kilogram is probably completely safe.

Also, when releasing the DFA* 50mm, Pentax designers said that they delayed the lens because its weight created stress which moved the lens elements ever so slightly. So they are aware of the effect of weight. And not worried about strucrural damage.
Interesting point about the DFA 50. I also hand support the 24-70, especially when extended out to 70 as the torque increases. This lens is about at the point, below which I don't worry.

06-05-2020, 02:44 PM   #5
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TBH as an "oldie", more weight means I would be far less likely to buy said item!

There's a "balance" to be struck between weight and "IQ", and thus "everyone" has to make their own choices - Not an issue for myself because I'm pretty happy with my current selection of lenses which do a pretty good job IMHO!

Thus, do "you" want the "ultimate / never to be surpassed" IQ, OR are you going to admit that what you already have is "pretty damned good enough for me!"????

PS: I'm in the latter group!
06-05-2020, 05:38 PM - 4 Likes   #6
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This is the equipment I bought recently to help me cope with the new heavy Pentax lenses. Recommended.



But yes, I do always support the DFA* 50 and DFA 15-30 with my left hand, or to be more precise, with the ball of my left thumb under the camera and the index and middle fingers supporting the lens. Irrespective of torque, it is a more stable shooting position than gripping the camera body alone.
06-05-2020, 07:19 PM   #7
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QuoteOriginally posted by BarryE Quote
As many of the recently released lenses are substantially heavier than older lenses - I'm thinking of the new 85 and the 15-30, maybe not the long telephotos with collars - I wonder if anyone has any ideas when the weight/torque might start to risk damage to the mount?

My thoughts would be that not supporting, say the 150-450 with one hand would be foolish, but lenses, like the new 85 and 15-30 are probably in the region that hand support would be advised. Personally, I support my 15-30 when used free-hand, but not on tripod where it is not going to be swung around. However, the new 85 is heavier than the 15-30 and is most likely to be used with no support - I'm thinking, portraiture.

So what thoughts do you have on weight/torque damage risk to a mount? Maybe there are some hard figures from the past? I suppose there many be a difference between using it and carrying it that may be relevant ...
I think someone who has correct handholding technique hasn't got anything to worry about, Barry.

Fingers of right hand are curled under the lens, palm bearing the weight, elbow pointing straight down to the ground like a Roman column.

The right hand used really only to stabilize and to press the buttons. You should be able to remove it entirely an nothing alters.
06-05-2020, 07:49 PM   #8
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DIY Lens Support Bracket - DIY Photography

06-05-2020, 07:58 PM   #9
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I actually hold my 150-450 by the tripod foot when shooting and when carrying the lens mounted. I still have a strap on the camera around my neck and shoulder. When I have it on a monopod, I carry it when moving by grabbing it at the foot/ballhead area rather than just carrying the lens camera like a scepter on the monopod. that could be a fun image, king of the monopod users.
06-05-2020, 08:15 PM   #10
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I've been swinging the FA*300 f/4.5 around for years and that hasn't damaged the mount. I think it's very unlikely to damage a mount unless you really swing it past 1g of force. Of course, the majority of time when handheld your hand will be under the lens as well. Stationary on a tripod should be find as well. It seems like on average, manufacturers start adding tripod collars to lenses around 1.5kg, so that might be the point where you'd want to be careful.
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