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p.4 #6 · p.4 #6 · IS unit of RF 100-500mm not parking - a mechanical weakness? | |
RCicala wrote:
Let me clarify a bit.
The lenses with cracked IS glass is alarming to us, we've never seen that before. But it most definitely is a shipping thing, in every case the lens was fine when it left and damaged when arrived. None have ever failed while being used or carried around by a photographer.
Many of you know how we pack: padded, then in a soft case, then padded in a Pelican case. We have lenses that have literally been run over by the delivery truck survive just fine. BUT all that packing doesn't keep internal components from being jarred when the box is dropped 3 or 4 feet. That happens with every shipment I think.
Why do we see it and Canon doesn't? Well, first, Canon ships lenses by the pallet full, not in an individual box. I'm pretty sure they don't drop pallet fulls of lenses much. Second, we ship these constantly round trip. We've got a LOT of these and all have made at least 8 or 9 round trips. So think of it as 4 fractures out of 1,000 shipments. So let's say B&H shipped 1,000 lenses out after taking them off the pallets, they might get a few complaints, might not think twice about it cause stuff happens, might think they arrived that way. I can't say.
The question is why this lens and not a lot of other lenses with non-locking IS that we've been shipping for years? I don't know yet, I'm scheduled to take some apart over the next few days, maybe that will give some ideas. Just looking form the outside I can't be certain what might be moving. It's also very possible that some had a flaw that others don't, maybe an early production run thing.
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EB-1 wrote:
I surely hope that LensRentals decides to use extra padding in future 100-500 shipments.
EBH
arbitrage wrote:
They will need to start shipping them attached to a powered on R5/R6...
EB-1 wrote:
Why do you think they are safer when powered on? I doubt that. You would need to do the drop test (shipping study) both ways. It would be rather difficult to simulate the powered drop test without invalidating the results.
EBH
EBH
cpe1991 wrote:
For the same reason you are safer wearing a seat belt in a car in a crash. You are constrained against being thrown against a hard surface on rapid deceleration.
I see no indication that the lens is parked when the power is on. If you have ever bumped an IS lens in use it visibly moves to the extent of travel. IS forces are rather weak in comparison to probable impact g forces that cause the cracking. A proper solution is to redesign the IS unit to withstand higher shock when unpowered, but Canon probably will not do that unless failure rates are high. It's cheaper to lose a few units than make design and production changes, stock multiple parts, etc.
EBH
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