Jesse Evans
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 p.3 #8 · p.3 #8 · New: Canon RF 10-20mm f/4 L IS STM Lens - $2299 | |
melcat wrote:
I had to look what a leadscrew was:
https://en.wikipedia.org/wiki/Leadscrew
But once I did, I recognised it as the troublesome mechanism that used to be in floppy drives, and indeed the article explains why at least some types of them jam. I remember how my father’s woodworking vice was easy to tighten down but could be fiendishly hard to undo.
Perhaps Canon’s leadscrew has no problems. How would I know? Ring USM, on the other hand, was a known quantity.
Given the high prices Canon asks for RF mount L lenses, their policy of outright refusing to work on lenses that are only a few years old, and that the main (only big) independent camera and lens repairer here no longer works on Canon, I will be steering well clear of this lens until it has established a reputation for reliability – and that will take 5 to 10 years. Likewise, I am somewhat put off Nikon lenses given what you say, but at least the techs I have always used still repair those....Show more →
This is incredibly silly reasoning. Leadscrew has nothing to do with the reason for something jamming. They are a technology that can be designed poorly or designed well, just like anything else. There is nothing about a leadscrew that would lead it to cause jamming other than being designed poorly. In the case of inexpensive floppy disk drives of old it was not the screw that was the problem, but that it was used to drive a thin flexible plastic housing that held the read head.
They were used commonly for dvd drives which required precise placement of a laser head at high speeds, and cd roms as well.
They have been used by Canon for over 10 years and by Nikon for a similar amount of time.
Of course the problem with Canons repair policy and not wanting to support them is up to you, but there is no reason to expect a leadscrew to be more prone to failure than ring USM.
Also, even in floppy drives it was not the read head or anything connected to the leadscrew that would jam in 99.9% of cases. It was the disk itself due to an under designed ejection mechanism. The disk would get stuck when trying to eject it.
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I wish I could slide a fixed polarizer that would give me the same contrast and clarity as my prescription Maui Jim sunglasses. It’s an often a letdown not being able to get the same polarization on an ultra-wide lens as I can with my sunglasses and I’ve been thinking more and more if a fixed linear polarizer would be an option for UWA lenses
