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07-25-2010, 04:49 AM   #31
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There's another clue Ash. I'd forgotten this. Of course we are making assumptions but it makes sense that if you have a rubber seal inside the barrel, it would stick to the opposing surface if it sits without use for a period of time.

Mine would do that as well. If it sat about, I'd have to quick shift the lens several times to get things working normally. On an underpowered motor, you are going to burn something up (contacts?) after awhile if it can't "unstick" the lens on it's own easily.

A lot of owners have reported this and that the lens periodically would be unable to move or lock focus in good light. This got progressively worse as the lens got older and then it would fail completely.

The thing that gets under my skin is that a lens like the $100 18-55mm WR has had ZERO reports of focus issues. The in-body motor has the power to overcome any seal sticking (if that's even really happening). I'll take the slight noise of the SD over crappy SDM any day of the week.

07-25-2010, 10:44 AM   #32
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QuoteOriginally posted by Peter Zack Quote
It's not a WS issue IMO but a weak motor issue.
You probably don't know anything more about how the SDM motor works than I do, but if it isn't a proper ring motor and instead a micromotor, it must be pretty weak if it is simply turning the screw drive from within the lens.

As I said in an earlier post, turning the screw drive by hand with a small screwdriver there was no more resistance than I had on my non-SDM lenses.
07-25-2010, 11:33 AM   #33

QuoteOriginally posted by philbaum Quote
In any case, the good news is that Pentax built SDM into their lastest camera, the 645D and the lens for that. I don't believe that any company would release an expensive camera like the 645 unless they were confident that the SDM issue had been solved.
Phil - what SDM issue? Wasn't it the view of Pentax that there is NO issue? Not that all users agree.
07-25-2010, 02:23 PM   #34
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First, Nikon has produced some of the finest AF lenses for underwater use ever devised so Nikon's choice of not stating their pro-grade lenses are weather proof must be by their plan. It's possible their pro-grade lenses are in fact weather proof (a friend shot an event during a rainstorm using his D200 and 18-200 to the point his wrist strap was soaking wet and yet he encountered zero problems) but I wouldn't be the Nikon shooter to test them. The safest assumption regarding Nikon is their market research found their customers don't want weather sealing enough to warrant the added expense.

I take it the OP is referring to both design and manufacturing tolerances related to the sealed points where moisture could enter a lens. Who knows for sure but I assume weather proof refers to the ability to shoot in light rain and not a deluge or a dunking. The AF speed for a camera and lens combo takes into account many factors so I don't think it's safe to assume a WR lens focuses slowly because of the seals required.

08-21-2010, 02:49 PM   #35

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Sometimes its simply the companies' view of customer perception and liability. I know that my employers and our suppliers could often outperform the advertised specs. We chose to limit our risk assessment to limit our liability, whether in the legal or customer relations areas. There are a host of reasons for that.

A conservative company will let its customers figure out better-than-advertised-spec performance and decide for themselves what use to make of that info. Nikon may be just that conservative. Their target markets are high-tech B2B and consumers with good credit scores and advanced tastes. That kind of customer eventually hears the un-voiced message.
08-21-2010, 04:04 PM   #36
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QuoteOriginally posted by SpecialK Quote
The Canikon answer.

Seeing as for a start, Canon is the most-used photojournalism brand in the world, including in some of the world's most extreme environments, I don't think this is a valid point.

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