Nikkor 16-85 discontinued?

Started May 9, 2012 | Discussions thread
Youngjun91
Junior MemberPosts: 40
Like?
Re: Nikkor 16-85 discontinued?
In reply to PRW_Photo, May 10, 2012

PRW_Photo wrote:

Youngjun91 wrote:

I can actually think of one advantage of the plastic mount (wear).

Actually, wear is the primary DIS-advantage of a plastic lens mount. The lens mount on the camera is metal. If you have plastic and metal surfaces sliding against each other (when mounting/dismounting the lens) you are going to have more wear of the plastic than if you have metal sliding against metal. If the metal is chrome-plated, that reduces wear even more.

I think the primary advantage of a plastic lens mount is less weight...

Paul Wossidlo
http://www.PaulRichardWossidlo.com

When you write about "plastic" and "metal" I assume you know more specifically than I do what plastic and metal Nikon is actually using on their lens side as well as body side?

I realize that perhaps I was overly presumptive in assuming certain things like, maybe the plastic Nikon chose was a low friction plastic (when sliding on steel). Just to give you an idea where I'm coming from - for example, nylon would be an excellent material to rub against stainless steel since nylon is often used as an inexpensive bearing for steel axles or rods. This is because the coefficient of friction between nylon and steel is very low, around .16. See http://www.dotmar.com.au/co-efficient-of-friction.html . The nylon wears for a very long time when the coefficient of friction is so low against the steel. Certain stainless steel rubbing on certain stainless steel is often avoided in cases where there is significant rubbing, like when there is a high load between the two surfaces or the relative surface velocities are significant. Do you know exactly what kind of steels (I'm assuming a type of stainless) Nikon is using? I know hard steel rubbing on hard steel is not good from a friction standpoint - the coefficient of friction is in the .78 range (see http://www.roymech.co.uk/Useful_Tables/Tribology/co_of_frict.htm ). I designed some parts out of stainless steel in my career, parts that had to rub against other stainless steel parts, and I had to be very careful about the particular stainless steels I chose because there is a common phenomenon called "galling" between certain stainless steels http://www.scribd.com/doc/36205864/63/Wear-Galling-Resistance-Chart-Of-Material-Combinations . For example, you would avoid any applications where there were high loads or velocities between 304 stainless and 304 stainless because they would gall (cold weld) against each other unless there was a reliable lubricant placed on the mating surfaces.

I'm looking at my metal and plastic mounts and I don't see any real wear on either materials. This is not surprising since the load and velocity when mounting and dismounting lenses is relatively low. Can you tell me exactly what plastic and steels you are talking about in these Nikon applications? I can look them up and tell you their relative wear and friction characteristics.

Thanks,
Young

Reply   Reply with quote   Complain
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow