Mount change?

Posted 08/09/2010 - 10:23 Link
Is it a feasible to change the plastic mount on my 55-300D AL, with the metal mount from a broken 28-80 F AL? I am a little nervous about doing this, although there is an article on another forum which gives details. I am hoping that some of the members on here who are adept at dismantling and servicing lenses can perhaps give a few tips.

Thank you in advance for any info received.

John.
Pentaxophile
Posted 08/09/2010 - 13:07 Link
I definitely would not bother! Can't see any real advantage in it and even if you didn't ruin the lens, who would want to buy a lens tinkered with in this way if you sold it.
robbie_d
Posted 08/09/2010 - 15:11 Link
It may be possible.

But I've always been a believer in just because something can be done, doesn't necessarily mean it should be done.

Pentaxophile has hit the nail on the head.

Out of interest, why would you want to do it?
If you can't say something nice about Pentax, you won't say anything at all.

Apparently.
Posted 08/09/2010 - 15:37 Link
As someone with an engineering background it is my firm belief that precision components, eg: a lens mount, made of metal are superior to plastic, in both dimensional stability and wear-resistance. I believe that the durability of metal will allow more lens changes without wear than will plastic.
Dangermouse
Posted 08/09/2010 - 15:47 Link
I've had the plastic-mounted 18-55mm DA-L with my K-m for over a year now, and it shows no signs of serious wear despite the fact that I frequently change lenses. I really don't think it will be a problem. The lens will most likely have been replaced by an upgraded model long before the mount wears out!
Matt

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.
fatspider
Posted 08/09/2010 - 16:12 Link
Stick the broken lens in a cupboard somewhere and save it just in case the plastic mount shows signs of wear, why give yourself grief if its not necessary.
My Names Alan, and I'm a lensaholic.
My PPG link
My Flckr link
robbie_d
Posted 08/09/2010 - 16:25 Link
merryhampton wrote:
As someone with an engineering background it is my firm belief that precision components, eg: a lens mount, made of metal are superior to plastic, in both dimensional stability and wear-resistance. I believe that the durability of metal will allow more lens changes without wear than will plastic.
Now I may not be able to throw around lines such as "engineering background", but...

How many lens changes are you planning on making? If you do nothing all day but change your lens then perhaps it would be worthwhile. If however you spend some of your time taking pictures, then I'd guess the plastic mount may outlast you.

Plus, what durability you may gain from a metal mount will surely be offset by the fact that the structural integrity of the lens in original factory state will have been breached. I'm fairly sure Pentax would take a dim view warranty-wise too.

I've never heard of anyone who has suffered a wear problem on a Pentax plastic lens mount.
If you can't say something nice about Pentax, you won't say anything at all.

Apparently.
jackitec
Posted 08/09/2010 - 16:31 Link
Keep a magnet handy when all the ball bearings go everywhere

Jack.
robbie_d
Posted 08/09/2010 - 16:42 Link
If you can't say something nice about Pentax, you won't say anything at all.

Apparently.
Edited by robbie_d: 08/09/2010 - 16:45
Hardgravity
Posted 08/09/2010 - 16:47 Link
I have a 35-80 with plastic mount, it's a lot older than my camera, but shows no sign of wear.

My 80-320 is the same.

Don't bother changing the mount, it will give you a head ache and could render the lens US!
Cheers, HG

K110+DA40, K200+DA35, K3 and a bag of lenses, bodies and other bits.

Mustn't forget the Zenits, or folders, or...

PPG entries.
fatspider
Posted 08/09/2010 - 17:21 Link
Quote:
My 80-320 is the same.
??? all the 80-320 I've seen had metal mounts, you sure your not confusing it
My Names Alan, and I'm a lensaholic.
My PPG link
My Flckr link
Dangermouse
Posted 08/09/2010 - 17:47 Link
Another thought:

The plastic mount introduces a weak point into the system, but does so on a relatively cheap and easily replaced part.

I'd far rather buy a new lens after a knock broke the mount than have to replace the camera because the lens mount has been wrenched partly off! Same as some vehicle manufacturers deliberately make driveshafts slightly weaker than differentials and gearboxes. They're cheap and can usually be replaced at the roadside with a few tools.
Matt

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.
Don
Posted 08/09/2010 - 18:12 Link
I've swapped mounts on a damaged sigma 400... it's not easy...
my advice, don't fix it if it ain't broke.
Fired many shots. Didn't kill anything.
Hardgravity
Posted 08/09/2010 - 20:03 Link
fatspider wrote:
Quote:
My 80-320 is the same.
??? all the 80-320 I've seen had metal mounts, you sure your not confusing it
Just taken it off my MZ-10 and...

...I was looking at the body not the lens...

,,,,,oops.
Cheers, HG

K110+DA40, K200+DA35, K3 and a bag of lenses, bodies and other bits.

Mustn't forget the Zenits, or folders, or...

PPG entries.
Hardgravity
Posted 08/09/2010 - 20:05 Link
But the 35-80 IS plastic, and a damn good lens for general use.
Cheers, HG

K110+DA40, K200+DA35, K3 and a bag of lenses, bodies and other bits.

Mustn't forget the Zenits, or folders, or...

PPG entries.

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