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Mounts shiny yet not steel: plastic body flanges

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pdeley View Drop Down
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Post Options Post Options   Quote pdeley Quote  Post ReplyReply Direct Link To This Post Topic: Mounts shiny yet not steel: plastic body flanges
    Posted: 01 August 2012 at 07:24
My a500 and a450 both developed a slight wobble over time in their mounts, probably from taking most or all of the weight of my monster 600 f4 from the inevitable occasional bumps or nudges while setting it down on solid ground with either body attached, or maneuvering past doors with protruding doorknobs etc etc. Eventually the wobble became bad enough that it would intermittently cause the electronic signals with the lens contacts to be interrupted, which in turn makes AF roll back to infinity at the wrong moments, loss of aperture control and (since the early a5xx models have no release priority setting) inability to fire shots whenever the camera thinks there's no lens.

So I dug out a battered old maxxum 7000 body from my pile of feebay/craigslist surplus and decided to swap out its all-steel mount ring with my a450. In doing so, I was more than a bit surprised that the latter's mount consists of a steel surface ring overlying a separate flange ring made of... black plastic.

No wonder these mounts suffer from weakening grip when used on heavyweight lenses! After transplanting the 7000's ring onto my a450 the body mount fits tight and solid - will add pictures tomorrow to show the difference.

Haven't seen this listed in any specs of alpha models (not even in Michael Hohner's massively detailed table where all the models are listed to have steel mounts) but looking through web reviews with body-only shots, I now notice that except for the a77 and the discontinued a850/900, the flanges are in fact also black (so very likely plastic) in all the recent models including a580, a57 and a65. Arrgh sony ... enough already with the pinching of pennies on parts that need to be simply solid!

For anyone thinking of mounting any of these "steel veneer" mounted bodies on really long and heavy teles like the biggest Sigma primes or the Sony 500G: once warranty on the body is out then you'll likly need a DIY swap with a solid steel ring from an old maxxum too - fortunately doing that requires next to no tech skills.

Edited by pdeley - 01 August 2012 at 07:33
a450, a500, a700, a57, a65, 600si, 700si & other 35 mm bodies, 11-18, Sig 20 1.8, 30 2.8 macro, 24-85, Quanty 50 f2.8 macro, mf Viv 90 f2.8 macro, 70-300G, 300 f4, 500 f8, 600 f4
 



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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 09:09
Swapping it for the 7000's one is a great tip.
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nigelbrooks View Drop Down
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Post Options Post Options   Quote nigelbrooks Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 10:06
Skimping on mounts is nothing new, well done by the way for you moment of inspiration with the 7000.

When I worked for Nikon, waaay back in the early 1980's, the Nikkormat front mounts were routinely ripped out by long lenses. In that case it was worse as the mount would invariably rip away part of the body casting making the camera a write off.
Away until August 2014 at the earliest.
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Post Options Post Options   Quote Peekayoh Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 11:47
One of the Canon Guys at the Club just ripped his mount out with a 600mm lens.
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Post Options Post Options   Quote kefkafloyd Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 13:42
The 7D and a700 also had metal flanges. The 5D had the plastic flanges, as did a bunch of other Minolta consumer bodies. Not just a Sony practice, I'm afraid.
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 14:36
So it appears that the magnesium alloy bodies get the metal mount then.
 



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pdeley View Drop Down
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Post Options Post Options   Quote pdeley Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 16:25
Yes it looks like only the 7, 8 and 9 series come with the solid steel version for digital alpha bodies. Here's a picture of my grafted a450:



The maxxum's steel ring has a fraction of a mm smaller diameter than the sony combo so there's a narrow gap between the orange plastic ring of my a450 and the replacement I grafted on (doesn't matter for anything functional).

Bottom left: the original steel ring + plastic flange ring combo I took off my a450. Red arrows pointing at the dented edges of the flanges. Middle: a solid steel mount from an old maxxum 5000 body (5000 and 7000 both have the genuine article - in those days a 5 series body didn't skimp on build quality). Right: the six screws from the maxxum. These are NOT the same length and pitch as those in a Sony, so if you do this too then make sure to keep the two sets of screws separate and use ONLY the Sony screws to tighten the maxxum mount onto your alpha!
a450, a500, a700, a57, a65, 600si, 700si & other 35 mm bodies, 11-18, Sig 20 1.8, 30 2.8 macro, 24-85, Quanty 50 f2.8 macro, mf Viv 90 f2.8 macro, 70-300G, 300 f4, 500 f8, 600 f4
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Post Options Post Options   Quote bharnois Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 16:36
Originally posted by kefkafloyd kefkafloyd wrote:

The 7D and a700 also had metal flanges. The 5D had the plastic flanges, as did a bunch of other Minolta consumer bodies. Not just a Sony practice, I'm afraid.


I thought (was positive) that my 5D had a metal flange. I'll check later but it is possible that both were used.
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Post Options Post Options   Quote 9000AF Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 16:56
Nice surprise that the old flanges still fit the A5xx bodies. Great job! The worst ones of the past were the Minolta 500si and below with their all-plastic mounts. Sony's "veneer" at least keeps wear from changing lenses down and most people won't notice.
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Post Options Post Options   Quote kefkafloyd Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 17:44
Originally posted by bharnois bharnois wrote:

Originally posted by kefkafloyd kefkafloyd wrote:

The 7D and a700 also had metal flanges. The 5D had the plastic flanges, as did a bunch of other Minolta consumer bodies. Not just a Sony practice, I'm afraid.


I thought (was positive) that my 5D had a metal flange. I'll check later but it is possible that both were used.


Mine didn't. The difference between mounting a lens on the 5D versus the a700 was actually pretty noticeable; the a700 was a lot stiffer.

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Post Options Post Options   Quote bharnois Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 18:08
Dan, then I'll assume that is one you've upgraded. If so and mine is in fact plastic then I'll probably do this as well. I've got a 7000i that doesn't AF and since I have another one that is perfect as well as a Maxxum 5 I'd be more than happy to have it be a 'donor' after which it will see a fitting funeral.
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2012 at 18:24
Originally posted by bharnois bharnois wrote:

Dan, then I'll assume that is one you've upgraded.

Eh? I don't see that Dan upgraded anything. He's showing you the standard 5D with black composite (plastic) flanges just like mine and presumably just like yours. But the surrounding ring is, of course, metal.
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Post Options Post Options   Quote pdeley Quote  Post ReplyReply Direct Link To This Post Posted: 02 August 2012 at 07:33
Originally posted by pdeley pdeley wrote:


For anyone thinking of mounting any of these "steel veneer" mounted bodies on really long and heavy teles like the biggest Sigma primes or the Sony 500G: once warranty on the body is out then you'll likly need a DIY swap with a solid steel ring from an old maxxum too - fortunately doing that requires next to no tech skills.


Oops ... there I went again thinking things are that easy. This evening I tried to swap the equally flimsy mount of my a500 with that of a maxxum 5000 (the one included by way of example in my earlier picture). Let's just say that this second experiment proceeded - ahem - a bit less smoothly.

First off I made the mistake of holding the a500 in my left hand while lifting out the steel+plastic mount rings. Out came not only those two rings but also the aperture control cam and its three tiny plastic bearings. And then while finnicking about to fit those back in, the AF drive coupler jumped out like a tiny jack-in-the-box! Turns out that its bracket holds it only loosely, and even worse there's a decidedly springy spring hiding underneath. I could almost hear the coupler going "I'm free! I'm free!..."

Lesson 1: if you or I try this again - make sure to place the body flat on its back on the table, and keep it like that at all times.

After getting those jumpy bits back in their proper places, next came an even trickier surprise. The steel mount that I transplanted to my a450 the day before kept its flange clamps firmly in place during the entire process. But this time around the springy sheet ring carrying those clamps kept popping off the back of this particular steel mount, usually just before I could tighten everything in place with all six screws. I'd hear a pleasant little "pling" and suddenly the front of the steel mount would no longer quite center nor level properly anymore. Each time, the clamps apparently shifted out of place behind their respective flanges, and that just enough not only to prevent the mount ring from settling but also nudging the AF coupler bracket just enough to push back the tip of the coupler, preventing it from engaging the AF drive of my lens - if the lens would click in place at all. After about an hour of plinging, finally things happened to go in more or less the right way. My truly steel-mounted a500 works fine now, but getting there took a lot more undo-it-yourselfing than the previous attempt!   

Lesson 2: if you or I try this again - and if more than one maxxum body is available for surgery - check multiple mount rings from multiple maxxums and use only those with firmly attached clamps at the back. And if no additional bodies are available ... firmly glue the clamp ring in place and make sure to let it set fully first...?



Edited by pdeley - 02 August 2012 at 07:44
a450, a500, a700, a57, a65, 600si, 700si & other 35 mm bodies, 11-18, Sig 20 1.8, 30 2.8 macro, 24-85, Quanty 50 f2.8 macro, mf Viv 90 f2.8 macro, 70-300G, 300 f4, 500 f8, 600 f4
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Post Options Post Options   Quote berlin steve Quote  Post ReplyReply Direct Link To This Post Posted: 02 August 2012 at 08:15
I just took an old Maxxum apart as I was looking for a cog to fix a stripped gear on a teleconverter. Filing off the stripped gear and supergluing the donor cog in its place to repair the broken gear worked for my project, and I hadn't thrown the camera body yet, so I have a useful donor already in place for a steel flange.

I assume, but haven't yet checked that the a55 also has a 'steel venir'. When I find a dull moment, I'll get out the screwdrivers again, and save the dead maxxum parts till that day.

Good tip with the screws. I always try and save old 'micro' screws as they are easy to lose, and where do you buy new ones if you drop them? I'll take extra care with the Sony ones if they are not same as maxxum ones.

Edited by berlin steve - 02 August 2012 at 08:19
I'm an Englishman in Berlin...pics and more pics...
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