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Old Jan 31, 2009, 3:00 AM   #1
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I have viewed the adepters on Ebay for adapting my Takumar lenses to my K10D. The adapter I want should permit infinity focus for the lens. It appers that the proper adapters simply have so narrow a flange that the lens base will fit tightly against the camera facing.

I bought one of the cheap adapters that had the wide (interfering) flange, then filed off enough of the flange to permit the lens base to screw tight against the camera's face, and I get infinity focus capability. The resulting product appears to me to be about what the expensive adapters look like.

However, when I focus the lenses, sometimes the adapter and lens simply loose and screw partly off the camera. I suppose I could cure the separation by twisting the lens and adapter more tightly onto the camera. Is that the recommended procedure? I can make a two-prong tool to tighten or loosen the adapter.

An alternative to depending on friction would be to drill a recess in the base of the lens body to engage the normal locking prong on the camera after first determining exactly where the recessought to be when the lens is fully seated.

I hesitate to try the alternative as I don't have the proper tools for doing this, and there might be a harmful incursion of the drillings into the lens body. Also, is such a procedure likely to produce any better results than merely depending on friction to keep the lens fro rotating unexpectedly?

Perhaps someone has had experience in this problem, and can offer me some advice on the matter.

I understand it is foolish to spend the time to avoid paying 20 bucks or so for a proper adapter, but I have the time, and it gves me a sense of accomplishment to work out a problem myself rather than just buying my way out. Keeps my mind active, and, so far, at age 82, no diminshment of the thought process. Or, its at least fast enough for my boby's capability in keeping up with it. I think.

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Old Jan 31, 2009, 2:21 PM   #2
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i know quite a few that drill the base and it works.. if i did it i'm sure i would not do it with a drill. i'd get the bit and tape enough tape on it and drill by hand..
i haven't done mine mainly because even if the lens unscrews itself it's got a lot of threads to go before falling off the camera..

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Old Feb 10, 2009, 9:30 AM   #3
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I don't recomment a drill in any event. I've done a few slotting modifications to lock a m42 lens to a pentax K mount. A drill is difficult to use as it tends to wander & slip when you try to drill close to the lens' edge. It is better to use a small, sharp file to cut the slot. The metal is soft so a slot is not hard to file.

You can do almost as good a job securing the lens to the camera by slightly bending the lens' flange ears down with a hammer as shown below:

It really isn't necessary to cut a slot (I was experimenting). Just put the adapter ring on a frim table or floor & tap it with a hammer - or maybe position a screwdriver on the flange end & tap it down with a hammer.

Then mount the adapter on the camera and see if it is tight enough; if so, fine, if not, remove it and whack harder. What you are trying to do is to bend the end of the ear so it rubs firmly against the camera's flange when it is rotated into position.

It is easier than it sounds and is hard to mess up.

It is almost as good as slotting the lens (a slot provides a positive lock, while the friction fit is less precise/positive) but some people don't want to mess with the lens for a variety of reasons.

Dave

PS there are some M42 lenses with a base so small the locking pin doesn't touch the lens; in this cas bending ears is your best bet.


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Old Feb 10, 2009, 9:51 AM   #4
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i really don't think i'd use a hammer to achieve anything on my eqipment..

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Old Feb 11, 2009, 11:07 PM   #5
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Thanks to all for the very good suggestions. I am persuaded to try the flange-whack procedure on the adapter. If too much friction results from the whack, a simple filing to fit makes sense to me. As to whacking away on equipment, the adapter is what is being whacked, so little is at risk. Have to watch those fingers though.

I like that word...WHACK. Reminds me of my dad sevety years ago whenever I did something bad. Learned more from that than any school...... R.I.P. Pop.

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Old Feb 12, 2009, 11:58 AM   #6
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BOld Engineer wrote:
Quote:
Thanks to all for the very good suggestions. I am persuaded to try the flange-whack procedure on the adapter. If too much friction results from the whack, a simple filing to fit makes sense to me. As to whacking away on equipment, the adapter is what is being whacked, so little is at risk. Have to watch those fingers though.

I like that word...WHACK. Reminds me of my dad sevety years ago whenever I did something bad. Learned more from that than any school...... R.I.P. Pop.

Old Engineer
Be sure to bend the most clockwise ends of the flanges as I showed in the photo. Bending the other end of the flange will prevent the adapter from starting when you try to mount it.

Let us know your level of success.

Dave
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Old Feb 13, 2009, 2:04 AM   #7
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It will be a few days before I can do the whack job as I am deep in financial contortions trying to keep my nest egg from being fried. I will report my results as clearly as I can when they are available. Point taken on the place to do the work.

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Old Feb 13, 2009, 6:46 PM   #8
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Old Engineer wrote:
Quote:
It will be a few days before I can do the whack job as I am deep in financial contortions trying to keep my nest egg from being fried. I will report my results as clearly as I can when they are available. Point taken on the place to do the work.

Old Engineer
Not Whacked!!! You are doing a carefully considered design modification! LOL
:G :G
:G
:G:G:G:G

Dawg

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Old Feb 16, 2009, 9:26 AM   #9
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As an alternative to whacking, you might try squishing.

I successfully used vise-grip pliers to squish the appropriate end of the flange; if you try this be careful not to deform the flange mating surfaces.

On second thought, escalating whacks are probably a safer approach.
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Old Feb 18, 2009, 9:46 PM   #10
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a worry i would have with the whack method is that it is using friction to keep the bits together, more friction would equal more wear whenever you are putting on or taking off the lens, then it is a matter of what will wear first, the adaptor or the camera

ummm
how does bending the flange stop the lens unscrewing from the adaptor?
or am i missing something

maybe i should get back to work


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