Author Topic: Dandelion lets me down  (Read 1747 times)

Bjørn Rørslett

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Dandelion lets me down
« on: March 20, 2017, 22:22:48 »
The 'Dandelion' has got itself a mixed reputation over the years. Quite deserved according to today's sad experience.

I was busy shooting the evidence that blur circles are independent on format, when my 50/1.2 Nikkor AIS suddenly acted up and the camera went dead. Turned out the CPU pins of the Dandelion all of a sudden were shifted or torn off.

This lens couldn't hardly have been CPU-modified without the efforts of my friend Erik [aka 'Dr. Lens']. The contact pins were inserted through holes in the bayonet and I had hopes this would  protect them from undue wear. This bliss lasted for two years.

Before and after close-ups. The Dandelion really is a fragile design.

RonVol

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Re: Dandelion lets me down
« Reply #1 on: March 20, 2017, 22:56:09 »
Looks like an awesome job done by Doctor Lund.
Most people that do these conversions wouldn't have attempted such a modification.
A shame the quality of the Dandelion hasn't lived up to expectations.

benveniste

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Re: Dandelion lets me down
« Reply #2 on: March 20, 2017, 23:08:39 »
I had my 80-200mm f/4 chipped by legacy2digital and one of the "pins" sheared off in a similar manner.  A second chip also failed, but not for any obvious physical reason.  Both times I ended up being out the cost of 1-way shipping.

One of the nasty side effects of both failures was that my IR-converted D70 still thought it had a CPU lens attached, so I couldn't even use it in unmetered manual mode.

Erik Lund

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Re: Dandelion lets me down
« Reply #3 on: March 21, 2017, 00:00:04 »
Looks like we need to do another implant  :D
Erik Lund

Bjørn Rørslett

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Re: Dandelion lets me down
« Reply #4 on: March 21, 2017, 00:01:01 »
I have, on my own or in co-operation with Erik, CPU-modified a great number of lenses over the years. Must be well over 100 units by now, plus over the years I have sold more CPU kits than that for users to modify their own lenses.

As original brand new Nikon spare parts are used for the contact block, the mounting guard on the contact block is solid metal, and bespoke screws keep the components firmly in place, I have yet to see a failed modification using these kits.

The snapshot below is the outcome from one of my many trips to visit Erik. The CPU modification really makes using all those Nikkor gems from the past a breeze.

I'll have to discuss with Erik what is possible to do with the 50/1.2. Oops., he answered while I posted. Putting this on a future to-do list, then.

Akira

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Re: Dandelion lets me down
« Reply #5 on: March 21, 2017, 00:07:34 »
Sorry about your mishap, Bjørn.

If this Ais 50/1.2 is the ONLY lens among the ones you use that cannot transfer the lens info to the body, you could simply register the 50/1.2 lens to the body.  The "unchipped" 50/1.2 will always be correctly recognized as it is without switching between different registrations of more than one MF lenses.

That would be the easiest workaround.
"The eye is blind if the mind is absent." - Confucius

Bjørn Rørslett

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Re: Dandelion lets me down
« Reply #6 on: March 21, 2017, 00:24:28 »
One of the Nocts is still untouched. CPU-modifying it is quite risky, although Erik has done this several times. It was acceptable when he did the CPU modification on my old Noct AI (purchased for the princely sum of 150 USD by a stroke of luck). However, the newer one not only is AIS, it also cost me a bit more :(

Thus I have more than one lens of f/1.2 speed with no CPU, if the 50/1.2 remains in the current sad state. I have to pry off the Dandelion so the lens won't fry my cameras as well.  However, knowing Erik, he is making plans for this contingency already. What are good friends for if not in a time of despair.

Akira

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Re: Dandelion lets me down
« Reply #7 on: March 21, 2017, 00:33:50 »
Oh, so long as you take BOTH Noct and 50/1.2, the workaround won't work... :(
"The eye is blind if the mind is absent." - Confucius

Bjørn Rørslett

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Re: Dandelion lets me down
« Reply #8 on: March 21, 2017, 01:15:19 »
Mishaps are bound to happen as long as settings are to be remembered and entered manually. The CPU project aimed to eliminate that source of error.

Having both lenses concurrently in the field occurs more frequently than you might think.

Akira

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Re: Dandelion lets me down
« Reply #9 on: March 21, 2017, 11:28:08 »
Wait!  You say that "one of the Nocts is still untouched."  Then you should be able to refrain from using that untouched Noct?  Or, do you even need to switch between different Nocts?   :o :o :o
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Jack Dahlgren

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Re: Dandelion lets me down
« Reply #10 on: March 21, 2017, 11:37:59 »
The vertical sides of those pins are at fault. Looks like they are for a design which is intended for loads along the axis of the pin rather than the rounded contacts used by Nikon. Bad design indeed.

Bjørn Rørslett

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Re: Dandelion lets me down
« Reply #11 on: March 21, 2017, 11:41:52 »
Wait!  You say that "one of the Nocts is still untouched."  Then you should be able to refrain from using that untouched Noct?  Or, do you even need to switch between different Nocts?   :o :o :o

'Untouched' as never being  the victim of a Dremel :D

My Nocts are AI and AIS, respectively, and have subtle differences in their rendering. So yes, switching Nocts is a reality.

Bjørn Rørslett

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Re: Dandelion lets me down
« Reply #12 on: March 21, 2017, 11:45:06 »
The vertical sides of those pins are at fault. Looks like they are for a design which is intended for loads along the axis of the pin rather than the rounded contacts used by Nikon. Bad design indeed.

You correctly identified the main reason why the Dandelion pins shear off. They are spring loaded, but exert nevertheless much more pressure onto the camera contacts than do Nikon's design which also is favoured by much more robust solid pins with rounded tips.

Erik Lund

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Re: Dandelion lets me down
« Reply #13 on: March 21, 2017, 11:45:08 »
The vertical sides of those pins are at fault. Looks like they are for a design which is intended for loads along the axis of the pin rather than the rounded contacts used by Nikon. Bad design indeed.

Yes and the extremely soft and thin materials for the tubes just makes it even worse  :o :o :o
Erik Lund

richardHaw

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Re: Dandelion lets me down
« Reply #14 on: March 21, 2017, 14:43:54 »
i was in the impression that the contacts are made out of solid copper pegs :o :o :o
I have an idea that will do away with this but I am so busy I haven't even talked to my engineer friends about this project!
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