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M42 Fujinon Lens

Frogherder
Posted 16/05/2012 - 11:51 Link
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Hi All,

I've just aquired a Fujinon 55mm 1.8 M42 lens with a view to using on my K10.

On the outside there are 6 tiny screws which are pointed. The front set indicated by he red arrow in pic #1 release the front cowling, which is screwed in. On removal there is a silvery ring screwed down, which appears to hold the front elements (I've not touched this)

The back set red arrow 'A' are also pointed but after removal nothing appears to be loose.

I've filed off a small tab red arrow 'B' as this prevent location in a Pentax camera (using a suitable M42-PK adapter)

Not sure what the slot and hole do (cirled in yellow). Possible that a C spanner is required? Maybe a location, but in addition to the tab???

After this rambling preamble does any one know how to get inside this lens so that I can disable the pin actuator thus enabling me to use the lens manually

regards
Bernard
Algernon
Posted 16/05/2012 - 12:12 Link
You need to do a Google search for this lens type to see
if conversion is possible. Some lenses such as Helios
are simple to do..... some Yashica's can't be done.

The easiest solution is to buy a M42 to K converter with the
flange that pushes the pin down. Someone on one of the MF forums
sells them.
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Frogherder
Posted 16/05/2012 - 12:31 Link
Thanks Algi, I had already googled and found several references to 'fixing' the pin ranging from superglue to pushing it in until it jammed. What I would like to do is slide a piece if tubing over the pin, but this requires me to get at it and so far I've only managed to open the front and I'm bright enough to realise that if I disturb the lenses I've still got to get past the aperture and I'm not sure whether either of these would be a good idea.

Working on the priciple that someone put the lens together (albeit probably with fingers half my size) I should be able to take it apart, I've done it with several lenses in the past but this one is foxing me.

So having looked on other forums I thought I'd ask if any one here as done the same.

I have 2 M42 to PK adapters - one with an external flange, but this loses infinity focus; and a second which fits flush with the camera, which enables infinity fousing.
I didn't know about the internally flanged adapter, I'll have to check that out.

regards
Bernard
Edited by Frogherder: 16/05/2012 - 12:31
Stuey
Posted 16/05/2012 - 12:32 Link
I have no idea how to get into this lens Bernard but I did purchase some ball bearings for a lens I have been 'playing' with as I lost one and was not sure of the size so I have some spare small bearings (1mm and 1.5mm I think had to buy 10 of each so quite a few are spare)

So if you find yourself in a 'need bearings' situation following your dismantle PM me and I will send a couple FOC
K10D, K5 plus plenty of clueless enthusiasm.

My Flickr site link
Algernon
Posted 16/05/2012 - 12:33 Link
Took a bit of finding, but this is the supplier/thread.
link

You will see from the last post that Gareth bought one. I later
bought it off him from the PU Classifieds for £15 quite well made.
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
bernado
Posted 16/05/2012 - 12:33 Link
Call me Sherlock but I deduce someone used this with a generic M42 mount adapter permanently attached to the lens, wisely removing the adapter's locking pin beforehand preventing the thing getting stuck on the camera should the locking mechanism bust (as they are prone to do on the cheapola ones). How do I know this? - Bring on Exhibit A, the yellow circled groove someone has cut into the lens to allow the camera body's lens locking pin to engage with the lens, thus keeping it secured and functioning in a standard K (or other bayonet) Mount stylee.
Elemantary my dear Bernard
Edited by bernado: 16/05/2012 - 12:38
Frogherder
Posted 16/05/2012 - 13:25 Link
Thanks Stuey - So far I've been lucky, the last one I took apart ejected a small ball bearing which bounced off my monitor and landed on the rug below my feet. Magnet in hand I managed to locate and retrieve it. If it had missed the monitor it would probably have finished up in miscellaneous 'junk' behind my desk.


Algi - I look into that link

Bernado - not sure that your deductions are correct. The slot and hole were cut prior to anodising. The hole is little more than a countersink.


Further examination suggests that the entire aperture assembly is part of the sliding lens assembly, so I'm wondering if this lens was assembled through the front as when I squint through the back there are 2 long rods (20mm?) which engage with the aperture mechanism
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Bernard
Algernon
Posted 16/05/2012 - 14:21 Link
The top one looks like a guide to stop the other part of the
helicoid turning. The other looks to move radially. It could well
connect to the iris for some reason.

It's very unusual for a lens to be assembled just from the front?

You can glue the pin in, but I wouldn't risk bits of glue breaking
off inside the camera.
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Frogherder
Posted 16/05/2012 - 14:38 Link
Spot on, the right hand one moves with the aperture ring.

The lower set of screws refered to earlier must have something to do with it, but once these screws are out it doesn't want to slide or unscrew and is not releived in any way. In fact the only movement is that of the focusing helicoid and thats not even part of the bit with the screws in.

I'm tempted to follow the frontal attack and see if this removes the lens/aperture as a complete assembly. If so, with the actuation of the aperture, effectively disabled I might be able to attack it through the rear hole. At least there would be some tweezer room and I could see what I'm doing a bit better.


Have already rejected the glue idea for the same reasons.

I did consider cutting of the pin flush then tapping the hole and effectively replacing the pin with a long grub screw, but the piece inside would still be too long to remove

regards
Bernard
Algernon
Posted 16/05/2012 - 14:57 Link
I suppose if you can get at the pin from the front and Dremel
it off it might work. EDIT::: DON'T KNOW WHY I SAID THAT!!!
It has to be pushed in and there's usually a spring
mechanism at the other end..... so you have to do all
the work at the other end otherwise there won't be
any give in the system.

The reason some of the Yashica's are impossible is that the pin
acts as a pivot for other items and you can't reassemble the
lens with the pin pushed in, which rules out using a piece
of plastic from and electric cable. The helicoid is also a
pig to get back together.

Fujinon lenses used to thrash Pentax lenses in tests
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Edited by Algernon: 16/05/2012 - 15:16
Frogherder
Posted 16/05/2012 - 15:28 Link
So far so good

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Bernard
Algernon
Posted 16/05/2012 - 16:46 Link
That looks very unusual Normally there's a sort of inner
column that everything else attaches to. That looks like it's
built onto the external aperture and focusing rings. I would
expect it to wobble a bit on a worn lens. Early Tomioka's were
built in a similar fashion even to the point of not having to
remove the beauty/name ring.

Just need to wedge the pin up now
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Edited by Algernon: 16/05/2012 - 16:49
Frogherder
Posted 16/05/2012 - 20:04 Link
Basicaly this one comes apart by turning the focus to minimum (0.45m), this exposes the 3 screws shown in pic#1.
Loosen these screws until flush enables the front ring to be unscrewed.

This reveals 4 dome headed screws with bronze washers which hold the focusing barrel onto the lens/aperture assembly (top left and right in the last pic).

At this point the lower index ring can be removed by loosening the 3 screws until flush and lifting off (Holding down the aperture setting ring to avoid losing the ball bearings - there appear to be 2)

This reveals a further 3 countersunk screws which can be removed to release the entire aperture mechanism (top centre) and the setting ring.

The pin is then removed by loosening 2 dome headed screws which hold the bell crank lever assembly (about 2'o clock in the top centre item).

Put about 3-4mm of sleeving over the pin (cut from the shaft of a cotton bud) and carefully re-assemble in reverse order.

regards
Bernard
sorted78
Posted 16/05/2012 - 20:42 Link
Sorry I didn't come to this thread earlier today - I've got the EBC version and did a similar thing to that to shim the pin that actuates the diaphragm (I couldn't find a simpler way to do it, if that's any consolation!)

Anyway, I hope you enjoy it. I really like mine, it gives the Takumar 55/1.8 a run for its money. It's razor sharp although the colours are slightly cooler than Pentax lenses, but the bokeh is smoother.
Algernon
Posted 16/05/2012 - 21:07 Link
That's great Bernard you managed it! There's nothing worse
than stripping a lens down and finding it can't be done
The insulation off copper electrical wire is usually quite good.

Now you have a bit of testing to do

Up to f/5.6 I don't bother opening the aperture. The camera
can focus at f/5.6. Metering is usually spot on at f/5.6
as well.
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Edited by Algernon: 16/05/2012 - 21:08

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