problem matching Fujinon EBC 55/1.8 withTamron 2X P-CS

[bazza59]

tried searching the forum but no joy, so apologies if this subject has been covered before...

I have a Fujinon EBC 55/1.8 and would like to use it with a Tamron 2X P-CS convertor.
Problem is the aperature pin sticking out of the back of the Fujinon does not meet anything solid on the convertor and therefore does not depressed - so I have only wide open available.

Is there a fool proof way of forcing the aperature pin in without the possibility of damage to the lens and/or convertor.

#1 fujinon ebc 55/1,8 and tamron 2x convertor


#2 Aperature pin which needs depressed

[RioRico]

The main reason I stopped buying Fujinons and other auto-only M42 lenses is just because the pin on the lens is difficult to deal with. The lens can be modified: glue the pin down, or pull the lens base and remove or block the pin. But this reduces any resale value. I have read that thin metal tape will hold the pin down, but I haven't tried that yet, and won't until I return home in a few weeks.

I currently have 3 M42 Auto TC's and have sold 7 others. (Helios, Vivitar, Sears, Spiratone, etc.) Each had a bar for engaging the auto-aperture pin, activated from below, from the camera. Ah, this gives me an idea: modify the TC, not the lens! M42 TC's are pretty cheap and common. You can get one probably for under US$10, and sacrifice it for use to stop-down those auto-only lenses.

[martyn_bannister]

It is possible to buy "auto" M42 tele-converters which either have a mechanism to transmit the movement of the pin or just a "landing" to force the pin in and convert the lens to manual mode.

If you can remove the mount and extract the pin then it's possible to slide a piece of plastic tube over the pin and re-assemble. The lens is then permanently in manual mode. But of course the surgery is reversible.

Hope that helps

PS. I have just noticed from your OP that the tele-converter you have is already "auto". Is therefore the problem the M42 adapter you are using? What body?

[bazza59]

Rico and Martyn many thanks for the suggestions.

Some clearer images of the convertor (Tamron 2X-PCS) below
#1 camera side


#2 lens side


#3 pin depressed


The combination is being used on a Canon Rebel Xs with a simple M42 to EOS adapter that ensures the convertor pin is depressed. The problem is trying to get the convertor pin mechanism to align exactly with the lens pin. When the lens is tightly mounted on the convertor they are not aligned, for them to be aligned the lens is too loose on the convertor and any nudge will cause the pair to move out of alignment.

The easier fix for this combination would be to modify the pin on the lens so that it remains depressed but I haven't done anything like this before and would be reluctant to aatempt it in case I ruin the lens trying - the lens has a good reputation and I still have my old Fujica ST801 to use it on if the desire arises.

I was hoping that there might be -
a/ some type of magic tape (such as Rico's suggestion) or
b/ a convertor that somebody had first hand knowledge of using successfully with this lens

thanks again

[walter g]

If the line up is close. Try making a shim to go between converter and lens so it does stop in the right place.

[scsambrook]

The easiest way might be to get another teleconverter. Most of them have a metal plate to bear against the lens pin, rather than the cylindrical one in your converter. I suppose that was to allow for variations in the way different lenses indexed on different bodies. M42 converters can still be bought at low prices, so there's another inducement !

[martyn_bannister]

As scsambrook suggests, I believe that your converter is the fault. It should have a plate connected to the pin with a screw. You can see the thread where the screw fits. Another tele-converter is your answer

[bazza59]

thanks guys - looks like I'm in the market for another M42 convertor.