screw mount pin.

[shots worth sharing]

Since I now have a (genuine pentax) screw-mount adapter, I picked up a inexpensive 55mm screw-mount lens on ebay

just for fun. I note that it has the pin which has been the subject of several horror stories here but I

couldn't find them Could someone point me in the direction of a reference which will steer me away from danger?

[hinman]

Dave, from what I remember, most screw mount M42 lens will have a pin on the back for aperture stopping down. And there is usually a M/A setting for aperture. I set it to M and if you push the pin, you see the blades closing in as in stop-down metering. That is NOT the pin that cause problems.

 

The horrible pin that people get problems with stuck lens is likely from Ricoh K mount or some other related mount. In those funny K mount lens, there is an extra pin that is likely located in one of the electrical contacts responsible for AF engagement. I think the troubling pin in the Ricohr mount does not have a spring on the back and it will jam up the lens in the body. The quick fixing is usually to wiggle and push the AF switch on body from MF to AF to engage Auto focusing hoping the push action on the AF pin on body will push out the intruding pin.

 

To study the AF engagement pin, you can dismount the current lens in your K10D, and then switch from AF to MF on body and do that again, you should be able to see the AF pin coming out of the mount while switch from MF to AF. If I find the stuck pin thread in DPReview, I will come back with a link

[hinman]

This is the thread that detail the stuck pin, which is a K mount lens, not the M42 lens.

 

Stuck pin thread in DPReview:

 

http://forums.dpreview.com/forums/read.asp?forum=1036&message=25796905

 

Some people actually go the extra step in pushing the pin inwards with some glue for some reason, that I don't quite know what the benefits were. As for myself, I leave it unchanged. I set the A/M setting on the lens to M and mount with adapter and off we go with stop-down metering in M mode and have fun with the M42 lens.

 

I wrote few blog posts on M42 lens, you can make reference to mounting/dismounting and the 2 custom settings required for M and M42 lens

 

1. Genuine Pentax M42 to K adapter

 

http://techtheman.blogspot.com/2008/05/genuine-pentax-m42-to-k-adapter.html

 

 

2. Warning on 3rd party M42 to K adapter

 

http://techtheman.blogspot.com/2007/09/setup-with-pentax-m42-mount-lens.html

 

 

3. Custom settings on camera for M or M42 lens

 

http://techtheman.blogspot.com/2007/12/warning-on-bower-m42-adapter.html

 

 

4. How to convert a M42 mount to K mount

 

http://techtheman.blogspot.com/2008/02/how-to-convert-m42-to-k-mount.html

 

 

5. How to dismount a genuine M42 to K mount adapter, provided by Mos in another forum. This one is *IMPORTANT* to read

 

http://www.mosphotos.com/PentaxScrewmountLensAdapter.html

 

 

MOUNTING:

 

Basically what you need to remember is this logic. In mounting, it is straight forward, you mount the adapter, use finger nail to push the spring plate inward and turn the adapter clockwise until the adapter stops. No tool required

 

 

DISMOUNTING:

 

In the official instruction above, it uses a pen. I use two fingers to get into two holes with one hole opening to a spring plate that is locking the lens in secure position, I push the spring plate inward and then, I turn in the opposite direction in counter clockwise.

 

 

WARNING:

 

Even the genuine adapter can get you into trouble the first few times, be careful in not dropping your adapter into the mirror. I dropped it once with the silly 3rd party. And it is more safe in not laying your camera flat on its back side while doing the un-mounting as you are more likely to drop your adapter into the mirror housing.

[hinman]

While we are discussing M42 lens, my most proud LBA lens as of late is this guy -- <a

href="http://techtheman.blogspot.com/2008/10/zeiss-jena-sonnar-180mm-f28-m42.html"><b>Carl Zeiss Jena Sonnar

180mm f/2.8 (M42)</b></a> and I am sending it to Rose after my rental period. This is the <b>most difficult</b>

M42 lens that I have encountered in mounting and dismounting as the lens is like a football in size. I actually

call it my Zebra Football Lens. Its filter size is <b>95mm</b>, lens cap is a woooping <b>119mm </b>.

<br><br>

I literally have to screw my K10D onto this lens.

<br><br>

<p align="center">

<a href="http://techtheman.blogspot.com/2008/10/zeiss-jena-sonnar-180mm-f28-m42.html"><b>Carl Zeiss Jena Sonnar

180mm f/2.8 (M42)</b></a>

<br><br>

<img src="http://farm4.static.flickr.com/3014/2978915019_dfc4009b52.jpg">

<br><br>

<img src="http://farm4.static.flickr.com/3186/2979773742_f928561e2d.jpg">

<br><br>

All of my other lens with K 300mm f/4.0 and Vivitar Series 1 zoom become small and slim<br>

<img src="http://farm4.static.flickr.com/3203/2979752154_16a3ef3779.jpg">

<br><br>

<img src="http://farm4.static.flickr.com/3058/2980218808_930739e74a.jpg">

</p>

The lens weighs 1100g or 2.4+lb.

[shots worth sharing]

Thanks, Hin! I'll study this carefully. That zebra lens is cool looking. I have similar problems handling the 500mm Takumar. I wish I had big hands like Garry.

[miserere_mei]

Dave, I think you are confusing the M42 pin (innocuous and harmless) with the Ricoh K-mount pin (evil, ruthless and detestable).

 

You are fine with that M42 pin. Just remember (just like Hin said) to set the lens to "manual", not "automatic".

[personalphotos]

Yeah Dave, Hin and Mis have it right. Nothing to worry about.

 

I'm only posting to say HOLY CRAP Hin. I saw that lens for sale but had no idea it was that big! The Tak 300mm is

big and the Ziess makes the 300 look like a kit lens. It will be interesting to hear and see your results with

this lens. To see if the Ziess really is as good as the legend.

[snik75]

Yeah Hin, wow!

 

I would add, the reason people sometimes adjust the screwmount pin - not all M42 lenses have a manual/auto switch, some are manual only. This means that on an adapter there is no way to stop them down. There is a nice hack posted here:

 

 

Again. Wow! What a lens.

[shaloot]

To quote Peter: "HOLY CRAP"!!

[pinwu_xu]

For M42 lenses with the pin, but without the A/M switch, you may need to "permanently" push the pin in.

 

The simpler way is to use a sharp pin, just push the pin in, that worked for me with 2 of the Sears

lenses, and try to waggle a bit so the pin will stay in.

If possible, like on my other lens, I cut a section of ball-pen tube, stick around pin from the rear-opening

on the lens, and this plastic tube keeps the pin in.

 

Hope this helps.

 

Pinwu

[rose_duclos]

Hin, I'm still surprised that you will be able to let this lens go. :) (It will be my X'mas present to myself).

 

(((Who needs jewelry, purses or shoes - when there BE good glass?)))

[kfrog]

Great timing Hin. I just got my first M42 lens, a Super-Takumar 35mm f/3.5 yesterday. It has a manual/auto switch. The Pentax adapter should arrive soon so I'll take your suggestions to heart.

 

Lord, that is a huge lens.

[shots worth sharing]

Thanks all for the commentary. Tomorrow, I'll dig out that lens and play.

[garry_young1]

Dave - I have a solution for your need of bigger hands and the big lens - just send the lens on to me and I'll tell you all about the experience!!!!!!