Problems with pka extension tube

My friend with pka extension tubes the aperture value is not shown on the LCD display. I have readden that it is possible scraping off the insulating paint on the body so the tubes works good as pka but where he must scrape? There is the link with figures?
On a Z1 they work good but with a IstD the aperture values are not visible, why it is possible?

Have a look here.

How can I put an image in this forum?

It depends on where you are uploading them from. Check out the instructions on the Your Photos thread. If it is this particular thread you want to upload to maybe you can't and you will have to use the Your Photos one.

J

Upload the image to flickr etc. Right click on the image and copy the image location. In your reply on this forum, click on Image (below the comment box) and paste the image location in between like this:

(img)http://farm3.static.flickr.com/2447/3619006667_d7789b5265.jpg?v=0(/img)

https://www.pentaxuser.com/photo/tubo-prolunga-7879
Tell me about this tubes and the problem as I wrote. There isn't paint to scrape...

Turn it round!

Excuse me I don't understand what you means please.

You're looking at the wrong end!