1








This lens is the  APO-Telyt 280/4,
 one of the best ever made by any brand.

Thanks to a loan from a customer we can write the following instructions.
2

















It is a R-cam lens.
3
















First, remove the bayonet screws.
4















Push the aperture lever until the bigger gap side.
5













This way, it is possible to remove the bayonet and the black shroud all together.
6
There is no need to disassemble the black shroud.

NEW!
With the new Leitax mount model, you can reuse the black tube to avoid flares, take a look here.
7



















The small bearing ball is in place.
8














Put some grease into the hole with spring where the ball goes, and some more on the ball.
9










Now we can install the new bayonet, the red dot close to the scale center.

First the four longer screws, and tight all the screws in a cross pattern, a bit one after another.
10
















All is black inside except a couple of bright metal screws.
11














So, I've painted them with the flat black marker I got from Micro-Tools.
12














Also note this lens has lost the red plastic hemisphere.
13
















With a bit of glue the lens looks  better now.
Ready







Ready, now it is possible to use this lens on Pentax and Nikon-F cameras.

I would like to say thanks to our customer and friend James for the possibility to try the Leitax bayonet on this lens.
Back to the Pentax page 
Back to the Nikon page
Back to the Sigma page
Back to the Sony page