Adjusting diaphram on SMC pentax 165mm f/2,8

[Soeren]

I was perhaps a bit too fast in buying this lens and I have found out that the blades in the diaphram makes an odd shape at f/4.0 to f/5.6+½.The opening is symetric but the edges is kind of "starlike" well not quite but I don't know how to descripe it more precise. Can the aperture blades be adjusted? will it cost a fortune? The lens was cheap and I may be happy to use it either wide open or stopped down to f/8. There is a waranty on it so maybe.
Cheers
Søren

 

[luvcameras]

I have used this lens for years and it has great bokeh - dont worry about the blades....unless you shoot at night and are concerned about the shape of lights.....see an example here

http://members.aol.com/dcolucci/bokeh.htm


and here ( some links broken )

http://members.aol.com/dcolucci/p67.htm

 

[Soeren]

Thanks Luvcameras
Are you saying that the strange shape made by the aperture blades until stopped down to f/5.6 is normal for this lens?
Cheers
Søren

 

[luvcameras]

can I see the shape ? I dont know what you think "strange shape" is

 

[max_ebb]

After reading this post, I was curious so I looked at the shape of the aperture on my 165 pentax lens. When it's barely stopped down (f/4.0 to f/5.6), I noticed it has kind of a circular saw tooth shape. It's normal. No lens has a perfect circle shaped aperture opening, especially if it's only slightly stopped down.