Summaron 35 2.8 irregular diaphragm shape

[edwliang]

hello, i found many summaron 35 2.8 have uneven diaphragm shape as they stop down starting from f8 to f22. anyone discovered that problem? some of my friends also have noticed this problem of their coppies.

attached are the pictures of each aperture, f4 is perfect, f5.6 seems still ok. from f8 on, the shape becomes so asymmetry. Is it normal for summaron at all?

 

[edwliang]

f11, f16 and f22

 

[Frontman]

Not sure about the Summaron, but it's common in enough other lenses, I have some Nikkor and Olympus lenses which do the same thing as they are stopped down. It seems to make no difference I can notice on the images.

 

[edwliang]

Not sure about the Summaron, but it's common in enough other lenses, I have some Nikkor and Olympus lenses which do the same thing as they are stopped down. It seems to make no difference I can notice on the images.

thank you. i cannot notice quality of images either. however i have other summicron lenses that have perfect symmetry shape at each stop. For summaron 35 2.8, it is odd that each time stopping down get random shapes.

 

[michaelwj]

thank you. i cannot notice quality of images either. however i have other summicron lenses that have perfect symmetry shape at each stop. For summaron 35 2.8, it is odd that each time stopping down get random shapes.

They should be symmetrical,so something is not quite right. But,if it doesn't impact your images and doesn't get any worse then I think it's best to let sleeping dogs lie...

 

[pyeh]

edwliang,
I have two Summaron 35/2.8 which I just pulled out to check. The older one, earlier than yours, has a reasonably but not totally regular aperture shape when stopping down. The newer one, bigger serial number than yours, has a very irregular aperture shape, probably more so than yours, as far as I can tell from your pictures.
I hope this is normal for this lens.

 

[edwliang]

edwliang,
I have two Summaron 35/2.8 which I just pulled out to check. The older one, earlier than yours, has a reasonably but not totally regular aperture shape when stopping down. The newer one, bigger serial number than yours, has a very irregular aperture shape, probably more so than yours, as far as I can tell from your pictures.
I hope this is normal for this lens.

Thank you so much Peter. I think it is probably caused by the oil on the blades? However I am not doing anything about it as long as it does not affect image quality.

I wonder if this happens on Summicron 35 v1(8-element) as well since they share the same barrel.
regards

 

[edwliang]

They should be symmetrical,so something is not quite right. But,if it doesn't impact your images and doesn't get any worse then I think it's best to let sleeping dogs lie...

thanks Michael

 

[flyingpalm]

My 2217537 Summaron doesn't have such problem, perfectly round through F11-F22.

 

[bayernfan]

mine is perfectly round-ish (symmetric) from f/4 to 22.

 

[jonmanjiro]

I think it is probably caused by the oil on the blades?

Possibly. Oil on the blades can cause drag between aperture blades which can distort the aperture shape, and in the worst case even cause the aperture blades to pop out of position (speaking from personal experience here).

 

[teddy]

I wouldn't worry about it. I've had 4 Summaron 35/2.8 lenses and one of them was like this but couldn't notice it on photographs. Blades could get cleaned with isopropyl alcohol perhaps, this could free them or reset them.

 

[edwliang]

thank you all for replies.
best regards.