SEL50F18 aperture is not round?

[blaz07]

Hello,

I have question for sony fast lens users, is my aperture normal (not perfect 'rounded')?

This is at F11, but noticed at F9 - F22. Lens is Sony 50mm F1.8.

[blaz07]

Yes, picture is from an angle, but no matter from what angle I look into lens, the same side (blade) is longer (of course distortion must be taken into account).

Last week I check some new lenses in photo store and also other lenses have that kind of missaligment. Even expensive Zeiss F1.8. I think this is normal on fast big apertures.

If you have that kind of lens, look closely and pay attention at small aperture values (F11, F16, F22).

[TLysholm]

I think it's perfectly normal. I have six lenses here right now, vintage and modern (Yashica, Sigma, Sony including the FE50/f1.8), and none of them are 100% perfectly aligned. So don't sweat it. I'm sure it's all fine. I haven't noticed anything irregular in my photos. Even now that I know, I don't see it in the bokeh stopped down. Maybe very high end lenses have perfectly aligned blades ..? I don't know.

Maybe what you can take away from this is that now you know, and you know there's a sort of acceptable margin. Maybe they simply have to make the blades a little bit "loose" like that. After all the blades have to work for many years and open and close a million times. Having a tight and snug fit would maybe wear them quickly. I dunno, I'm just riffin' here ... but as long as they keep working and I can't tell in my photos, I'm fine.

Anyways, know I've checked.

EDIT: I just grabbed this screenshot from a video review of the Sigma 50mm/1.4 Art lens. Same thing.

[blaz07]

Yes, this is normal. Maybe is for some reason (for long time working), maybe because is difficult to allign this small parts. Great, now we all know something new bokeh is great, and the lens (Sony SEL50F18) is just perfect, have very sharp images and I love it. If I compare kit lens vs this prime lens..it is almost unbeliaveble difference

Thank you for all answers.