Aperture blades on SEL35f18 not fully retracting -- just my copy or is it really an f1.6 lens?

Started Jan 10, 2013 | Discussions thread
Mike Wee
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Re: Aperture blades on SEL35f18 not fully retracting -- just my copy or is it really an f1.6 lens?
In reply to SQLGuy, Jan 11, 2013

SQLGuy wrote:

Mike Wee wrote:

take a picture while you are looking at the front of the lens. If it's anything like my nex5 it will fully open just before taking the picture.

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Ex-Tee-Eye * 50 1,8 * 17-85
En-Ee-Ex-5 * 16 * 18-55 * 55-210 * CV 35 1,4 * FD 50 1,4

I think you're missing the point. When in A mode, the lens will stop down to exactly the aperture you ask for, so that you get correct DOF preview. I can watch the blades close down step by step as I move it from 1.8 to 2.0 to 2.2 etc... all the way to 22. At 1.8, the blades are still visible around the edge of the lens. I don't think there's enough extra glass there to go to 1.6; maybe not even enough for 1.7, but it is interesting that Sony decided to always, in effect, have the lens stopped down a bit. I wouldn't be surprised if having the sharp edges of the aperture blades in place at F1.8 helps the sharpness of this lens when it's wide open. I wonder if the SEL50F18 has similar behavior.

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Nex-7 with kit lenses, Contax G 35, and a number of legacy lenses (mostly Canon FD)

That's not what's happenning on my NEX-5. The aperture in Live view is always about 1/3 stop more closed than the value displayed on the screen. It opens to the requested value only when you half-press or take the picture. After the picture it closes a bit.

See this: http://forums.dpreview.com/forums/post/39951116

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Ex-Tee-Eye * 50 1,8 * 17-85
En-Ee-Ex-5 * 16 * 18-55 * 55-210 * CV 35 1,4 * FD 50 1,4

 Mike Wee's gear list:Mike Wee's gear list
Sony RX100 II Canon EOS 400D Sony Alpha NEX-5 Canon EF-S 17-85mm f/4-5.6 IS USM Sony E 18-55mm F3.5-5.6 OSS +10 more
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