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05-02-2012, 05:51 PM   #16
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QuoteOriginally posted by ChopperCharles Quote
Does that half stop make it worth upgrading to? Or am I better off just keeping my 1.7?
User monochrome hit the nail on the head.

The difference between f/1.7 and f/1.4 is rather inconsequential.

You'd get the f/1.4 version for its different bokeh. It has under-corrected spherical aberration which makes the background bokeh smoother than that of the 50/1.7 but it isn't as sharp as the 50/1.7 in the range of f/1.7-f/2.8.

The 50/1.4 also has more field curvature (the focus plane isn't as flat as that of the 50/1.7) which makes it a lesser choice for using it in combination with extension rings / bellows.

Summary, get the 50/1.4 for its different rendering ("look" of images), if it appeals to you. The 50/1.7 is technically the better lens in a number of disciplines, but its rendering isn't as smooth as that of the 50/1.4.

05-02-2012, 08:00 PM   #17
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QuoteOriginally posted by ChopperCharles Quote
I have the SMC-FA 50mm f1.7 lens, and I love its low-light performance and quick auto-focus.... however, the 1.4 *is* faster. Does that half stop make it worth upgrading to? Or am I better off just keeping my 1.7?
If you just care about the difference in speed, it is not really worth an exchange. You may want to look for an f/1.2 instead Or as others recommended already - consider the DA* 55/1.4.
05-04-2012, 07:09 PM   #18
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If you really want an upgrade maybe look at the DA*55-1.4... You get the half-stop AND massively increased IQ...
05-04-2012, 07:59 PM   #19
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I'd keep the lens you already have and look for a different focal length for your next lens.

05-07-2012, 09:03 AM   #20
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Original Poster
I shoot a lot of low light, at ballroom dance events, and I cannot always use (nor do I always want to use) flash. Same deal for ballet recitals and such. I don't care about macro work, just low light performance and sharpness. Well, and dead-accurate autofocus. I can't manual focus to save my life with my Kx. With my full frame manual camera I can easily, and that's what I have the vivitar mounted to. It's a different lens optically though, it's far, far lesser quality than the FA1.7.


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