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Old 13-03-2012, 09:39 PM
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gregbradley
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Join Date: Feb 2006
Location: Sydney
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I disagree that image is nowhere near good enough. A large amount of distracting coma and tilt.

Martin has the highest standards and I can't see him posting an image with coma that bad. You'd never accept it in a scope.

Some of these short focal length lenses both Nikon and Canon but particularly Canon often get low scores for edge sharpness.It seems to be a difficulty with these super fast lenses. That is not always a big issue for terrestial photographers because they often shoot at F11 to F16 or so or are using for portraits and the edges are often out of focus blur of the background for bokeh effects.

You are using it F4 or F5.6 or so and the lens probably doesn't start to smarten up until F8 and by then you've lost your speed.

The simple 50mm F1.8 may be the better choice as its still fast but it lacks distortion and aberrations and often reviews of any 50mm lens seems to be very good. It must be the sweet spot for lens optics or they are relatively easy to make well compared to other focal lengths. I have both Nikkor and Canon 50mm F1.8 and in my limited use of the Canon 50mm F1.8 they both seem the same to me.
They are also very cheap and around $135.

Greg.
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