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05-18-2014, 12:16 AM   #1
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Are these bokeh lights ok?

This shot was taken wide open at f2.8 @2000th of a sec with the da*200. My understanding is that the lights are shaped by the aperture so if the lens was wide open the lights should be circular in shape in the crop shown. I am wondering if the aperture had not fully opened when the shutter operated.
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05-18-2014, 12:24 PM   #2
Ole
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Looks to me as if the spots are drops of water hit by sunlight rather than out-of-focus bokeh highlights (the latter one would expect to be parfectly circular as you say).
05-18-2014, 08:48 PM   #3
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Thanks. Seems like a good explanation. I wiil look through the other photos I took to check.
05-19-2014, 10:34 AM   #4
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I agree with Ole, those don't look like normal out-of-focus highlights. However, it should be noted that these highlights will only be perfectly circular when they're fairly close to the center of the image- the further from the center axis you get, the more mis-shapen they will become. This is a shot of Christmas lights I took with my 200/2.5 de-focused completely (which exaggerates the size of the highlight) note the differing shapes of the two on the edges and the one on the bottom.



05-19-2014, 07:16 PM   #5
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QuoteOriginally posted by clawhammer Quote
I agree with Ole, those don't look like normal out-of-focus highlights. However, it should be noted that these highlights will only be perfectly circular when they're fairly close to the center of the image- the further from the center axis you get, the more mis-shapen they will become. This is a shot of Christmas lights I took with my 200/2.5 de-focused completely (which exaggerates the size of the highlight) note the differing shapes of the two on the edges and the one on the bottom.
You are correct as shown in the photo below the bokeh lights are cirlcles in the center and become compressed, for want of a better word, as they get towards the outer edges.

I think the mistake I have made in my original photo at the beach is not taking into account the reflective elements in the background. As Ole pointed out the sand and the water are uneven reflective surfaces and refract the light in such a way that the lens struggles to form the reflected light into circles.

Not being technically minded this is just about the best explanation I can give. I am sure there are some on this board that could explain this much better than I.




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