03-08-2012, 10:49 AM
[quote name='IanCD' timestamp='1331202060' post='16471']
Re the 'purple fringing' issue, I think the shot taken at f/1.8, with the single wooden post and green wire fence, is showing this: follow the horizontal wire set against a white background along from the post to the right. Here, the fence wire seems to be the same width as the 'fringing' artefact.[/quote]
Good find, but I think this is simply "regular" bokeh fringing. The wire slowly runs out of focus towards the right border. Closer to the wooden post, you can find wire sections that are almost perfectly in focus and show only very small traces of fringing.
However, I've often wondered if the large amount of PF often seen in sample images with fast primes (not only the AF-D 85) is basically only Bokeh fringing, resulting from using the lenses wide open on unsuitable subjects. The DOF with such a fast lens is very thin, any high contrast subject not perfectly in focus will show purple or green fringing. And most real-world subjects usually don't fit well into the focal plane of a fast lens used wide open.
[quote name='IanCD' timestamp='1331202060' post='16471']
Markus: is the 50/1.4G review on D7000 coming soon?
[/quote]
I'll see what I can do. Maybe a few zooms first, maybe some primes. Or a mix of both, depends on my mood <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' /> In any case: next review to be published will be the Sigma 17-70 OS.
Anyone interested in another sneak preview? AF-D 180/2.8 maybe?
-- Markus
Re the 'purple fringing' issue, I think the shot taken at f/1.8, with the single wooden post and green wire fence, is showing this: follow the horizontal wire set against a white background along from the post to the right. Here, the fence wire seems to be the same width as the 'fringing' artefact.[/quote]
Good find, but I think this is simply "regular" bokeh fringing. The wire slowly runs out of focus towards the right border. Closer to the wooden post, you can find wire sections that are almost perfectly in focus and show only very small traces of fringing.
However, I've often wondered if the large amount of PF often seen in sample images with fast primes (not only the AF-D 85) is basically only Bokeh fringing, resulting from using the lenses wide open on unsuitable subjects. The DOF with such a fast lens is very thin, any high contrast subject not perfectly in focus will show purple or green fringing. And most real-world subjects usually don't fit well into the focal plane of a fast lens used wide open.
[quote name='IanCD' timestamp='1331202060' post='16471']
Markus: is the 50/1.4G review on D7000 coming soon?
[/quote]
I'll see what I can do. Maybe a few zooms first, maybe some primes. Or a mix of both, depends on my mood <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' /> In any case: next review to be published will be the Sigma 17-70 OS.Anyone interested in another sneak preview? AF-D 180/2.8 maybe?
-- Markus
Editor
opticallimits.com
opticallimits.com