I shoot a SONY a900 with very pleasing results with all of my lenses except one. When I use my Minolta 200mm F4 macro I get a very unpleasant bokeh that consists of a pallet of squares instead of a desireable smooth result. Any ideas?
Tim
Concrete, WA
Posted by Ramamohan Pai on October 19, 2010 at 1:59 PM
Posted by Bruce King on October 20, 2010 at 3:09 PM
Hey Timothy, how far is the bg from the subject in your example? At the risk of stating the obvious the more distance the smoother the bokeh and some lenses are bertter than others. Also consistant tones, highlights and shadows in the bg will promote a smoother bokeh.
Posted by Buck Ward on October 20, 2010 at 3:31 PM
The bokeh here doesn't look great, but I don't see the 'pallet of squares' you describe. One of the things that can affect the bokeh of a lens is the number and shape of the aperture blades.
The best way to compare the performance of different lenses is to make identical photos with exactly the same settings. If you have other lenses with the same focal length, set up a shot and just change lenses and see how they differ. It could be that the bokeh of your macro lens appears poor only when you are near its minimum focusing distance with the background fairly near the subject. If that is the case you may not be aple to duplicate that shot with a non-macro lens, and it would be the minimum focusing distance of the non-macro lens that would control the set-up.
The bottom line is: if the performance of the lens is unsatisfactory, replace it with one that is satisfactory.
The backround of the subject, in this instance, is quite close. Funny, I've been using this lens for years (Bill Fach uses one too) and only recently have I noticed this adverse effect.
Posted by David Bostedo on October 21, 2010 at 9:17 AM
Timothy, I really don't see any particular issue here. Everything looks pretty smooth. Is this a 100% crop.
David, it is a 100% crop. I do notice, now, that the example posted does look smoothed out. How/why can that be? My initial RAW images, when processed show the bad bokeh. Could it be the definition created by the extremely large file size (24.6 mp) is showing it? Then. would the file be smoothed out when I drastically reduce it for web publication?
Tim
Posted by David Bostedo on October 21, 2010 at 12:17 PM
Then. would the file be smoothed out when I drastically reduce it for web publication?
Tim - I thinking were mixing definitions of "100% crop". What I'm asking is, is this the same view you get at 100% view in PS or another image editor? I.e. is this 720 pixels of the original full image? (That's the typical meaning of 100% crop as I'm used to it.)
If not - if this is the full image and you're down-sizing for the web, you can definitely get a smoothed out appearance, because multiple pixels in the original image are used/averaged to create a single pixel in the final image.
If you could post a crop from a 100% view, that may illustrate things better.
Posted by Dan Borzynski on October 21, 2010 at 8:06 PM
Discussion
10 repliesTim
Concrete, WA
The best way to compare the performance of different lenses is to make identical photos with exactly the same settings. If you have other lenses with the same focal length, set up a shot and just change lenses and see how they differ. It could be that the bokeh of your macro lens appears poor only when you are near its minimum focusing distance with the background fairly near the subject. If that is the case you may not be aple to duplicate that shot with a non-macro lens, and it would be the minimum focusing distance of the non-macro lens that would control the set-up.
The bottom line is: if the performance of the lens is unsatisfactory, replace it with one that is satisfactory.
Tim
Tim - I thinking were mixing definitions of "100% crop". What I'm asking is, is this the same view you get at 100% view in PS or another image editor? I.e. is this 720 pixels of the original full image? (That's the typical meaning of 100% crop as I'm used to it.)
If not - if this is the full image and you're down-sizing for the web, you can definitely get a smoothed out appearance, because multiple pixels in the original image are used/averaged to create a single pixel in the final image.
If you could post a crop from a 100% view, that may illustrate things better.