moiz Posted May 13, 2003 Share Posted May 13, 2003 Just something I was thinking about the other day, wondered if someone could enlighten me. When people talk about bokeh, they talk about the number of diaphram blades in the lens. The more blades, the closer the approximation to a circle and therefore better bokeh. Now, assuming what I said in the previous sentance is correct (tell me if it isn't), does that not mean that you would have the best bokeh when the lens is wide open as there are no blades visible and the opening is a perfect circle, not an approximation to one? Moiz Link to comment Share on other sites More sharing options...
johann_fuller Posted May 13, 2003 Share Posted May 13, 2003 My 50mm F2 summicron has awfull out of focus rendering (Bokeh) wide open. My Hassleblad 150 F4 lens with only 5 aperture blades has very nice out of focus rendering - as do my large format lenses. Link to comment Share on other sites More sharing options...
roger c Posted May 13, 2003 Share Posted May 13, 2003 All other things being equal, yes. However, in practice bokeh is influenced by a lot more than the shape of the iris, such as its position in the lens and how the lens is corrected for various aberrations in front of and behind the point of focus. Iris shape is a secondary consideration. Link to comment Share on other sites More sharing options...
mark_salkowitz Posted May 13, 2003 Share Posted May 13, 2003 Someone please correct me if I am wrong, but I believe that bokeh refers to the out of focus rendition, not the number of blades used to achieve the rendition� Link to comment Share on other sites More sharing options...
Guest Posted May 13, 2003 Share Posted May 13, 2003 The number of blades <I>can</I> be a factor in bokeh, but it isn't the only one. When I shoot my Nikkor 50mm <I>f</I>/1.8 wide open, out-of-focus highlights are circular, but this doesn't make them particularly better than the heptagonal or hexagonal (or whatever) ones at <I>f</I>/2 - though the shape is much less distracting. But Nikkor isn't a byword for good bokeh.<P>People who know more about lenses than I do appear to say good bokeh has to do with <I>un</I>corrected spherical aberration, and Nikkors are quite <i>well </I>corrected. Link to comment Share on other sites More sharing options...
moiz Posted May 13, 2003 Author Share Posted May 13, 2003 You lost me on that last bit Ian. Could you explain a little further? BTW, I love the photo you have uploaded.....is the kid on the right related to Roy Keane at all?? Link to comment Share on other sites More sharing options...
Richard Williams Posted May 13, 2003 Share Posted May 13, 2003 <html> <head> <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"> <title></title> </head> <body> There's a nice comparison of wide open <span style="font-style: italic;">vs</span> slightly stopped down Bokeh (for Nikon) here:<br> <br> <a href="http://www.majid.info/radio/stories/2002/08/25/aTaleOfThreeLenses.html">http://www.majid.info/radio/stories/2002/08/25/aTaleOfThreeLenses.html</a><br> </body> </html> Link to comment Share on other sites More sharing options...
moiz Posted May 13, 2003 Author Share Posted May 13, 2003 Richards link illustrates perfectly what I was talking about. However, I am well aware that, as other have pointed out, the iris is only one consideration with bokeh. Can anyone provide similar examples to Richards showing the effects of the other factors? Link to comment Share on other sites More sharing options...
Guest Posted May 13, 2003 Share Posted May 13, 2003 Thanks, Moiz, but it's <i>not</I> my photo: it appeared by some bizarre software glitch! I've never uploaded any photos because I don't have a scanner. It appears twice on someone else's page, and I'm just waiting to hear from admin/the owner whether I should delete it.<P>Sorry, I was just parroting other people about the uncorrected spherical aberration. It seems to be the consensus among people who know about such things, but as I have little knowledge of optics I can't come to a judgement about whether or not this is plausible. As far as I can remember, uncorrected spherical aberration means that rays from a single source hitting the edges of the lens come to a focal point slightly off the focal point formed by rays striking the centre of the lens. I have no idea how this happens or how it would be remedied. Still, if lenses are more important than the camera, it seems reasonable to try and learn a bit about them in theory just as we try and learn what our lenses do in practice.<P><a href="http://medfmt.8k.com/mf/bokeh.html">This</a> might be a useful link, though.<P>You can see from Richard's link just how bad the bokeh is on my Nikkor. Better wide open than stopped down a bit, but even here the brightness is concentrated on the edge of the circle, not in the middle. The link I gave has a link at the top of the page to something Ken Rockwell has written about bokeh, giving clear examples of bad, neutral and good bokeh. I've read this and followed it. It's about the limit of what I know. The Harold Merklinger articles (if those links still work) are pretty technical and I can't pretend to understand them. Link to comment Share on other sites More sharing options...
douglas k. Posted May 13, 2003 Share Posted May 13, 2003 The 35mm 'Cron 4th version has absolutely lousy bokeh when set wide open. So there's more to it than a round diaphragm. Link to comment Share on other sites More sharing options...
jbq Posted May 13, 2003 Share Posted May 13, 2003 Here's an example of very bad bokeh: http://www.geocities.com/jbqueru/eugenia20030125.html Notice the highlights on the dark green car in the top-right. Link to comment Share on other sites More sharing options...
charles_stobbs2 Posted May 13, 2003 Share Posted May 13, 2003 Even wide open the blades are still defining the opening. If this were not the case the lens mount would be the determining factor. Look through the lens from the rear with the lens wide open and you will see the blades determine the aperature. Link to comment Share on other sites More sharing options...
albert_smith Posted May 13, 2003 Share Posted May 13, 2003 I posted this before, but I have cleaned it up a bit since. I have and use both a Nikon and Leica M system, using both for various things. I have seen over time that there is a difference in the rendition of highlights between both brands at same apertures. I posted some examples at this link:<P> <a href="http://www.photo.net/photodb/presentation.tcl?presentation_id=203105"> Bokeh for Leica 90mm and Nikkor 105mm at less than maximum aperture </a><P> I don't know what the cause of the effect is, but I suspect it is the quantity and shape of the aperture blades. There are more blades on the 90mm lens. Link to comment Share on other sites More sharing options...
jbq Posted May 13, 2003 Share Posted May 13, 2003 Here's a good read: http://www.kenrockwell.com/tech/bokeh.htm Link to comment Share on other sites More sharing options...
tom h. Posted May 13, 2003 Share Posted May 13, 2003 Sorry to be slightly OT here, but I've NEVER seen a photograph where "bokeh" was a noticeable, or valid component. The only time I EVER notice out of focus highlights is when a "mirror" lens is used, giving that weird donut effect. Tom Link to comment Share on other sites More sharing options...
stephen hazelton Posted May 13, 2003 Share Posted May 13, 2003 If aperture shape/ number of blades made that much difference, you'd probably see more waterhouse stops. Link to comment Share on other sites More sharing options...
lee_shively Posted May 13, 2003 Share Posted May 13, 2003 Did you guys ever notice nobody talks about "bokeh" in really good photographs? The only time it comes up is in mediocre photographs. As in, "Yeah, this picture really sucks but it's got nice bokeh." But not, "Yeah, Smith's 'Walk to the Paradise Garden' picture is great but the bokeh kills it." Link to comment Share on other sites More sharing options...
Robin Smith Posted May 13, 2003 Share Posted May 13, 2003 What a tremendous fuss. Specular highlight rendering is only a part of what bokeh is. It is rarely if ever an issue as far as I am concerned. There is always the odd shot with too prominent back ground specks rendered weirdly even with lenses of renowned good bokeh. Most recently I noticed this with my 150mm Sonnar for the Hasselblad where the background was spruce leaves, but my feeling is that any other lens would have produced an equally weird result, just different. I am positively amazed how sensitive people are about this so-difficult-to-quantify issue. Robin Smith Link to comment Share on other sites More sharing options...
andrew_lee2 Posted May 13, 2003 Share Posted May 13, 2003 It may not be a main component of a picture, no, and discussion of anything ad nauseam can get tiresome, but I think boke is certainly a valid component - however small, latent, or subjective - that can add or detract from a picture's overall quality or appeal. For me there's just a certain je ne sais pas about good boke that, while not apparent to the casual or undiscerning viewer, can make a good picture that much better. Link to comment Share on other sites More sharing options...
marco_hidalgo Posted May 13, 2003 Share Posted May 13, 2003 Moiz: with the lenses I have used, it doesn't matter too much how many blades they have and how good is their Bokeh, The Hasselblad lenses have 5 blades and get very nice out of focus gradations. Some Leica glass do have great Bokeh too. but a Schneider Symmar 210/5.6 LF lens has a lousy Bokeh or out of focus gradation and it uses a compur shutter with to many blades to count them. So the number of blades really doesn't count if the lens design is not good for Bokeh. Maybe the number of blades will help with a lens designed for good Bokeh such as portarit lenses, I have a Russian Jupiter 85/2 lens with about 16 blades and has very nice Bokeh. Link to comment Share on other sites More sharing options...
paulstenquist Posted May 13, 2003 Share Posted May 13, 2003 My personal definition of "bokeh" includes all elements that are extremely out of focus, not just specular highlights. The way a lens records these elements is important and can be a very significant part of a composition. However, it is much more important with extremely long lonses, since out of focus elements are a part of almost every composition. The bird I've attached here was shot with the SMC Pentax 400/5.6. By my personal definition, this lens has the best bokeh of all the long lenses I've used.<div></div> Link to comment Share on other sites More sharing options...
doug herr Posted May 13, 2003 Share Posted May 13, 2003 Paul, your thrush photo doesn't show what I consider 'good' bokeh. I see a lot of double-line effect, a.k.a. ni-sen bokeh. Branches or other such lines in the foreground or background can be a bokeh nightmare. IMHO the 400mm f/6.8 shows excellent bokeh:<P> <CENTER> <IMG SRC="http://www.wildlightphoto.com/birds/gbhe.jpg"> <BR> <B>Great Blue Heron</B><BR> <I>Leicaflex SL, 400mm f/6.8 Telyt</I> <P> </CENTER> Link to comment Share on other sites More sharing options...
kelly_flanigan1 Posted May 13, 2003 Share Posted May 13, 2003 Out off focus of a 50 year old 105mm F2.5 LTM Nikkor; between F2.8 and F4; 1/250 sec; M3.........Best focus is at players left hand; about 4 inches up the stick. Player was 45 degrees to the 1/2" plexiglass stratched window; and is blurred somewhat.<BR><IMG SRC=http://www.ezshots.com/members/tripods/images/tripods-406.jpg> Link to comment Share on other sites More sharing options...
kelly_flanigan1 Posted May 13, 2003 Share Posted May 13, 2003 <IMG SRC=http://www.ezshots.com/members/tripods/images/tripods-213.jpg> Link to comment Share on other sites More sharing options...
kelly_flanigan1 Posted May 13, 2003 Share Posted May 13, 2003 <IMG SRC=http://www.ezshots.com/members/tripods/images/tripods-380.jpg><BR><BR><IMG SRC=http://www.ezshots.com/members/tripods/images/tripods-381.jpg> Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now