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Best bokeh for a givin subject


denisbergeron

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I was thinking which lens (Canon EF) will give me the best bokeh.<p>

 

I look at the offering and use <a

href="http://ca.geocities.com/lokejul/jlcalc.htm">the famous lens calculator

from Julian Loke</a>. <p>

 

I end with <a href="http://denis.b.bergeron.googlepages.com/lensesbokeh"> this

table </a><p>

 

So if my understanding are right, the best lens for the best bokeh with the less

DOF is the 85mm f.12. <p>

 

For the same field of view, so the same subject, I got less DOF from this lens

than any other lens of Canon including the famous 200mm f1.8 !<p>

 

What did you think about that ?

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Read about bokeh here:

 

http://www.vanwalree.com/optics/bokeh.html

 

I think the 200 f/1.8 is probably the ultimate king in bokeh quality, although the 85 f/1.2 can run it close, as can the 135 f/2.

 

Incidentally, the size of the blur patch is a non linear function of the OOF object distance subject distance, aperture and pupil magnification ratio of the lens. The formula can be found here:

 

http://www.vanwalree.com/optics/dofderivation.html#eq4

 

A consequence is that when reproducing a subject at a given magnification with different focal length lenses, you will find that a longer lens typically gives greater blur at a narrower aperture than a shorter lens beyond a certain crossover difference in distance between the subject and the OOF subject. This works both for foreground and background OOF subjects. That means you might do better with the longer lens when trying to blur out a wire mesh fence at a zoo if you can't get close to it, for example. Experiment with van Walree's very comprehensive DoF calculator that includes point of interest blur calculations to see the effects:

 

http://www.vanwalree.com/optics/vwdof.html

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If its any help I have taken grab shots with both the 200 1.8 and the 135 2.0. My daughter was taken with the 200 and one on my neighbours with the 135, both were fantastic. The 200 had staggering bokeh, but is expensive and difficult to get hold of, in reality depending of course on your use, I think the 135 is outstanding and a great portrait lens in addition to its other potential uses.<div>00IF3L-32683384.jpg.d7097c6ab4c39ae0e0bbff5ac16c1285.jpg</div>
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yea,, bokeh and DOF are not the same. so you can't use a DOF calculator to decide which lens has the shallowest DOF and say that is the one with teh best bokeh.

 

there is though a correlation (make sure to look up that word) between lenses with good bokeh and capability of shallow DOF. but that is becuase they are usually high quality lenses designed for such things.

 

a couple of things in a lens to look for for 'possible' good bokeh,, is the number of aperture blades; the more the better because point light sources will be shaped like your aperture, or a star with the same number of points as you have blades. a sample image to see if the out of focus parts graduate together nicely and don't look like blobs.

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"It is quite possible to have shallow DOF and bad bokeh."

 

Good point that deserves to be repeated. What gives that elusive quality to the out of

focus areas is a mystery, but in my experience it tends to be in inverse relation to the

complexity of the lens design. Classic Hasselblad lenses with just four or five elements

often manage to rise above the impediment of their pentagonal shutter blades, conversely

you'll often see shots from complex zooms, where the background looks wirey and

intrusive even though it's rendered well out of focus.

 

I see this regularly when I compare the results from my 70-200 2.8L IS (great lens but

poor bokeh despite a very narrow depth of field) versus my 35 1.4L (exquisite bokeh but a

deeper depth of field). The best bokeh I've seen from any Canon lens is from the 135mm

2.0L.

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  • 4 years later...

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