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I used 50mm @ f1.8 to take a portrait snap. Light source (fancy lights) was near to subject (~3-5ft). I couldn't get bokeh with big circles with the subject there, but without the subject I could get a snap with big circles.

Is it possible to get bokeh like this with a subject in thr foreground with a 50mm lens or do I need a long lens to blur background?

This was the pic which I took (with the subject cropped out). You can see the bokeh circles I want, but I'm disappointed by how small they are. I was hoping for a more dramatic effect, which I could get when the subject wasn't there.

enter image description here

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    show the image with the subject in it, and write down the camera settings in both pictures, so we can see what's up. – Michael Nielsen Dec 28 '12 at 8:42
  • How close were YOU to the subject? – Digital Lightcraft Dec 28 '12 at 9:26
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  • @mattdm pic in question is with subject(cropped). Answer below and the link above are what I needed. I wanted a more prominent circle. – GoodSp33d Dec 28 '12 at 13:05
  • So, the above is what you got, but you wanted even more? I'm just trying to be clear here, because at this scale it looks about the same as in Matt Grum's answer below. – mattdm Dec 28 '12 at 13:09
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It's perfectly possible to get the effect you are after with Here's a shot I produced for another question to show the depth of field possibilities of a 50 f/1.8 on APS-C:

It was shot indoors using standard fairy lights for the background. The subject (which stands about 4 foot / 1.2 meters tall) was chosen to give a good approximate for tight headshot. The background was about 8 feet / 2.5 meters from the subject.

Larger circles in the background would be possible if the lights were further away but that would require a large room or an outdoor shot.

  • Ahh that was what I was looking for. In my case there were too many lights closer which ruined the bokeh(circles) and it was closer to subject as well. – GoodSp33d Dec 28 '12 at 10:37
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    @2-Stroker subject to camera distance is critical too - if you back the camera away from the subject the circles will shrink rapidly - even though they are further away. Close focus distances provide much shallower depth of field. – Matt Grum Dec 28 '12 at 10:42
  • Yep got it, point taken. – GoodSp33d Dec 28 '12 at 10:45
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    @2-Stroker Check this website to calculate DOF, it would make it super easy for your to get what you want: Online Depth of Field Calculator – Omne Dec 28 '12 at 19:07
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There are a couple of things that could be the reason.

  • The distance between the subject and the lights needs to be more. Further the distance, more out of focus the lights will be.
  • The photo without the subject that you have, might not have the same focal length as the one with the subject. (It may be shorter)
  • The aperture needs to be wide open to get a very shallow DOF. This also might get you better results.
  • Does it depend on the light source as well ? Because the lights I used were pretty much tiny(fancy/christmas lights) – GoodSp33d Dec 28 '12 at 9:46
  • @2-Stroker Not really. As long as it shows up on the photo when in focus, it should show up when out of focus too. But if they are too small or if the background is white/bright, they may not be noticeable. – Vaishak Suresh Dec 28 '12 at 10:16
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I guess the subject is too close to the background, that's why you didn't get that type of bokeh with the lights. Try increasing the distance from your subject to the background and use the lowest aperture possible (f1.8 with your lens). Keep in mind that the further the lights from the subject, the smaller it will appear. So you might not be able to reproduce that light bokeh that big. But, you'll get nice bokeh'd lights though. Happy holidays!

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As asked "How to take a portrait with dramatic bokeh circles when the subject is close to the lights?" the answer is: be even closer.

Basically decide how large you want your bokeh circles to be. Draw one around one of the pertinent lights in the 3D scene. Now from this circle you put a cone with its tip in your focused object and opening up again towards your camera. The diameter to which it has opened up again when reaching your camera is your "entrance pupil", focal length divided by aperture. Or effective focal length divided by aperture and crop factor.

Looking at your example image, I see about 20cm of bokeh circle. You used 50mm/1.8 = 28mm of entrance pupil. The distance between lights and portrait was 3 to 5 ft, and to get from 28mm pupil to 20cm bokeh circle, you'll need to be about 7 times closer to the subject than the subject is to the lights. So try for a subject distance below 1 foot.

I might be overestimating the bokeh diameter, but you see the principal problem: you need to get as close as feasible.

Now the funny thing is that you can do better with a longer focal length. While you need exactly the same aperture number for getting the same bokeh diameter in the scene when getting the subject at equal size in the frame, being at a larger distance means that the lights (and thus their bokeh circles) don't shrink as much due to perspective in comparison with the subject as they would on the short focal length.

It's just that, well, with a 50mm/1.8 lens you'll be hard put to find a lens with longer focal length that will retain aperture number.

So the only realistic option is to rearrange the scene. Put some more significant distance between lights and subject.

Or, well, mess with the blur in post-processing.

Or get a large format camera where you can achieve that kind of subject framing at a longer focal length.

  • Or get a faster lens – lijat Dec 8 at 15:05
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your subject should be in front of the light and he/she is 3 to 5 ft from the light. It should be nice and bokeh will appear.

  • Yes subject was in front of light source which was 3~5 ft behind the subject, but still bokeh was not that good as without subject like the one above. – GoodSp33d Dec 28 '12 at 7:41
  • Where do those numbers come from? – Imre Dec 28 '12 at 9:44
  • @Imre Nos are approximate values. – GoodSp33d Dec 28 '12 at 9:45

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