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How can I get dramatic shallow DOF with a kit lens?

Is it possible to generate shallow DOF with a "kit" lens, and how?

In my case, I have the Nikon D7000 with the 18-105mm f/3.5-/f5.6.

I am exploring my new camera and learning photography as I go. I have a few things in my head i want to learn how to do early and one of them is take images where the background is blurry behind a subject, so to make super nice portraits.

So far, all my initial shots have everything in focus. How do I get a shallow DOF effect? Or can I even do it with the kit lens?

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marked as duplicate by chills42 Mar 4 '11 at 14:33

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

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See this very similar question (but ignore the accepted answer ;) photo.stackexchange.com/questions/5493/… –  Matt Grum Dec 22 '10 at 22:01

4 Answers 4

up vote 13 down vote accepted

I gave pretty much the same answer before, but here it is again for completeness. To minimise DOF and get the blurred background effect you should:

  • Use as long a focal length as possible.

  • Use a wide aperture low f/ number (but don't zoom out increase the f/ number as the actual lens opening gets no bigger)

  • Use as close a focussing distance as possible (but don't zoom out to get closer). Depth of field diminshes very quickly with focus distance, so much so that it becomes a major problem with macro photography getting a non blurred background (or subject!)

  • Compose so that the background is as far away as possible. The further away objects are from the focussing distance the blurrier they will be.

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2  
Zooming out to get closer is the best way to limit DoF (staying within a reasonable range to avoid perspective distortion) -- and in this case it also has the side benefit of allowing a larger maximum aperture. The key is to keep the framing of the main subject the same. Long lenses don't give shallower DoF as much as they give greater enlargement. –  user2719 Dec 23 '10 at 2:07
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@stan I'm afraid that's not the case. Zoom to 18mm f/3.5 and shoot a subject 18 feet away and your depth of field will be infinite (everything behind the subject will be in focus). Back up to 105 feet and zoom to 105mm f/5.6 to get the subject the same size and your DOF will be 77 ft total, and everything 50 behind will be blurred. –  Matt Grum Dec 23 '10 at 13:15
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I think what Stan is staying is correct...from a "framing/composition" perspective. Granted, the actual physical size of DOF can be an interesting technical discussion, but that isn't really the point of the question or the answers that should be provided. The point is to get the thinnest possible DOF for a particular framing of a subject, and what Stan has stated is correct. Using a wide angle lens with a wide aperture at a very close distance will produce the thinnest (most limited) DOF possible for a particular subject framing. –  jrista Dec 28 '10 at 21:19
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@jrista The statement "Zooming out to get closer is the best way to limit DoF" is not universally true there are cases when you will get a larger DOF so I can't agree that it is the best way. It's true you mostly gain only magnification with a long lens however there is a point at which DOF increases when you zoom out to maintain subject size (I assume this is what you mean by "same framing"). At the end of the day the questioner is trying to get subject isolation. Telephotos are the best way to achieve this. When was the last time you saw a portrait with a 400mm that had a sharp background? –  Matt Grum Dec 29 '10 at 10:45

What you are after is a lack of DoF. Get close (as close as you can without making the subject look weird), use aperture-priority or manual exposure and keep the lens as wide-open as possible (clearly, you're somewhat limited here by the maximum aperture of your lens) and try to keep some distance between your subject and the background.

The field depth at any given aperture increases with the distance to the subject, so getting as close as you can without creating an unnatural perspective is key.

EDIT: I should add here that the maximum aperture of your lens changes with the focal length as well -- it's significantly wider at the wide-angle end of its range than it is at the telephoto end. That adds to the "get closer" advice.

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this is contrary to the logic (at least to me) of peole using a focal length of 100+ to zoom in on people and get a nice DOF effect. if i understand you correct i need to zoom out and get in close to my subject with max perture? ... just saw your edit, so im correct in my asumption here then... or am i? –  kacalapy Dec 22 '10 at 20:45
    
Exactly. Your camera has a smaller-than-full-frame sensor, so something in the 50-55mm range on the zoom would be the "portrait" part of the spectrum (compares to the 70-90mm range on a full-frame 35mm), and you can probable move in to the 35-40mm range for most people without making them appear "beaky". That assumes fairly tight framing, of course (a "headshot" or half-length portrait). To get a narrower DoF from a distance, you really need a lens that's quite a bit faster than the one you have. –  user2719 Dec 22 '10 at 20:57
    
kacalpy is correct in that you will get shallower depth of field at the long end of the zoom (as the f-stop x focal length is larger). You still want to get as close as possible, but don't zoom out to do so... –  Matt Grum Dec 22 '10 at 21:56
    
I don't know how many different ways there are to say this: DoF is a function of distance and aperture, not focal length. The only reason why there is apparently shallower DoF at longer focal lengths is the magnification factor of the finished image. Using Tech Pan (which out-resolves just about any lens so you can enlarge to the same final subject size), you can prove it to yourself if you wish. With approximately the same framing (obviously the relationships will be different), a shorter lens used closer at the same aperture will provide a shallower DoF. –  user2719 Dec 22 '10 at 22:33
    
@Stan, this page seems to disagree with you: dofmaster.com/dofjs.html, e.g. it shows DOF of 6.61ft at 55mm, f/16, 10ft from subject, but DOF of 1.63ft at 105mm, f/16, 10ft from the subject. (Ah, those two settings will produce differently framed photos..) –  Alex Black Dec 23 '10 at 0:46

Yes, shoot at 100mm f/5.6, get close to your subject, ensure you have nothing behind your subject!

http://www.dofmaster.com/dofjs.html

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If you want a shallow depth of field, you can increase the aperture width. The easiest way to do this is to switch to aperture priority mode (A on the dial) and set the largest available aperture (smallest f-number).

Like others have said, there are other factors as well, such as subject distance and focal length, but often you have less control over those, since they affect the framing of the shot. If you are able, you will get the shallowest depth of field by increasing focal length and aperture size, and decreasing the distance to your subject.

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see comment below, im confused –  kacalapy Dec 22 '10 at 20:46
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Wider aperture does get you a shallow depth of field, but with this lens you'll have a shallower depth of field at 100mm @ f/5.6 than at 18mm @ f/3.5 –  Alex Black Dec 22 '10 at 21:36

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