# Blur background with kit lens



## robbyrob (Feb 20, 2012)

Ok I am a noob at photography and never realized the thinking that went into taking some of the awesome pictures I have seen here. I see most portraits have blurred background. I have been reading my manual and specs on most pic in flickr and see that most pics were shot with a low aperture of f1.2 to 2.4. Reading another thread on here of prime lenses I saw a link to a page which showed a picture shot by a cannon at f3.5 which had the background blurred. This leads me to beleive I can get the same effect with my kit lens. 

Ive tried to shot in A mode at f3.5 but it doesn't seem to come out with background blurred. any tips you guys can give me or something I could be missing. I try to focus on one item of person but photo comes out all in focus. I was thinking maybe changing my focus to single focus and maybe that would do the trick.

Thanks

Rob

Sony A390 with kit lens


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## Mach0 (Feb 20, 2012)

http://www.cambridgeincolour.com/tutorials/depth-of-field.htm


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## o hey tyler (Feb 20, 2012)

robbyrob said:


> Ok I am a noob at photography and never realized the thinking that went into taking some of the awesome pictures I have seen here. I see most portraits have blurred background. I have been reading my manual and specs on most pic in flickr and see that most pics were shot with a low aperture of f1.2 to 2.4. Reading another thread on here of prime lenses I saw a link to a page which showed a picture shot by a cannon at f3.5 which had the background blurred. This leads me to beleive I can get the same effect with my kit lens.
> 
> Ive tried to shot in A mode at f3.5 but it doesn't seem to come out with background blurred. any tips you guys can give me or something I could be missing. I try to focus on one item of person but photo comes out all in focus. I was thinking maybe changing my focus to single focus and maybe that would do the trick.
> 
> ...



It may have been this photo that you saw, I might have posted it in a prime lens thread because I am huge fan of prime lenses. 







I shot this at f/3.5, but I did so with an 85mm focal length on a full frame camera, which gives me more reduced DoF than on an APS-C camera w/ the same settings, focal length, and subject framing. 

The longer your focal length, the shorter the DoF at f/3.5... So for example, if you're shooting at 18mm @ f/3.5 your DoF is going to be 1.48 meters. If you're shooting at 85mm @ f/3.5 your DoF will be .05 meters. 

As you can see, there's a drastic difference that focal length will make at a constant aperture. So the least DoF you can get with your current setup is 55mm on your kit lens at f/5.6 which would be .15 meters (without knowing the close focus distance of the lens).


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## Josh66 (Feb 20, 2012)

Just make sure the background is far from the subject (and you are close) and it should be doable.


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## robbyrob (Feb 21, 2012)

thanks you all for your help with this.. *Mach0 *and *o hey tyler* thanks for the technical aspect. It helped me learn and understand DOF in relation to the subject and lens. *http://www.thephotoforum.com/forum/members/22540.htmlO|||||||O* thanks for the layman's terms. Sometimes I need to hear the "for dummies" version to understand the technical. in all I took this picture which i think put what all you said into perspective. I wasn't worried about composition or didn't even do any post production. That's a whole other war going on in my head. Just trying to do it one technique at a time and actually have fun taking pictures. Well here the pic I took which had the effect I wanted and didn't even need to get another lens to do it..

thanks guys


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## Crollo (Feb 24, 2012)

That looks pretty good. Just get a farther background and stick a human face in the middle [or wherever fits compositionally] and you're golden.


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## rickztahone (Mar 1, 2012)

Just so that you know, the technical term is bokeh. As you noticed, the LARGER the aperture, the better the bokeh. As o hey tyler explained, this has to do with DOF (depth of field). The closer the subject is to the lens the easier it is to get bokeh but a lot of it depends on the lens as well. 

The following photograph depicts bokeh at f4. The lens has a 2.8 potential but you can see that the bokeh is still there. some lens just have a harder time with the DOF.  



Griffith Plant by rickztahone, on Flickr


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## MTVision (Mar 1, 2012)

rickztahone said:
			
		

> Just so that you know, the technical term is bokeh. As you noticed, the smaller the aperture, the better the bokeh. As o hey tyler explained, this has to do with DOF (depth of field). The closer the subject is to the lens the easier it is to get bokeh but a lot of it depends on the lens as well.
> 
> The following photograph depicts bokeh at f4. The lens has a 2.8 potential but you can see that the bokeh is still there. some lens just have a harder time with the DOF.
> http://www.flickr.com/photos/rickztahone/6879527139/
> Griffith Plant by rickztahone, on Flickr



You get a shallow depth of field from large apertures not small.


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## rickztahone (Mar 1, 2012)

MTVision said:


> rickztahone said:
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lol, yeah, sry that's what i meant. It still confuses me at times. 

OP, LARGER aperture's for bokeh

(FIXED)


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## DiskoJoe (Mar 1, 2012)

Go get you a Minolta 50mm f1.7

They are pretty cheap and give you almost a full range of aperture.


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## rickztahone (Mar 1, 2012)

also, Rob, what specific lens are you shooting with?


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## rickztahone (Mar 1, 2012)

DiskoJoe said:


> Go get you a Minolta 50mm f1.7
> 
> They are pretty cheap and give you almost a full range of aperture.



This. 

I was actually going to get the 50 1.7 but i think i might go with the Sigma 50 1.4 instead. But i have heard nothing but good things about the 50 1.7


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## DiskoJoe (Mar 1, 2012)

rickztahone said:


> MTVision said:
> 
> 
> > rickztahone said:
> ...



Bokeh refers to the quality of the blur. The large aperture makes it blurrier not better. Things like more aperture blades and better quality glass make better bokeh.


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