blurring background

[tinkabella627]

Can someone tell me how you can blur the background and only focus on the item you are taking a picture of? TIA

 

[jfinke]

It is called bokeh. You generally have to use a large aperture (smaller number such as f2.8 or larger, eg. 1.8, 1.4, 1.2). However, this also results in a smaller Depth of Field (dof) for focusing. So, you also need to make sure that your focus is spot on.

http://en.wikipedia.org/wiki/Bokeh
http://www.dofmaster.com/dofjs.html

 

[MarkBarbieri]

Simple question...complicated answer. What you are talking about is "depth of field." In particular, you are looking for shallow (also known as narrow) depth of field. That is when the range of subject matter that is in focus is narrow and the rest is out of focus.

Several factors help you get shallow depth of field. They include sensor size, aperture size, focal length, and subject distance. I'll try to de-geek those terms as I explain them.

The first term, sensor size, refers to the size of a digital camera's sensor. That's the part that sees the scene and translates it into a digital image. On a film camera, it's the piece of film. Point and shoot camera's have very small sensors. Small sensors have lots of depth of field, so it is hard to get a picture with the subject in focus and everything else blurry with a point and shoot digital camera. DSLR camera's have much larger sensors and so it is much easier to get that affect with a DSLR.

The next factor is the aperture size. The aperture is the hole in the lens that let's light in. It adjusts in size based on how much light is available (the less light, the wider it opens), how long the shutter is open (the longer the shutter is open, the smaller the aperture is), and how sensitive the camera is (that's the ISO setting). To get the shallowest depth of field, you want the widest possible aperture. Most cameras have a mode that let's you adjust the aperture while the camera automatically sets everything else. The mode is typically labeled "Av". Go to that mode and make your aperture as wide as possible. Confusingly, smaller aperture (also called f/stop) numbers mean a wider opening. So you want to set the aperture to the smallest number possible.

The focal length is the amount of zoom. The more you zoom in, the less depth-of-field you'll have. So if you want just the subject in focus, zoom in as close as possible and then back up.

Finally, how close your subject is to the things behind it has a big effect. If your subject is leaning up against a wall, it is very hard to have them in focus and the wall blurry. On the other hand, if they move forward a long way and you stay focused on them, the wall will be blurrier.

So to summarize, set your camera to the widest aperture (smallest f/stop number), use your longest zoom, and move your subject as far from the background as possible. If you really want shallow DOF, consider getting a DSLR. If you really, really want shallow DOF, get a DSLR with a larger sensor (also called "full frame") and a lens with a really big aperture.

 

[tinkabella627]

oh my! I didn't realize it was such a complicated answer! THank you for taking the time to answer me!

 

[bob100]

also you can blur the background with Photoshop using lens blur filter, gradient mask layers, etc.

 

[Experiment_626]

Yeah, it's depth of field. Learning to control DoF and get what you want is one of the marks of a good photographer -- or at least of an experienced one.

"Bokeh," technically speaking, refers to the aesthetic quality of the blurred elements of the image -- the shape of highlight areas and so on. To a great degree, it is subjective, whereas depth of field is objective. You can have the depth of field you want and still have what might be considered poor bokeh. Bokeh is affected by the way the lens in made, to oversimplify matters greatly.

SSB

 

[seashoreCM]

Most cameras have a smaller maximum aperture when you zoom. So while you make the depth of field shallower by zooming, you deepen the depth of field (counteracting your efforts) by being forced to the smaller aperture.

All told, depending on the settings, notably the aperture, available on your camera, you may or may not get the background blurred to your liking.

If you have manual focusing, you can try focusing for an imaginary object closer than your subject to see if/when the subject remains in acceptable focus while the background gets more blurry.

Digital camera hints: http://www.cockam.com/digicam.htm

 

[wenrob]

also you can blur the background with Photoshop using lens blur filter, gradient mask layers, etc.

Yeah but you have to be pretty good at it or it looks really, really bad. With true bokeh your subject is sharp and fades off, with photoshop your subject is sharply outlined and usually people go overboard with the blur. With as precise as you have to be if you're inexperienced in photo editing the time and effort aren't worth it when you can get it in camera.

 

[jfinke]

I actually went around the neighborhood the other night with my nifty fifty ($80 lens) for this sole purpose. I got nice and close to my subject matter on these, so my DOF was pretty narrow. The further away you are from your subject, the larger your DOF will be and the less blurring you will get.

I didn't PP this one at all. I got lucky with the light.

I think I bumped up the saturation on this a bit. It is interesting because a dandelion is a bit blurry in the first place.

I know I played with the tone curve a bit on this one and added a bit of vignetting.

This is all pretty doable with $400-$500 worth of equipment. Probably could go even cheaper.

On this one, you can almost trace the edges of the DOF vertically along the bush.

 

[Chikabowa]

To add just a touch on the great information provided... focal length has a ton to do with how much bokeh you'll get in your photo. When you get into higher-end lenses (those will fixed aperture settings) you'll find that you are able to shoot wide open when extended all the way out and it creates some beautiful creamy bokeh.

Both of these shots were taken in New Mexico last week - just some flowers I found on the side of the road.

(Very little post processing - Just a little color pop and sharpen/resize for web)

D3, 70-200mm f2.8 lens
ISO 200, f2.8, 200mm, 1/3200

D3, 70-200mm f2.8 lens
ISO 200, f2.8, 180mm, 1/3200

 

[JR6ooo4]

It is really easy when you have about a thousand feet from the subject to the background.

Mikeeee

 

[wenrob]

Here's an example of being zoomed out and the subject set away from the back round. My EXIF is on my EHD and I'm too lazy to go get it but I know I was stopped down a little bit maybe f/3.5-4 on the Tamron 28-75mm f/2.8.

 

[MHolleman]

I have a p&s camera, and to get this image all I did was stand a few feet back off the subject, and zoom into the image as much as I could without losing the focus. This is the non pro way of explaining it for me at least. Hope this helps.

 

[brandydandy]

Here is my first attempt. I just got the camera on Thursday... it is a Nikon D200. I am just snapping like crazy reading and watching. Thanks for the info