Knowledge You Can Build On — Est. 1998
OT: Question for you photo experts...
Peter Teubel
>Please forgive the very ignorant (and somewhat OT) question, but how does one take pics like this? The object is in focus yet the background is out of focus. I've always wanted to learn to do this but I don't even know what the terminology is called. My apologies to Rick Allen from whom I blanently stole the pic from his Irene Gafert demo page because it caught my eye and is EXACTLY what I want to figure out how to do.
Darn! Where'd the pic go?
Peter Teubel
>
Macro lens- Digital's sometimes uses flower icon
steve antonucci
>Macro lense will close focus, which limits the depth of field. DOF is measured "by infocus objects", and with the macro lense, DOF is <1-2", which softens the focus outside that range. The easiest way to achieve this is to have the background be "way back" from your subject.
Steve
Re: OT: Question for you photo experts...
Tom In Red Deer
>Hi Peter,
I believe it is called depth of field control or depth of focus control. It is accomplished by using a small aperature on the camera. Unless you have a camera that has manual shutter/aperature controls you likely won't be able to do it.
On the old lenses there was a depth of field scale that would tell you what distance would be in focus at a given aperature setting. With a bit of practice it was a usefull tool.
You could try on an auto camera having your subject as close as possible to the camera and still focus, then, have the background farther away.
I'm sure someone else can explain it better.
Tom in Red Deer
Re: OT: Question for you photo experts...
mainebowlman
>Peter, the more you close down the lens aperture (opening) the more things in front of and behind your primary focus will also be in focus (depth-of-field). Inversely, the larger your lens aperture the less on either side of your subject will be in focus. Also the closer you are to the primary focus, the more the "out-of-focus" is emphasized.
If you can manually control the lens opening (e.g. f4/ f8/ f16) choose the lowest number, get close to your subject and have some distance behind it. That will help produce that effect you're looking for.
If you just have general settings on the camera, choose "portrait", "flower" or the corresponding icon.
Jack
Re: OT: Question for you photo experts...
Barry Turner
>Actually, Tom, for a shot like this you need less depth-of-field, not more. With a small lens opening like F16 or F22 you get more depth of field. With a large lens opening like F1.8, you have less depth-of-field..........and it's much easier to focus on the object and throw the background out-of-focus. So, try opening that lens up as far as it will go and set the shutter speed accordingly for the right exposure.
Re: OT: Question for you photo experts...
john Lucas
>Peter
That shot may have also been done in telephoto mode or Zoomed in a lot. That coupled with a wide aperture as mentioned before will give you limited depth of field. If your camera has aperture priority which means you can control the aperture in Automatic mode you may be able to select a wide open aperture such as 2.8 or 4 or whatever your camera will let you do.
Re: OT: Question for you photo experts...
John K Jordan
>Having the background out of focus is a great way to and "focus" attention on the subject and separate it from the background clutter. This type of shot will require either a camera with manual controls, a low-light situation, careful planning, or some good luck! You want to get the smallest depth of field possible.
The depth of field depends primarily on the aperture of the lens, the "F-stop" setting on a lens. The numbers are funny - the smaller the number, the larger the opening, i.e., the "wider" the aperture. The depth of field is the smallest when the aperture is the largest, i.e., when the F-stop number is the smallest. The term "stop down the lens" means to turn to a smaller aperture (higher F-stop number).
For example, a lens might have F-stop settings ranging from F1.2 (wide open) to F16 (stopped down to a very small opening). At F1.2 the depth of field is the smallest so if you focus on an object, things a few feet behind the object (and in front) will probably be out of focus. At F16 the depth of field is the greatest so if you focus on an object, the background is more likely to be in focus.
The depth of field is sort of a soft range of focus which depends on several factors, so if you know exactly what it is for each F-stop you can control exactly what is in focus. This is important if you have a bowl on a table, for example, and want both the front and back edges of the bowl in focus.
Note that even with an SLR or camera with a through-the-lens viewfinder that has manual adjustments you can be tricked by what you see in the viewfinder. The camera normally keeps the lens wide open (smallest F-value) to make it easier to focus, even if you stop down the lens to a higher value. What appears in the viewfinder to be a beautiful blurred background may come out sharp and clear in the photo! With some cameras (many SLRs) you can actually see the depth of field in the viewfinder before taking the photo - you press a preview button which stops down the lens. Also, some cameras/lenses have a clever indicator to show you the depth of field.
Note that the overall exposure for a given amount of light depends on both the F-stop and the shutter speed. If you use a smaller F-stop (wider aperture), you will have to use a faster shutter speed or the photo will be overexposed. Some digital cameras let you vary a third parameter, the sensitivity (ISO value), the equivelant of switching to faster or slower film in a traditional camera. In this case, switching the the slowest setting (lowest ISO, least sensitive) will help since it will tend to force you (or the automatic camera) to use a wider aperture.
The effect you want to get is harder if there is a lot of light in the scene and easier if it is relatively dim. Out in bright sunlight, for example, you may not be able to set the shutter speed high enough and may need to use a smaller aperture (higher F-stop number) just to avoid overexposing the shot. This will make the out of focus background difficult or impossible. Shots taken indoors are much easier to control.
As someone mentioned, it is also helpful to put the background further from the foreground object.
BTW, there is another way I've used on occasion to make the background out of focus after the photo is taken. It requires a good image editing program such as Photoshop and being unafraid of some tedious work! Just duplicate the background layer, make a mask of the foreground object and cut away the background, then blur the background layer. Making the mask is the hard part - Photoshop has some tools such as the Extract tool which helps separate fuzzy edges and fine detail. I use this method not only to blur or soften but to do other things to the background such as darken, color correct, or even replace the entire background with another. For example, I sometimes replace the entire sky of a photo with a more interesting sky.
The attached photo is an example I did to illustrate extracting the foreground from the background using Photoshop.
JKJ in East TN
Now my picture disappeared!
John K Jordan
>Try again, example of extracting the foreground from the background.
JKJ in East TN
Try once more.
John K Jordan
>OK, there's something wrong. I've uploaded many photos and carefully did not make any edits after previewing. I'll try once more, posting without previewing. Example of extracting the foreground from the background? Please?!
JKJ in East TN
Thanks everyone!
Peter Teubel
>
Re: OT: Question for you photo experts...
Tom In Red Deer
>Hi Barry,
Yup, that's what I meant but not what I said...confused as usual. I know how to do it but not how to tell someone to do it.
Thanks for sorting out my confusion.
Tom in Red Deer
