100-400mm L Lens Question?

[Csst]

ok here my question i just got my new 100-400mm L Lens from canon and i want to know what i can do to get the whole picture in focus i do have all 7 points on but i have notice that my pictures come out great but the background is blur now thats not a bad thing but i would like to know what i can do to get the whole picture in foucs without the background blur.
Thanks

[iamhives]

I suggest you buy a basic book on photography and learn about depth of field. You have discovered that the longer the lens the shorter the depth of field (the distance that is in sharp focus). Using a smaller (higher number) aperture helps but at 400mm the depth of field is very short.

[cecilc]

There's a couple of things you might try:

* Use a high aperture setting (f16 and up should do it)
* Keep your subject close to the background.

I'm positive that you'll get some other suggestions, too, from some others in this forum who know a bunch more about this than I do ....

[Csst]

ok my question is would i need alot of light putting the f at 16 or higher i'm still learning this stuff myself .and any input is great input thanks.

[Belmondo]

Based on a constant amount of light, a smaller aperture (larger number) means slower shutter times and a greater depth of field. The converse is a larger aperture (smaller number), faster shutter speed, and narrower depth of field.

This is pretty basic stuff, and the suggestion that you do a little reading is a good one.

[Jim_T]

There's quite a bit to know about optics if you really want to use the full capabilities of your lenses and camera. The effect of aperture and focal length are very important...

Here's a great site with a DOF calculator.. You type in the values and it returns the depth of field. You'll see at long focal lengths and wide apertures, the depth of field is very shallow.. Just a matter of feet. Everything outside of the depth of field will get more blurry as you move away. If you poke in a few real world values, you should start seeing why you're getting the results you are.

http://dfleming.ameranet.com/dofjs.html

Another important aspect is hyperfocal distance.. Knowing this will let you know if you can get your subject and the background both in focus.

http://www.mountainstorm.com/HyperFocal/HyperFocal.html

If you browse the web, you should be able to find other sites on lens physics with examples etc.. Of course most libraries have good books on the subject.. That's a good way to go..