Kirk is a Professional Wedding Photographer in Windsor Ontario Note: If you would be so kind as to give us a G+ and a Face Book Like if you like this post -Go Here for FB & G+Links -Thanks for dropping by.
Introduction:
One of the real gems of DSLR cameras is the ability to control the depth of field (DOF) of the image. It is closely related to Bokeh but it is NOT the same thing. Our next post will cover Bokeh (pronounced bow-kah).
If we set up 3 objects in a row about 6 inches apart and try to focus on the center object, the closest and farthest objects go out of focus. That means they become blurred. The distance from the in focus object or sharp object to a point front and back of the center object where we lose focus or sharpness is called our Depth of Field.
The amount of the DOF increases with increasing the F stop that we use. Very small F-stops like F1.4 on a 85 mm lens can be as little as 2" inches in front and 2" in back of your focus point. That means as you move away from your focus point things start to go soft(out of focus). Holding the camera still can be a challenge under these conditions.
Masters-TIP: Keep your elbows tight to your body.Breath slowly or exhale and hold your breath.
Here is a tool to help you calculate the DOF
The depth of field is a function of :
1.Lens focal length
2.Distance from the object
3.Camera type sensor size: "c" or "FF" (full frame).
4.F Stop used.
Masters-Tip: You may have to setup the micro adjustment in your Canon Camera if it has one, to check for Front or Back focus problems. More on this in another post.
Masters-Tip:
1.Choose a low F Stop for those tight closeup of one person. Start with F4 and work down to F 1.4 with your 50 mm lens.
2.Choose a F Stop of 5.6 to 8 when shoot groups and don't crop too closely. Focus on the middle row. Use a lens of 50 mm to prevent Volume Anamorphosis (see post of VA) if your don't have the software to correct for it. You may even try shooting the same group of people with F5.6 then F 7.0 and then F 8.0 and look at the results.
3.Practice shooting with low F stops. F4 then F2.8 and F2.0 F1.8 F1.4
4.Use an F stop of 16 -20 if you want everything to be in focus ie Landscape Photography Canon I believe should not be shot above about F22 (technical reason)
5.Try using the DOF button on your lens or camera.
6.One of the first questions you must ask your self when shooting groups of people or even a single person is "What F-Stop do I want to use to shoot this picture"?
It is extremely important for you to fully understand the impact of DOF on your photography. It will elevate your photography to new levels over a point and click camera.
In times long past, you could simply look at your lens and there was a chart on it showing you the DOF and F Stop.
You don't have to run out and buy an expensive 70-200 mm IS F 2.8 (unless you are loaded) when an F 4.0 IS 70-200 mm will do the job. More on this in another post and MastersTips on another post. Yes the F2.8 now is a good lens but I don't really see differences here until I get to the low 2's. The F2.8 was pushed when we couldn't shoot high ISO's (ie 6400, 12800). It is only 1 stop at twice the price. Go out and look at images shot at say 200 mm and 100 mm at F2.8 and F4.0.
Practice this over and over.
Next topic: How NOT to go Broke tying to get Bokeh.
Note: If you would be so kind as to give us a G+ and a Face Book Like if you like this post -Go Here: FB & G+ Links-Thanks for dropping by.
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