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How can I equally focus everything while shooting with my canon t3i?

coolhandluke67
Contributor

General info: I have a canon T3i. I shoot 30 frames per second at 1920-1080. I have a 64GB SD card that does 70mb per second.

 

If click on the link below you will see a pic of our set. Notice that the owl (in the middle on the bottom) is out of focus. But yet our cups which have much more detail, and that are also not even near the middle of the frame have a very crisp look.

 

Now I wonder can I get the owl and everything else to be equally focused. Even if that means that we will be less focused then a video where I focus only on our heads like I did here. Also I tried auto-focus and that didn't seem to help or do really anything for that matter. Also we have light in the front so I know that isnt the problem.


Hope you can help. And yes I am a beginner so please be very detailed with you comments. Thanks.

 

https://www.dropbox.com/sc/287fezpsprx65bu/AAAr2vPfxV3B9EHP6mOXFRzza

3 REPLIES 3

TTMartin
Authority
Authority

@coolhandluke67 wrote:

General info: I have a canon T3i. I shoot 30 frames per second at 1920-1080. I have a 64GB SD card that does 70mb per second.

 

If click on the link below you will see a pic of our set. Notice that the owl (in the middle on the bottom) is out of focus. But yet our cups which have much more detail, and that are also not even near the middle of the frame have a very crisp look.

 

Now I wonder can I get the owl and everything else to be equally focused. Even if that means that we will be less focused then a video where I focus only on our heads like I did here. Also I tried auto-focus and that didn't seem to help or do really anything for that matter. Also we have light in the front so I know that isnt the problem.


Hope you can help. And yes I am a beginner so please be very detailed with you comments. Thanks.

 

https://www.dropbox.com/sc/287fezpsprx65bu/AAAr2vPfxV3B9EHP6mOXFRzza


There are two ways to deal with this.

 

One is to increase your depth of field by using a smaller aperture (larger f/number) so more of the scene is in focus.

 

The second is most likely you have auto AF point selection on. The camera will focus on the closest thing that has sufficient contrast that falls under an active AF point (including the one at the bottom where the cup is).  By choosing a single AF point over where you want the camera to focus, you will move the plane of focus closer to where you want it.

 

edit: As for the owl not being sharp. Soft fuzzy things aren't supposed to be sharp. The rim of the owl's glasses looks pretty sharp to me.

diverhank
Authority

There are several factors that would affect the depth of field which is the band of distances in front and behind the spot where your focus is at.

 

1. First and foremost you need to make sure where the focus is at.  Many cameras, if left to its own (auto-mode) may pick the closest object to focus on, like the cup.  You may want to pick your own focus point, which is, for this case, one of the eyes of a person.

 

2. When you have more than one person, you'd want all of the people - in your case, both persons - to be in focus.  The first and most important factor in controlling the depth of field is to set your aperture to a larger value (smaller opening).  For two people, you'd want f/5.6 or larger.

 

3. The second factor in controlling depth of field is the focal length (FL)...for the same everything else, if you set the FL at 18mm versus 55mm, you will have more depth of field (more distance in focus) at 18mm than FL set at 55mm.

 

4.  The third factor is the distance from your camera to the subject.  The closer you are to the subject, the less depth of field you're going to get.

 

There is an online calculator where you can obtain the depth of field for different camera/settings.  I find that the best way to is experiment with your own equipment a few times.

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Diverhank's photos on Flickr

"There is an online calculator where you can obtain the depth of field for different camera/settings.  I find that the best way to is experiment with your own equipment a few times." 

 

http://www.dofmaster.com/dofjs.html

 

That page gives background information.  But, I prefer to use the table, or gridview, display of the data.

 

http://www.dofmaster.com/doftable.html

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