Having touble with Depth of Field

grandpaw

Senior Member
For those of you that are having a little trouble figuring out the depth of field for a given focal length, camera and F stop, you may find this link very helpful. It is very easy to use and you may find it useful.

I would like to add that if you look on the left hand side of the page you can get this calculator for your phone and other devices so you can have it with you while you are out shooting.

Online Depth of Field Calculator
 
I have had that app on my phone for a while now. What I really like about it is it shows the Hyperfocal distance. Great for shooting at night when you have nothing to focus on. Find the Hyperfocal distance and then find an object at least that far away and focus on it. That is what I have been doing with my milky way shots.
 

Lawrence

Senior Member
I have had that app on my phone for a while now. What I really like about it is it shows the Hyperfocal distance. Great for shooting at night when you have nothing to focus on. Find the Hyperfocal distance and then find an object at least that far away and focus on it. That is what I have been doing with my milky way shots.

Don how do you find the focal distance of stars without a rocket to take you there? Please explain
 

Lawrence

Senior Member
Clearly if we had rockets in this part of the world certain members would not be driving into buffalo.

Now you are not getting off that easily (rocket or not) ... seriously how do you use this information to focus on stars?
I haven't shot any stars so everything would be new to me.
 
Clearly if we had rockets in this part of the world certain members would not be driving into buffalo.

Now you are not getting off that easily (rocket or not) ... seriously how do you use this information to focus on stars?
I haven't shot any stars so everything would be new to me.

You find the hyperfocal distance of the lens you are using at the aperture you are using. For example using my 11-16 at 16mm f2.8 the hyperfocal distance is about 15 feet. So you look around and find a light or a building or anything you can see that is at least 15 feet away and focus on that. Now everything past that will be in focus. Big difference if you are using a 50mm f1.8. The hyperfocal distance is 230 feet. Now move to the 70-300 at 300mm the hyperfocal distance is over 2600 feet.

So once you focus on anything that is further away than the hyperfocal distance of the lens you are using the stars will be in focus.
 

J-see

Senior Member
You can easily calculate it too:

HyperFocal = (focal length * focal length) / (aperture * CoC).

The circle of confusion for the D7100 should be 0.019.
 
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