eyes and nose

[Pehpsi]

hey, i've noticed a few shots of my pets have their eyes in focus, but usually not their nose. is this because there at different lenghts?


is their a technique i should know about?

i always focus on their eyes to make sure they are in focus.

thanks in advance.

[Glen]

It depends on the Depth of Field. Post an example and this site will be helpful after http://www.dofmaster.com/dof_defined.html

DOF is the amount of the photo in focus. Generall high numbers of F stop (smaller apertures) give greater depth of field. Low numbers give a shallow depth of field. Read that page and post a pic and we can explain in your particular instance.

[Pehpsi]

thanks, glen. maybe a smaller aperture will help, i'll give it go.

this shot kind of shows it:


http://www.dslrusers.net/viewtopic.php?t=22715

[Glen]

Hi Pehpsi,

go to this site and put in the details for that shot. http://www.dofmaster.com/dofjs.html

I know it was 56mm length and f4.5 and a D70. I guessed you were about 40cms away. The calculator says that if you focussed on a point 40cm away, the closest point in focus is 39.5 cm and furthest 40.5 cm meaning that only one cm of your photo is in focus. That is why the nose is out of focus. This can be used to good effect as shown in the POTW on the front page. Even if you changed to f11 you only get 2 cm in focus. If you tried getting f11 at 140 cm away you get 30 cm in focus. Have a play on the calculator and see how changing different variables effect the result.

Bottom line, smaller aperture give greater depth of field, more so at greater distance.