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derekinla
02-08-2006, 06:59 PM
It sounds like alot of people seem to love the Nikkor 50mm F1.8 for razor sharp results and the "low light" capabilities...often obviating the need for flash indoors to get a proper exposure. My question is that as you get to very low F stops (i.e. <3), won't the depth of field be so narrow as to affect what you can photograph indoors?

Jason25
02-08-2006, 09:15 PM
Just make sure you focus on the right part of the subject and you'll be fine :)

derekinla
02-09-2006, 06:11 AM
Just to clarify...

If I wanted to take a pic of the family dog... and let's say you have the ISO set at 800 or even 1600.... You're in shutter speed priority mode and to avoid hand shake you dial in 1/60" (and avoid a tripod), and in order to get the right exposure (without flash)..... the camera selects the aperture of 1.8... Won't the DOF be so narrow that only the dog's nose will be in focus?

coldrain
02-09-2006, 06:30 AM
Yes, that is why you need to learn how and when to shoot with such a big aperture. For instance, learn to focus on eyes instead of noses.
It is just one of the tools... if you need a less shallow depth of field, you need to use extra light.

jamison55
02-09-2006, 06:42 AM
DOF is also proportional to the distance to your subject. If the DOF is too narrow, take a couple of steps back. For instance the DOF (using a D70) of the 50 f1.8 @ f1.8 and 5 feet is about 3". Move back to 10 feet and it's almost a foot.

This might help figure out the whole DOF thing: http://www.dofmaster.com/dofjs.html

Ray Schnoor
02-09-2006, 06:46 AM
Just to clarify...

If I wanted to take a pic of the family dog... and let's say you have the ISO set at 800 or even 1600.... You're in shutter speed priority mode and to avoid hand shake you dial in 1/60" (and avoid a tripod), and in order to get the right exposure (without flash)..... the camera selects the aperture of 1.8... Won't the DOF be so narrow that only the dog's nose will be in focus?
Yes, the depth of field will be the least at F1.8. One of the big positives of having a F1.8 lens, though, is being able to stop it down. Just because you have an F1.8 lens does not mean that you have to take all of your photos at F1.8. It gives you a lot more flexibility with lighting situations, though. Most if not all lenses are not their sharpest wide open. You usually have to stop it down a stop or two. That is one of the advantages of having an F1.8 lens. You can stop it down to get a sharper more depth of field shot and still have a lot of light, or you can leave it wide open to decrease the depth of field.

Ray.

derekinla
02-09-2006, 06:57 AM
Thanks for the help. The DOF calculator is pretty nifty.... Here is what I am taking home:

Realizing the DOF is narrower at bigger apertures, some things to be aware of is 1) Knowing what to focus on (i.e eyes vs nose), 2) Not necessarily using lowest F stop if possible can increase DOF... 3) Can also increase DOF by increasing distance from object (standing back 10 feet vs 5 feet = 1 foot vs 3 inches for DOF)....:)

Great!!!

jamison55
02-09-2006, 06:57 AM
The other part of the DOF equation is focal length. If you want a better low light lens with greater DOF at wider apertures, why not have a look at a 35 f2 or a Sigma 20 f1.8. The wider the lens, the greater the DOF at wide apertures.

I have an 8mm fisheye, and that thing is in focus all of the time, regardless of the aperture!