Portrait Photography

[Stud_Pilot]

I am currently in an Introduction Photography class at my college and we are just starting our portrait assignment. I am a little confused with my aperature settings. On one of the first days of class, my instructor said that one of the main functions of the aperature is if you need to photograph something that is relatively far away. Now, when she assigned the portrait assignmnent, she said to use a relatively big f number (8, 11 etc.) to increase sharpness of the picture, but it seems this would bring the background into focus, and she doesnt want the background in focus. She wants focal seperation of the foreground and the background.
Also, she said that when i chage the f number on my camera, i should be able to see the sharpness change in my viewfinder, but i dont see any difference.
Any Help is appreciated.
THanks,
Seth Chapman

 

[Digital Matt]

Aperture controls two things. It's one part of the exposure equation, controlling the intensity of the light entering the lens. It also controls depth of field. Depth of field is also affected by distance to subject. The closer you are focused, the shallower the depth of field will be. If you want your background thrown out of focus, you can either open up your aperture, (small number), move closer to your subjet, or move the subject away from the background.

If you want to see the affect of aperture on DoF, you'll need a DoF preview button on your camera. When you are focusing, the lens is always wide open, to allow the most light in.

 

[Christie Photo]

What camera/lens are you using?

 

[Stud_Pilot]

I have a Cannon EOS RebelG with a 28-80mm lens.

 

[BloodMaple]

Hmm, I'm not sure about using a large f-number with portrait photography. I've always heard to use the smallest, all you need to worry about then is making sure the picture is sharp through your focusing. Another thing you could probably do is separate your subject farther from the background, that way you could get away with a larger Depth of Field.

 

[Stud_Pilot]

Yeah, my instructor said that it doesnt hurt to close the lens more, it will only make the image sharper. but that confuses me, because if i close the lens more, it seems like it would put the background into focus because the bigger the f number, the more depth of field you get.

 

[Sw1tchFX]

Shoot at 80mm, f/8, on a tripod.

You'll have plenty of separation because when you change the focal length of the lens, it also effects your DOF. If you focus on something relatively close (6 feet) and zoom in, you'll notice that the background will get even more out of focus. That's what you want.

Don’t shoot at a focal length shorter than 50mm, you’ll create distortion and increase your DOF. You dont' want that for this assignment.

 

[Christie Photo]

Yeah, my instructor said that it doesnt hurt to close the lens more, it will only make the image sharper. but that confuses me, because if i close the lens more, it seems like it would put the background into focus because the bigger the f number, the more depth of field you get.

You can have both. Choose a scene that is "deep." Make sure the distance between your subject and background is great enough to allow the background to be soft. Depending on the lens and f stop, this might be 10, 20, 30 feet or more.

I hope this helps.

Pete

 

[cvjarrod]

Since it is a beginning photo class, the instructor is just trying to make it easier to get a sharp picture. Stopping down gives you a lot more room for focus error in any shot. Also, since it is a beginning class, the professor probably assumes that kit glass is used that doesn't hold up very well wide open. I'm sure the instructor will cover shallow DOF lessons later in the class.

For now, you should really be concentrating on lighting since the instructure already told you what aperture to use. The following link will give you some good examples of how to get different types of portrait lighting.

http://www.photoflexlightingschool.com/Lighting_Lessons/Basic_Lighting/Portrait_Indoor/index.html

You don't need all the expensive equipment shown in the lessons. Using available light from windows and cheap reflectors can yield stunning results. My favorite cheap reflector is the top of one of those disposable coolers. Just have your subject hold the reflector out of the frame and you don't even need a light stand.

Do a search for DIY projects on this site and you'll be surprised with what you can accomplish on a very limited budget.