Suggestion: Portrait photos -- large/small stop and anything important?

[Phrasikleia]

you could add:

6) distance to subject: The closer, the more distortion of proportions.

7) Longer lens = appearence of less distance between foreground/background and vice versa.

Also good points for portraiture, but these are factors of another sort. The list of 5 I compiled all pertain to background blur/bokeh. They are the only 5 factors I can think of that have an effect on the amount of blur.

 

[compuwar]

If you're talking about Canon's L lens, that lens is way too heavy to handhold for an extended period of time. It IS a great lens, though.

You have *got* to be kidding. A 300/2.8 is difficult to hand hold for an extended period of time. A 400/2.8 is difficult to hand hold for a short period of time. A 70-200 is a piece of cake.

Also good points for portraiture, but these are factors of another sort. The list of 5 I compiled all pertain to background blur/bokeh. They are the only 5 factors I can think of that have an effect on the amount of blur.

Lens quality, atmospheric conditions, what's in the actual background and to some extent background lighting all also have an effect.

 

[compuwar]

I'm gonna be working on portraits and I've been reading two interesting articles with good and believable recommendations, but there's conflicting report:

for a blurry background one says that it's best to keep the ƒ-value as high as possible e.g. ƒ/5.6;

Actually, for portraiture with photographer-controlled lighting, you generally have 2-3 good choices for sync speed (1/60th, 1/125th and 1/250th depending on camera,) and the aperture will fall where it does based upon your lighting, which you set up depending on the look you wnat and what lighting equipment you have at your disposal.

the other says the ƒ-value should be as "small as possible" to avoid motion blur and a higher shutter speed e.g. ƒ/3.

Motion blur is more of an issue with natural light than it is with artificial light where flash duration is typically fast enough to no make it a factor.

But as I can remember, the smaller the number, the aperture would open bigger and thus shortening the exposure. This will also produce a more blurry background. Am I correct?

Subject->background distance is the best way to ensure a good background, but for portraiture, unless you're doing environmental (where too much blur is bad) or senior portraits (where it depends,) you'll want an artificial background and unless you're doing something weird it'll be ok.

Something else: at what focal length do you recommend? I was thinking about 50-60mm for a rough guess (don't have my camera with me at the moment).
[/quout]

It depends on the results you want. I generally shoot portraits on a 1.5x crop factor body with a 35-70mm zoom, but where I zoom depends on what result I want to achieve.

Also, I will probably be using flash in a darkish room. I'll get bouncers (not the party ones), I think for a classic portrait would be light from slightly to the sight and a bit higher than the person's face.

In general, my key is 45 degrees from the subject (but the side depends a *lot* on the person's face or if they wear glasses,) but a fair bit higher than their head. I generally do fill from near the camera position opposite the key and just a bit higher than the head (ratio depending on results) and a background light for high-key or a hair light for most everything else from the key side and up high for hair and from below and fill side for background. I tend to use a softbox on the key for studio shots and a shoot-through on location these days with regular umbrellas for the fill and a grid for the hair light.

Reflectors are difficult to get right for fill, a fill light is easier to use and easier to get the ratios right on, but if you've got a subject that needs one under their chin, that's easy to do.

Any other thing I should make note of? Thanks!

Read up on short and broad side lighting, and if possible get and read "Light: Science and Magic." Chuck Gardener's site's got some good information on it too.