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

Discussion in 'Digital Photography' started by iSamurai, Aug 26, 2008.

  1. iSamurai macrumors 65816

    iSamurai

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    #1
    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;

    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.

    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?



    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).

    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.


    Any other thing I should make note of? Thanks!
     
  2. cosx macrumors newbie

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    #2
    True. f 2.8 will create a blurrier background than an F 8 for example.
    The bigger the F ... the more you have in focus.
    I would say you have to experiment with the settings and see what suits you best.
     
  3. 66217 Guest

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    Jan 30, 2006
    #3
    The focal length depends. What type of portraits do you want?

    You could use from 35mm to 100mm. Or if you want extreme bokeh, a 200mm f/2.8 would be a nice one.

    I don't know what camera you have, but the 85mm f/1.4 Nikkor seems to be a legend for portraiture work.


    As for lighting, the first thing you want is to eliminate shadows (unless the shadow is an important part of the photo of course). Normally for this you use three flashes. But I'm no expert in flash photography. One technique I like with flash photography is the light coming from the back of the subject, specially good in glamour/model photography.
     
  4. ChrisBrightwell macrumors 68020

    ChrisBrightwell

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    #4
    Also, the further your target is from their background, and you from the target, the more out-of-focus the background will become.

    Even at f/5.6, a target who is hundreds of feet from their background will "pop" out of a super-blurry background.
     
  5. GoCubsGo macrumors Nehalem

    GoCubsGo

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    #5
    First, I don't know many who suggest a 200mm lens for portraits. Extreme bokeh is not achieved just by using a 200mm lens.

    85mm is fantastic and is the so-called "legend" because it works and is used by many portrait photographers, 105mm even better in some cases. You want a "blurry" [bokeh] background no matter what (imho). So you will want to open as wide as possible without risking the sharpness of your subject. You will compensate with your shutter speed and ISO, depending upon where you're shooting. If you don't want to shoot full manual mode you should shoot "Aperture Priority".

    Lighting:
    Yes, three flashes is ideal if you're going to go that route. Three light sources in general is ideal. You can get away with two if placed properly, one if going to some other look. You really want to go to strobist.com and educate yourself. Lighting isn't easy and is not as forgiving as some may think. A poorly lit portrait is not something you can repair post processing. (for those bouncing out of your chairs, I said poorly lit not poorly exposed)

    If you have but one flash in a "darkish" room you'll find you will only be able to light the face straight on (yuck) or from the side (dramatic but may not be the look you want). Also, the light Roco speaks of is called "backlight".

    Portraits in studio will usually consist of two strobes with barn doors (sometimes) and at least a hair light. Again, visit strobist.com, you'll find way better answers with full diagrams there. You cannot go wrong at that site.
     
  6. seenew macrumors 68000

    seenew

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    #6
    ^just wanted to throw in some more support for Strobist, go check it out!
     
  7. iSamurai thread starter macrumors 65816

    iSamurai

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    #7
    Thanks for that site. it looks interesting while glancing over. I'll definitely read it in detail later.

    Here's what I have:
    • sony a100
    • 18-70mm
    • 75-300mm
    • 1 flash (could be wirelessly controlled)
    • some bouncing boards (white, semi matte)
    I could also do this outside, but the background must be dark and I don't think direct sunlight would do because it must be something like a "coporate" portrait (you know, people in suits, looking neat etc.)


    And... you guys gave me a wide focal range... I dunno which lens to use now. Yes, if I use the short lens, which I need to zoom in -- but starting from about 50mm it's ƒ/5.6 all the way.

    With the long lens, starting at 75mm with f/4.5 doesn't make that much of a difference. I'll try 100mm, but not 200 :eek: because I'm doing this indoors... the place is not that big lol.



    Oh, and I have total control over the room light -- it can go bright, or dimmed out totally. Should I leave it really dark, slightly dark or fully lit? The light is halogen globes, very yellowish/orangish colour.
     
  8. 66217 Guest

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    #8
    I know it is not ideal for portraits because it is too long. But the bokeh of the 70-200 f/2.8 Nikkor, for example, is one of the best. And I have seen some amazing tight portraits with that lens at that focal length. It really depends in what you want to achieve.

    105mm is a nice focal length for portraits. Tho I find it too long in some occasions, specially because of the crop factor.
     
  9. ChrisA macrumors G4

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    #9
    Your problem is with the meaning of "small" and "large". f/2.8 is a large f-stop
    while f/5.6 is smaller. The number is after all on the bottom of the fraction.

    So you need a large aperture, like f/2.8 or f/1.4 for blur out a background. The number, f/x is the effective diameter of the lens. "f" is for Focal Length. So if you have a 100mm long lens set to f/4.0 the effective diameter is 25mm if set to f/2.0 if would be 50mm in diameter. Back in the 1800's photographers used a metal plate with a hole in it placed in front of the lens. Back then "using a larger f-stop" was easy, it meant using the plate with the larger hole in it. The terminology has not changed in over 100 years

    So what to do? The best starting place is likely about f/2.8. but like everything else "it depends."

    Which focal length is best? Don't think that way. Think about camera to subject distance. This distance sets the perspective. Then choose a focal length that frames the picture correctly. That said, many people only haveone lens so for them the lens defines the required camera to subject distance. For what you are doing I'd go with a 50mm lens. The 85mm would work too but you'd need a larger room.

    Sounds like you have a good reason to pick up another lens or two. Those f/5.6 zooms are attractive do to the price but as not so useful

    About lighting. You can use anything. It need not be a flash. A 300W work light from Home Depote works Ok and you can see the effect by eye before to take the picture. Window light works too as do reflectors

    Get a stand in and practice a lot. Experiment. Shoot a few hundred frames and look at the result on the computer before the real subject sit for the sesion.
     
  10. ZballZ macrumors regular

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    Nov 11, 2006
    #10
    You got a wide range, because you are not very specific about your shot. Is it a really tight shot, just the face, then go long, like 85+. Is it head/neck shot, a little shorter 60+, head/shoulders a little shorter again, like 50+

    The thing is; a portrait can be a zillion different things. It could be a wide shot, full-figur of a guy sitting in a chair! Or a tight shot of someones eyes. So the question is: what do you want??

    A good rule of thumb: stand 2-3 meter away from your subject - then use whatever focal range, that gives you the desired composition.
     
  11. 66217 Guest

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    Jan 30, 2006
    #11
    What type of portraits are you doing? What is it that you are taking photos for?

    I remember when I first did this (just a month after getting my camera). It ended being quite a disaster, but I learned a lot.:)
     
  12. GoCubsGo macrumors Nehalem

    GoCubsGo

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    #12
    He said "corporate portraits". He's probably been hired to do a job that he is not quite qualified to do. That is ok, it happens.

    OP: What is the fixation on f/5.6? I'm confused. Did someone just tell you that is what you needed? I really, really, really urge you to read strobist.com and start reading up on portrait photography. You can read books (great books) on this at bookstores (you don't have to buy, I do it all of the time) or libraries. If you are asked to do a job in which you will be paid for and you accept, you owe it to your client to disclose your skills so they know what they're getting for their money and educate yourself. I am not at all saying this cannot be done, but it may not turn out the way you intended.

    Again, one off-camera flash may be fine but it will not matter how many cards and such you use to bounce, you can only guide the light you have, which isn't much. Being able to use a dimmer switch in a room is hardly good measure for any sort of photography.

    Budget setup: grab a lamp with a standard bulb and use it as a "hot lamp" that means, always on. Set it off as you would the flash and compensate for that light by adjusting your other flash. I'll refrain from telling you to go to strobist.com again because I probably sound like I run the site (which I don't).
     
  13. ZballZ macrumors regular

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    #13
    It was mentioned earlier, that the lens he will be using is something like a 4.0-5.6. And since he probably will be shooting longer than 50 mm. The aperture maxes at 5.6. - which honestly IMO is not ideal for your type of portraiture. I would say 2.0-2.8 is good, maybe 3.5 to avoid risc of blurred images...

    idea:
    What you could to is find a large window, preferably facing north (soft light!, no direct sunlight). Place your subject in a 45 degrees angle towards that window, and gently soften the opposite (shaded) side of the face with your flash. Make sure the background is nice :) This should give you a simple setup, and nice images. Of course, since daylight is changing all the time, it is difficult to reproduce the samme excact look dozens of times...
     
  14. ManWithhat macrumors regular

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  15. GoCubsGo macrumors Nehalem

    GoCubsGo

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    #15
    Ah I missed that in all the lens hype. :)
     
  16. 66217 Guest

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    #16
    Nice calculator. I gave it a try, and it approximates the values near what the lens manual says. What other factors can change between lenses that changes the result?
     
  17. obeygiant macrumors 68040

    obeygiant

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    #17
    All the technical aspects aside you should consider what a portrait actually is. Its a moment in time capturing who the person is at that time in their life. A photograph can be viewed 100s or millions of people. If you're just taking class photos thats different, but if you look at your job as part documentarian you come to realize the importance of what you're doing. I can't tell you how many times I've taken a photograph of someone and soon after they die or are killed. Those images become priceless to their family. So if you are taking portraits of people for fun or for hire, take some time to observe them, you can add that into the image. Most of the time people just want to look their best but sometimes you can add something extra that makes it a wonderful image.


    Also look into the work of John Singer Sargent.
     
  18. ChrisBrightwell macrumors 68020

    ChrisBrightwell

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    #18
    I know lots of professional portrait photographers who use a 70-200/2.8 for their primary portrait lens.
     
  19. jhamerphoto macrumors regular

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    #19
    This is true, but the 70-120mm range is a little more commonly used. Not only because it's an easier focal length to work with space-wise, but most lenses are sharpest in their mid-range.
     
  20. ManWithhat macrumors regular

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    #20
    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.
     
  21. ChrisBrightwell macrumors 68020

    ChrisBrightwell

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    #21
    You should be using a tripod (or at least a monopod), anyway. :p
     
  22. pprior macrumors 65816

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    #22
    Give me a break: hit the gym, dude!

    I hold that lens (70-200/2.8LIS) ALL the time on a 1D body and it's not at all difficult to handhold.

    I handhold the 300/2.8IS as well and that does get a bit tiring - it's a LOT heavier than the 70-200 but definitely hand-holdable!

    And for the record, I'm a skinny 150lb guy, not some giant bodybuilder.


    As to the OP, I shoot the bulk of my headshots at F8 using studio lighting. Remember - larger aperture = more bokeh but less IN focus as well, so less forgiving. The 85L/1.2 is my favorite lens and I will shoot it wide open for fun, but if you're doing business portraits that's not the kind of look you're going for.

    Separate your background from you subject (at LEAST 6-8 feet) and light it appropriately and don't obsess over the aperture. Make sure you have at least a flash and a reflector or 2 flash units.

    Quite honestly, it sounds like you're in over your head, but good luck.
     
  23. ChrisBrightwell macrumors 68020

    ChrisBrightwell

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    #23
    This echoes a piece of advice given to me by a staff photog for the local paper: "Shoot f/8 and be wherever you need to be to get the shot."
     
  24. Phrasikleia macrumors 601

    Phrasikleia

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    #24
    I think the only factors are:

    1) Aperture
    Smaller aperture (i.e. higher f-number) = more background blur

    2) Focal length
    Longer lengths = more background blur

    3) Circle of confusion (i.e. sensor size)
    Larger sensor = more background blur

    4) Camera's proximity to subject
    Closer = more background blur

    5) Subject's distance from background
    Greater distance = more background blur

    I've grossly oversimplified here, but it's a good nutshell to keep in mind.
     
  25. ZballZ macrumors regular

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    #25
    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.
     

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