1) Exposure - with digital - even a slight brightness often "kills" the colors by "blowing them out". When I shoot outdoors (I live in a very sunny country) I find it very hard to set exposure - as "normal" exposure often is much to bright and colorless, if I start to underexpose - I get dark spots in the frame? Any tips on outdoor shots in bright light ?
First off, if you aren't doing so already, I recommend shooting in RAW. Unlike JPG, where adjusting exposure in post processing can impact image quality, with a RAW image you have a lot more latitude to adjust exposure, white balance, etc.
What body are you using? Some bodies have a tendency to over- or under-expose by 1/3 or 1/2 stop.
Are you using evaluative metering? You could try experimenting with other metering modes.
When you review images on your LCD, do you use the histogram? I find that that combined with exposure compensation can handle most situations.
2) Portraits. Everyone talks about using a small f/stop >=2.8 to produce background blur (bokeh) and give the shot a nice affect. However I find - that f stops 2.8 and smaller - can easily produce blurry shots as the smallest movement of the subject (not to mention a group shot where people are not all the same distance from you) causes blur. I found that nothing ruins a nice portrait more then a blurry kind of picture (unless this was intended for some artistic purpose)
What is the best F/stop for portraits ? What about if you use a flash ?
Not sure what you mean by f/2.8 causing blurry shots due to subject motion - those two aren't directly related (although indirectly, a wider aperture usually means a faster shutter speed, which should reduce
the effect of subject motion).
In terms of shutter speed, generally 1/60 s is sufficient to stop subject motion for a person 'holding still' for a photo. If you need to shoot slower (1/30 s, etc.) to get enough light, take several shots to increase the chances of getting one without motion blur.
If you're using a flash, the same rules apply unless most of your light is coming from the flash. If there's a fair bit of ambient light, a slow shutter speed means enough light on the subject for motion to become evident. If you increase the shutter speed (max is 1/200 s to 1/300 s, depending on your camera, and assuming you don't use high-speed sync), you will freeze motion, but then almost all the light will be from the flash - that can be good if you're bouncing it off a white ceiling for more flattering light, but not for direct light (but then, I avoid direct flash except as fill light for outdoor portraits).
The issue with a wider aperture is the trade off with depth of field. If the aperture is too wide, the DoF can be so thin that you cannot get the entire subject in focus, and that's especially true for group shots. But that's not movement, that's DoF.
There really isn't a 'best f/stop for portraits' - the goal is to use the aperture you need to get the subject in focus and separated from the background. If your DoF is thinner than the subject, at least get the eye(s) in focus. Three factors affect DoF - aperture, subject distance, and focal length. So, with a given focal length - say, 50mm - if you're close enough to nearly fill the frame with one subject's head and torso, f/1.8 might be too wide an aperture, but with the same lens far enough away for a small group shot, f/1.8 may be ok. The other factor is distance from subject to background - if there is already some spatial separation between subject and background, it's easier to blur that background out.
There are online DoF calculators (e.g. DoF Master
), and there are smartphone apps that do the same thing. After a while, you will develop the experience to know which aperture to select depending on your subject(s), lens, and distance.
Here are three examples to illustrate the point. The first is at 85mm f/1.8, shot very close to the subject, with only one eye in focus (which is what I wanted - eye, nose, and rose in focus). The second is at 70mm f/2.8 but from further away, and both subjects are in focus. Third is 105mm f/4, very close to the subject, showing that even with f/4 you can get a thin DoF (eye is in focus, ear is not). In all three cases, the background is out of focus, even though in the first image, that background is the couch that her head is resting on - just a few inches behind the subject's eye and rose which are the focal points.
EOS 5D Mark II, EF 85mm f/1.2L
II USM @ 1/60 s, f/1.8, ISO 400
EOS 5D Mark II, EF 70-200mm f/2.8L
IS II USM @ 70mm, 1/250 s, f/2.8, ISO 100
EOS 5D Mark II, EF 24-105mm f/4L
IS USM @ 105mm, 1/160 s, f/4, ISO 100