Because You're Worth It

Drew,

Without going to extremes, yes, the flash helps freeze action outdoors too.
We're talking about very powerful flashes with special concentrating reflector attachments in some cases.
My evil Nikon toting brother-in-law uses long range, concentrated flash when shooting song birds, humming birds (freezes their wings) etc.
I'm not saying capturing eagles in flight 50 meters away, nor are you talking about catching a baby in flight 50 meters away.

If you're taking a picture of a kingfisher or an eagle then the chances are you'll be outside in bright daylight - have a look at all the animal "action" shots and you'll notice very few are taken in anything other than direct sun.

As others have said, to freeze action you need the fastest shutter speed you can muster. The problem is that you also need X-amount of light to make a picture.

If your shutter's going to be open for an incredibly brief time you need to increase the light some other way. You can go for a very large aperture (but suffer with a very thin depth of field), you can increase the ISO rating (but suffer with increased noise) or you can add your own intense light to the scene (that's where flash comes in).

For indoor shots then flash is really the way to go. A 50/1.4 would be a good general investment (and fun to use) but I think you may get the results you want by buying a flash that can be used off-camera - your K10D can remotely control the Pentax AF360FGZ and AF540FGZ flashes as well as some third party models. This way you can get the light closer to the subject and it won't look as "flat" as on-camera flash. But that's a whole other topic entirely...

No, it doesn't.

In that specific case it is probably the Auto-Focus tracking system, and in case of not bright light, the high ISO performance, up to ISO 2000 for example on the nikon D3 is perfectly usable, and gives 3-4 extra stops.

Lens Aperture value is constant, as much as shutter speed is. All lenses will allow the same light in, at a given aperture. The image quality will vary, if the lens used is a better one.

So the combination of fast lens (f1.4 / f2.8 for telephotos) / high ISO performance / fast accurate AF / distance from the subject (because of depth of field issues) / flash or studio lighting for close subjects / and definitely fast shutter speed - will result in the photograph you mean. Compromise on all of these is possible, and results can often be achieved with non-professional gear.

Hope this helps

I'll certainly give it ago. Watch me revolutionise your profession!

Forgive me but in your original post you mentioned taking photographs indoors in a domestic situation.

You have a partial grasp on some of the fundamentals of photography. However, another fundamental is that for every 'gain' you make there is a reciprocal 'loss'. So, you are right in thinking that a faster lens will allow a faster shutter speed (gain) but with reduced depth of field (loss). In a normal room lit by window or artificial light, there just wont be enough light, even with an f1.4 lens, to have a shutter speed fast enough to stop the motion you describe. Hence everyone's mention of using flash. So in this hypothetical room with beans being thrown, the camera could be using a shutter speed, for arguments sake, of 1/125 sec. but the flash duration might be 1/50000 sec. - the effective shutter speed and capable of stopping motion. The high power of the flash also enables a smaller aperture giving you greater depth of field.

Light levels outdoors are considerably greater than indoors. At the moment I'm sitting in a room with enough light to read by but the level outdoors is some 64 times brighter.

No need for flash with the kingfisher, just skill, experience and probably some luck!

Depth of field is not wholly dependent on aperture, focal length has an effect too, so for any given aperture setting, lets say f8, a wide angle will have greater dof than a telephoto.

F4.5 allows the same amount of light through no matter what the lens is, size and price have no effect on this.

Now this how you stop motion! link

No, a quick snap of a king fisher or eagle, would depend on the speed of your reactions. Though you would need a long lens, the difference between say F/2.8 and F/4 is minimal.

Plus, whose gonna be shooting these things in the dark? You should easily have enough light.

Oh you're so right. This thread has genuinely helped clarify things though, and after having read these pages, I've decided to buy a flash.

I have one more question though. I have many times taken pictures of my daughter running or ducks flapping, in the sunshine, and they are never frozen entirely. Do I set the camera to TV and adjust the speed or set the camera to AV and adjust the aperture? I'd instinctively think to adjust the speed of the shutter to be fast and the aperture would be set automatically as according to how bright it was. But when I do this the camera always responds by saying it's not bright enough (the flash symbol... flashing). This is outdoors in bright light. This is why I always assumed that I needed a faster lens.

Only if you have a right big flash.

In this instance you do need a faster lens. Take this as a hypothetical situation:

It's a typical, overcast autumn day and you want to take a photo. Your camera (set at 400 ISO for the sake of argument) meters the scene and decides it needs 1/125 of a second at f/5.6 in order to have enough light to capture it. To speed up the shutter you need to open up the aperture; each time you move up one whole stop you double the amount of light let through the lens and you can then halve the the shutter speed to compensate.

So the same amount of light would be let through at:

1/125 @ f5.6
1/250 (halve amount of light coming in) @ f4 (double amount of light coming in)
1/500 (halve amount of light coming in) @ f2.8 (double amount of light coming in)
1/1000 (halve amount of light coming in) @ f2 (double amount of light coming in)
1/2000 (halve amount of light coming in) @ f1.4 (double amount of light coming in)
1/4000 (halve amount of light coming in) @ f1 (double amount of light coming in)

Fast lenses can be good for making the most of what you have, but at some point you'll run up against a brick wall and you'll need to get the light from somewhere else.

You can raise the sensitivity (ISO) but take the downside of noisier pictures. If you were using a zoom with a max aperture of f5.6 (so nowhere further to go in the scenario above) then you could perform a similar trick as before; now 1/125 second at f5.6 and ISO400 becomes 1/250 @ ISO800, 1/500 @ ISO1600 (limit of the K10D) and 1/1000 @ ISO3200.

Alternatively, you can get your extra light from an external source like a flash unit (but don't rule out just switching on lights in a room for starters ). If using flash then you can pretty much just choose your aperture and fire away - as others have said, the effective shutter speed will always be that of the flash itself - counted in milliseconds and capable of freezing pretty much anything! The downside of flash is its lack of spontaneity - good lighting takes time, skill and practice to put together (which I personally don't have in abundance).

Is that as clear as mud?

You can get the same result with Av, but Tv is the more usual mode when shutter speed is the priority. TAv (on K10/20D) can be handy as well.

Even with ISO 100, the flash symbol coming on indicates that the light isn't really all that bright afterall, or that you have an extreme shutter speed or small aperture selected.

A faster lens may help a little sometimes, but mainly you need more light (whether that be daylight or flash). When you can't get more, use a higher ISO setting and the slowest shutter speed that you think will do the job.

What shutter speeds have you tried so far?

Experiment with your ISO settings. A high ISO setting produces more noise, but this is less annoying than unsharp images.

It is all linked together: Open up your lens by 1 f-stop or double your ISO to allow 1 step shorter exposure time.