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Shutter Speeds


sukumaran_r

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While I guess it is mainly through practice that one learns sbout setting

shutter speeds (using S priority on D2H), where I can find guidance on setting

appropriate shutter speeds for (i) moving objects (say) kids moving, a train

passing or a dance programme etc and (ii) still objects (say) portraits,

building interiors etc . How does the lighting (interiors and exteriors)impact

the shutter speed? Any help is appreciated.

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Sounds like you could use a good book on exposure in general. The appropriate shutter speed depends on what kind of sense of motion you want to display. Depending on what you want to convey in your photo a shutter speed of 1/15s, 1/60s, 1/250s, or 1/1000s may be appropropriate in similar situations for moving objects. I'd recommend reading the book <a href="http://www.amazon.com/gp/redirect.html?link_code=ur2&tag=cyclingshots-20&camp=1789&creative=9325&location=http%3A%2F%2Fwww.amazon.com%2Fgp%2Fproduct%2F0817463003%2Fsr%3D8-1%2Fqid%3D1154568674%2Fref%3Dpd_bbs_1%3Fie%3DUTF8">Understanding Exposure</a> by Bryan Peterson.
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A digital camera, particularly with the EXIF data encoded in the image, is a remarkable learning tool if you leverage it. When I was learning the basics of photography many years ago I took voluminous notes. Comparing the notes to the results was how I learned some basics.

 

The issue of shutter speeds and how it conveys 'motion' in an image is at least two-fold. The first is 'camera' or 'photographer' motion. Assuming that you aren't using a tripod, there is a lower limit to what you can hand-hold and still render images reasonably sharp. The 'rule of thumb' that most photographpers rally around is that your shutter speed should be at least as fast as the reciprocal of your focal length. So for a 50mm lens, you need to shoot at 1/60th or faster in order to account for your own hand tremors, etc. Photographers will differ on what they can actually 'get away with', and the rules are actually a little different for cropped digital, but the debate usually begins with that rule and departs from there.

 

Second in conveying motion is how is the subject moving? For most 'human speed' sports, freezing motion begins at about 1/250th. You want to trend faster from there if you're interested in freezing the 'sweat drops' coming off of a soccer header. You can shoot a little slower from there if you pan with the action and you don't mind blurry extremities (I personally like photographing someone speaking at a shutter speed of 1/30 - 1/60th with narrow depth of field and the hands gesturing, registering as a blur).

 

Interior lighting is going to drive you into the slower shutter speeds. With a digital camera like the D2H, you can compensate for it somewhat by bumping up the ISO. Having an understanding of how ISO, Aperture and Shutter Speed interact to form the exposure level is key. You have to understand that there's a 'math tradeoff' that goes by the fancy name 'reciprocity'. Change one leg, and you'll need to change one of the others to compensate for it. Once you have that concept down, you can begin to understand balancing a creative 'trade study' for a given lighting situation. You can jack up the ISO and live with the noise. You can lower the shutter speed and live with the motion blur. You can open your lens up wide to f/1.4 (if you have a fast lens) and deal with narrow depth of field.

 

Once again, you have a tremendous learning tool in front of you. Look at your images in an EXIF enabled reader (Nikon View or even Picasa) and read the data. Try to figure out why one image is 'successful' and another is not. Have fun!

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Excellent advice from Eric and Todd.

 

What you need to remember about aperture is that it refers to the opening in the blades that are built inside each lens. The best way to see this is to take your lens off the camera, to hold it at eyelevel and to look through it with the lens wide open (incidentally, a small number like f:2.0 refers to a wide aperture, and a high number like f:16 to a small aperture). If you now turn the aperture ring from f:2.0 towards f:16 (unless you bought a G-lens from Nikon, but that's a different debate), you will see the aperture blades close down with each click stop. Most lenses have click stops at full apertures (1.4 - 2.0 - 2.8 - 4 - 5.6 - 8 - 11 - 16 - 22 etc), some at half stop intervals. What your lens actually does is to cut down the light coming through the lens by half with each click stop. So at 2.0 you get half the light as with 1.4, and at 2.8 the light reaching your film or sensor is reduced four times with regards to the initial 1.4 setting.

 

On the other hand you have your shutter speeds, which on a professional camera can go from 30 seconds to 1/8000th second. Again, each change in shutter speed represents exactly half or double as the previous or following one. To give you an example: starting at 1/125th sec, if you now select 1/250th sec you reduce the amount of light reaching your film or sensor by half. If you select 1/60th sec, you let twice as much light through.

 

The third factor in the equation is your film speed, which will determine how much light needs to reach your sensor in order to get a correct exposure.

 

At ISO 100, a basic exposure in bright sunlight would be 1/250th sec at f:11. You will get exactly the same exposure at 1/500th sec and f:8, because you shorten the time span light falls on your sensor, but you compensate by opening the aperture and let more light through.

 

Look at it this way: open up your kitchen tap and let water run in a small trickle (= small aperture f:16). You will need a relatively long time to fill a glass of water. Now empty your glass and start again, this time opening up the tap to let water run more swiftly (= wide aperture f:2.0), you will need less time to fill your glass. Aperture and shutter speeds are related to each other in exactly the same way.

 

Using the same comparison, a small ISO number like 100 needs more light to get properly exposed, a big ISO number like 400 needs less time, because it is more sensitive to light. Replace your glass (ISO 400) by a bucket (ISO 100).

 

Follow Todd's advice and take loads of pictures, each with different settings, and you'll soon start to understand the principles. And don't worry, even myself, after 30+ years in photography, get it occasionally wrong.

 

As far as shutter speeds and moving objects are concerned, two factors are important: motion speed and direction of movement. A race car at full speed requires a high shutter speed in order to freeze any motion, a galopping horse needs less, and a person walking can be photographed at a relatively slow speed and still be sharp. Next is the direction of movement: a race car moving from left to right of the camera at a 90 degree angle can be photographed at a speed of let's say 1/2000th sec. If that car was moving at a 45 degree angle towards the camera, you'd need a faster shutter speed, and still faster if that car moved straight towards the camera.

 

Hope this helps to some extent. Get a basic book on exposure with lots of pictures and practice.

 

Jan

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