Introduction to Photography Scotten W. Jones sjones@georgetownfun.org http://www.georgetownfun.org/miscellaneous/photography.html
Cameras I will focus on Digital Single Lens Reflex (DSLR) cameras, but the general principles apply to all cameras. Cell phone cameras will lack the ability to control the settings I will discuss. Point and shoot cameras will have more adjustability, but a DSLR will have the most adjustability and is recommended for serious photographers.
DSLR Optical Path
Lens Lens are specified based on focal length in millimeters and aperture in f stops. Longer focal length equals more magnification but narrower field of view. Lower f stops equals better low light performance.
Image Path Image sensor captures the image. The data is buffered and then written to the memory card. The memory card is slow so the buffer size determines how fast you can take pictures and the buffer is built into the camera.
Megapixels The number of millions of pixels in the image sensor. The more megapixels the larger you can print or view a picture and have it remain sharp. Megapixels 300dpi 200dpi 150dpi 6 10.0 x 6.7 15.0 x 10.0 20.0 x 13.3 8 11.5 x 7.7 17.3 x 11.5 23.1 x 15.4 12 14.1 x 9.4 21.2 x 14.1 28.3 x 18.9 16 16.3 x 10.9 24.5 x 16.3 32.7 x 21.8 24 21.1 x 13.4 30.1 x 20.1 40.1 x 26.8 36 24.5 x 16.4 36.8 x 24.6 49.1 x 32.7
Sensor Size 35mm film was 24mm x 36mm, that is a full frame sensor used in the best DSLR cameras. Smaller sensors lose some quality particularly in low light. Full frame, Canon or Nikon FX are 24mm x 36mm. APS-H (Canon) is 28.7mm x 19mm this causes a 1.3x increase in lens focal length. APS-C (Nikon DX, Pentex, Sony) is 23.6mm x 15.7mm this causes a 1.5x increase in lens focal length. APS-C (Canon) is 22.2mm x 14mm this causes a 1.6x increase in focal length.
A Good Photograph In focus Properly exposed Well composed
Focus Most cameras today focus for you and most pictures will be in focus, but. The camera will focus where you point it and may not focus properly if the subject is off center. Focus takes time, may not be right for fast moving subjects. Focus takes light, make not work in low light.
Exposure Exposure is determined by three interrelated factors.
Iso Speed The higher the ISO speed the less light you need for a photograph. ISO scale: 50, 100, 200, 400, 800, 1600, 3200, 6400, 12800 Every time you double the ISO number you need half as much light to properly expose a photograph. Higher ISO numbers result in noisier photographs, how high you can go and still take an acceptable picture depends on the camera.
Aperture f number Smaller f number is wider aperture, larger f number is smaller aperture. f number scale: 1.4, 2.0, 2.8, 4.0, 5.6, 8.0, 11, 16, 22, 32 Every time you double the f number you get half the light.
Aperture depth of focus f/3.2 left side only the center of the image is in focus. f/22 right side the entire image is in focus. Caveat, at high f numbers diffraction can reduce the image sharpness, Shoot in the center of the range if possible.
Shutter Speed Determines how long the light is reaching the sensor. Longer shutter speeds can lead to blurry images due to motion of the subject or camera shake. Hand held camera rules of thumb: Slow moving or stationary subject the longest allowable shutter speed is 1/focal length. 50mm lens = 1/50 sec, 100mm lens = 1/100 sec, etc. Fast moving subject such as in sports the longest allowable shutter speed is 1/(4 x the focal length). 50mm lens = 1/200 sec, 100mm lens = 1/400 sec, etc.
Camera Modes Av or A aperture priority the user sets ISO and aperture and the camera sets shutter speed automatically. B (bulb) the user manually sets ISO and aperture and the shutter stays open as long as the shutter release button is pressed. Not very common anymore. M (manual) the user sets ISO, aperture and shutter speed manually. P (program) the user sets ISO and the camera sets aperture and shutter speed. Tv or S shutter priority the user sets ISO and shutter speed and the camera sets aperture.
Composition Rule of thirds Divide the image into thirds vertically and horizontally. Place important elements on the lines or line intersections.
Example Photographs
GMHS Band Concert Hand held ISO5000 80-200mm f/2.8 lens f/3.5 1/250 sec 80mm Exposure manually adjusted Shot from the back of the GMHS auditorium
GMHS - Play Hand held ISO3200 24-70mm f/2.8 lens f/3.2 1/250 sec 58mm GMHS auditorium Manual exposure Shot from the back of the auditorium
GMHS - Grand March Hand held ISO200 24-70mm f2.8 lens f/4 1/250 sec 70mm Quantum Qflash GMHS auditorium Shot from the front row Exposure manually adjusted
GMHS - Graduation Hand held ISO320 28-300mm f3.5-5.6 lens f/10 1/640 sec 28mm Cropped out other photographer Auto exposure
GMHS - Graduation Hand held ISO320 28-300mm f/3.5-5.6 lens f/5.6 1/100 sec 26mm Taken in the shade with a flash to get even lighting
Penn Brook - School Dance Hand held ISO12800 24-70mm f/2.8 lens f/2.8 1/30 sec 27mm Penn Brook gym Exposure manually adjusted
Moon Tripod with remote shutter release ISO100 80-200mm f/2.8 lens on a 2x tele converter f/8.0 1/200 sec 400mm Cropped Exposure manually adjusted
Fireworks Tripod with remote shutter release ISO200 24-70mm f/2.8 lens f/11 4 secs to capture movement 34mm
Newburyport Cruise Hand held ISO5000 24-70mm f/2.8 lens f/2.8 1/100 sec 58mm Shot from the deck of a boat Exposure manually adjusted
911 Remembrance Hand held ISO5000 24-70mm f/2.8 lens f/13 1/250 sec 56mm Fill flash Shot across from the fire station Exposure manually adjusted
Concert Photo Tripod ISO5000 28-300mm f3.5-5.6 lens f/5 1/60 sec 28mm Shot remotely using a Cam Ranger I am actually in the picture under the lights. Exposure manually adjusted
Nature Hand held ISO800 24-70mm f/2.8 lens f/11 1/500 secs 50mm Shot at the Ipswich River Wildlife Sanctuary Exposure manually adjusted
Waves Tripod with remote shutter release ISO80 80-200mm f/2.8 lens f/11 1 sec 200mm Neutral density filter
Portland Head Light Tripod with remote shutter release ISO100 24-70mm f/2.8 lens f/11 1/25 sec 24mm Neutral density filter. Shot at Portland Head Light Exposure manually adjusted
Macro- Water Drop Tripod with remote shutter release ISO200 f/14 1/125 sec 105mm f/2.8 macro lens Flash Exposure manually adjusted Cropped
Macro- Smoke Tripod with remote shutter release ISO200 f/8 1/125 sec 105mm f/2.8 macro lens 2 flashes with colored gels Exposure manually adjusted
Macro- Flowers Hand held ISO200 60mm f2.8 macro lens f/11 1/80 sec 60mm macro Used a white poster board to reflect light Exposure manually adjusted
Snow Storm Hand held ISO400 24-70mm f/2.8 lens f/11 1/500 sec 40mm In front of town hall Auto exposure
Sports Photo Basketball Monopod ISO6400 80-200mm f/2.8 lens f/2.8 1/1000 sec needed to freeze the action 100mm GMHS gym Exposure manually adjusted A good lens for basketball is a 70-200mm f/2.8, it will cover the whole court.
Sport Photo - Football Monopod ISO1000 80-200mm f/2.8 lens f/2.8 1/800 sec- to freeze the action 200mm Cropped Good lens for football are a 70-200mm f/2.8 on one body and a 400mm f2.8 or 600mm f/4 on another body. For less money use a 2x teleconverter on the 70-200mm f2.8.
Sports Photo - Football Monopod ISO1600 80-200mm f/2.8 lens f/7.1 1/1250 sec- to freeze the action 92mm Cropped
Sport Photo - Baseball Monopod ISO5000 80-200mm f2/8 lens with 2x teleconverter f/5.6 1/1600 sec to freeze the action. 340mm Baseball needs multiple lens with a 70-200mm f/2.8 on one body and a 400mm f/2.8 or 600mm f/4.0 on a second body. For less money use a 70-200mm f/2.8 on a 2x teleconverter.
Natural Bridge Hand held ISO400 28-300mm f3.5-5.6 lens f/9 1/320 sec 48mm Natural Bridge Virginia Auto exposure
Portrait Tripod ISO200 80-200mm f/2.8 lens f/5.6 1/250 sec 100mm Main flash into a soft box and a second flash off a card at ¼ the power.
Light House Hand held ISO400 28-300mm f/3.5-5.6 lens f/9 1/320 sec 28mm HDR filter in Lightroom
Donohoe Race Hand held ISO320 24-70mm f/2.8 lens f/11 1/500 sec 40mm
Architecture Hand held ISO200 28-300mm f/3.5-5.6 lens f/9.0 1/320 sec 92mm Taken in aperture priority mode Taken from a boat in Newport Harbor