camerabasics fall 2011 · - information in our midtones-information in our highlights (instead of a...
TRANSCRIPT
Camera Basics
-Cameras and the camera body-Lenses-Exposure-Metering-Aperture-Shutter-Reciprocity Law-Equivalent exposure-Depth of Field-Plane of Critical Focus-Bracketing-ISO-Histogram
CAMERA OBSCURA
Abelardo Morell from Camera Obscura
Abelardo Morell, Empire State Building in Bedroom, 1992
Abelardo Morrell
LARGE FORMAT VIEW CAMERAS (8X10 OR 4X5 SHEET FILM)
MEDIUM FORMAT CAMERAS (120 OR 220 FILM)
PARALLAX
SLR (SINGLE LENS REFLEX) CAMERAS
POINT AND SHOOT CAMERAS AND CAMERA PHONES
PLASTIC CAMERAS
PINHOLE CAMERA
JERRY SPAGNOLI from PANTHEON
Film and sensor sizes
dSLR Camera Anatomy
CAMERA SENSOR
ANATOMY OF THE 35mm SLR
LENS-allows light into the camera body-amount of light entering is controlled bythe aperture and shutter
Zoom Lens (long)
• Use when you canʼt or donʼt want to be close tothe subject.
• Medium long lens is good for portraiture.• Long lens has less depth of field, flattens space,
relatively small aperture• Disadvantages – heavy, bulky, more expensive.
Wide Angle Lens (short)
• Have considerable depth of field, allows you towork in close quarters.
• Edges of frame distorted, things closest to lenshave distortion
CROP FACTOR
35mm film marked with digital camera sensor sizes.Green: Canon 1.3x
Red: Nikon DXBlue: Canon 1.6x.
Nikon FX and Canon full-frame are the same size as the image in the film
Image from 35mm film or full-frame digital camera 1.3x sensor camera (Canon 1D series)
1.5x sensor camera (Nikon DX digital)1.6x sensor camera - Canon consumer dSLRs
Multiply a lens' focal length by a camera's factor to get thefocal length of a lens which, when used on a full-frame or35mm film camera, gives the same angle of view as that
lens does on that digital camera
CROP FACTOR
A 100mm lens on a 1.5x factor camera shows the same area of view that a150mm lens would show on a 35mm film or full-frame camera
10mm 16mm12mm 19mm14mm 23mm16mm 26mm17mm 28mm18mm 29mm20mm 32mm24mm 39mm28mm 45mm35mm 57mm50mm 81mm60mm 97mm70mm 114mm85mm 138mm100mm 162mm135mm 219mm200mm 324mm
This lens on the CANON T1i or T2i 35mm CAMERA
EXPOSURE
EXPOSUREIs a combination ratio of aperture and shutter speed
-space and time
Exposure (EV)= Intensity (of Light) x Time
What does good exposure do for me?- Information in our midtones- Information in our highlights (instead of a flat white
shape where a cloud should be)- Information in our shadows (instead of a flat black
shape where the shadow of our subject is)
So proper exposure will result in a good tonal ragewith details in the highlights and shadows.
Exposure is measured by your camera’s light meter.
MANUAL EXPOSURE DISPLAYS
DIFFERENT IN CAMERA METERING OPTIONS
There are two main variables that you control whenphotographing manually that affect exposure
- aperture- shutter speed
APERTURE
- the size of the lens openingthrough which light passes
- controls the amount of focusfrom front to back in yourpicture
SHUTTER
controls when and the length oftime the shutter is opened
controls the likelihood offrozen/blurred movement
-leaf shutter (located in the lens)
-focal plane shutter (located infront of the sensor or film)
Eadweard Muybridge
Jeff Wall, Milk, 1984
Jeff Wall, Milk, 1984
Jeff Wall, Installation View
A Sudden Gust of Wind (after Hokusai), 1993
Katsuskika Hokusai, A Gust of Wind in Ejiri (1831)
Francesca Woodman
Hiroshi Sugimoto
Exposure can be changed in intervals called ‘stops’. A stop is adoubling or halving of the amount of light that you are allowing into expose your film.
For instance…If you are at 1/125th sec and you change your shutter speed to1/250th, you are cutting the amount of light in your exposure byhalf, or, a ‘stop’
Aperture can be changed in regular stop intervals aswell…each interval is double or half the amount oflight depending on whether you are opening orclosing your aperture.
opening up (increasing the light by double)stopping down (cutting the light by half)
Here is a list of the whole F-stops and shutterspeeds, found on all manual cameras or dSLRs:
Apertures in whole f stops:
1.4 2 2.8 4 5.6 8 11 16 22 32bigger hole, more light <……> smaller hole, less light
left to right each stop is half the light of the previous stop
for example f/2 lets in half the amount of lights at f/1.4,f/2.8 lets in half the amount of light as f/2…
Shutter speeds in whole stops:
B 1 2 4 8 15 30 60 125 250 500 1000 2000
Reciprocity Law: The theoretical effect on exposure of therelationship between length of exposure and the intensity oflight stating that an increase in one will be balanced by adecrease in the other. The law does not hold true for veryshort or very long exposures.
Raising the value of one, in other words, meansyou will have to lower the other, and vice versa.
Equivalent Exposures
• Knowing the whole f-stops and shutter speeds isessential…consider them rungs on a ladder.Knowing where the steps are gives you a clearmethod of stepping up or stepping down atregular, predictable intervals.
• Shooting manual offers creative control of yourimage. On most cameras:
- M is manual setting- Av is aperture priority- Tv is shutter speed priority
Things to consider when selecting aperture / shutter speed
• Do you want everything in the image still or frozen?
• Do you want to show movement of something in your scene?
• Do you want to show the movement of thecamera/photographer?
• Do you want lots of focus from foreground to background inyour image
• Do you want a thin plane of focus in your image, witheverything else ‘soft’?
Depth of Field– the range of distance in the scene that is acceptably
sharp.– THREE things that affect the depth of field
• aperture• lens type• distance to the subject.
The Plane of Critical Focusthe part of the image that is the most sharply in focus
the range of focus increases with smaller apertures
LENS
- The longer the focal length of the lens, the smaller thedepth of field- The shorter the focal length of the lens, the larger the depthof field
DISTANCE TO SUBJECT
- The closer the camera is to the subject the less depth of field
HOW CAN YOU USE DEPTH OF FIELD?
Henri Cartier-Bresson Rue Mouffetard, Paris 1954
Elliott Erwitt Dog Legs 1974
Elliott Erwitt Ernst Haas 1955
Sally Mann, Candy Cigarette 1989
Candida Höfer Ca' Dolfin Venezia I, 2003
Candida Höfer
Mark Ruwedel from Westward the Course of Empire
Mark Ruwedel from Westward the Course of Empire
One last variable that affects exposure
ISO - International Standards Organization
– Number rating the light sensitivity of film or of camera’ssensor.
– This also affects the exposure– The higher the ISO the more sensitive the sensor is to
light. A rating of 200 is twice as sensitive as 100.– Standard ISO settings:
50 100 200 400 800 1600 3200
Slower ISOs have
- finer detail- less noise- better color saturation- less color aberration
Higher/Faster ISOs have
-increasingly more noise
-less color saturation
-more color aberration
John Divola
John Divola
LIGHT METERS
- Meters measure the intensity of light. It does not judge thequality of light or the mood or feeling it evokes.
- The meter reading you get when you compose your shotyour viewfinder is called the indicated meter reading,
- All meters are programmed to produce correctly exposedphotographs when they detect middle-toned, or “middle-gray,”subjects. (The term “middle gray” refers to tone, not color)
Bracketing
BRACKETING
purposefully under and overexposing your image to ensureyou have a good digital negative to print from
Why do something other thanwhat the meter says?
• Meters can be fooled• Meters assume you have an even distribution of
shadows, midtones, and highlights• Meters are usually wrong to a small or large
degree• Bracketing over and under your indicated
exposure reading is one method to compensatefor this
using a gray card• Yes a gray card will take
the light in a givenscene and reflect 18%of the light, or ‘middlegray’, which is what yourmeter is calibrated tolook for
• A gray card helps tounfool the meter
• You must walk up closeand take the meterreading off the gray cardonly (don’t cast ashadow on it!)
• Then, you back up andshoot with the exposuresetting the gray cardmeter reading provided
What if I don’t have a gray card?- Meter off of something that seems close to middle gray- The sky is almost always too bright, so never meter with the sky in
your frame, it will cause underexposure. If you learn to correctlyidentify middle-toned areas in your photos, you can always take accuratelight readings using your camera’s spot-metering mode.
LENS FLARE
If the sun is just outside the frame,you can use either a lens hood oryour hand to block the light fromstriking the glass surface of thelens, which will often prevent theflare.
If you can see the sun in the picture, thenthe flare is impossible to eliminate unlessyou partially block the sun with someelement in the photograph or you usePhotoshop in post-processing to clone itout.
Joseph Holmes amnh #2
Joseph Holmes amnh #35
Corrected exposure• We can use a ‘corrected’ exposure (our educated guess)
as opposed to our indicated exposure reading (what themeter says)
• Sunny 16 - set your aperture to f/16 and set yourshutter speed to the speed closest to the ISO
- for ISO 100 you would shoot at f/16 @1/125
Well, I shoot with a dSLR, how can I tell if I have goodexposure??? I don’t have negatives!
Exposure with dSLR
• Many things are the same with exposure andshooting with a dSLR
What is different then?
• dSLRS disadvantages:– Less Dmax (density max), meaning they can’t
get as many highlights, midtones, andshadows in the same shot as a negative can
– A harder time rendering shadows– A propensity to blow out highlights easily
dSLRS
• Any Advantages?
dSLRS• Advantages also include THE HISTOGRAM
The histogram• A histogram is a graphical representation of where all the tones of
your image fall according to how the image was exposed
• Most DSLRS have an option to show the histogram of the imageyou are viewing
• When highlight/shadow info is lost, it’s called ‘clipping’
Blocked up blacks, clipping occurs on left side
Highlight clipping (you can see it in the image and it is representedon the histogram on the right side
Good exposure
Bad Exposure
Highlights clipped
Using your judgement
Last thought about DSLRs andthe histogram
• Don’t rely on the screen, always check thehistogram to see if all the necessaryinformation is in your picture/file!
• If you are in low lit scenes or high contrastscenes….bracket, bracket, bracket