camerabasics fall 2011 · - information in our midtones-information in our highlights (instead of a...

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