Forensics Photography - Topic 1

What does it mean to have a "normal" lens?

A normal lens is when the camera does not magnify the image and it does not result in a defect in the image.

What are telephoto lenses?

A telephoto lens is when the cameras focal length is longer than 50 millimeters. Additionally, the lens center is further away from the digital sensor

How is camera orientation (horizontal or vertical) important to filling the frame?

Camera orientation is essential because if the object is long horizontally and short vertically, that would mean there would have to be a different angle used to capture the entire image. If a piece of the object was cut out of the image, that could result in a valuable piece of information being lost.

How does f/stop relate to shutter speed? What does this mean for how f/stops are read and used?

F/Stop relates to shutter speed by determining how long the camera lens. The F/Stop is a circular opening that lets light to capture the image.

True or False: In order to produce high-quality photographs, you must have access to high-end cameras and equipment.

FALSE

True or False: Wide-angle lenses are okay to use because they give a fair and accurate representation of the scene.

False

What is Focal Length

Focal length is the distance in millimeters between the occipital center and the sensor inside of the camera to focus on infinity

Define foreground and background.

Foreground means the area closest to the object that is being photographed and the background is what will be behind the image photographed.

Can it be done in any other plane? If no, why not?

It can be done but it will result in some of the object being out of focus

How does f/stop come into play with hyperfocal focusing?

The F/stop aligns with the infinity symbol which can make the image have no blur.

What is the sunny day rule?

The Sunny day rule is to F/16 and to convert the ISO to the Shutter speed.

Hyperfocal Focus:

The background is at an infinite, which means there is no stop

Aberrations

The camera can result in an image that has a defect which was produced by the lens.

Program Exposure (P)

The camera does the work by choosing the F/stop and the shutter speed depending on what the camera detects from the scene.

Sharpness

The clarity of the entire image showing details without any blur

What should be your first choice of lenses for crime scene photography? Why?

The first choice when photographing a crime scene is a "normal" lens which has a focal length that is equal to 50 millimeters.

Diffraction

The light in a photo which bends because it is hitting an edge.

Aperture Priority (A or Av)

The only thing to set up is the F/stop while it selects the shutter speed depending on the light.

How much of a forensic photograph needs to be in focus?

The primary object needs to be in focus during a forensic photograph.

What is the rule of thirds?

The rule of thirds is when the DOF is at different distances in the front and back on the plane of focus.

Reciprocal Exposure:

The smallest lens opening on the camera.

True or False: A positive exposure stop halves the exposure from the previous stop?

True

What are two techniques to maximizing DOF?

Two techniques that are effective to maximize DOF is hyperfocal focusing and zone focusing

f/5.6

a. This is used when photographing during a cloudy day and additionally can be used for bracketing.

What are the two concepts that the term "single lens reflex" involves?

a. When the shutter button is pressed, it will be open for a specific amount of time b. When there is a photo being taken the light hits the sensor, which records the image.

Camera to subject distance

cannot use hyperfocal focusing for close distances and has infinity in the image.

f/stop Choice

this can maximize or minimize the depth of field for an image

True or False: All things in a crime scene photo should be in focus, if it is not then the photographer should try to recompose the scene so that the out-of-focus areas are no longer in the field of view.

True

True or False: F-stop (or aperture) represents the diaphragm of the lens and how much of it is open.

True

True or False: Shorter shutter speeds lead to overexposure.

True

True or False: Shutter speeds are shown in whole numbers but represent fractions of a second.

True, Seconds are represented as whole numbers. For example, 15 seconds would just be 15"

What are two techniques that we use to maximize DOF?

Two techniques that maximize DOF is zone focusing and hyperfocal focusing .

What do we use to meter with these kinds of scenes?

Using a meter in these kinds of scenes can help get an accurate measure on the colors in the scene

How can we adjust exposure using ISO? What is the problem with adjusting exposure using only ISO?

We can adjust the ISO with new cameras such as moving the dial on the back and with older cameras, there are buttons to adjust the ISO. Adjusting the ISO can cause a loss in midtones and the possibility of the image being grainy.

What is the difference between under and over exposed?

When a photo is under exposed it means that the photo is too dark due to many different things such as the aperture or the ISO. Additionally when a photo is over exposed which means the photo is too bright.

How do we adjust the camera for light scenes? For dark scenes?

When adjusting for a light scene you adjust the aperture by opening to 1 ½ - 2. Additionally, when adjusting for a dark scene you close the aperture by 1 ½ - 2.

Zone Focus

When infinity is no longer in the background, which means there is a stop to the background.

If we use our palm to meter, what is the percent of light that strikes it?

When metering our palm, it reflects about 36% regardless of skin tone.

What is the main thing we must consider when taking photographs? What do we do to fix the photos if it is out of our norm?

When taking photographs, we must consider the ISO, aperture, and lighting to take an effective and accurate photo. When a photo is out of the norm you can adjust the settings on the camera and if the lighting is incorrect you can supplement a light such as a flash.

Prefocus

When the image is taken with a macro lens.

When would the photograph not want to abide by the third cardinal rule?

When there is a reflective object that can create a glare or accidentially show the photographer in the image.

Distortion

When using a macro or telephoto lens it results in an image being distorted if zoomed in too far.

In what plane is manual focusing most successful?

When using manual focusing, the film plane should be parallel to the top of the object to make the image the most effective.

In what circumstance/why would we want a 1:1 magnification ratio?

When using the 1:1 magnification ratio is when using the macro lens which magnifies smaller objects to fill the entire frame

What shutter speed should most images for crime scenes be captured at? What are the four f/stops that it should be in combination with?

While photographing a crime scene the best shutter speed of 1/60th of a second. The four f/stops are F/22, F/16/ F/11/ F/8

Shutter Priority (S or Tv)

You set up the shutter speed while the camera sets the F/stop up based on the lighting available

Manual (M)

manually sets up the F/stop and adjusting the shutter speed for each photo taken.

How is a shutter release cable used and how do we indicate on the camera that we are using it?

A shutter release cable is used by going to the Bulb "B" section on the camera, the reason we use it is to get a longer shutter speed than the ones available on the camera.

What is lens flare? How can this be eliminated?

An effective way to eliminate lens flare is to not take photographs with the sun directly in front of you.

What does it mean to bracket a photo? Why do we do it?

Bracketing a photo means taking multiple photos while using different settings for each image to get different exposures.

1. What does the book mean by the circles of confusion?

Circles of confusion mean light has to converge on a point on the sensor. Additionally, to get an effective photo you have to have light converge on the sensor to get an effective photo.

Why are macro lenses useful to forensic photography?

Macro lenses are useful because it makes a small object much larger looking on the photo.

What does it mean to meter?

Metering is when you compare the brightness to the subject to prevent the subject from being backlit or too bright.

When preparing to take a photograph, you note that your shadow is in the frame. How can you eliminate or reduce this?

Move to a different area where your shadow will no longer be in the image.

In order to properly fill the frame, the photographer must get _____ to the subject, which puts as many as the camera's ______ over the subject as possible.

1. Close 2. Digital Pixels

What is the compression effect?

A compression effect is when the camera makes an image larger because it is zoomed in.

What is the difference between fast and slow lenses?

A fast lens will have a wide aperture while a slow lens a narrow aperture.

What is the difference between a hard shadow and a soft shadow? If one has to be in the photo, which is preferred?

A hard shadow is the darker part that shows no details and a soft shadow is softer but shows some details. It depends on the time and area where the photo is being taken place, such as time, location, weather and season determine which is more effective.

How does using a large aperture affect DOF?

A large aperture affects DOF by letting more light into the photo resulting in overexposure.

What are considered normal and non-normal scenes?

A normal scene is when there are easy settings to work with such as a relatively clean environment where the focal point with not have conflicts. A non-normal scene is where there is an overabundance of waste such as a hoarders house which makes it difficult to photograph the scene.

What does composition mean to you in terms of photography?

Compostition in the terms of photography means to specifically choose certain elements to photograph to gather evidence during a crime scene.

Define depth of field.

Depth of field is the area that will show in foucs.

Why is it important to avoided diagonal photographs?

Diagonal photograhs can create an issue between the foreground and the background.

What ISO is typically used for bright days? What about at night?

During a bright day a common ISO is 1600 while during night scene photography and good ISO is 800

What are the four issues a photographer should address before taking a photograph?

Four issues that a photographer should address are finding the primary subject to photograph, determing the exposure to photograph, getting an proper focus on the image and determing the best lighting to use for the photograph.

What is a cool fact about green grass?

Green grass additionally reflects about 18% of light in a photo

Is it appropriate to use autofocus? If yes, when? If no, why?

It can be used it in most cases the image will turn out of focus.

What is the rule of thumb when it comes to focal length per distance between camera and subject?

Rule of thumb is when the depth of field may be at a different distance from the front or behind the plane of focus in the image.

List the four variables that directly affect exposure:

Shutter Speed, Aperture, ISO, Lighting in the scene

What is our standard card for light metering? Why do we use this?

The standard card for light metering is the 18% gray card, we use this because it can help reflect most objects and it helps reflect 18% of light.

List the three cardinal rules

The three cardinal rules are to fill the frame with an object, to maximaize the depth of field so the image turns out well and lastly is to keep the camera parallel to the object to properly record the evidence.

What are the two things that we use when talking about reciprocal exposure?

The two things that are used are the F/stop and the shutter speed while using reciprocal exposure.

What do we use spot meters for?

The use of spot meter is to measure a small area of a scene. Additionally, it will let the camera make the measurements.

Why is there more than just one "correct" exposure? When would a photographer want to take a photo that is "incorrectly" exposed?

There can be certain objects that need different lighting than other objects, such as a rifle. With a rifle there needs to be "correct" exposure to be able to get details such as the seriel number or any ingravings. Additionally, if there is an object that has a reflective surface, such as a blade, you would want the exposue "incorrect" so there is no glare on the object.

How do we bracket?

There is manual and automatic bracketing. Manual is selecting a specific F/stop such as F/22 while decreasing the smallest aperture. Automatic will do all of the work instead.

In midrange photographs, what is the film plane held parallel to? Why is this important for this type of photograph specifically?

There needs to be an accurate distance between the objects and when both objects are at the same distance from the photographer it can make the image more effective.

Resolution

This ability is the camera system having the ability to figure out what lines get thinner and closer together

f/8

This is used when bracketing the camera for overexposure

f/16

This is used when photographing a crime scene during the sunny day rule

f/11

This is used when photographing with the reciprocal exposure setting

What does it mean to "keep the film plane parallel?

This means the camera has to be parallel to the subject when photographing.

Acutance

This means the sharpness on the image's edges and corners.

What does it mean to "be in focus" in a photograph?

To "be in focus" means there is no blur on the subject and be the primary focus of the image.

What does it mean to "eliminate the irrelevant" in a photograph? Why is this important? How can it be accomplished?

To "eliminate the irrelevant" means to get rid of the excess in an image, for example if there was a handgun being photographed, it would be a good idea to zoom in enough to capture the entire image while getting rid of the excess.

Lens Choice

there are different F/stop's depending on the type of lens which means there can be more effective F/stop's