digital camera usage 101

Digital Camera Usage

Shooting modes
Auto programs

Full Auto: This allows the camera to select everything for you in terms of exposure. It will decide the aperture and shutter speed along with ISO and white balance.

Sports: This is a shutter priority setting. The camera will choose the highest possible shutter speed and adjust the aperture and ISO accordingly.

Landscape: This is an aperture priority setting. The camera will select the best aperture for the focal length and then adjust the shutter accordingly.

People (or Portrait): The priority is placed on an averaging exposure for a skin tone.

Please note that in all of the program modes, jpeg is the only format available. Auto White Balance is also defaulted to and the camera will set the exposure for an average of the percentages of tones. If you are wanting to shoot a silhouette, high key, low key, or studio lit set up, the camera won’t let you decide that.

Manual and Priority modes


TV (or shutter priority): Select the shutter speed, which will remain locked, and the camera will adjust the aperture as you move around from lighting condition to lighting condition.

AV (or aperture priority): Select your aperture for depth of field and it will remain locked. The camera will now adjust the shutter speed to match the selected aperture.

M (or full manual): You independently set the aperture and shutter speed for your taste. This takes all decision making away from the camera and puts it in your hands. Best for studio lighting since it allows you to adjust your exposure for the look you want. Also, the camera has no way of metering once the shutter has been released, therefore it will be unable to judge exposure values.

ISO Settings

The ISO (or film speed to use an old term), sets the sensitivity of the chip for your exposure. The higher the ISO, the less light needed for an exposure. Also, the higher the ISO, the more grain the image will have. Grain will become more quickly evident with even the slightest under exposure at higher ISO settings.
One advantage digital has over film is the ability to change ISO mid shoot, maybe even for a few frames only, without having to load a roll of film for it or have a separate camera.



Guide for ISO

100: Good for bright sunny days, shooting in the studio with strobes. Highest quality with lowest grain.
200: Good for overcast days, shooting at sunrise or sunset.
400: Ideal for indoor with mounted camera flash. Also good for very overcast days or shooting sports when a very high shutter speed is needed to freeze action.
800: Can also be used for indoor shooting when there is a low level of available light, such as a dance floor. Good for stage lighting also.
1600: use for available light in churches. Or other events that a flash would be inappropriate for, or too distant to be effective. This speed has the highest grain and gain (contrast) of the options.

File Formats

Jpeg vs. Raw

Jpeg is a lossy format for digital imaging. In order to compress the file to save storage space, the algorithm for jpeg takes a sampling of the areas around each pixel and “combines” similar ones together. The lower the quality setting, the more liberal it is with judgment on similarities and will compress the image info more. When you open the image, the algorithm is reversed and detail filled back in. As with any mathematical equation, there will be slight variations every time you open, make changes and resave. Detail can be lost over time when working on images multiple times. This is what makes it a lossy format. When shooting in jpeg, you are already not recording all the information that your camera is capable of obtaining due to the compression of the files generated.
When shooting in jpeg mode, the settings you select for the camera, namely white balance, will be applied permanently. If the white balance is too far off, you will not be able to correct it. Color shifts and cross curves (opposite color casts within the tones of the image) are much harder, if not impossible to correct in a jpeg file.

Raw is the native format for digital camera. It is the equivalent to having a digital negative in terms of correction ability. As the name implies, Raw is nothing but the raw data the camera captures for any image regardless of any settings beyond exposure you might have set. An under or over exposed image is still under or over exposed in Raw and will suffer accordingly.
The advantage is that any other processing the camera would have done is still an option in post production. White balance can be completely changed from what was shot, and the image will appear as if it had been shot that way initially.
Raw records the maximum amount of data possible from your camera. It will generate the largest size file also. When shooting, it is best to shoot in Raw and then convert with corrections to a printable format. Printers will not print from a Raw file. Each camera model does have its own unique tag on the Raw file that will require either the camera software for conversion or that Photo Shop has the tag for it. When new cameras come out, you will be able to download an update for the tag.
But don’t think that Raw is the save all answer. You will still need to get the exposure right. An underexposed image by several stops will still be lacking in the shadow detail the properly exposed image would have held. Same with overexposed, if the highlight detail is gone, it’s gone and pulling the exposure value down in a program will not bring it back. I recommend being no more than ½ stop off plus or minus from ideal for best results.

Color Space

sRGB vs. Adobe 1998 RGB & Adobe Pro

sRGB is a color space developed by HP and Microsoft to best simulate the colors available in web based imaging. It is a limited color space that is designed to look good on the lowest common denominator monitors in use. SRGB encompasses about 35% of the visible colors in its range

Adobe 1998 RGB was developed by Adobe to be worked in for the color range that is reproducible in the photographic field. It has 50% of the visible colors available in its gamut, for about a 50% increase in the palate. The colors most affected by the increase are deep greens brighter magentas and oranges (skin tones fall here), and more subtle variations in high tones. Again the Adobe 1998 RGB will capture more data for you when shooting. If you want to discard it later, then you will have the option.

Adobe Pro is a newer color space designed for an even fuller gamut of color. Designed for the newer monitors it is great for digital designers with better gradations.

Choosing a color space to shoot in is only a factor when shooting in jpeg. When shooting in Raw the camera will automatically capture the highest amount of information. When converting the files to a printable format is when you will want to decide whether to choose sRGB or Adobe 1998 RGB



File numbering and other card care stuff

When using a new CF Card for the first time, select the FORMAT option on the camera and have the camera format the card. This will wipe any thing off the card, and give you the full amount a storage available.
When going to delete images. You can either delete single images, or delete all. When choosing the delete all option, the camera will actually delete the images, not the folders that they are in. Later when you go to download the new images, there will be several empty folders on the card that had never been deleted. To get rid of the images and the folders, choose the FORMAT option on the camera and reformat the card.
Should you reformat or delete images by accident, the images are most likely (not definitely) there. Until you shoot new images and write over the old ones, there is a possibility to recover the deleted images. There are several programs out that specialize in image data recovery from CF Cards. The free one from Lexar (available at their website) is excellent.

When selecting the numbering options on a camera, if you will be shooting more than one card for an event or trip, it is best to select the continuous option. If not selected then the camera will start over at 1 every time you put a new card in. If there will be more than one card used, then you will have several images #1. From an organizational standpoint, this makes life much more difficult for you.

Keep cards while not being used in a carrying case that closes tight. This will keep dust and dirt out of the port contacts and help improve data flow fro the camera to the card, and then from card to camera.

The difference in CF Cards is mainly in the speed of them. The higher the speed, the faster the camera can write to them, and a computer can copy from them. Unless you are a sports photographer, the write speed from camera is not much of an issue. Rarely will you need to fire 10+ shots off in rapid succession in the studio (moving toddlers excepted of course), and then have to wait for the camera to catch up in writing from the buffer. The difference will be in the post production. You will save time in copying the files onto the computer for editing. If you have a big event to download, the time savings could be considerable.


Sensor Maintenance

It is important to keep the camera sensor clean. Dust on the sensor will result in black spots on the images. This is due to the light being blocked by the dust from registering on the sensor. The sensor will see this as a shadow and result in a dark spot.
Take the lens off the camera, select SENSOR CLEAN in the menu and OK it. The mirror will lock in the up position and you can then clean the sensor.
DO NOT TOUCH THE SENSOR WITH ANYTHING NOT SPECIFICALLY DESIGNED TO DO SO WITH!!!!!
The best way to clean is with either a sensor vacuum or swabs designed to be used for the specific purpose of cleaning sensors. Do not blow on the sensor, the moisture from your breath can fog it, and accidental spit will spot it. Both will result in poor image sharpness. Do not use high pressure air, this can damage the sensor. Hold the camera angled down so that dislodged dust will fall out of the camera and with a back and forth motion, gently swipe off the sensor. Turn the camera off to reset the mirror.

Never used compressed air on your sensor. Canned air is made up of gas in a liquid state, you can accidently hit your sensor with some of the liquid and cause serious damage to it.

Delkin makes a great cleaning kit with a sensor vacuum and cleaning wands. It also includes a magnifier with light for inspection of the sensor. Make sure not to touch the bristles on the vacuum, the oil from your fingers will then smear across the sensor.


LCD Screen

The only option you have on the LCD screen adjustment is brightness. This is listed on the menu. You will not have a contrast or color adjustments available. Because of this, you can not adjust the screen on the back of the camera to be 100% accurate to what has been shot. Never judge the quality of the image or exposure value based on the image being shown on the camera back. This will be covered in the Histograms section.

Custom Parameters

There is an option on most cameras to set up custom parameters for different shooting situations. The most common set of variables you can adjust are Contrast, Sharpness, Saturation, and Color Tone. They are used as follows.
Contrast: Your tonal range available between the absolute white and absolute black in the image. The higher the contrast the lower the range of tones available. Images will have harsher transitions. The lower the contrast the more tones between absolute Black and white. Images will be flatter and more muddy with tones running together at lower contrast settings. Depending on the situation will determine the contrast range you want. A very overcast or even foggy day will benefit from a higher contrast, while Very sunny day will need a lower contrast to help even out shadows and highlights in the image.
Sharpness: The sharpness determines the degree of the sharpening filter applied to the image. While it might seem the sharper the image, the better, that’s not always the case. When dealing with small details or contrasting boundaries, images can be over sharpened. The best example would be fine hair catching some backlight against a dark background. The fine detail of the hair when over sharpened will result in stepping of the image area. Stepping occurs when the smooth transition of a line is made to look jagged, like a series of steps. It is most prevalent around areas that are very contrasting in tonal ranges. This includes areas of secular highlights such as catch lights in the eyes, hair and lips. If the image you’re shooting will not have contrasting areas of tone, then sharpening can be used more. It’s best to experiment with the threshold of the camera in use to determine when stepping will occur.
Saturation: Saturation is the intensity of the color in the image. Zero saturation is B/W, super saturation will render images similar to the Andy Warhol style paintings with diminished transitions in tonal value. Bumping the saturation up for outdoor images, especially in the fall, will give you more vibrant colors. Again this is not always a good thing. Makeup on people will become more apparent, red faced individual will become more so, and smoother skin tone transitions will suffer. One trick is to set the saturation lower when dealing with a person who does have a very red complexion who is grouped in with others who don’t. The color of the redder person will come down faster than that of the others, thus helping to minimize the difference.
Color Tone: Color tone deals with skin tones and other colors to a lesser extent. The “+” setting create a cooler skin tone while the “-“ settings are for warmer shin tones. Experiment to your choice. If shooting in Raw, it’s not needed since you will be adjusting the tones in post production.

If you shoot in Raw, all of these options are not needed. You will apply your own preferences for these variables in post processing.



White Balance

After exposure the single most important setting is the White Balance. Light is a continuous spectrum of colors blending together, the part that we can see is called the visible spectrum. Infra Red is below and Ultra Violet is above. So, at the low end of what we can see are the reds, at the high end are the blues, with all the other colors mixed in between. At the center of our perception is white light.
The human brain will smooth over variables in light temperature and adjust our perception of colors to what it believes they should be. Camera sensors don’t do that. They need to be told what the light temperature is in order to apply an equation to the data to correct it to what we would like it to be. This is the White Balance setting.
Incandescent light produces a yellowish light that is at the lower end of the visible spectrum. It is lacking in blue to balance it out. Therefore the camera must add a certain amount of blue into the image to compensate for it. Set the camera on the incandescent setting and you will be able to get well balanced photos indoors using incandescent light source (filament bulbs). Forget to change the settings and go outside or start using a flash and the images will be very blue. This is because the camera is still applying the blue filtration to overcome the lack of blue light, but is now doing so to a full spectrum image that has the light it was previously missing.

Some Common Light Sources and how the Photograph

Incandescent: Yellowish cast. Indoor floor lamps and regular house lights
Fluorescent: Couple of options. Most common has a green tint to it. Used in offices and some stores. Another has an orange cast, usually found in more industrial settings and some stores. There is a full spectrum fluorescent available that does produce white light. That is what we use at the lab.
Mercury Vapor: Very strong orange color. Found mostly in school gymnasiums and warehouses.
Tungsten: Blue light. Used mostly in Theater and other event hall settings that want to use bright or focused lights.
Camera mounted or Studio Strobes: Full spectrum light sources designed to recreate full daylight colors.

Mixed Lighting

The most troublesome lighting condition a photographer can come across is a bad mixed lighting situation. Some can be easy to remedy such as shooting outdoor under a shade tree. The surrounding area will be full spectrum, while the shade under the tree will be blue. Simply using a fill flash on the camera will add the missing colors in the spectrum without eliminating the feel of the lighting situation.
The most difficult (and sometimes uncorrectable) situation deals with interior shoots that have multiple light sources. Churches are notorious for this. Some staging venues, such as the alters at some churches, will use a mixture of lights to achieve an effect they want. Unfortunately these effect might look good to the human eye, but rarely to a camera.. An example would be a sky light (full spectrum) that is only hitting a certain area, the back portion is then lit with a series of tungsten lights with the front being fluorescent. So, the people in the front of the group will have a green tint, the middle will be normal, and the back will be blue.
Using a camera flash will help, assuming that all the light levels are equal. Otherwise, if one is brighter than the other, there will be some fall off in color in order to balance the exposure. If the venue has decided to use gells on the lights for even more color effects, then it’s near impossible to balance all of those out unless you completely overpower them with a strobe unit.

Shooting in RAW will allow you correct for any one specific light source in post production. If there is a mixed temperature problem, it will not fix them separately within the same photo. A solution is to fix each light source, save the individual corrections as a separate file, and then in Photoshop combine the images to make a final with the values balanced out. This is a lesson that will be covered in a future Photoshop posts.

Exposure

The single most important aspect in getting a good image is making sure the exposure is right. Getting the exposure right with a digital camera is much easier than with film. It is true that digital cameras are much more demanding in terms of getting the exposure right than negative film was, but it is about the same as positive film was.
What makes it easier to get the exposure right is not the little preview of the image that is shown right after the picture is taken, but the histogram option on the camera. LCD screens on cameras can be improperly calibrated, and lacking the ability to correct color and contrast, never can be fully correct. Therefore, do not trust them.
The histogram is the tool to use for determining if the exposure is correct.

Histograms

So what exactly is a histogram? It is simply a chart of statistical data charted in terms of percentages along a linear path. They have been in use long before photography was around and can be applied to almost any situation where you would want to see a visual representation of distribution for just about anything.
In photography, a histogram is a graph of the exposure value placements of the image. The horizontal line represents the brightness value of a pixel. The Value 0 being total black, the value 255 being absolute white. The vertical line is the percentage of pixels that have that value. The more pixels with the density value at that point on the graph, the higher the peak.
An ideal histogram will not have a peak that pushes up against either end of the density range. Doing so will represent an area that will not contain any detail, or ever will. So a histogram with a large spike on the highlight end (right) will be overexposed and the image will be blown out. A histogram with a large spike pushing into the shadow end (left) will be under exposed and blocked up.
That said, there is no such thing as a good or bad histogram. Only the correct one for what you are trying to accomplish with the shot.
A low key image will be heavy on the shadow side, but do not let the exposure to go so low that it will block up. Keep the spike from just touching the max density end of the chart.
A high key image will be heavy on the highlight end of the scale. Be careful to keep the spike from flattening out against to right end, otherwise the image will be blown out and not have any detail.
Look at the image, analyze the percentages of density and where they are in relation to the graph. If you have a large percentage of black in the picture (men in tuxedos, black shirts, etc…) then it is perfectly alright for there to be a large spike at the shadow end of the graph. Again, make sure it is not bottoming out and not keeping detail. Also, if there is a large percentage of white, such as a wedding gown worn by a pale woman standing outside on a bright day, then expect a large spike on the right side of the histogram. Just make sure it doesn’t run up against the right end of the scale, thus blowing the image out and losing all detail.
All a histogram can do is tell you where the percentages are in your exposure, not if it is a good exposure. That is completely up to the photographer to decide. Use judgment in the analysis of the image. The histogram is not a light meter, it will show you the dynamics of the exposure and if any of it falls out of the range of the camera to capture.