Smartphone Photography II
In part one, I briefly talked about the main features of smartphone cameras. Now I can begin with fundamentals of photography, in particular, using the phone as a camera.
Exposure in photography indicates the amount of light reaches either the film or digital sensor. To decide how much light any given scene needs, most cameras are equipped with a tool called Light Meter, or meter for short. Light Meter, however, uses the entire scene in front of the lens to calculate how much light would be appropriate. Although light meter can accurately measure the required light most of the time, under a particular circumstance, is unable to come up with a right answer. Bright scenes often cause confusion for the meter, and it may overexpose the scene, the same may occur to dark scenes, with underexposed results. The main reason is the meter does not know the area of interest within a frame, tries to average out the light throughout the entire scene which may not be the right amount for the darker or lighter areas of the field of view. Recent models of smartphones tried to overcome the problem with a focus point. In an overall bright scene, by tapping a dark area, a shade, you are telling the camera this is the area of interest, it will focus on the spot and meter the spot to calculate the exposure. Located next to the focused and metered square, there is an icon of the sun, sliding up of the screen would increase the exposure, and down decrease it, to fine tune the exposure. Tapping and holding on the screen would provide the photographer a chance to lock exposure and focus. With this in place, again one may increase or decrease the exposure as noted above. For some time, smartphones are able to capture High Dynamic Range, HDR. Cameras do not have the dynamic range of the human eye. To capture scenes with a broad spectrum of tones, a technique called bracketing helps overcome the limitation of the camera. With bracketing one can photograph a scene with three, five, or seven, even nine exposures, capturing very dark and light parts of a field. The various exposures, each will capture a specific range of tones, can be blended using an HDR program. Smartphones have the HDR feature, although it is done automatically. It takes three images( some of the cameras only two images) one with optimal exposure, one with one stop overexposure for dark details, and one with one stop underexposure for highlights. The smartphone has the program to blend these images, and renders two copies, one HDR, and other, with optimal exposure. To get HDR, the elements of the scene should be static, motion creates what is called ghosting, shadows around the moving part, a tree in windy weather. To develop a better HDR, one can obtain three different exposures, with above description, and take them to an app to get a picture close to real HDR.
Metering the sky while provides more details in clouds, makes the foregraound underexposed.
Smartphones are able to capture panoramas with a relatively large file for print. There is an arrow on the left to start the photography, tapping the arrow changes its direction from right to left. The smartphone should be moved slowly, it gives a warning if it moved too fast, even without the warning one may get breaks in the final image. The key is a steady slow move for one direction to other. Panoramas can be made vertically as well. In framing a shot one has to be careful about the foreground. Not uncommonly smartphone panoramas are beautiful landscapes in the background with no foreground, creating an unbalanced image.
iPhone 7 and upper has two different lenses(in fact two different cameras) one 28mm and other 56mm, called portrait lens. The image stabilization is through the wider lens. iOS 10 enables the camera uses both lenses in portrait mode, it captures the portrait with 56mm lens and uses the wider lens to create a shallow the depth of field. The default setting is to use the blurring the background which can be disabled in the menu. With the blurring on, the camera renders two images, with and without blurring.
Images are stored in iPhone in different places, like photos, memory, album and shared. Each format has its own features making it distinct from others. In Photos, the images are kept chronologically, from earlier, top, to more recent, bottom. On the top left of the screen, there is collection, which manages the images considering time and place. For iPhone to tag the pictures with the location, one has to turn on the location services for that app. Above collection, there is Years. Tapping years will show the images based on the year they captured. Sliding a finger over a small thumbnail will provide a slightly larger thumbnail, and keeping the finger pressed the enlarged thumbnail will display the image in its original size.
Album is another format to organize the photos. The iPhone itself creates some of the albums, and some can be built.
Tapping album will open a screen with many albums. Top left is the camera roll or all the images. There are few other defaults albums based on the location, techniques used, time lapse and panoramas, places, and people. IOS 10 can scan all the images for facial recognition, and creates an album containing all the pictures of a given person.
Another default album is favorite. To place an image in the favorite album, just tap on the image to open it, then tap the heart icon on the bottom of the screen.
To create an album, on the main page of the album, tap +icon, a dialog box opens to name the album, after naming, tap save. To add images to that album, or any other one, open the desired album or camera roll, tap select on the top right, and tap on the pictures you want to add to a specific album. Tap “add to” on the bottom of the page, which opens the album page, tap on the target album.
To delete a single image, tap on the image, then tap the trash can icon on the bottom right. To delete multiple pictures at once, tap select on the top right, either slide your finger over the photos if there were next to each other or tap individual images, then tap trash can icon. Deleting an image from an album would remove the image from that album, but the image will stay in the camera roll. Deleting from camera roll would erase the image permanently. Although there are ways to retrieve an accidentally deleted image on the camera roll. By default, all the deleted pictures move to a Recently Deleted Photos; the system will keep the copies for a month. During this period, the images can be transferred back to camera roll by opening the album.
To search for a specific image, tap on the magnifying glass on the Photos page, type what you are looking for, location, for instance. San Francisco, it will bring all the images taken in the area. IOS 10 also can collect data on the content of the image, without assigning keywords; typing Cars, would bring all the photos containing cars and so on.
The section of exposure of iPhone, for the most part, covers the Androids smartphones as well. Regarding metering, to overcome matrix technique, averaging the amount of light in the scene, one could use spot metering, by tapping a single spot on the scene or choose a larger area. One ubiquitous difficulty with capturing images with the sky is they tend to become overexposed. Instead of spot metering, one could try to reduce the exposure by two or three stops; in post-processing, the shadows can be opened up particularly if low ISO has been used. If the smartphone is on a tripod, the alternative is to take two pictures, one metered for the sky, and other, the foreground or point of interest. There are several techniques the two images can be blend together, exposure blending. Tapping a spot on the screen beside activating the spot metering, will focus on that spot as well. Recent models have manual focus, although it can be somewhat cumbersome for some, in that case, it is better to use touch focus. By and large, there are two variables in smartphone cameras to manage the exposure, shutter speed, and ISO. For the most part, one wants to keep the ISO at the lowest, 100 to 200. Although raising ISO value will increase the exposure, the downside would be noise; digital artifacts camera create when transferring the data from the sensor to its processor. It is the same as grain in analog photography. Shutter speed can be lowered in a low light situation to increase the exposure; since shutter speed of lower than 1/60 second tends to introduce shake and motion blur, the recommendation for longer shutter speed is to use a tripod. I should add 1/60 is for the normal lens of 50mm focal point, the rule of thumb is one over the focal length, 1/100 for a 100mm focal point. Another technique to overcome exposure difficulties is to use HDR mode which discussed above.
Metering for the dark foreground captures details, yet blows out the sky, at the point of no recovery.
Capturing panorama images with android smartphone is similar to iPhone. By opening the panorama app, an image in the center of a rectangular comes to display with arrows pointing to either side. By moving the camera in either direction, the center image moves to the far right or left based on the course, with empty rectangular becomes a guide to move the camera within its space. As noted above, it is important to move slowly to avoid creating breaks in the image. Regarding composition, it is important to reiterate, to have an element in the foreground, not just relying on background, which creates a balanced picture.
Google has an app to build a blur in the background which makes up for the lack of the second lens. It has been available for some time, very user-friendly. The app has instruction how to use it. In summary, after capturing the primary focus of interest, the photographer, slowly moves his/her arm upward until hearing a beep. The app applies some degree of blur with a sharp focal point, although one can tap the image to pick up the sharp point and by moving a slider at the bottom, increase or decrease the blur. The app also has features to create slow motion, panorama, and sphere. It is a free app.
Organizing the Images
Organizing system is very similar to iPhone. Images are in Photos app, some of the manufacturers, like Samsung, call this gallery. Pictures are in chronological order. It contains all the photos, whether taken by the phone camera or shared and saved. By tapping the side menu icon, one may open device folder containing camera roll, the images captured by the device.
The images can be organized based on the time of capture, events, albums and so on. On any page, swiping to the right will open the categories on the left side with images on the right. Zooming in with two finger gesture will decrease the number of pictures on display, zooming out will increase the number of photos. While the images are open, they can be selected and moved to a specific album. They can be selected and dragged into an album, or after selection, tap top right, More, which opens all the folders, one can make a copy of the image, or just move the thumbnail to an album. To delete an image, it can be selected, then tap the trash can icon; multiple pictures can be removed with the same technique.
On the next, and last, part, I will discuss the apps and accessories for smartphone photography.