When I first got my iPhone 6S, one of the features I was most interested in was the ability to capture RAW photos. The native camera app can’t capture RAW photos, but there are a number of third-party apps that can. At first I was using Manual, which captures RAW photos and gives you full control over various settings such as ISO, focus and white balance. (There’s also an automatic setting that takes care of all of that for you.) I still Iike Manual, but I recently read about Halide and decided to give it a try. I found it to be a powerful camera app that’s surprisingly easy to use.
Basic controls
At the top of the screen — in what Halide calls the Quick Bar — are a few basic controls that are available in manual mode and automatic mode. A white icon indicates that the option is turned off; a yellow icon means that it’s turned on.
Flash (on or off; there's no automatic option).
Location: If it's off, location won't be included in the photo's metadata. Unlike with most other camera apps that I've used, location is off by default, and Halide doesn't ask for permission to use location until you turn it on.
Grid and level indicator: Rather than being a single horizontal line as in other camera apps, the level indicator is a rectangle that aligns with the middle rectangle of the grid. It turns yellow when the phone is perfectly level.
RAW: If it's on, photos are captured as Digital Negative (DNG) files, Adobe's implementation of the RAW image format. (All iOS apps that can capture RAW photos capture them as DNG files.) If this setting is off, photos are captured as JPEG files, just like with the native camera app.
A control that provides access to the user manual and allows you to rearrange some of the controls on the Quick Bar.
Histogram: If on, a live histogram is displayed on-screen. (This article from B&H Photo and Video provides an overview of histograms in digital photography. It's written for users of digital cameras, rather than camera apps, but the same concepts in the "How to Read the Histogram" section also apply to apps like Halide.)
or 
A mode indicator (automatic or manual). Tapping the indicator changes modes.
A control to change between the front and rear cameras.
Gestures
Most of Halide’s controls are adjusted with gestures, so it’s easy to control with one hand, even in manual mode. The settings you would most commonly change while taking a photo (exposure compensation, focus and shutter speed) can easily be changed by swiping or dragging with your thumb while holding the camera with one hand.
Automatic mode
In automatic mode, denoted by at the top of the screen, Halide only provides one other adjustment — exposure compensation (EV). As with other controls in Halide, you adjust it with gestures. Drag up on the screen to increase the EV, down to decrease it. Double-tap the EV indicator to reset it to 0.0.
Manual mode
In manual mode, indicated by at the top of the screen, you can adjust ISO, white balance and shutter speed. ISO is adjusted by tapping the 
button in the Quick Bar and adjusting the ISO control that appears above the focus controls. White balance is controlled by tapping the white balance icon to the right of the manual indicator; the icon indicates the current white balance setting and thus varies depending on the selected setting.
Shutter speed is adjusted in the same way that exposure compensation is adjusted in automatic mode. (The EV indicator becomes the shutter speed indicator, denoted by S, in manual mode.) Drag up to increase shutter speed (for a longer exposure) or down to decrease shutter speed (for a shorter exposure).
Focus
In manual mode or automatic mode, you can use either autofocus or manual focus. The focus control can conveniently be controlled simply by swiping. With autofocus engaged, just swipe right to activate manual focus, and drag the slider to adjust the focus manually. Swiping left will reactivate autofocus. (Tapping the 
button will also activate or deactivate autofocus.)
Focus peaking
Halide includes a focus peaking feature, activated by tapping the 
button. With focus peaking turned on, Halide highlights in green the parts of the image with the sharpest contrast.
Photo view
Halide’s photo view displays a very limited subset of the photo’s metadata: file type (JPEG or RAW1), date and time, shutter speed and ISO. To see all metadata, you’ll need another tool (I like ViewExif) but it’s nice to be able to see at least some metadata without leaving Halide.
In this view, you can also “favorite” a photo by swiping right (a feature I don’t often use) or delete a photo by swiping left (a feature I find to be very convenient). There are also buttons that perform the same functions if you don’t like the gesture-based controls.
Changing orientation
When rotating the phone from portrait to landscape (and vice versa), the controls that rotate or change position do so in a very natural looking way (with one exception noted below). While it’s not anything that would make or break an app, it’s an extra little detail that makes Halide that much nicer to use.
In many apps, rotating the phone means that the entire interface rotates, and not in a very graceful way. In Halide, the controls at the top of the screen briefly disappear and then reappear in the correct place when the phone is rotated. When rotating the phone counterclockwise into landscape orientation (so that the shutter button is under your right hand), the EV button (in automatic mode) or shutter speed button (in manual mode) smoothly rotates into the correct orientation. (The small preview of the last photo taken rotates as well.) When rotating clockwise to landscape (so that the shutter button is under your left hand), however, the EV/shutter speed button and last photo preview swap places. While it doesn’t look bad, it’s just not as smooth as the other interface changes.
Documentation
Halide’s documentation, which simulates a paper user manual, is attractive but not very informative; it’s little more than a “getting started” guide. The website contains descriptions of a few key features (but not necessarily how to actually use them), but no real documentation. I had to figure out a few of the settings myself, but now that I have, I find Halide easy to use. Still, I think it would be helpful if the app had better documentation.
The missing feature
One feature I’d like to see in Halide is RAW+JPEG capture. RAW files retain all of the image data, but they generally don’t look good without some post-processing, and not every photo app on iOS can handle RAW files. If you want to share RAW files via email, text or social media, you need to convert them to JPEGs first.
JPEG files on the other hand are processed in-camera. Some of the image data is lost during that processing, but JPEGs are universally readable and usually look good enough to be shared.
Manual, the app I mentioned at the beginning of this post, can capture a RAW image and a full-resolution JPEG at the same time. It’s not a deal breaker for me, but it would be nice if Halide added a similar feature in a future release.
Aside from that, however, Halide is probably the best camera app I’ve used. I use it for all of my iPhone photography except throwaway JPEGs (for which I still use the native camera app).
-
The photo view just displays the photos from your phone’s camera roll, so you may also see PNG files if you have screen shots in your camera roll. ↩
