Long Exposure On iPhone Explained

There are some terms used in iPhone photography that are, for the most part, relevant to photography in general, but some terms, when referring to the iPhone, are a little more nuanced. And quite often we just accept them as they are used because we know what is meant.

Let’s start by looking at the term “iPhoneography”. It’s not hard to imagine that it means iPhone photography, and that’s exactly what it means. The term was coined in 2008 by a chap from the UK named Glyn Evans, who, after coming up with the term, started The iPhoneography Blog where he shared his photos taken with an iPhone. The term became a popular hashtag on social media and has been going strong ever since. I decided to call my podcast “The iPhoneography Podcast” so folks would know exactly what it was about and I was surprised when I went to get the URL “iphoneography.ca” and found that it was available. Mr. Evans already has the dot com version locked down.

Long Exposure is a term being used more and more in iPhoneography, but the iPhone doesn’t – or can’t – do along exposure in the same way a traditional camera can. In fact, I like to refer to it as “Long Exposure Sequences”. Most traditional cameras have a mechanical shutter that can remain open for as long as the photographer wants. The iPhone has an electronic shutter whereby the sensor actually turns on and off to create the exposure. Prior to the iPhone 14 Pro, the maximum time the electronic shutter (we’ll call it shutter going forward) could stay active was only 1 second. Apple did this by design to prevent the chipset inside the phone from overheating. The 14 Pro phones have a very powerful set of processors and the shutter can now stay active for up to 10 seconds. This is only possible, however, in Night Mode. More on that shortly.

Long exposure with the iPhone goes back as far as the iPhone 4, which was released in 2010. The first app to do this was Slow Shutter Cam and it’s still very popular today. Apple introduced Live Photos in 2015 with the iPhone 6s. But if the iPhone’s shutter can only work for 1 second, how did we take long exposures? Well, apps like Slow Shutter and iPhone’s Live Photo took a series of exposures and stacked them, and of course, it’s not as cut and dry as that. 

I’ll start with Live Photos. When you open the Camera app, your iPhone is actually taking frames, without tapping the shutter button, and temporarily storing them, then deletes them if they aren’t needed. For a Live Photo, at the point when you do tap the shutter, the camera saves the frames taken 1.5 seconds before and records frames for 1.5 seconds after, plus (and I’m assuming this is only when Live Photo is turned on) it records audio and saves it for that 3 second time period. It then puts all the frames and the audio together to produce a short 3 second clip that isn’t a movie per se, but more like an animated gif of full resolution images with audio. But if a Live Photo is like a 3 second “movie” with sound, why am I talking about it here? 

When iOS 11 was released in 2017, Apple added three effects to Live Photos: Loop (that would play the Live Photo repeatedly), Bounce (that would play the Live Photo forward and reverse repeatedly) and Long Exposure (which is stacking frames). When the iPhone stacks frames, it averages the exposures as the frames are built so the final output isn’t over exposed. At least that’s how I suspect it is done. There may be a more technical way to explain it, I’m not sure. With a Live Photo set to the Long Exposure effect, the images are only stabilized as well as the camera is able, so if there is enough camera movement, the final image could come out blurry. 

Night Mode, as I mentioned earlier, does long exposure a little differently, sort of. When it first appeared on the 11 Pro series phones, it could only have the shutter active for a maximum of 3 seconds. The longest Night Mode shot that was available on the 11 Pros was 10 seconds and the Neural Engine determined the length of exposure in each frame and how many frames were required to produce an image, depending on the lighting conditions. Starting with the 12 Pro series, the maximum exposure time was increased to 30 seconds and anything over 10 seconds required a tripod, so, theoretically, a 30 second shot would consist of ten 3 second exposures. The 14 Pro phones, with their increased power in the chipset, can now do a 30 second Night Mode shot using three 10 second exposures. That sure makes a difference in what you can achieve. 

Night Mode is more complex than anything I can say about it, but I think I covered the main points here, and while taking photos at night is cool, the ability to capture long exposures in the middle of the day without a tripod is even cooler. There are some apps that can produce long exposures in RAW but that’s another article for another day. Slow Shutter Cam is a good app, there’s no doubt about it, but there’s a recently released app that I’ve been using a lot lately that is simple, both in its design and ease of use, but very powerful in how it creates great long exposure images. What sets it apart from the rest is its ability to do this without a tripod. The app is called ReeHeld, and the special part of it is that you can do long exposures in broad daylight for up to 30 seconds… handheld! Yes, 30 seconds handheld. And when you nail it, the results are amazing. 

Mastering ReeHeld is easy. You point, touch to focus if you wish, select the duration of your long exposure, hold still and shoot. The app now has a stability indicator on the screen while the exposure is building to help you keep the camera still. What ReeHeld does under the hood is magical. Building the image, or taking a long exposure sequence, works like any other app by using frame averaging. The difference with ReeHeld is that the app uses AI to align the frames as opposed to just using the image stabilization, whether it’s optical or with the sensor. There is one other app that does handheld long exposures, Spectre, but it relies only on the image stabilization of the camera and isn’t nearly as good as ReeHeld for image clarity. Spectre is also limited to a 9 second exposure.

ReeHeld’s image alignment technology is more forgiving than the stabilization method so good results are easier to achieve, but you still have to be careful in how you take the shot. Any off axis movement can cause parts of the image to blur, and that is why they’ve included the indicator as it really helps with not only keeping the camera centred, but it also keeps you from “twisting” it on its axis.

Most long exposure apps have features that allow you to adjust exposure settings before the shot, which can have an effect on the final image. Even Night Mode allows you to move the exposure slider that is present in the Apple Camera app, but ReeHeld doesn’t have this. It relies on the camera’s meter reading to give the best exposure, and in my experience, it does a very nice job. I always do some minor tweaks to my images in post to make them more to my liking anyway, but it’s not necessary. 

We are living in very exciting times when it comes to iPhoneography. Taking long exposures is one of my favourite types of photography with my iPhone, and the ability to do it not only in bright daylight conditions, but without a tripod no less, just makes it so much fun. There are so many apps available for iPhone users to do this type of work, but sadly, the same is not the case in the Android space. The Android market has so many phone types that take amazing photos, and those phones have different sets of proprietary software built in that developing an app that will work on all of them is difficult. The only app for Android that I know of for this type of long exposure work is called Motion Pro, but I obviously don’t have any experience with it. I believe some Android phones have long exposure functionality built in, but again, I’m not familiar with that side of it. 

Long exposure photography with iPhone is fun, can be rather easy to do, and with it, we can create some amazing images. I’ve been doing it since 2012 when I first discovered Slow Shutter Cam with my iPhone 4s. The close up image of the water flowing through the leaves was a 4 second exposure using Slow Shutter and since I didn’t have my tripod, I had to prop my iPhone on the lens cap of my Canon camera. The other image, the one of a creek, was a 15 second handheld shot using ReeHeld. We’ve come a long way with this stuff and I’m excited to see what’s around the corner.

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