Cover photo by Brian van Daal.

LE HDR is a great little mode in Triggertrap Mobile, but one that some people can have trouble wrapping their heads around at first. We thought we would delve into this mode, take a look at some frequently asked questions, and provide some tips and tricks along the way!

What is HDR?

HDR stands for high dynamic range. When we talk about dynamic range, we are referring to the difference between the darkest part of your scene, and the brightest part of your scene. HDR photography allows you to shoot a set of exposures that will accommodate high contrast scenes, so ones with very bright and very dark areas. Typically this means shooting an underexposed image, a well exposed image, and an overexposed image. These images are then combined in post production to create a photo that has a great exposure throughout its dynamic range. 

What about the LE part?

Adding the long exposure element to HDR photography means we can bring effects to our photos that we wouldn't have otherwise been able to. For example water smoothing, as well as LE HDR being the perfect tool to shoot HDR at night.

Let's take a look at the app

Middle exposure -  this is effectively your bench-mark exposure. All of your other exposures are going to be over- or under-exposed when compared to it, so your middle exposure should be as close to a 'good' exposure as you can get. Before switching your camera to bulb to use with this mode, you can find out what your middle exposure should be by using a manual exposure mode, with evaluative or matrix metering.

Number of exposures - this refers to the number of exposures you want in your HDR set. Five shots usually gives you plenty of flexibility when editing. If you have a scene with particularly high contrast, you may need to experiment with shooting a larger number of exposures.

EV step - the gap between the exposures in your HDR set. One EV step works really well.


Why isn't there a 'normal' HDR mode?

A question we get asked quite a lot through our customer support channels is why we only have an HDR mode specifically for long exposure. It’s all down to how Triggertrap kit connects to the camera. As the Triggertrap Mobile kit uses the cable release port, we're fairly limited as to the control we have over the camera. The only way we can change the exposure for HDR is by having the camera set to bulb and then sending signals to the camera for the exposure lengths required. The problem is that the majority of cameras will not allow for an exposure in bulb mode shorter than around 1/15th of a second, which is why we have a long exposure HDR mode.

Why can't I shoot any faster than 1/15?

As we just mentioned, the fastest shutter speed that most cameras can achieve on bulb is usually 1/15th of a second, which is why this is the fastest shutter speed available on the LE HDR mode. Try to aim for a middle exposure of at least one second if you can, as an exposure of this length will give you plenty of stops either side. If your middle exposure is too short, with a large number of exposures in the HDR bracket, or with too large an EV step, your camera will not be able to capture all of the exposures. The Triggertrap Mobile app will try to warn you when a situation is impossible by limiting your number of exposures, or you could end up with a series of exposures all taken with the same shutter speed.

If you find that your middle exposure isn't one second, try stopping down your ISO or aperture and adjusting your shutter speed to compensate. If this still isn't enough, try adding an ND filter to the front of your lens. If you're not sure how to use an ND filter, take a look at our tutorial.

When can I use LE HDR?

An obvious use for long exposure HDR photography is for capturing nighttime HDR shots. But this mode does wonderful things to your landscape photography too. By using LE HDR to create the photo below, we were able to achieve some silky water smoothing as well as giving the illusion that no boats had passed.   

LE HDR of the O2 Arena taken with Triggertrap Mobile.

Something else that LE HDR mode can make light work of is interiors. It can be tricky to balance the exposure indoors, especially when there is a window in view. The image on the left shows as close to a good exposure as we could get without using HDR. There are areas in shadow as well as areas completely blown out. By using LE HDR to create the image on the right, we have been able to achieve a much more even exposure in the shadows and highlights. 

LE HDR shot taken with Triggertrap Mobile.
LE HDR shot taken with Triggertrap Mobile.


  • When shooting an HDR set, it's important to not move the camera at all between shots, so make sure to get yourself a sturdy tripod. When it comes to editing, we're going to be combining our shots. This means that we want our composition to be exactly the same each time.
  • Another point to consider is when you are framing up your shots, take a look and see if there is anything moving in the frame. Moving elements like water or clouds can really benefit from the effect that long exposure gives. But other elements not so much. Take a look at the image below:
LE HDR shot taken with Triggertrap Mobile.

The moving crane in the shot above caused a bit of a problem when editing the HDR together, as well as the red flag blowing in the wind. 

Want to go out a shoot some LE HDR?

If you've now got the taste for LE HDR but need a little bit of help setting up, check out our How to shoot an LE HDR photo tutorial below. If you've got all the shots but don't know where to start with the editing, our How to assemble an HDR image tutorial will be able to help you out. 

We want to see your photos

Taken any cool HDR shots lately? We would love to see your photos over on our Flickr pool. Get in touch by tagging us #Triggertrap and @Triggertrap on Twitter, Instagram, and Facebook