Take a long exposure!

Long exposure is a photographic technique. As its name suggests, it involves taking a rather long shot, from a few seconds to several minutes or tens of minutes.

This technique creates a sensation or illusion of movement in an image. (which usually freezes / fixes a reality). It is often said that an image is the immortalisation of a moment in time. Long exposure captures a space in time, which is different from video.

Long exposure photography during the day will give the illusion of movement in the clouds by creating trails, and a creamy, dreamy effect in the waterways, etc... Obviously, to get the best results, you need movement! There's no point trying a long exposure if there isn't! Other examples: photographing waterfalls or waves on the beach gives fantastic misty or vaporous effects! As you can see, long exposure is really creative!

What do you need to do long exposures? Good news! First of all, you don't need top-of-the-range or professional equipment to make beautiful long exposures!

• Your camera (obviously! otherwise it could get complicated! 😁)
• Your tripodWhen you're shooting, you'll need to keep your camera perfectly steady at all times, so a tripod is essential. (Otherwise, beware of camera shake).
• A wired or wireless triggerto release the shutter and/or keep it open for the set time (programmable shutters are available).
• Neutral density (ND) filtersThis is essential for long exposures in the middle of the day. These more or less dense neutral grey filters will allow you to reduce the amount of light reaching the camera's sensor, allowing you to extend the exposure time as much as you need for your effects. You can even superimpose several filters! You will commonly find ND400 ND800 ND1000 filters. The numbers are the exposure time multiplication coefficients:
  • For example, with ND 1000, and a photo normally taken at 1/100, when you add the ND1000 filter, the exposure will last 100×1000 =100000 or 10 seconds.
  • Don't worry either if your neutral density filter tends to give your image an overall tint, this is easily corrected in post-production.
• Your mobile phone to either calculate and time or, better still, use an application to calculate long exposures! ✌️

The first thing with long exposure is to take your time, because the shots are long 😏 sometimes even very long!

• Setting up your camera on your tripodand find the right location for a good shot!
  • Deactivate the stabiliser, as it is useless on a tripod and, paradoxically, if there is nothing to stabilise, pumping the camera in search of stability can lead to a loss of sharpness!
• Set your camera to RAW file format for shooting. This format gives you all the flexibility you need for post-production processing, in particular for correcting white balance (as well as possible colour drift due to neutral density filters).
• Use the lowest possible ISO sensitivity. The lower the sensitivity, the less noise your photos will have. Some cameras have a "long exposure noise reduction" option, so if this is the case, activate it.
• Choose shooting mode Av: aperture priority.
• Setting your aperture I suggest 2 possibilities:
  • or use the best aperture value to obtain the best sharpness generally somewhere between f/5.6 and f/11
  • or (if your objective is good) close your diaphragm to f/22 or more. (unless you have already noticed diffraction, i.e. a big loss of sharpness at these apertures). f/22 or more are very small apertures which will limit the entry of light and will already naturally lengthen the exposure time.

I think everything's ready, set up, framed, now focus where you want and take the shot! Check that the photo is exactly what you want.

If you're happy with the exposure, framing and sharpness, you're all set. Now switch off the autofocus if you had been using auto-focus (once the focus is set, you don't need to touch it again, and in any case your autofocus won't work with neutral density filters because it will be too dark).

Now that If you have a "reference" photo with the basic exposure time, we can calculate the long exposure!

• Set the shooting mode to B (for Bulb) or T depending on the make of your camera..
  • Bulb mode is a capture mode that keeps the shutter open as long as you keep your finger on the button, and closes the shutter when you release it. This makes it possible to take photos lasting more than 30 seconds, which is not possible with other modes.
  • Some recent or top-of-the-range cameras (such as my Canon 5D IV) have timers to determine the exposure time. So there's no need for a shutter release!
• Place one or more ND filters depending on the creative effect you are looking for. (The more you put in, the stronger the effect will be, so determine this according to your tastes and the speed of movement of clouds, waterfalls, etc.).

Example of how to calculate exposure time

Let's assume that the reference photo taken above was 1/50 at f/11 and that I used an ND800 filter; my exposure time would be : 800×50 = 4000 or 4 seconds.

However, be careful, if I've placed 2 or more ND filters, the effect multiplies: if I placed an ND800 and an ND1000: I would have a total ND of 800×1000 = 8000.

My calculation of the pause time (still based on my reference photo taken at 1:50) will then be 50×8000 = 400000 or 400 seconds, i.e. 6 minutes 40 seconds.

The shot

Once the calculation has been made, there are 2 possibilities:

• Manual: Press and hold down your remote control, at the same time as the stopwatch on your phone, for the preset time. On release the shutter will close, the photo is taken. (Fortunately, some remote controls can be locked, phew 😜 ! That avoids thumb cramps!
• Automatic: you can either programme your appliance if it has this function, or programme your remote control if it's programmable! I have to admit, it's really practical!

Don't be surprised if the camera remains in reflection for a long time after capture! This is perfectly normal.

Well done, your long exposure photograph is in the box! All that remains is to post-process it ! I'll see you in a future article where on my youtube channel!

Photographically yours,

David