Long Exposure Fetish-Sony A7RII

Over the years I have seen and admired a lot of long expousre shots and even shot a few but never did any serious stuff. And then one day the bug bit me!

A long exposure shot is one where your shutter speed is very slow so as not to freeze the action but to allow it to happen while the shutter is open thus rendering water, clouds and anything flowing as a soft misty subject rather than a sharp, ‘frozen by the shutter’ type subject.

And if you try it in cityscapes you can make people vanish out of your composition and just get the architecture…that’s a pretty interesting thing actually!

What one needs:

A wide angle lens (typically):
Given that landscapes are suited best for this genre it is best to have a wide angle lens (anything wider than 50mm) but that does not preclude you from trying some creative stuff with a standard or tele lens if that is all you have

I took all the photographs appearing here with a Canon 16-35 f4 L IS lens

Camera with ‘Bulb’ Setting:
Setting the camera shutter speed to the ‘Bulb’ mode ensures that the shutter is open as long as you desire. Generally the maximum time the shutter can remain open is about 30 seconds if not set in ‘bulb’ mode
I used a Sony A7RII for all these shots

Remote trigger with lock:
Now if you need the camera shutter to be open longer than 30 seconds it is impractical to click and hold it for that long. Therefore you would need a remote release with a ‘lock’ function which you would release once the exposure time is up
I used the Sony remote trigger with lock for these shots

Neutral Density Filters:
These are available in different configurations. They essentially cut light thereby increasing your exposure time for a given aperture value. They can cut light anywhere between 1 stop to 10 stops or more and if you need more than that you can also stack filters one on another but if you are going to stack you are better off buying square filters rather than round ones as if you stack round filters you might get some ugly vignetting and ruin your pictures

If your picture is going to have some sky you also would need a neutral graduated filter which basically is half dark so you can cut light only from the sky and render an even exposure. It is rectanglular rather than square so that you can adjust the dark portion to cover just the sky if the sky is on the top third or two thirds of your composition rather than exactly half of the frame

Also read a lot of reviews of the filters as cheap filters will leave color casts when the exposure is long thus ruining color pictures and some also render the picture soft (loss of sharpness)
I got the Formatt-Hitech filter set of 1 10 stopper, 1 4 stopper and a neutral graduated filter

Sturdy Tripod:
Obviously if your exposure is going to be long then you need a tripod and if you are going to click in windy conditions (best for moving clouds) and/or in flowing water you need the tripod to be really sturdy
I used a Giottos tripod with Ballhead for this series

Long Exposure App:
Now when your exposure time goes beyond 30 seconds not only do you need a timer/stopwatch but also some means to calculate your exposure time. There are several apps available in andriod and apple platforms for this
I used the app called ‘LE Calculator’

The Shooting Process:

Composition: Obviously the first step. Set your camera on the tripod and compose the picture
Most mirrorless cameras have a tiltable LCD screen at the back which helps if your camera is at a low angle. You can tilt the LCD and view your composition in live view

Exposure Calculation: Once you have set the camera up decide what aperture value you need for the shot. Generally f8-f11 should be adequate if you are shooting with a wide angle lens as the hyperfocal distance formula will ensure that pretty much everything is in focus. Read more about Hyperfocal Distance here
Going beyond f11 is not recommended as lens diffraction sets in and you might lose sharpness. Read about the reviews of the particular lens you have and at what aperture diffraction sets in and avoid those very narrow apertures

Focusing: You can use autofocus to focus but make sure you turn it to manual focus mode on the lens after you get the focus locked on. Also make sure you focus at approximately the hyperfocal distance as per the aperture you have set if you need a lot of foreground and background (till infinity) to be in focus

Note Shutter Speed: In the Aperture Priority Mode note down the shutter speed as indicated by the camera
Mirrorless cameras offer an advantage over SLRs in this case as you can exactly see what is falling on the sensor via the LCD/electronic viewfinder so you will never go wrong with exposure

Manual Mode: Now turn your dial to M mode, set Shutter Speed to ‘BULB’, set the same aperture and ISO as you had in aperture priority mode and then start stacking filters. You will notice that the viewfinder goes very dark and this is why you had to take exposure reading and complete focusing before stacking the filters
Now reach out to the ‘app’ and figure out what the shutter speed should be vis a vis the ND filter value you have stacked on the lens

For example:

At f11, for ISO 100, in aperture priority mode if your camera suggested 1/10 shutter speed then:

With a 10 stop filter:
Shutter Speed: 1 min 42 seconds

With a 10 stop filter stacked on a 4 stop filter (net 14 stops)
Shutter Speed: 27 min 18 seconds

Also insert the neutral graduated filter to the extent you want to cover the sky. Do this before you stack the ND filters as if you do it after you might not be able to see anything

Click: Now with your shutter speed in ‘BULB’ mode press the remote trigger and lock it while simultaneously starting the stopwatch on the app. Wait till time runs out on the app and release the lock. Note that for long exposures a little bit of difference between locking/releasing the shutter compared to the app will not cause a lot of change in exposure so you don’t have to be too worried about timing it perfectly

View: View your output and enlarge to see if the tripod/cam moved and if everything is tack sharp and your overall exposure is good else repeat the process with adjustments

Notes: Make sure your sensor is clean and devoid of dust as at higher/narrow aperture values the dust becomes visible and will appear as spots on the final picture. If there is dust you will have to clean it in the Post Processing stage