This is the second chapter of a series about Long Exposure Photography. A new post is published every Wednesday.
Camera gear matters. And when it comes to Long Exposure Photography, it matters even more.
Whatever camera we use (it could be a phone or a 8x10 large format camera), we need to be able to control the shutter speed and increase it for extended periods of time.
The greater control you have, the better.
Now, there are still ways to shoot long exposures even if we can't control the shutter speed. We'll talk about those too.
Almost every digital camera will let you set the shutter speed up to 30 seconds.
Ideally, your camera will have a bulb mode. When selected, the camera will take an exposure for as long as the shutter button remains pressed, allowing us to go beyond those 30 seconds.
If you have a digital camera, you should find bulb when shooting in M (manual) mode. If you have an analog camera, it should be one of the options for your shutter speed.
No bulb mode? No worries, you can still take long exposures - just limited to the longest shutter speed your camera offers.
Cable Release / Shutter Remote (maybe)
We don't want to keep our finger on the shutter button while taking a long exposure. First, because we'd get tired. And second, because we'd introduce camera shake and blur the image.
Why do I say "maybe" then?
It depends on the time - only in bulb mode do we have to keep the button pressed. If we select the shutter speed in the camera, then we can release the button and the shutter will remain open for that time.
Other cameras, like some Olympus, have the option to keep the shutter open until the camera thinks the exposure is correct. No interaction needed, thus no remote required - I'm really intrigued by this feature, and I want to try it someday.
Analog cameras like my Bronica SQ-Ai have lenses with a built-in T mode. Unlike bulb, we don't have to keep the button pressed when we have T mode on. Instead, the lens will keep its shutter open until we turn the switch off. The cable release would only be required if we want to avoid camera shake when pressing the shutter button at the beginning of the exposure -the longer the exposure, the less significant that shake will be.
Lastly, some cameras don't even support a cable release even though they have bulb mode. I'm looking at you, Holga! You can still try holding the button during the entire long exposure, as I did a few months ago. As you can tell from the blurry images, do this only if you are after this look or get a blister on your finger.
Now that we know how to keep the shutter open for as long as we want and how to avoid camera shake, we are ready to move on to one of the key aspects of long exposure photography: ND filters.
The problem with having the shutter open for long periods of time is that, even using the slowest ISO available for the camera (50, or even 25) and the smallest aperture possible (say, f/64), our images would be overexposed after just a few seconds.
How can we take a long exposure of several seconds, or longer, like minutes, hours, and even days then?
We need sunglasses for our camera - 😎
Introducing Neutral Density Filters. A ND filter is a piece of glass we put in front of our lens that blocks the light. A good one will block it evenly throughout the spectrum, a worse one will create a color cast.
ND filters can block more or less light, something that is usually measured in stops.
For example, a 2-stop ND filter will let through just 25% of the light; a 10-stop ND filter will only let 0.1% of the light pass through!
As you can imagine, our shots would be rather dark if we don't adjust the settings. To increase the exposure we can either open the lens (using a smaller aperture number) or... you guessed it, increase the shutter speed!
Example: our camera is giving us settings of 1/60sec, f/7.1 and ISO100. If we use a 2-stop ND filter, we can increase the shutter speed by 2 stops: 1/60 -> 1/30 -> 1/15. If we had a 6-stop ND filter, that'd be: 1/60 -> 1/30 -> 1/15 -> 1/8 -> 1/4 -> 1/2 -> 1 second. If we used a 10-stop ND filter, we'd get 16 seconds. And if we had a 15-stop filter, we could take a 8:30 minute long exposure!
This is how we are able to shoot long exposures without overexposing our images.
What ND filters to buy
There are two types of ND filters: variable and fixed.
A variable ND filter can replace a whole set of fixed ND filters, but they come with serious drawbacks. That's why I'd recommend to stick with fixed ND filters for long exposures.
They are usually cheaper and better. Furthermore, none of the variable filters I've used indicate how many stops of light they are blocking, making it really hard or near impossible to calculate an accurate exposure time.
Among the multiple brands you can find, I can only talk about Lee. I have a few of them: 6-stop ND, 10-stop ND and 15-stop ND. The overall quality is phenomenal even though they have a slight blue cast.
I use those 3 in very different scenarios: the 6-stop ND for night photography, sunrises and sunsets, the 10-stop for right after sunrise / before sunset, and dark days, and the 15-stop filter for mid-day photography.
They are not cheap, but they will last a long time if you treat them well. Mine are still perfect after months of use.
There are more brands out there, like NiSi or B+W. Unfortunately I haven't used any of those, so you'll have to do some research if you want to find out which one is the best.
Along with the ND filters, you have to buy a holder (for example, the Lee holder) and an adapter for your lens. The adapter is surprisingly expensive too, so I bought a rather big adapter (72mm) and then got cheap step-up rings for each lens I have.
The cheap route
I know what you are thinking: long exposure photography is expensive. It is true, good ND filters aren't cheap. Luckily, there are alternatives.
One of them, that I used for a while, was to use welding glass. As I said, an ND filter is just like sunglasses for your lens, and welding glass pretty much accomplishes the same.
You can buy this kind of glass for a few bucks in a hardware store (or Amazon), and there are some tables with the equivalence in stops of light. Give them a try before going out to make sure the table you have is right, though. This is the one I used before:
As you can imagine, there's a reason why people still spend money on ND filters. A few, actually.
The first one is quality. Welding glass isn't as friendly to light as a ND filter, and you'll get softer images. Also, you'll get a strong color cast. It can be fixed in post, but it's a pain.
I didn't mind those two issues because my images aren't about being sharp, and since I shoot in black and white, I don't care about the color cast.
I still went ahead and invested in ND filters because they are so damn convenient. You can't really use a holder with welding glass, so I had to somehow attach them to the camera with a rubber band.
This approach doesn't really work with long cameras like the Bronica SQ-Ai, nor does it work well with a lot of zooms (the pressure of the rubber band will make the lens collapse, so you lose your framing).
If you shoot with DSLR-like camera and use mostly primes, and you are just getting started with long exposure photography, please go and buy some welding glass and rubber bands before investing in expensive ND filters.
It almost goes without saying, but in order to keep the camera in place during the exposure, you'll need a tripod.
The bigger and heavier the camera, the better the tripod should be. A shitty tripod will ruin your image under the lightest wind.
The longer the focal length you are using, the better the tripod should be. If you are shooting wide, a few vibrations here and there will not be noticeable. If you are using a telephoto lens, do not breathe within 10 feet of the camera or you'll ruin your shot.
I use a Manfrotto 055XPRO3 and am very happy with it (it's heavy though!).
Software-based long exposures
There's another way to take long exposures that doesn't require bulb mode, ND filters, or even a tripod! It comes with some downsides though.
Instead of keeping the shutter open, we take a bunch of shots and then blend them together with special software -for example, Adobe Photoshop.
This creates the effect of a long exposure.
One downside is that the light in your image only averages, it doesn't "add up". That means that while a 10-minute exposure of a rather dark scene can give you a properly exposed image, a million averaged shots within those 10 minutes will still produce a pitch dark image.
Another downside: taking dozens, hundreds or even thousands of shots isn't that good for your camera (shutters have a limited life expectancy). Having the shutter open for a long time is no problem, though.
And while you don't have to use a tripod -software like Photoshop can align the images-, the worse you are keeping the camera steady the more cropped your final composition will get.
Lately, I've seen some apps popping up that let you take long exposures this way, and they take care of the whole thing for you. Adobe Lightroom offers this feature, still in beta. The image you can see above was taken that way.
You might need to cover the viewfinder of your camera, if it leaks light. Cardboard or a big cloth should work, but keep the wind and shake in mind.
When using bulb mode, you will need something to measure time. You can use your phone, or go fancy and get a Casio watch like mine. Just sayin'.
It's a lot of gear
If you want to become a long exposure photographer, be ready to spend some money, make room in your backpack for all this extra gear and prepare yourself to spend a lot of time outside -actually, this is the best thing about long exposures, it's such a relaxed way to make images.
My recommendation is to go the welding glass route first, if you can, and then upgrade to a ND filter system.
As usual, do not obsess over sharpness or color accuracy too much. Long exposures are very different from regular shots and will require different compositions - we'll talk about this next week.