One sentence matters more than everything else on this page: the filter that protects your eyes and the filter that protects your camera are two different objects, and you need both. Eclipse glasses are certified to sit in front of a human pupil a few millimetres wide. A lens is a light-collecting funnel with an entrance pupil dozens of times larger, concentrating everything it gathers onto a shutter curtain, a mirror or a sensor. Point an unfiltered telephoto at the Sun for a few seconds and you can cook the internals — and if you are looking through an optical viewfinder while you do it, the damage will not be limited to the camera.
The filter goes on the front of the lens
A solar filter for photography mounts over the front element, so light is attenuated before it enters the optical system. Screwing a dark filter onto the back, or holding one behind a telescope eyepiece, means the full concentrated beam still reaches the glass — a good way to crack a filter and ruin an eye in the same instant.
What does not work: eclipse glasses taped over a lens hood. They are safe for eyes and genuinely useless for imaging. The film is not optically flat, so it degrades resolution badly; it is sized for a face, not for an 80 mm front element; and any tape job that comes loose in a breeze at the wrong moment turns a safety device into a hazard. Buy a purpose-made solar filter — sheet film cut to size in a rigid cell, or a screw-in solar filter for your thread diameter — and check that it seats tightly enough that it cannot be knocked off.
Everything else changes with the filter on. Autofocus hunts on a featureless disc, so focus manually on the solar limb once, at full magnification in live view, then tape the ring and leave it. Autoexposure misreads a black frame with one bright dot in it, so work in manual. And use live view rather than the optical viewfinder — it keeps your eye out of the light path entirely.
A phone or a long lens, and what each one can actually deliver
Be realistic about the size of the Sun in the frame. The solar disc is small, about half a degree across, which is why a phone at its default wide angle records a bright dot and nothing else. That is not a reason to leave the phone at home — it is a reason to give it the job it is good at.
A phone, used well, photographs the scene: the landscape going dark, the colour of the sky, the faces of the people next to you, the horizon glow around a full circle. Those images survive better than a slightly soft telephoto sun, and almost nobody comes home with them. If you want the phone on the partial phases too, a piece of solar film held flat over the rear camera works, but lock the exposure manually or it will keep trying to brighten the frame.
A camera with a long lens photographs the object. You need several hundred millimetres of focal length before the Sun stops being a dot and becomes a subject with visible structure, and considerably more before it fills the frame. If your longest lens is a kit zoom, accept it and shoot wide rather than chase a crop you cannot get. Whatever you use, shoot raw: the dynamic range you will need later is not in a JPEG.
The one window where the filter comes off
Inside the band of totality, and only during the exact seconds when the solar disc is completely hidden, the filter comes off the lens — because with the photosphere covered there is simply nothing left bright enough to damage anything. The instant totality ends, it goes back on, before the first sliver of Sun returns. That is the same rule that governs your glasses, and it is set out in full in our guide to watching safely.
Exposure during those seconds is the part people get wrong. The corona is not one brightness; it spans an enormous range, from bright inner structure close to the limb out to faint streamers several solar radii away. No single exposure captures all of it. The standard approach is to fix your aperture and ISO and bracket the shutter speed aggressively across many stops, from very fast to fairly slow, either by holding down the shutter with auto-bracketing configured or by running an intervalometer. Fast frames record the prominences and inner corona; slow frames record the outer corona and, if you are lucky, earthshine on the lunar disc. You blend them afterwards, or you simply keep the two or three you like.
Set this up beforehand. Totality here is short, and it is not the moment to be navigating menus.
Framing a Sun that is nearly on the horizon
This is the part that makes 12 August genuinely different from a textbook eclipse, and it cuts both ways. Across the Spanish band the Sun sits roughly between 2° and 12° above the horizon during totality, with its azimuth drifting from about 279° in the northwest of the country to 287° in the Balearics — figures that come from the project’s own city data and are laid out in the sunset eclipse.
The gift is that a low Sun lets you put the corona and real ground in the same frame. A black disc with the corona around it, sitting above a ridgeline or a coastline in deep twilight colour, is an image you cannot make at a midday eclipse at any focal length. It is worth composing for deliberately, with a moderate lens, rather than treating it as a consolation prize.
The costs are three. Obstruction: a hill, a treeline or a block of flats that would be irrelevant with the Sun overhead will hide the entire event, so the exact patch of western horizon on your azimuth has to be clear. Atmospheric extinction: near the horizon you shoot through far more air, which dims and reddens the Sun and softens the detail, so expect to need more exposure than any generic table suggests and expect poor seeing. And haze, which can make focusing impossible at the end — check focus early, while the Sun is still reasonably high in the partial phase.
A near-horizontal target does make the tripod easy: no awkward upward tilt, no angle finder, no ball head fighting its own limit. Use one anyway — long lenses at slow speeds in fading light are unforgiving handheld, and you want the framing to stay put while you are looking at the sky rather than the screen.
Rehearse on a real sunset
This is the highest-value hour you can spend, and almost nobody spends it. Go to your chosen spot several days beforehand, at roughly the same point in the evening, with the gear you intend to use. You will learn things no app tells you: whether the ridge you dismissed actually clips the Sun, where it sets relative to a landmark you can find again in a hurry, whether the ground is level enough for a tripod, whether the access road is gated at night, and how long the whole setup takes you.
Do the boring checks the same evening: batteries charged and spares in the bag, cards emptied, stabilisation off on a tripod, long-exposure noise reduction off so the camera does not lock up mid-sequence. Your own town’s timings and horizon are on its municipality page.
The advice nobody wants
Totality here is short. If you spend it checking the back of a camera, you will have photographed an eclipse you did not see. The corona at the edge of night, over a landscape you know, is not something a screen gives back to you afterwards.
So pick one of two plans. Either automate: prefocus, prefocus again, set the bracket, start the intervalometer at second contact and do not touch the camera until it is over. Or, better for a first eclipse, shoot the partial phases properly, get one wide shot of the darkened landscape composed and running, and then stand still with your hands empty for the seconds that matter. The photographs from that plan are worse. The memory is not.