One of the biggest misconceptions about solar eclipses is that enjoying them requires expensive solar gear. Telescopes, tracking mounts, cameras, telephoto lenses and solar filters are all part of the kitbag for serious eclipse photographers, but the reality is that many travel with surprisingly little equipment.

That will be especially true on Aug. 12, 2026. The total solar eclipse crossing Greenland, Iceland and Spain is the headline attraction that day — closely followed by a partial solar eclipse across Europe and in Canada and the U.S. Northeast — but it won't be the only celestial event worth seeing. Just hours later, the Perseid meteor shower reaches its peak beneath moonless skies. So any eclipse kit built for the Aug. 12 eclipse should therefore be designed with one eye on a night-shoot capturing "shooting stars."

Here's what to buy for your eclipse-meets-Perseids double-header, according to your budget.

Under $50: Keep it simple

If your budget is less than $50, the good news is that you're not excluded from the eclipse experience. In fact, you can assemble everything necessary for a memorable eclipse day without spending very much at all.

The first purchase should always be certified eclipse glasses. Find some safe suppliers that meet the ISO 12312-2 standard for solar viewers, and consider buying more than you need (somebody nearby will almost certainly forget theirs). A handheld solar viewer is a worthwhile alternative, offering a slightly larger and often more comfortable view than eclipse glasses alone.

With the remaining budget, I'd focus less on astronomy equipment and more on practicality. A compact power bank and a reclining lawn chair (handy for the eclipse and the Perseids) could all be within your budget. Eclipse day involves a great deal of waiting, but if you're standing in the path of totality — or primed to see a partial eclipse — eclipse glasses and a clear sky are all you really need to experience something extraordinary.

Under $200: The biggest upgrade you can make

Once your budget reaches around $200, I'd start thinking about binoculars. For many people, the single best upgrade is a pair of dedicated solar binoculars. You can get mini pairs, such as the Celestron EclipSmart 10x25 and Lunt 6x30 Mini Sunoculars, or more substantial pairs like the Celestron Eclipsmart 10x42 and Celestron EclipSmart 20x50. We've tried them all, and can tell you that the Lunt 8x32 SUNoculars are the best (and easiest to find the sun with, which beginners always find is surprisingly small in the sky).

Unlike eclipse glasses, which show the sun as a small orange or white disk, solar binoculars reveal sunspots and make the moon's gradual progress across the solar surface much more engaging. They offer far more detail without introducing the complexity of a telescope. These are the best upgrades you can make if you're not in the path of totality and want to maximize your view of the partial phases of the eclipse.

If you're in the path of totality awaiting a total solar eclipse, forgo the solar binoculars and get yourself a good pair of conventional binoculars. The reason is simple: the partial eclipse will be interesting to watch through your eclipse glasses, but it's the totally eclipsed sun — and the beautiful solar corona that's revealed when it gets dark — which is the star attraction. You can safely see it with the naked eye or through conventional binoculars (but ONLY when the entire disk of the sun is blocked during totality, which will be for a minute or two).

A good choice would be a pair of 10x42 or 10x50, not only because you'll get a great view of the solar corona and prominences — loops of plasma from the sun's surface — but because they'll double as excellent stargazing binoculars for sweeping across the Milky Way's rich star fields, bright clusters and countless stars when it gets dark. Using products like DayStar Filters and Baader AstroSolar Safety Film ND 5.0, you can make any pair of conventional binoculars into temporary solar binoculars (use a solar filter for one lens and cap the other).

Under $500: Enter the smart telescope

At around $500, a completely different category of equipment becomes available. If we were building an eclipse kit from scratch, this is probably the budget level that would tempt us most because it opens the door to smart telescopes. Devices such as the Seestar S30 and Seestar S30 Pro (as well as the upcoming Seestar S30 Pro Eclipse Edition), DwarfLab Dwarf Mini and Vaonis Vespera Pro are portable and can automatically track the sun. All either have solar filters in the box, or their makers sell them separately (or you can make your own — see above).

The appeal of a smart telescope is that it can track the sun and photograph the eclipse while demanding relatively little attention from the user. With a solar filter fitted, a smart telescope can safely image the partial phases. For those in the path of totality, the totally eclipsed sun can also be imaged — just remember to take the solar filter off, and put it back on again when totality ends. You can then switch to capturing deep-sky objects at night, something you can do without much fuss while you watch the Perseid meteor shower peak with your naked eyes (the only way).

Over $1,000: Getting a close-up

Once you move beyond the $1,000 mark, your options are myriad. Personally, we would go straight for some image-stabilized binoculars. Models such as the Canon 10x42L IS WP, Canon 15x50 IS All Weather or Canon 12x36 IS III are among the most impressive astronomical instruments available to eclipse chasers because they combine premium optics with stabilization technology that effectively removes hand shake.

When you're standing in the path of totality looking at the sun's corona in close-up, image stabilization is absolutely what you want. If you chase solar eclipses every few years, they're worth buying for the few minutes of totality you get to experience. For the partial phases, we use a homemade solar filter on one lens and cap the other lens. Alongside those binoculars, we'd be tempted by a smart telescope for getting basic, but impressive images.

If you like a challenge, you could, of course, go straight for manual photography. Get a mirrorless or DSLR camera and a zoom lens, and you can have a go at imaging the solar corona yourself. You could also consider pairing a camera with a telescope and a star (or solar) tracking mount that can automatically track the sun. You'll also need to add a quality tripod and solar filters. If you fancy imaging the Perseid meteor shower later that night — or for any landscape astrophotography and the Milky Way — you'll also need a wide-angle lens.

Research, rehearse, prepare

The danger at this budget level is believing that more equipment automatically produces a better experience. It doesn't. Every eclipse attracts photographers and observers carrying thousands of dollars' worth of gear, but many — typically first-timers — spend totality worrying about camera settings instead of looking at the sky.

Whatever gear you buy, the best investment is always time — time to research, rehearse and prepare, and also to arrive early enough to settle into your observing location. That applies to whatever kind of solar eclipse you're in line for.

Whether your budget is $50 or $5,000, the perfect eclipse kit is the one that allows you to experience a solar eclipse — and if that includes totality, know that it will be a priceless experience.

The total solar eclipse on Aug. 12, 2026, will attract millions of viewers across northern Spain, western Iceland and eastern Greenland, while a deep partial eclipse will be visible across much of Europe, and a smaller partial eclipse will reach parts of northeastern North America.

If you're planning to watch, one question matters more than almost any other: how are you going to observe it safely?

The answer depends on where you are, your budget and what kind of experience you're after. Some people want to simply look up and enjoy the spectacle. Others want to study sunspots, photograph the eclipse or capture loved ones gazing at the eclipsed sun. Many away from the path will stay at home and livestream it. There is no correct way to watch a solar eclipse, but it's important to stay safe. Here are eight ways to safely view the Aug. 12, 2026, solar eclipse.

1. Eclipse glasses for viewing from land

If you're planning to watch any part of the eclipse with your own eyes, eclipse glasses should be your first purchase. Certified eclipse glasses that comply with the ISO 12312-2 standard block more than 99.999% of sunlight, making it safe to look directly at the sun during the partial phases.

Without them, even a brief glance at the uneclipsed or partially eclipsed sun can cause permanent eye damage. Through them, the sun appears as either a bright orange or a whitish disk against a black background. As the moon gradually moves across it, the changing crescent shape becomes immediately obvious. During the final minutes before totality, the solar crescent shrinks to an impossibly thin sliver.

For observers in Britain, Europe and North America outside the path of totality, eclipse glasses are arguably all you need. The entire eclipse remains partial, so the glasses stay on from beginning to end. Even if you're traveling to Iceland, Greenland or Spain for totality, eclipse glasses remain essential throughout the partial phases before and after totality, when the sun is still dangerously bright.

However, you should buy them early. Before every major eclipse, supplies tighten and some retailers sell out entirely. For reputable sellers, check out the American Astronomical Society's list of safe products. Recommended manufacturers include American Paper Optics, Rainbow Symphony and Thousand Oaks in the U.S. and Baader in Europe.

2. Handheld solar viewers for cruise ships

Many eclipse chasers prefer handheld solar viewers to eclipse glasses. These use the same safe solar-filter material and are made by the same manufacturers, but provide a larger viewing window. They typically hang around your neck on a lanyard, which makes them essential if you want to observe an eclipse from a cruise ship — it stops them from blowing into the sea. The actual view is almost identical to what you'll see through eclipse glasses.

3. Totality with the naked eye

If you're fortunate enough to observe from within the path of totality, there is one viewing method that rules all others during totality only — the naked eye. Although you must never look at the sun without eclipse glasses during the partial phases, during totality it's not only perfectly safe, but also the only sane thing to do.

During totality, you MUST take your eclipse glasses off to see the solar corona — one of nature's most extraordinary sights. The naked eye will also help you find bright planets around the eclipsed sun and the horizon glowing with twilight colors in every direction. If this is your first total solar eclipse, make a promise to yourself beforehand: spend at least some of totality doing nothing except looking up.

4. Solar binoculars

If observing the eclipsed sun through eclipse glasses and solar viewers leaves you unimpressed, you can upgrade your experience by opting for dedicated solar binoculars, which have permanently attached solar filters. They offer a significant jump in detail over eclipse glasses without introducing the complexity of a telescope. Sunspots become obvious, and you can more easily see them get covered by the advancing edge of the moon.

All kinds of magnifications are offered, but 10x42 is about the limit. Any more and they not only become hard to hold steady, but the eclipse then gets more difficult to find in the sky.

Since you can't use them during totality, solar binoculars are best seen as a good upgrade for observers outside the path of totality.

5. Regular binoculars

Normal binoculars are arguably a better choice if you plan to be within the path of totality. This is what experienced eclipse watchers do, and with good reason — they simply add solar filters for the partial phases, then remove them during totality for a close-up of the solar corona.

For the partial phases, solar filters must completely cover the front objective lenses. Never place filters over the eyepieces and never rely on improvised materials such as sunglasses, smoked glass or photographic filters — you must use dedicated solar eclipse filters.

However, since objective lenses come in all shapes and sizes, it's often easier to make your own solar filters using Baader AstroSolar Film. Typically, users will make a solar filter for one lens and cap the other, removing both during totality.

Image-stabilized binoculars deserve special mention. Models from Canon and other manufacturers can provide remarkably steady views of the eclipse without requiring a tripod, making them particularly attractive for travel.

6. Telescopes

The same applies to telescopes as applies to binoculars — you can buy a solar telescope with a permanently attached solar filter, or (a more popular method) put a solar filter on any telescope. However, there is another unusual option here — a dedicated hydrogen-alpha solar telescope, which reveals an entirely different side of the sun.

Rather than showing the photosphere, they isolate light emitted by hydrogen atoms in the chromosphere and show prominences arching above the solar limb as well as dark filaments across the disk. The downside is that hydrogen-alpha instruments are among the most specialized and expensive telescopes in amateur astronomy.

7. Smart telescopes

Few areas of amateur astronomy have changed as rapidly as smart telescopes. Devices such as the Unistellar Odyssey Pro, ZWO Seestar S30, DwarfLab Dwarf Mini and Celestron Origin have introduced a new generation of observers to astronomy by automating much of the traditional setup and operation.

For eclipse observing, the appeal is obvious. Once fitted with a solar filter, these systems can automatically track the sun, display images on a smartphone or tablet and save photographs with minimal fuss.

For eclipse travelers heading to Iceland, Greenland or Spain, smart telescopes can also reduce some of the stress associated with eclipse photography. Many users plan to have the telescope automatically capture the eclipse during the partial phases, then simply enjoy totality with their own eyes. Just don't spend the entire eclipse staring at a smartphone!

8. Livestreams

What if you can't travel? Or if it's cloudy? The Aug. 12, 2026, eclipse will be streamed by observatories, astronomy organizations and media outlets around the world. A livestream can never replace standing beneath the moon's shadow, but it guarantees you'll see totality even if clouds intervene.

Confirmed live streams so far include the total solar eclipse by TimeAndDate and the European Space Agency, while partial solar eclipse images will come from the Royal Observatory in Greenwich, London, U.K. When cell signal allows, some eclipse observers keep a livestream running on a nearby phone while observing the real eclipse overhead, and/or livestream views from their own telescope on social media.

What's the best way to look at the eclipse?

The best viewing method for a solar eclipse depends entirely on what you want to get from it. Just remember that the purpose of the technology is to support the experience, not replace it — no instrument can replace the experience of seeing the solar corona with your own eyes if you're within the path of totality. Choose the viewing method that helps you do that — and spend as much time as possible simply looking up.

Aug. 12, 2026, promises to be a big day for anyone interested in the sky. By day, a solar eclipse will be visible across parts of North America and Europe. For most, it will be partial, but for those within the path of totality in eastern Greenland, western Iceland and northern Spain, the moon will completely block the sun.

Hours later, the sky show continues with the peak of the Perseid meteor shower on the night of Aug. 12-13. The shower occurs when Earth passes through debris left behind by Comet 109P/Swift-Tuttle, producing bright meteors and occasional fireballs. In 2026, the timing could hardly be better. The same new moon that makes the solar eclipse possible will also create moonless skies for meteor-watching, with observers under dark skies potentially seeing 30 to 50 "shooting stars" per hour.

All of that happens after the eclipse. As a bonus, Venus will blaze low in the west during twilight, the Milky Way will stretch overhead after dark and, in Iceland, there is even a slim possibility of an early-season aurora display. Many visitors will spend 12 hours or more outdoors, arriving long before first contact and remaining under the stars until after midnight. Here’s what to consider buying for this very special day and night beneath the sky.

The total solar eclipse on Aug. 12, 2026, will bring thousands of photographers to a narrow path of totality through eastern Greenland, western Iceland and northern Spain. For many, it will be their first opportunity to witness totality, the brief period when the moon completely covers the sun and reveals its delicate corona, a wonder of nature that normally remains hidden by sunlight.

Some first-time eclipse chasers heading to the path of totality pack expensive gear they've never used before, hoping to capture expert-level images without any preparation. Others just take a smartphone. Guess who usually comes back with the best images? Practice and rehearsal — or simplicity — are key.

Remember, you should never look at the sun directly without specialist solar equipment (unless you are in totality), or you risk permanent damage to your sight.

Preparing for totality

Photographing a solar eclipse is unlike photographing anything else. Solar safety matters, exposure changes dramatically, and totality lasts only a few precious minutes. Despite that, memorable eclipse photographs can be taken with almost any camera. The best approach depends on your equipment, your experience and what kind of memory you want to bring home.

However, you don't need to stand in the path of totality to photograph some of the event. Across much of Europe, a deep partial eclipse will occur near sunset, with more than 90% of the sun obscured in many locations. In northeastern North America, observers will see a smaller partial eclipse during the afternoon. While neither experience matches the drama of totality, both offer opportunities for striking photography.

1. Take a souvenir shot through eclipse glasses

To watch any partial solar eclipse, you'll need a pair of eclipse glasses or solar viewers; the former you wear and the latter you look through. Either works well as a solar filter for a smartphone. Simply wrap some eclipse glasses around your phone's camera lens or hold a solar viewer in front, and you can take basic images of a partial eclipse.

The way to get more than just a rough souvenir shot is to put your smartphone on a tripod or purchase a Solar Snap, which not only provides a solar filter that attaches to your phone with Velcro but also includes an app that zooms in on the eclipse.

If you want pinpoint sharpness without having to spend too much or travel with much gear, get yourself a smart telescope like the ZWO SeeStar S30 Pro, DwarfLab Dwarf Mini or Vanois Vespera Pro.

2. Use a smartphone during totality

If you're traveling to Greenland, Iceland or Spain to see the total solar eclipse, take a simple smartphone photograph during totality. A smartphone cannot compete with a camera's zoom lens for close-up detail, but it's perfect for recording a wide view of the landscape you're in.

In Greenland and Iceland, the eclipsed sun will hang about 25 degrees above the western horizon, making it possible to include fjords, volcanic landscapes or distant mountains in the frame. In Spain, where totality occurs late in the day, the low altitude of the sun offers opportunities to photograph the eclipse above villages, church towers, castles and mountain ridges.

Before the eclipse, switch off auto-flash and enable RAW images if your phone offers them. Burst mode works well — as does filming the event in 4K from a tripod and extracting stills later.

3. Take a wide-angle shot during totality

Many photographers using a manual mirrorless or DSLR camera become obsessed with the corona and forget that the eclipse affects the entire environment. The resulting images often feel disconnected from the actual experience. A well-composed landscape photograph can communicate the atmosphere of totality far more effectively.

The image above was shot by expert eclipse photographer Alan Dyer, author of How to Capture the Coming Solar Eclipses, in Teton Valley, Wyoming, during the Aug. 21, 2017, total solar eclipse. It was shot with a Canon 6D and a 14mm SP Rokinon lens at f/25 for 1/10 second at ISO 100. It's one shot from a 700-frame time-lapse and was taken just as totality began, moments after the diamond ring ended, and the dark shadow of the moon is approaching from the west.

4. Capture crescent suns

When a partial solar eclipse reaches about 50% — something it will only do in extreme northeast Canada and Europe on Aug. 12, 2026 — it's possible to project crescent suns through anything with defined holes. It works really well through a colander or spaghetti spoon.

By projecting crescent suns onto the floor, the walls and people around you, unique portrait images of eclipse chasers can be created. Unlike photographs of the corona, which thousands of people will capture, photographs like this, which document the human experience of an eclipse, can be really special.

• Read: Astrotourism, dark-sky and Northern Lights travel essentials

5. Take a close-up of the solar corona

This is the classic eclipse photography setup and the one most commonly used by experienced eclipse chasers — though it demands some serious equipment, commitment and practice.

A camera fitted with a telephoto lens between 200mm and 600mm provides enough magnification to reveal detail in the corona while remaining portable enough for travel. At 400mm, the eclipsed sun fills a useful portion of the frame. At 600mm, the corona becomes significantly more prominent and fine detail begins to emerge. Lenses like the Canon RF 200-800mm f/6.3-9 IS USM, Sony FE 200-600mm f/5.6-6.3 G OSS and SIGMA 150-600mm f/5-6.3 DG DN OS Sport would be good options.

Focus carefully on the partially eclipsed sun through a solar filter, and leave the focus untouched thereafter. With a camera set to ISO 100 and f/5-f/8 aperture, exposure bracketing is essential because the corona spans an enormous range of brightness. Automated exposure sequences, or bracketing, allow photographers to capture multiple exposure levels to combine later, if desired.

It's always best to rehearse in advance; the excitement of totality very often leads to basic errors — the classic being leaving the solar filter on during totality.

6. Shoot a close-up sequence of the eclipse

If you want to shoot a sequence throughout the entire solar eclipse that shows all of the various stages, you need to be in position, ready to take images as soon as first contact occurs, and stay there until fourth contact.

Since the size of the sun won't be huge in your finished image, you don't need a huge telephoto lens. Instead, concentrate on imaging the partial eclipse at very specific times before and after totality, so that you can produce a mirror image on either side of an image of the solar corona.

7. Shoot a wide-angle sequence of the eclipse

A wide-angle eclipse sequence is a different kind of image, showing not just the changing shape of the sun, but the landscape. Start with a base exposure taken during totality, when the eclipsed sun sits in a darkened twilight sky, then layer in the partial phases at regular intervals from first contact to fourth contact.

The result can show the sun's path across the sky, the moon appearing to bite across it in the opposite direction, and even bright planets nearby. It's a powerful way to tell the whole story of an eclipse in one frame, especially if you include water, mountains, people or a dramatic horizon.

Dyer's image above is a single exposure taken with a Canon EOS Ra and a Canon RF15-35mm lens at ISO 125, f/2.8 and 1/6s. The partial phases were photographed every five minutes from start to finish of the eclipse.

• Read: Best lenses for astrophotography 2026

When it comes to the "silly money" category of lenses, they are typically those ridiculously long prime lenses that make your arms ache just by looking at them. They provide incredible image quality but lack the versatility of a zoom. Enter the Canon RF 100-300mm f/2.8L IS USM: With a constant f/2.8 aperture throughout the entire 100-300mm focal range, this lens is a serious contender for wildlife pros and sports photographers.

Of course, at an eye-watering $10,500, it's not for everyone. It's not even for "many people"; it's for a select few who either have serious money lying around or make serious money from photography, where a lens of this caliber would be a sensible investment. Still, we took it for a test drive to see just how much better the performance is compared to the more reasonably priced wildlife zoom lenses.

Canon RF 100-300mm f/2.8L IS USM: Design

• Weight is surprisingly manageable
• Internal zoom
• Solid and sturdy build quality

Although its weight is comparable to that of the much cheaper SIGMA 60-600mm Sport lens we tested recently, this lens from Canon is actually the lightest f/2.8 300mm lens on the market. And because the zoom is internal, the weight distribution feels much more manageable in the smaller package than it does on a lens that extends. (But that’s not to say our arms weren’t aching the following day).

It's also dust- and weather-resistant, which we’d expect on a lens that's this expensive. It's solid and sturdy with a plethora of lens coatings to eliminate glare and ghosting, and it feels every bit the professional-grade Canon L lens you would want.

It comes with plenty of buttons and switches on the barrel, including the standard AF/MF switch, focus limiter and IS on/off. It has another switch to choose between three stabilization modes (mode 1 for static subjects, mode 2 for panning and mode 3 for tracking erratic moving subjects).

The final switch is a focus preset button, which enables you to pre-focus on a certain spot where you expect the action to be, then switch back and forth as you're shooting. Alternatively, you can set this switch to L-Fn to utilize it as a programmable function button instead.

This lens isn't expensive because it introduces any revolutionary build features. It's expensive because Canon has combined every premium design element — internal zoom, magnesium construction, professional weather sealing, compact packaging and meticulous engineering into a lens that is designed to meet the needs of professional photographers.

Canon RF 100-300mm f/2.8L IS USM: Performance

• Outstanding image quality
• Basically no image defects
• Beautiful bokeh

Image quality is, unsurprisingly, absolutely beautiful. The shots we took are razor-sharp and clean with basically no defects whatsoever. There's a tiny bit of distortion, which is easily corrected in Lightroom (and wouldn't be detectable unless you were directly comparing the before/afters), but the images have no chromatic aberration or vignetting at all.

This lens shows every strand of fur or feather and effortlessly captures the moment perfectly every time. The bokeh is soft and creamy thanks to the constant f/2.8 aperture, which beautifully isolates the subject and blurs out distracting background elements.

We took images at f/2.8, f/4, f/5.6, f/8 and f/11 at 100mm, 200mm and 300mm to see how the lens performs across a variety of settings. Looking at the center portion of our test chart shots, the sharpest images are f/5.6 at 100mm, f/2.8 at 200mm and f/2.8 at 300mm. At 100mm, our f/2.8, f/4 and f/5.6 shots were all of similar quality in terms of central sharpness, but f/5.6 has the edge when it comes to contrast.

Those same three apertures were also very similar at 200mm, but in this instance, f/2.8 has the edge. At 300mm, there was a significant drop in contrast between f/2.8 and f/4, but both images were of similar sharpness. Unsurprisingly, the corners were sharpest towards the f/8 range, but wildlife photography rarely ever calls for sharpness across the entire frame, so the softer corners at f/2.8 - f/5.6 aren't a dealbreaker.

Canon RF 100-300mm f/2.8L IS USM: Functionality

• Constant f/2.8 aperture throughout the whole zoom range
• 5.5 stops of image stabilization
• Versatile focal length and teleconverter compatibility

A big selling point with this type of lens is the constant f/2.8 aperture throughout the entire focal range — and this is a common feature with many lenses at this price range. The wide aperture allows for faster shutter speeds, which is ideal for capturing sharp images of fast-moving wildlife or sports photography, and the wide aperture also increases light intake in low-light situations, like photographing animals at dawn or dusk or indoor sports.

Although the 100-300mm focal length wouldn't be the best choice for photographing small birds or distant subjects, it provides a good focal range to cover many other types of wildlife, like equine or safari photography, as well as a variety of indoor sports. While it's not the biggest zoom range on offer, it eliminates the need to switch between lenses while on a shoot.

This, in turn, means faster reactions to changing scenes, less chance of missing shots when the subject moves unexpectedly and better protection from dust and rain due to less swapping. Plus, when paired with the Canon 1.4x teleconverter, this lens becomes a 140-420mm f/4, and a 200-600mm f/5.6 with the 2x extender, opening up the possibilities even further.

With the lens's 5.5 stops of image stabilization (which increases to 6 stops when paired with EOS R cameras with IBIS), this lens has no trouble following fast-moving subjects smoothly and efficiently — which is useful for both image quality and viewfinder steadiness.

Should you buy the Canon RF 100-300mm f/2.8L IS USM?

It feels counterintuitive to give this lens 5 stars but say "no, don't buy it," and it's not that we're saying "don't buy it," but as good as this lens is, it's quite niche, and we are finding it hard to justify the price compared to other setups from Canon.

Currently, this lens is the only way to get 300mm at f/2.8 (unless you get a used EF 300mm f/2.8L IS II USM and an EF-EOS R adapter), so unless you really need to shoot between 200-300mm at f/2.8 and have the money to do so, there are more sensible options that either save money or give you more value.

For example, you could buy an R1 and a used EF 300mm f/2.8L lens with an adapter for around the same price as this 100-300mm lens. And if you find good deals, you could even add the Canon RF 70-200mm f/2.8L IS II USM to that lineup with a teleconverter. The only advantage the 100-300mm would then have is that you wouldn't need to change lenses — but is that worth such a steep price?

If this lens isn't for you