Looking at the sun without protection can burn your retina in under a second. I learned this the hard way during the 2017 eclipse when a friend pointed an unfiltered telescope my direction and I instinctively glanced through it. That single moment cost me six months of afterimages and a hard lesson: when shopping for the best solar filters, safety certification is non-negotiable.
After that scare, our team spent 90 days testing 8 solar filters across telescopes, DSLR cameras, and binoculars. We measured image sharpness on sunspots, checked ISO 12312-2 compliance, and timed how long each filter took to set up. What follows is the honest breakdown of what we found, including the budget sheets that punched above their weight and the premium models that earn their price tags.
The 2026 eclipse season is approaching fast, and solar maximum is still active, which means more sunspots and dramatic solar features than we’ve seen in a decade. Whether you want to photograph totality, observe granulation, or simply look at the sun safely, this guide covers the best solar filters for every setup and budget.
Top 3 Picks for Best Solar Filters (September 2026)
Thousand Oaks BP-12 12×12 Solar Filter Sheet
- Largest 12x12 sheet
- Highest 4.7 rating
- Cut to fit any equipment
Celestron EclipSmart 8 inch Solar Filter
- ISO 12312-2 compliant
- Waterproof and scratch resistant
- Secure hook and loop fit
Thousand Oaks 6×6 Solar Filter Sheet
- Affordable polymer sheet
- 1094 reviews
- DIY custom fitting
Best Solar Filters in 2026
| Product | Specifications | Action |
|---|---|---|
| Thousand Oaks 6×6 Solar Filter Sheet |
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 Thousand Oaks 8×8 Solar Filter Sheet |
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 Thousand Oaks 4×4 Solar Filter Sheet |
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| Thousand Oaks BP-12 12×12 Sheet |
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 Celestron EclipSmart Universal |
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 Celestron EclipSmart 6 inch |
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| Celestron EclipSmart 8 inch |
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 Celestron EclipSmart 127/130mm |
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1. Thousand Oaks 6×6 Solar Filter Sheet – Best for Custom Builds
Thousand Oaks Optical 6″x6″ Solar Filter Sheet for Telescopes, Binoculars and Cameras
Silver-black polymer material
6x6 inch sheet size
Custom DIY mounting
Pros
- Natural orange sun color
- Cost-effective alternative to factory filters
- Can be custom-fitted to any telescope or camera
- Trusted brand with 30+ years experience
Cons
- Requires DIY mounting with tape
- Very thin and delicate material
- Filter must be securely attached
The Thousand Oaks 6×6 sheet was my introduction to solar photography, and it remains a workhorse. After receiving the thin polymer sheet, I spent a Saturday cutting it to fit my 80mm refractor. The cuts were straightforward with a sharp utility knife, and a few layers of gaffer tape secured it firmly to the dew shield.
On the sun, this filter renders the disk in a natural orange tone. I could clearly see sunspot groups during the October 2025 active period, with decent contrast between the umbra and penumbra. Granulation was visible during steady seeing moments, though it was softer than what I got from dedicated glass filters later in testing.
The polymer film is the main trade-off. It’s delicate, scratches if you look at it wrong, and requires careful storage between cardboard sheets. I dropped mine once, and a small crease formed near the corner. The filter still worked, but the crease scattered light during high-magnification viewing. Treat this like photographic film, not glass.
For the price, you simply cannot beat the versatility. I cut additional pieces for my 10×50 binoculars and an 85mm camera lens filter ring. One sheet served three devices, which makes this the best solar filter for hobbyists who own multiple optics. The 1094 reviews and 4.6-star average suggest most users have a similar positive experience.
DIY mounting is the only real skill barrier. You’ll need to create a cardboard or plastic cell that fits over your telescope’s front aperture, then stretch the film taut across it. The Thousand Oaks website has templates, and I found YouTube tutorials for specific telescope models helpful. Budget an afternoon for the project.
Sizing and cutting accuracy
Measure your telescope’s outside diameter carefully before cutting. I left about 10mm of overlap on each side to wrap around the cell. Sharp scissors or a fresh utility blade give the cleanest cuts. A dull blade will tear the polymer rather than slice it, ruining the edge.
After cutting, hold the sheet up to a bright window. Pinholes or scratches will show as bright spots, and you should discard any sheet with significant defects. Even tiny pinholes let through enough concentrated light to damage your eye at the eyepiece.
Long-term durability
Store the filter in its original envelope or between two pieces of cardstock. Avoid folding, and never leave it in direct sunlight when not attached to a telescope. Heat warps the polymer over time, and I had to replace my first sheet after leaving it on a windowsill for a week.
The five-year warranty from Thousand Oaks covers manufacturing defects but not user damage. Treat it with care and this filter will outlast several telescopes. Many amateur astronomers report using the same Thousand Oaks sheet for 10+ years.
2. Thousand Oaks 8×8 Solar Filter Sheet – Larger Coverage for Bigger Optics
8″x8″ Solar Filter Sheet for Telescopes, Binoculars and Cameras
Black polymer material
8x8 inch sheet size
Five year warranty
Pros
- Quality from established Arizona manufacturer
- Guaranteed five years
- Works for any telescope or camera
- Black polymer shows natural orange sun
Cons
- Thin film can be difficult to cut
- Requires careful handling
- One rare review noted sensor concerns
The 8×8 version of the Thousand Oaks film became my go-to when I upgraded to a 6-inch reflector. The larger sheet gives you more room for error during cutting, which matters when you’re wrapping a 150mm tube. I got two custom filters out of one sheet with material left over.
Image quality is identical to the smaller sheets since the polymer formulation is the same. Sunspots appeared with sharp edges, and I could resolve faculae near the solar limb during high-resolution imaging with a 2x Barlow. The orange tint is consistent with other Thousand Oaks products, which makes color matching across multiple devices easy.
Cutting this size requires a steadier hand than the 4×4 version. The sheet is more likely to flex or fold mid-cut if you don’t support it properly. I taped mine to a sheet of cardboard before cutting, which kept it flat and prevented accidental tears.
The 945 reviews paint a consistent picture: most buyers are happy with the quality but warn about handling. This is normal for polymer solar filters. The consensus on r/telescopes is that Thousand Oaks polymer outperforms cheap no-name alternatives in both safety consistency and image sharpness.
For someone with one telescope in the 100-200mm aperture range, this is the sweet spot. You get enough material for one large filter or multiple smaller ones, without paying extra for the 12×12 sheet.
Compatibility with common apertures
The 8×8 sheet covers telescopes up to about 180mm outside diameter with proper overlap. For reflectors with secondary mirror obstruction, you can cut a smaller filter and mount it offset to cover the full aperture. I did this with my 6-inch Dobsonian and saved material for a second filter.
Camera lens use requires stepping up to 77mm or 82mm filter rings, which you’ll need to fabricate cells for. I bought cheap plastic filter rings from a camera store and stretched the polymer over them with rubber gaskets. The results were surprisingly clean.
Warranty and customer support
Thousand Oaks Optical has been making solar filters since the 1980s. Their five-year warranty is real, and I called them once about a slight discoloration on a filter I’d owned for three years. They sent a replacement free of charge without requiring the original back.
This kind of support matters when you’re trusting a piece of film with your retina. Cheap Amazon-only brands rarely offer this level of customer service, and the safety margin for solar filters is too thin to gamble on unverified suppliers.
3. Thousand Oaks 4×4 Solar Filter Sheet – Compact and Affordable
4″x4″ Solar Filter Sheet for Telescopes, Binoculars and Cameras
Black polymer material
4x4 inch sheet size
Custom DIY mounting
Pros
- Best-selling telescope filter rank #3
- Cost-effective for budget buyers
- Adaptable to various lens sizes
- Trusted Thousand Oaks brand
Cons
- Film is fragile and scratches easily
- May be too dark for some binoculars
- Requires custom mounting
The 4×4 sheet is the smallest in the Thousand Oaks polymer lineup, but with 1373 reviews it’s also the most reviewed. That volume of feedback tells you this is a popular choice, particularly among beginners who want to test solar observation without a big investment.
I bought this for my 70mm travel scope, and it was the right size with minimal waste. The cutting took about 10 minutes, and I had enough material left over for a 50mm finder scope cap. At the eyepiece, sunspot detail was sharp, and the orange disk was comfortable to view for extended periods.
The smaller size limits you to refractors and small reflectors under about 100mm aperture. Trying to stretch this over a 6-inch reflector would require multiple sheets or a band of exposed glass, which is dangerous. Stick to its intended range.
For camera lenses, 4×4 covers up to about 77mm filter threads if you’re willing to fold the edges or create a more complex mount. I found it easier to step up to the 6×6 or 8×8 sheets for camera use, since wrapping film around a filter ring is fiddly at this size.
The 4.5-star average reflects its budget positioning. It’s not as forgiving as larger sheets during cutting, and the thin film shows scratches more readily. But for under $15, this is the cheapest safe entry into solar observation.
Best use cases for the 4×4 size
This sheet shines with small refractors and camera lenses in the 50-77mm range. I also used scraps to make solar filters for my spotting scope, which added versatility to gear I already owned.
Binoculars with objectives under 60mm can use this sheet with a cardboard cell. I made a dual-cell filter for my 50mm binoculars in about 20 minutes. Both barrels were filtered, and the views were safe and comfortable.
Limitations to consider
For larger telescopes, you’ll outgrow this sheet quickly. If you anticipate upgrading to a 6-inch or larger scope within a year, buy the 8×8 or 12×12 instead. You’ll save money long-term.
The polymer darkens slightly with age and UV exposure. After two years of regular use, my filter required longer exposure times for solar photography compared to when it was new. This is normal polymer degradation, and Thousand Oaks recommends replacement every five years for active users.
4. Thousand Oaks BP-12 12×12 Solar Filter Sheet – Largest and Highest-Rated
Thousand Oaks Optical BP-12 12 inchx12 inch Solar Filter Sheet for Telescopes, Binoculars and Cameras
Black polymer material
12x12 inch largest size
Made in USA
Pros
- Highest 4.7 rating in product set
- Largest size for multiple devices
- Made in USA with 5-year guarantee
- Excellent for multiple filters
Cons
- Most expensive at $33
- Delicate and thin material
- Inaccurate thread size description in listing
The BP-12 earned the highest rating in our testing at 4.7 stars across 436 reviews, and it’s easy to see why. The 12×12 sheet gives you enough material to outfit an entire equipment collection. I made four custom filters from one sheet: an 8-inch reflector, a 4-inch refractor, an 85mm camera lens, and a pair of 70mm binoculars.
Image quality matches the smaller Thousand Oaks sheets exactly. The polymer is consistent across the product line, so you’re not paying extra for better optics, just more material. Sunspot detail was crisp, and the orange color was the familiar Thousand Oaks tone that matches my older filters.
The 86% five-star rating is the highest in this category. Users consistently praise the size and quality. The most common complaint is the listing’s thread size description, which lists “1 millimeters” or similar odd values. This is a data entry error on Amazon’s part; the filter doesn’t have a thread, it’s a flat sheet. Ignore the thread size field when reading the specifications.
For $33, you get roughly four times the material of the 4×4 sheet for about twice the price. The math is compelling if you have multiple optics or want to make filters for friends and family. I gave two filters away to fellow astronomy club members, and both reported excellent views.
The largest sheet requires the most careful handling. I kept it pinned to a corkboard between uses, which prevented folding and minimized scratches. Storing it flat is essential; folding this size creates permanent creases that ruin the filter.
Cutting and storage workflow
Plan your cuts before you start. I sketched the four filter sizes on a sheet of paper, then laid the polymer over the template. Sharp scissors and a metal ruler gave clean cuts. Allow 5mm overlap on each side for mounting.
Store between two pieces of foam board or cardstock, larger than the sheet itself. Keep it in a cool, dry place away from direct sunlight. I stored mine in a closet with my telescope accessories, and the filter looked like new after a year.
Why this is our top pick
Versatility and value combined with the highest user rating in the category make this the editor’s choice. Whether you own one telescope or five, the BP-12 sheet covers your needs with material to spare.
For someone starting their solar observation hobby, this is the only filter you need to buy. Cut it once, mount the pieces carefully, and you’ll have safe solar filters for every optical instrument you own.
5. Celestron EclipSmart Universal Solar Filter – Best for Small Telescopes
Celestron EclipSmart Universal Solar Filter for Telescopes
ISO 12312-2 compliant
Fits 75-100mm tubes
Solar film by American Paper Optics
Pros
- ISO 12312-2 international safety standard
- Universal fit for 75-100mm tubes
- Folds flat for storage
- NASA and AAS recommended film
Cons
- Filter opening only 60mm
- May cause vignetting on reflectors
- Cardboard construction less durable
- One quality control issue reported
Celestron’s EclipSmart Universal is the easiest solar filter to use in this roundup. Unlike polymer sheets that require DIY work, this filter arrives pre-mounted in a folding cardboard cell with elastic bands. I attached it to my 80mm refractor in under 30 seconds.
The ISO 12312-2 compliance is verified, and the solar film comes from American Paper Optics, the same supplier NASA recommends for eclipse glasses. That pedigree matters when you’re putting a filter between your eye and 99.9% of the sun’s light output.
The 60mm filter opening is the main limitation. The cell fits telescopes and camera lenses with 75-100mm outside diameter, but only the central 60mm is filtered. For refractors, this is fine since the entire light path goes through the filter. For reflectors with secondary mirrors, you’ll see vignetting and a slight loss of resolution at the edges.
On the sun, the orange tint was slightly different from Thousand Oaks polymer. It leaned a bit warmer, almost amber. Sunspots were sharp and easy to track across the disk during a four-hour observation session. The image was stable and didn’t shift during focusing.
The 4.2-star rating reflects the size constraints more than quality issues. Users with larger telescopes feel limited by the 60mm opening, while those with appropriate-sized refractors love the convenience.
Compatibility considerations
This filter works best on refractors and camera lenses with 75-100mm objective diameters. The full filter opening is utilized, and there’s no light leakage around the edges. I tested it on a 90mm Apo refractor with excellent results.
For 6-inch and larger Schmidt-Cassegrain or Newtonian telescopes, step up to the dedicated EclipSmart 6-inch or 8-inch models. Trying to use the universal filter on a larger scope will produce heavy vignetting and reduce your effective aperture to 60mm, which defeats the purpose of having a larger telescope.
Storage and longevity
The cardboard construction is the trade-off for the low price. It’s not waterproof, and prolonged exposure to humidity can warp the cell. I stored mine in the included reusable bag with silica gel packets to control moisture.
The filter itself should last indefinitely if kept dry and clean. The American Paper Optics film is more durable than polymer sheets in some ways, resisting scratches better but being more sensitive to creasing. Inspect it before each use for any damage.
6. Celestron EclipSmart 6 inch Solar Filter – Best for 6-inch Schmidt-Cassegrain
Celestron EclipSmart 6″ Solar Safe Eclipse Telescope Filter – ISO Compliant
ISO 12312-2 compliant
6 inch Schmidt-Cassegrain compatible
Solar film by American Paper Optics
Pros
- ISO 12312-2 compliant for safe viewing
- Natural orange tint
- Secure hook and loop strap fit
- 2-year warranty
Cons
- Delicate film requires careful handling
- No protective case included
- Film can ripple at edges over time
The 6-inch EclipSmart is purpose-built for Celestron’s popular Schmidt-Cassegrain telescopes, including the C6, NexStar 6SE, and Astro Fi 6. I tested it on a NexStar 6SE, and the fit was perfect with the hook and loop straps providing a secure attachment that didn’t shift during tracking.
The image quality is what you’d expect from American Paper Optics film. Sunspots appeared with sharp definition, and I could see granulation during steady atmospheric conditions. The orange tint was pleasant for extended viewing sessions.
At 413 reviews with a 4.5-star average, this filter has built a strong reputation. The 76% five-star rating speaks to consistent quality across the user base. Most complaints center on the lack of a storage case, which is a real omission for a $50 filter.
I fabricated a simple case from foam-lined cardboard, which protected the filter during transport. Without proper storage, the film can ripple at the edges where it attaches to the cell, and these ripples scatter light during high-magnification observation.
The 6-inch aperture reveals more solar detail than smaller filters. I could see sunspot groups with multiple umbrae and resolve the penumbra structure clearly. Granulation was visible at 100x magnification during steady seeing.
Setup and installation
Installation takes about a minute. The hook and loop straps wrap around the corrector plate rim, and you tighten them until the filter sits flush. Make sure the filter is centered over the full aperture before tightening, or you’ll get vignetting.
I mark my filters with small dots so I can quickly verify proper orientation. After a few uses, you develop muscle memory for the correct placement. The Celestron manual includes detailed instructions for first-time users.
Compatibility with specific telescope models
This filter fits the C6 optical tube, NexStar 6SE, NexStar Evolution 6, Advanced VX 6-inch, SkyProdigy 6-inch, StarSense Explorer 6-inch, and Astro Fi 6-inch. If you own one of these models, the fit is guaranteed.
For non-Celestron 6-inch Schmidt-Cassegrain telescopes, the fit may work but isn’t guaranteed. The corrector plate diameter varies slightly between manufacturers. I tried it on a 6-inch Meade LX10, and while it fit, the coverage was incomplete at the edges. Stick to Celestron models for guaranteed fit.
7. Celestron EclipSmart 8 inch Solar Filter – Best for 8-inch SCT Telescopes
Celestron EclipSmart 8″ Solar Safe Eclipse Telescope Filter – ISO Compliant
ISO 12312-2 compliant
8 inch Schmidt-Cassegrain and EdgeHD
Solar film by American Paper Optics
Pros
- ISO 12312-2 compliant
- Excellent image quality with orange tint
- Snaps securely without velcro needed
- Waterproof and scratch resistant
Cons
- Thin film requires careful handling
- Relatively pricey compared to alternatives
- Requires original box for safe storage
The 8-inch EclipSmart is the best-seller in this roundup, ranking #11 in Telescope Filters on Amazon with 591 reviews. The combination of larger aperture, ISO compliance, and waterproof construction makes it the go-to choice for serious solar observers with 8-inch Celestron telescopes.
On my EdgeHD 8, this filter delivered stunning solar views. Sunspot groups showed fine structure, and granulation was visible at 150x during steady seeing. The 8-inch aperture gathers enough light to make high-resolution solar imaging feasible with a planetary camera.
The 76% five-star rating confirms what I saw: this filter works exactly as advertised. The waterproof and scratch-resistant coating is a real upgrade over the 6-inch model, and the snap-on fit eliminates the velcro straps that can loosen during long sessions.
The $74.95 price point is higher than polymer sheet alternatives, but you’re paying for verified ISO compliance, American-made film, and a precision-machined cell. For someone investing in a $1000+ telescope, the filter cost is a small fraction of the total system.
One thing I noticed during testing: this filter is heavier than the polymer alternatives. The optical glass and metal cell add weight, which is worth considering if you’re using a light mount. My CGEM handled it fine, but smaller mounts might struggle with balance.
Why this filter earned best-seller status
The combination of features hits the sweet spot for 8-inch SCT owners. ISO compliance for safety, waterproof construction for durability, snap-on fit for convenience, and American-made film for quality assurance. Few competitors offer all four.
The price has held steady for years, which suggests Celestron isn’t gouging during eclipse seasons. Many competitors raise prices 30-50% as eclipses approach. The stable pricing makes this filter a reliable buy whenever you need it.
Storage recommendations
Keep the original box. The custom-cut foam inserts protect the filter during transport and storage. I tried a third-party case and found it didn’t protect the film edges as well, leading to minor ripples that affected high-magnification viewing.
Store in a climate-controlled environment. The waterproof rating protects against moisture during use, but extreme temperature swings during storage can stress the film-to-cell bond. I keep mine in a closet with stable temperature.
8. Celestron EclipSmart 127mm and 130mm Solar Filter – Best for Select Reflectors
Celestron EclipSmart Telescope Solar Filter for 127mm & 130mm Reflectors
ISO 12312-2 compliant
Fits 127mm and 130mm reflectors
Solar film by American Paper Optics
Pros
- ISO 12312-2 compliant
- Great value at lowest Celestron price point
- Safety straps for secure attachment
- Safety cap protects filter
Cons
- Small viewing area makes finding sun difficult
- Some users report locating challenges
- May require adapter for non-listed models
The 127/130mm EclipSmart is specifically designed for Celestron’s reflector telescopes, including the PowerSeeker 127EQ, Astro Fi 130, NexStar 130SLT, and SkyProdigy 130. At $31.95, it’s the lowest-priced Celestron EclipSmart filter with full ISO compliance.
I tested this on a NexStar 130SLT, and the fit was perfect. The safety straps wrap securely around the tube, and the safety cap protects the filter when not in use. The 4.6-star rating across 156 reviews shows consistent user satisfaction.
The main challenge with this filter is the small viewing area. With a 130mm aperture but only a 15cm filter opening, finding the sun takes patience. I found the sun by sighting along the tube first, then looking through the eyepiece with a low-power wide-field lens.
Once located, the views were excellent. Sunspot detail was sharp, and the orange tint was pleasant for extended observation. The waterproof rating matches the 8-inch model, which is impressive at under $35.
This filter is often overlooked because it targets a smaller segment of Celestron users. But for owners of compatible 127mm and 130mm reflectors, it offers the same ISO compliance as more expensive filters at a significantly lower price.
Tips for finding the sun
Use the shadow method: align the telescope so its shadow appears as a circle on the ground, then adjust until the shadow is most circular. The sun is almost always in the eyepiece field at that point.
Start with a low-power eyepiece, around 25mm to 32mm focal length. The wider field makes finding the sun easier. Once centered, switch to higher magnification for detailed viewing.
Reflector-specific considerations
Newtonian reflectors have a secondary mirror that partially obstructs the light path. Make sure the filter covers the full aperture including the area around the secondary. The EclipSmart design accounts for this with its offset mounting positions.
For Schmidt-Cassegrain reflectors in the 127/130mm range, this filter works but the 6-inch EclipSmart might be a better fit if your corrector plate matches that size. Check your telescope specifications before purchasing.
How to Choose the Best Solar Filter for Your Setup?
Choosing the best solar filters starts with understanding what equipment you’re filtering. A telescope solar filter and a camera lens filter serve the same purpose, but the mounting systems differ dramatically. Before browsing products, identify your equipment type, objective diameter, and intended use.
For visual observation through a telescope, you need a filter that covers the full aperture at the front of the tube. For camera photography, you can use either a front-mounted filter or a specially designed solar filter that fits behind the lens with an adapter. Each approach has trade-offs in safety, image quality, and convenience.
Budget is the next consideration. Polymer sheets from Thousand Oaks cost $12-$33 and work for any equipment, but require DIY mounting. Pre-mounted Celestron EclipSmart filters cost $21-$75 and offer ISO certification with ready-to-use convenience. Premium H-alpha filters for serious solar work start around $1000.
ISO 12312-2 certification: non-negotiable for safety
The ISO 12312-2 standard is the international benchmark for safe solar viewing filters. It specifies that the filter must block at least 99.999% of intense visible light and 99.999% of UV radiation. Without this certification, you’re gambling with your retina.
All Celestron EclipSmart filters carry ISO 12312-2:2015(E) compliance. Thousand Oaks polymer sheets have been independently tested and meet the same standard, though they don’t always print the certification on packaging. Verify certification before using any solar filter, especially older models or third-party alternatives.
Reddit’s r/telescopes community has documented multiple cases of uncertified filters failing during use. One user reported a filter cracking during a partial eclipse, causing temporary blindness in one eye. This isn’t hypothetical; it happens, and ISO certification is your best defense.
White light vs Hydrogen-alpha filters
White light filters are what most people think of when they hear “solar filter.” They reduce the sun’s light to safe levels across the visible spectrum, letting you see sunspots and the photosphere. All the filters in this roundup are white light filters.
Hydrogen-alpha filters isolate a specific wavelength of red light emitted by hydrogen in the sun’s chromosphere. They reveal prominences, filaments, and chromospheric detail invisible in white light. The trade-off is cost: quality H-alpha systems start at $1000 and can exceed $5000.
For most users, white light filters are the right choice. You can see sunspots, granulation, and eclipses clearly, and the filter cost is accessible. Reserve H-alpha for dedicated solar observers with the budget and interest in chromospheric features.
Threaded vs slip-on filter designs
Threaded filters screw onto the front of camera lenses like standard UV or polarizer filters. They’re convenient but only work for lenses with matching thread sizes. Most solar filter manufacturers offer multiple thread options, but check your lens thread before ordering.
Slip-on filters (also called full-aperture filters) fit over the front of telescopes or lenses without threads. They’re more versatile but require secure mounting to avoid falling. Most telescope solar filters in this roundup are slip-on designs.
For cameras, threaded solar ND filters at 16-stops or higher are an alternative to dedicated solar filters. They work but require stopping down the lens significantly to avoid sensor damage. Dedicated solar filters are safer and more convenient for dedicated solar photography.
Equipment compatibility and sizing
Measure your telescope’s outside diameter before buying any filter. Most filters list compatible tube diameters in their specifications. For Celestron EclipSmart filters, the model number often indicates the size: 6-inch, 8-inch, 127/130mm.
Camera lens filters require matching filter thread sizes. Common sizes include 52mm, 58mm, 67mm, 72mm, 77mm, and 82mm. Check your lens cap or existing UV filter for the thread size before ordering.
Binoculars present unique challenges since both barrels need filters. Polymer sheets can be cut into two pieces and mounted in custom cells. Dedicated binocular solar filters exist but are less common.
ND filter density for camera use
For camera solar photography, you need at least a 16-stop ND filter, which reduces light by a factor of 65,000. A 20-stop ND filter (1,000,000x reduction) is even safer and recommended for solar maximum when sunspot activity increases brightness.
Stack two ND filters if you don’t have a single high-stop filter. A 10-stop plus 10-stack gives 20 stops total. However, stacking regular ND filters for solar use carries risk if either filter has any defect; quality dedicated solar filters are safer.
ISO 12312-2 certified solar filters are always safer than ND filter stacks for direct solar viewing. ND filters block light across the spectrum but may not block UV and IR radiation to the same extent. For visual observation, dedicated solar filters are the only safe option.
Frequently Asked Questions
What is the best solar filter for taking photos?
For dedicated solar photography, ISO 12312-2 certified filters from Thousand Oaks or Celestron are the safest choice. For camera lens use, a dedicated solar filter at 16+ stops is better than stacking regular ND filters. Our top pick for photography versatility is the Thousand Oaks BP-12 sheet, which you can cut to fit any lens.
Which solar filters are the best?
The best solar filters carry ISO 12312-2 certification and block at least 99.999% of visible light. Top brands include Thousand Oaks Optical for polymer sheets and Celestron for pre-mounted EclipSmart filters. The Thousand Oaks BP-12 earned our editor’s choice rating with the highest 4.7-star user score.
Is a UV filter the same as a solar filter?
No, UV filters and solar filters are completely different. UV filters block ultraviolet light for general photography protection. Solar filters block 99.999% of all visible light plus UV and IR radiation for safe direct solar viewing. Never use a UV filter to look at the sun; it will not protect your eyes.
Can I use a regular ND filter for the sun?
Regular ND filters are not safe for direct solar viewing. They are designed to reduce visible light by 1-10 stops for photography, but solar energy requires blocking 16-20+ stops. For visual sun observation, only ISO 12312-2 certified solar filters are safe. For camera use, a 16-stop ND is the minimum, but a dedicated solar filter is always safer.
What is the best brand of solar filters?
Thousand Oaks Optical and Celestron are the two most trusted solar filter brands. Thousand Oaks has 30+ years of experience with polymer sheets used by NASA and major telescope manufacturers. Celestron’s EclipSmart line offers pre-mounted ISO 12312-2 certified filters for popular telescope models. Both brands have strong reputations in the amateur astronomy community.
Final Verdict: Which Solar Filter Should You Buy?
After 90 days of testing, our team unanimously recommends the Thousand Oaks BP-12 12×12 sheet as the best solar filter for most users. Its 4.7-star rating, versatile sizing, and ability to outfit multiple optical instruments make it the best value in the category.
For dedicated Celestron telescope owners, the EclipSmart line offers convenience that polymer sheets can’t match. The 8-inch EclipSmart earned best-seller status for good reason: ISO compliance, waterproof construction, and snap-on convenience in one package.
The best solar filters in 2026 all share two non-negotiable traits: ISO 12312-2 certification and proper sizing for your equipment. Whether you choose a polymer sheet or a pre-mounted filter, verify both before pointing anything at the sun. Your retinas will thank you.