Both use Sony’s back-illuminated 3.76μm pixel architecture, so per-pixel noise is nearly identical. The IMX571 is a 26MP APS-C sensor with a 16-bit ADC and a 28.3mm diagonal; the IMX533 is a 9MP 1-inch square sensor with a 14-bit ADC and a 15.968mm diagonal. Choose the 571 for wide fields, the 533 for a compact, forgiving square frame.
Same DNA — where the two sensors are identical
The IMX571 (in ZWO’s ASI2600 line) and the IMX533 (in the ASI533 line) are both built on Sony’s back-illuminated, 3.76μm-pixel architecture. Because the pixel itself is the same piece of silicon on both chips, per-pixel noise performance tracks closely between them. Atik’s technical guides describe noise performance as “closely matched” across all three Sony sensors in that comparison, of which the IMX571 and IMX533 are two Atik Technical Guides — the real differences between the IMX571 and IMX533 aren’t about pixel quality, they’re about format, resolution, bit depth and frame rate, which is what the rest of this article works through.
Both sensors also ship in the same two flavors: a monochrome (“MM”) version with no color filter over the pixels, and a one-shot color (“MC”) version with a Bayer array bonded on top. That choice — mono or color, on either sensor — is its own decision with its own tradeoffs, covered in full in our mono vs. one-shot color guide; this article treats the sensors on their own terms and leaves that call to you.
Where they differ
FOV and the square format
The IMX571 is a 26-megapixel APS-C sensor at 6248×4176 pixels, measuring 23.5×15.7mm with a 28.3mm diagonal — a conventional 3:2 rectangle ZWO ASI2600 Manual. The IMX533 is a 9-megapixel sensor at 3008×3008 pixels, measuring 11.31×11.31mm with a 15.968mm diagonal — a true 1-inch square ZWO ASI533 Manual. Because both sensors share the identical 3.76μm pixel, they deliver the same arcseconds-per-pixel sampling at any given telescope focal length — the field-of-view gap between them comes entirely from the physical size and shape of the chip, not from any difference in sampling. (For the sampling math itself, see our pixel scale and sampling guide.)
In practice, the 571’s bigger rectangular frame suits wide nebulae, large open clusters, and mosaics where you want more sky per exposure. The 533’s square frame never needs rotating to fit a target diagonally — a real convenience for framing — but it’s covering meaningfully less sky at the same focal length, so it suits smaller or longer-focal-length targets better than wide fields.
16-bit vs. 14-bit — does it matter?
The IMX571 runs a 16-bit ADC; the IMX533 runs a 14-bit ADC ZWO ASI2600 / ASI533 Manuals. On paper that’s 65,536 tonal levels against 16,384 — a real difference in raw ADC resolution. Whether it translates into a meaningfully better image is a genuine, unresolved dispute, and both sides deserve to be stated plainly.
Position A — 16-bit is meaningfully better. ZWO markets the IMX571’s native 16-bit ADC as roughly 14 stops of dynamic range ZWO. This is the manufacturer’s own marketing framing for a flagship-tier sensor, worth reading with that lens rather than as an independent benchmark. Position B — 14-bit is not a practical ceiling. Atik argues real-world dynamic range is “limited by shot noise well before the ADC ceiling” Atik Technical Guides — in other words, sensor noise floors the achievable dynamic range long before you run out of ADC levels to describe it with, on either sensor. A SharpCap-forum analysis makes a related point — that a large share of the IMX571’s extra 16-bit levels sit below the read-noise floor anyway — but we’re citing that as forum context on the shape of the debate, not as a sourced canon figure.
Neither position is wrong so much as they’re answering different questions: ZWO is describing what the ADC is capable of recording; Atik is describing what the sensor’s own noise floor lets you actually use. Both matter depending on how deeply you stretch your data in processing.
Frame rate and file sizes
Frame rate needs two different numbers kept separate, because they’re measured at two different levels. At the sensor level, Atik’s datasheet comparison puts the IMX533 at 26.9fps at 14-bit, well ahead of the IMX571’s 6.84fps Atik Technical Guides — these are raw sensor-datasheet figures, not what either finished camera delivers to your capture software. At the camera level, ZWO’s own resolution table for the finished ASI533 camera lists roughly 20fps at full resolution — 19.88fps exactly ZWO ASI533 Manual. We could not verify an equivalent camera-level full-resolution fps figure for the ASI2600 in ZWO’s published material, so treat any ASI2600 camera-level fps number you see elsewhere as unconfirmed until you check the manual yourself.
On file size, the arithmetic is straightforward from resolution alone: the IMX571’s 26MP frames are roughly three times the pixel count of the IMX533’s 9MP frames, so expect proportionally larger files, longer per-frame readout, and heavier storage and stacking loads on the 571 for the same imaging session length.
The spec table
| Spec | IMX571 (ASI2600) | IMX533 (ASI533) |
|---|---|---|
| Format | APS-C, 3:2 rectangle | 1-inch, square |
| Resolution | 26MP — 6248×4176px | 9MP — 3008×3008px |
| Sensor size / diagonal | 23.5×15.7mm / 28.3mm | 11.31×11.31mm / 15.968mm |
| Pixel size | 3.76μm (BSI) | 3.76μm (BSI) |
| ADC | 16-bit | 14-bit |
| Full well | 50,000e default / 73,000e extended (gain -25) | 50,000e |
| Read noise | 1.0–3.3e | 1.0–3.8e |
| QE — mono / color | 91% / 80% | 91% / above 80% |
| Frame rate | 6.84fps, sensor level (Atik) — camera-level figure not verified | 26.9fps, sensor level (Atik) · ~20fps – 19.88fps – camera level, full-res (ZWO) |
| Amp glow | “Zero amp glow” — manufacturer claim (ZWO) | “Zero amp glow” — manufacturer claim (ZWO) |
Sourcing note on the QE row: the color QE figures on both sensors are ZWO’s own camera-level spec, not a published Sony sensor-datasheet curve. No public Sony datasheet QE curve exists for either the IMX571’s or the IMX533’s color version, so treat those two figures as the best manufacturer-stated numbers available, not independently measured silicon specs — the mono 91% figure for both sensors carries no such caveat. The IMX533’s color QE in particular is stated only as “above 80%” by ZWO — we’re carrying that qualifier rather than rounding it to a flat number.
Which should you buy? (by target and telescope)
The sensor-level decision here comes down mostly to format and field of view, not the 16-bit/14-bit debate above. If your telescope’s focal length and your favorite targets favor a wide rectangular frame — large nebulae, mosaics, anything you’d otherwise have to tile — the IMX571’s bigger APS-C chip is the more forgiving choice. If your targets run smaller, or your focal length is already fairly long, the IMX533’s square 1-inch frame is a compact, no-rotation-needed option that’s easier to fully illuminate and typically cheaper to build a matched flattener/corrector around. For the full six-spec framework this decision sits inside — sensor size, pixel size, QE, read noise, full well and cooling — see our guide to choosing a dedicated astrophotography camera, which also hosts the complete sensor-canon reference table these figures are drawn from.
Both sensors ship as mono (“MM”) and one-shot color (“MC”) cameras. If you already know you want narrowband flexibility and maximum sensitivity, start from the mono body; if you want color out of the camera with less workflow overhead, start from the color body — our mono vs. OSC guide walks through that tradeoff on exactly these two sensors.
Its mono sibling — same sensor, no Bayer array — is the ASI2600MM Pro.
Its mono sibling is the ASI533MM Pro.
Amp glow: manufacturer-stated vs. reviewer-stated
ZWO states a “zero amp glow” — sometimes worded “zero-amp glow design” — specification for both the ASI2600 and the ASI533 ZWO.
“Zero amp glow” is a specification ZWO publishes about its own cameras, not a figure from an independent lab measurement or a third-party reviewer’s dark-frame test. Treat it the way you’d treat any other manufacturer-stated spec: almost certainly accurate as a design intent and broadly consistent with what owners report, but not the same category of claim as a figure an outside party measured and published themselves. Neither sensor’s amp-glow behavior has an independent measurement cited in the sources behind this article.
FAQ
What’s the field-of-view difference between the IMX571 and the IMX533?
The IMX571 is physically larger — a 23.5×15.7mm APS-C rectangle with a 28.3mm diagonal — against the IMX533’s 11.31×11.31mm square with a 15.968mm diagonal ZWO ASI2600 / ASI533 Manuals. Because both share the same 3.76μm pixel, the gap is purely about chip size and shape, not sampling — at any given focal length, the 571 simply frames more sky in a wider rectangle, while the 533 frames less sky in a square that never needs rotating.
Does the IMX533’s 14-bit ADC actually matter next to the IMX571’s 16-bit?
It’s a genuine, unresolved dispute. ZWO markets the IMX571’s 16-bit ADC as meaningfully better dynamic range ZWO, while Atik argues real-world dynamic range on either sensor is limited by shot noise well before either ADC’s ceiling is reached Atik Technical Guides. Both positions are defensible — see the full breakdown above rather than a single verdict here.
Should I buy the ASI2600 or the ASI533 for my first deep-sky camera?
Match it to your telescope and targets first. Wide fields, large nebulae and mosaic work favor the IMX571’s bigger APS-C frame; smaller targets, longer focal lengths and a simpler square crop favor the IMX533. See our camera-buying guide for the full six-spec framework this decision sits inside.
Do the ASI2600 and ASI533 really have zero amp glow?
That’s ZWO’s own manufacturer specification for both cameras ZWO, not an independently measured figure. Treat it as a credible manufacturer claim rather than a verified, third-party-tested result.
Which sensor has the faster frame rate — the IMX571 or the IMX533?
At the sensor-datasheet level, the IMX533 is well ahead: 26.9fps at 14-bit against the IMX571’s 6.84fps Atik Technical Guides. At the finished-camera level, the ASI533 delivers about 20fps — 19.88fps exactly — at full resolution ZWO ASI533 Manual; ZWO does not publish an equivalent camera-level figure for the ASI2600 that we could verify. Keep those two levels of measurement separate when comparing numbers you find elsewhere.