If you've ever wondered what actually happens when a camera is converted to full spectrum, you're not alone. It's one of the most common questions we get asked. The process sounds technical — and it is — but understanding it helps you appreciate exactly what makes a full spectrum camera so different from a standard one, and why the conversion has to be done right.
Why Cameras Need Converting in the First Place
Every digital camera sensor is naturally sensitive to a much wider range of light than the human eye can see — including near-infrared (IR) and ultraviolet (UV) wavelengths. Camera manufacturers consider this a problem. If left unfiltered, IR light in particular causes colour casts and reduces sharpness in standard photography. So they install a filter — known as a hot mirror or IR cut filter — directly in front of the sensor during manufacturing. This filter blocks UV and IR light, restricting the camera to the visible spectrum only.
A full spectrum conversion removes or replaces this filter, unlocking the sensor's full natural sensitivity. For a broader overview of what a full spectrum camera is and what it can do, read: What is a Full Spectrum Camera?
Step 1: Disassembly
The conversion begins with carefully disassembling the camera body. This is far more involved than it sounds. Modern mirrorless and DSLR cameras — like the Sony A7 series — are precision-engineered devices with hundreds of tiny components, ribbon cables, and circuit boards packed into a compact body. Every screw, every connector, and every component must be removed in the correct sequence and kept track of meticulously.
This stage alone can take an experienced technician an hour or more, depending on the camera model.
Step 2: Accessing and Removing the Filter
Once the camera is disassembled, the technician accesses the sensor stack — the layered assembly of glass and optical elements that sits directly in front of the imaging sensor. The hot mirror (IR cut filter) is bonded within this stack, typically as a thin piece of coated optical glass.
Removing it requires precision tools and a steady hand. The filter must be extracted without scratching the sensor, damaging surrounding components, or introducing dust into the optical path. Even a single dust particle landing on the sensor at this stage can ruin the conversion.
Step 3: Replacing the Filter (or Not)
Simply removing the hot mirror isn't enough. The filter has a specific optical thickness, and removing it without a replacement would shift the camera's focal plane — meaning the camera would no longer focus correctly. To compensate for this, one conversion technique is to fit a replacement optical glass of equivalent thickness installed in its place, but this is not how we do it at eAliens as it is a tricky method, and we have seen mixed results with the quality of these replacement glasses with image quality suffering.
In these Sony cameras the sensor sits on shafts that are calibrated for each individual unit, not just the model, but each individual camera. We measure these shafts with 0.01mm precision (10 microns) and adjust them so the camera can focus properly at infinity with any lens — all done without replacing any glass filter. It's a process that requires experience.
The sensor is still not "naked" as, under the filter removed, remains a very hard permanent factory fitted glass which protects the sensor, and it can still be cleaned normally.
For a true full spectrum conversion, this replacement glass is optically clear, allowing UV, visible, and IR light to pass through freely. For dedicated IR or UV conversions, a specific filter is installed at this stage instead. To understand the difference between a full spectrum and dedicated IR conversion, read: Full Spectrum vs Dedicated IR Conversion — Which is Right for You?
Step 4: Reassembly and Calibration
The camera is carefully reassembled in reverse order. Every ribbon cable is reconnected, every screw is torqued correctly, and every component is returned to its original position. This is just as painstaking as the disassembly — a misaligned component or a missed connection can cause the camera to malfunction entirely.
Once reassembled, the camera is tested, and autofocus accuracy is checked across multiple lenses and at infinity focus. This precision calibration process — including shimming the sensor to achieve perfect infinity autofocus — is one of the most technically demanding parts of a quality conversion. Read more about it here: Shimming for Perfect Infinity Autofocus After a Full Spectrum Conversion.
On certain Sony A7 bodies, this stage also involves assessing and shielding against internal IR LED contamination from the shutter assembly — a specific issue that affects long-exposure and high-ISO shooting on converted A7 II / III models. Read more: Internal IR LED Contamination on Certain Sony A7 Bodies — A Real World View.
Step 5: Sensor Cleaning
Before the conversion is considered complete, the sensor is professionally cleaned. Opening a camera body exposes the sensor to the environment, and even in a clean workspace, microscopic particles can settle on the sensor surface. A thorough sensor clean ensures the converted camera delivers sharp, spot-free images straight out of the box.
Why It Matters Who Does the Conversion
The full spectrum conversion process requires technical expertise, the right tools, and a clean working environment. A poorly executed conversion can result in front or back focus issues, sensor damage, dust contamination, or a camera that simply doesn't work. That's why choosing a reputable, experienced converter is essential. Our Full Spectrum Camera Buying Guide covers what to look for when choosing a converter.
At eAliens, every conversion is carried out by our skilled technician with extensive experience across a wide range of camera models. Each converted camera is thoroughly tested before it leaves our workshop — so you receive a precision instrument, not a gamble.
The Result
A professionally converted full spectrum camera looks and handles exactly like a standard camera. The difference is invisible from the outside — but through the lens, a whole new world of light opens up. Pair it with the right filter, and you can capture stunning infrared landscapes, reveal hidden UV detail, or conduct serious scientific imaging that simply isn't possible with an unmodified camera.
Explore our range of professionally converted full spectrum cameras and find the right model for your work.