Full-spectrum vs Just Infrared ?

Colour spectrum

One of common decisions people have is to go for full-spectrum or straight infrared. This is not an easy decision as there are pros and cons of both types of conversion:

Pros:

  • Greater flexibility with frequency ranges; including able to use more exotic dual and multi-band filters mixing UV, some visible light and infrared (see the dual and multi-band galleries for examples).
  • Using combined/stacked UV cut filter (common UV filter) and an hot-mirror absorption filter a full-spectrum camera can operate ‘normal’ again capturing just visible light; however, white-balancing can be quite sensitive and not as quick and simple as with a standard camera.

Cons:

  • The relatively high cost of dual and multi-band filters, especially if it is for multiple lenses.
  • The hassle of carrying and changing lens filters (and keeping track of what was used when).
  • Not being able to use lens filters with some ultra-wides and fisheyes.
  • Restricted to cameras with LiveView functionality (excludes cheap older DSLRs).

Other Conversion Options

Less common conversions, offered by a few companies are:

  • Visible+IR – a reduced full-spectrum, where the shorter UV wavelengths are cut so that the camera can shoot near-IR and, with a single IR absorption filter, capture just normal visible light.
  • SuperBlue – where I believe (not had full confirmation) a BG3 filter is used to give mix-band of some UV/Blue + near-IR from around 700nm. This has the advantage of capturing blue skies without the need for channel-swapping, plus with a lens filter capture just 700nm+, giving agin two options.

Personal Choice

In the end, it is a personal call on what you want to use and the images you are after. My main camera is full-spectrum, primarily because I like the results from dual and multi-band filters; however, I also have straight near-IR cameras – modified for 590nm, 660nm & 720nm – as I also like using ultra-wide lenses and, when travelling light, not having to carry a collection of filters.

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