Fig.1. Vivitar 285HV/285 before modification.
Fig.2. Vivitar 285HV/285 after modification.
Shane Elen
Disclaimer: Modifying your flash in this way should be left to qualified professionals as the procedure can be extremely dangerous due to high voltages and the pressurized flashtube possibly resulting in injury, blindness or death so PROCEED AT YOUR OWN RISK.
The ultraviolet modification was originally inspired by a report by Regit Young and although my modification follows the same basic principle as that described by Regit, I use a piece of UV glass that covers the entire opening rather than a circular photographic filter. Although this is a little more expensive it is not as restrictive size wise as the circular filter and therefore passes more UV.
As described by Regit, the yellow filter in front of the flashlamp needs to be modified to increase the UV output. There are two approaches to performing this, the safe way and the daredevil way. The former involves dismantling the unit to modify the filter, the latter involves cutting the filter away in situ. The latter involves no dismantling of the unit, requires a steady hand, but doesn't come without risk! I would tend to reserve either technique for a cheaply purchased unit and not a LNIB sale.
Fig.1. Vivitar 285HV/285 before modification. |
Fig.2. Vivitar 285HV/285 after modification. |
The UV or IR modified adapters are made by retro fitting the Vivitar flash/zoom adapter with specially selected UV or IR materials of very similar spectral characteristics to the Nikon SW-5UV and SW-5IR. There are many types of UV and IR materials available so it is important to know their spectral characteristics to ensure the success of the ultraviolet or infrared photography project.
There are several options for retro fitting the Vivitar adapter. One possibility is to fit a readily available 52mm round filter (47mm diameter window) to the adapter and block off the surrounding open area. Another is to fit the adapter with a readily available square filter and block of the surrounding area. While both these options will work, they both significantly reduced the UV or IR capability of the flash. Retrofitting the adapter with the appropriate sized rectangular material will maximize the UV or IR output. This is particularly important for ultraviolet photography when every little bit counts.
The following illustrates the surface area of the filter material for each of these options:Important Fresnel Lens Information for the Vivitar Flash Adapters
 Fig.3. UV opaque Fresnel Lens from the Vivitar 285 and 285HV flash. |
 Fig.4. UV transparent Fresnel Lens from a Vivitar 285HV flash. |
 Fig.5. UV opaque Fresnel Lens fitted with the UV adapter showing weak ultraviolet throughput capability. |
 Fig.6. UV transparent Fresnel Lens fitted with the UV adapter showing strong ultraviolet throughput capability. Removing the Fresnel lens results in even greater UV throughput as shown in fig 8. |
 Fig.7. UV adapter fitted to the Vivitar 285HV. |
 Fig.8. UV transparent Fresnel Lens fitted with the UV adapter compared to the UV adapter and no Fresnel lens. Removing the Fresnel lens results in even greater UV throughput. |
© Shane Elen 2006. Last updated Jan 9th, 2012.