1
\$\begingroup\$

I want to connect a set of low power halogen lamps to a dimmer. This would be used to illuminate plants who are then monitored using a hyperspectral camera.

I was wondering whether any spurious switching behaviour of the dimmer and transformer will show up in the final image. The exposure time will be in in the order of 1/1000 seconds.

Example set-up:

HTI DALI 315 DIM (dimmer) connected to HTM or HTN (transformer) 12V, 50W lamp

\$\endgroup\$
  • \$\begingroup\$ Why not test it? \$\endgroup\$ – Eugene Sh. Oct 6 '17 at 15:49
  • \$\begingroup\$ I have a limited budget and this set-up (lamps only) will cost about 750 euro, so I want to do it immediately right. I know the camera costs way more, but I can borrow that. \$\endgroup\$ – opieters Oct 6 '17 at 16:08
  • \$\begingroup\$ Why not to try with a single lamp? \$\endgroup\$ – Eugene Sh. Oct 6 '17 at 16:08
  • \$\begingroup\$ That would also take at least two weeks to just test it (slow university system to get approval). I'd also like to have the final set-up asap, so one order preferably... \$\endgroup\$ – opieters Oct 6 '17 at 16:12
  • \$\begingroup\$ I don't think you really want an AC lamp when using such a short exposure time... \$\endgroup\$ – Trevor_G Oct 6 '17 at 16:18
1
\$\begingroup\$

I don't think you really want an AC lamp when using such a short exposure time... The mains frequency alone will cause cyclic brightness variations.

Hook your lamps up to a decent bench power supply capable of supplying your wattage instead.

\$\endgroup\$
  • \$\begingroup\$ There may be some variation in brightness over the power cycle, but given the thermal inertia of the filament probably not much. Fluorescent lights and LED lights are another kettle of fish, and a fast shutter speed can be problematic with those light sources. \$\endgroup\$ – BobT Oct 6 '17 at 16:31
  • \$\begingroup\$ Can you suggest any lamp with a similar spectrum (the spectrum is the main reason these lamps were selected)? Since we want to reasonably mimic the solar spectrum. \$\endgroup\$ – opieters Oct 6 '17 at 16:40
  • \$\begingroup\$ I second Trevor to buy a simple adjustable DC power supply and power that lamp with DC. Such a supply is going to cost you about $20. \$\endgroup\$ – Janka Oct 6 '17 at 16:45
  • \$\begingroup\$ @BobT yup, but dimmed it will be more noticeable and I'm guessing any variation is a variable the OP doesn't need. I'm also pretty sure he can borrow a PSU too if he can borrow the camera. \$\endgroup\$ – Trevor_G Oct 6 '17 at 16:56
  • \$\begingroup\$ Ok... As a photographer this caught my eye. DC drive sounds reasonable. One issue he may have is that color temperature changes with dimming, so spectral measurements may be problematic in any case. \$\endgroup\$ – BobT Oct 6 '17 at 17:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.