2009منتدى Cameras (Film/Video/HD)
اختيار معدات الإضاءة لتسجيلات الفيديو العالية السرعة بمعدلات إطارية من 500 إلى 10000 فبر
مضى على هذا 17 سنة. قد تكون المعدات والأسعار قد تغيّرت منذ ذلك الحين.
ما توصّل إليه النقاش
- HMI lamps marketed as flicker-free can still exhibit intensity and color variations caused by plasma arc rotation or wobbling inside the bulb, independent of electronic ballast stability.
- A K5600 Joker 800 watt HMI demonstrated no noticeable flicker when tested at 6200 fps.
- Bulb age and condition significantly affect flicker performance, and replacing a faulty bulb can eliminate flicker issues that persist across multiple shoots.
- HMI lamps smaller than 4 kilowatts tend to introduce flicker more readily than larger lamps, though very small lamps with concentrated plasma arcs like the Joker 800 may perform well.
- Larger HMI bulbs carry a paradoxical drawback: increased gas volume raises the likelihood of plasma disturbances that cause visible flicker.
- Tungsten lighting can serve as a reliable alternative when authentic flicker-free HMI equipment is unavailable, though it requires wider aperture settings due to lower light output.
- Dedicated high-speed cinematography lighting heads like those from Dedolight provide concentrated illumination with minimal heat generation.
- Individual fixture performance varies significantly even among identical models, making testing with the actual equipment planned for production essential.
يعتمد على
- Testing of the K5600 Joker 800 was limited to a single frame rate and did not include comparative tests across multiple frame rates.
- Experience with tungsten alternatives was documented only in a specific geographic region and may reflect local equipment availability rather than universal performance characteristics.
- The claim about plasma wobbling in HMI bulbs was not experimentally verified in the thread.
- One participant's reference to an undisclosed high-speed camera model limits the applicability of that experience to unknown equipment specifications.
- No detailed technical specifications were provided regarding ballast frequencies or their relationship to flicker-free performance.