# Lumen reflections problem when strobe video, latency / refresh rate ?

**URL:** <https://forums.unrealengine.com/t/lumen-reflections-problem-when-strobe-video-latency-refresh-rate/1203398>\
**Category:** Rendering\
**Tags:** Reflections, unreal-engine, Global-Illumination, Lumen, Rendering, question\
**Created:** [June 18, 2023, 8:09pm UTC](https://forums.unrealengine.com/t/lumen-reflections-problem-when-strobe-video-latency-refresh-rate/1203398 "2023-06-18T20:09:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![WBDeSportVaL](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/wbdesportval/32/718785_2.png) [@WBDeSportVaL](https://forums.unrealengine.com/u/WBDeSportVaL)\
**Post date:** [June 18, 2023, 8:09pm UTC](https://forums.unrealengine.com/t/lumen-reflections-problem-when-strobe-video-latency-refresh-rate/1203398/1 "2023-06-18T20:09:06Z")

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Hello,  
Here’s my problem. I have integrated a led screen on my stage, but I have a rendering problem with lumen, the reflections don’t load quickly enough and when there are strobes or fast videos the reflections are super slow (video attached). In scalability i set Shadows, GI & Reflection to “High”.  
The video signal comes from a Blackmagic capture card, I have the same problem with NDI…

Maybe Lumen isn’t made for this idk ? I’m still new to unreal

Do you have any ideas?

Video : [Lumen reflections problem - YouTube](https://youtu.be/jAhmycCF0Iw)

PC Config :  
I9 10900X  
RTX 4070  
32GB RAM

Many thanks

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**Author:** ![jblackwell](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@jblackwell](https://forums.unrealengine.com/u/jblackwell)\
**Post date:** [June 21, 2023, 2:38pm UTC](https://forums.unrealengine.com/t/lumen-reflections-problem-when-strobe-video-latency-refresh-rate/1203398/2 "2023-06-21T14:38:08Z")

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Lumen won’t be able to solve your use case, I believe I offered a solution in another response to one of your posts?

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<div class="post-metadata">

**Author:** ![WBDeSportVaL](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/wbdesportval/32/718785_2.png) [@WBDeSportVaL](https://forums.unrealengine.com/u/WBDeSportVaL)\
**Post date:** [June 26, 2023, 5:42pm UTC](https://forums.unrealengine.com/t/lumen-reflections-problem-when-strobe-video-latency-refresh-rate/1203398/3 "2023-06-26T17:42:41Z")

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Hi,

Yeap, thanks a lot for your help !