Video production Edmonton logo white – Urban Video Inc.



We were recently hired to produce a short documentary piece intended for broadcast in China. The project is to be shot and edited here in Canada, and later sent to China. The shooting specs for this project are as follows: 1080i50 in a .mov wrapper. Seems simple enough. We’ll go ahead and switch our camera’s mode from NTSC (60Hz) to PAL (50Hz), and we’re ready to roll! Right?

Unfortunately, it’s not that simple. Because we’re shooting for PAL in an NTSC area, it is important that we understand why NTSC and PAL standards exist in the first place. Until recently, I thought PAL and NTSC standards were simply a matter of preference, sort of like America’s Imperial system vs. UK’s Metric system. However, that is not the case at all. As it turns out, there is a very tangible reason for the opposing NTSC and PAL standards.

50Hz vs. 60Hz,
a Little History

In the UK, Africa, Australia, most of Asia and Russia, the frequency of AC (alternating current) running through electrical mains is 50Hz (Herts). While in North America, and a few other countries (Japan uses both), the AC frequency is 60Hz. Why? There are many historical factors responsible for this divide but, in a nutshell, it comes down to economics. At the turn of the 21st century, to avoid competing with one another, manufacturers in America focused on producing 60Hz equipment while manufacturers in the UK focused on producing 50Hz equipment. Each region established its own monopoly and the rest is history.

It’s worth mentioning, 50Hz and 60Hz are not arbitrary frequencies. They were chosen for very specific reasons that go beyond the scope of this blog. But, to provide some perspective into it, certain lights tend to flicker when a low frequency current is run through them. If the frequency is sped up to 50Hz, the flickering, although still present, goes unnoticed by the human eye. This is one of the contributing factors to the popularity of 50Hz.

How does Household Electrical Frequency affect Video?

As mentioned, at 50Hz the flickering effect goes unnoticed by the human eye – the key word being human. The camera’s eye (its sensor) can still see this flicker. The sample footage below was shot in PAL, 1080i50, 1/50 shutter speed, at a school in Edmonton, Canada with 60Hz florescent lighting. While our camera operator was seeing a clean, flicker-free image, the camera itself was seeing something entirely different. Notice the grain and flickering effect over the dark blue curtain. Thankfully it was just a test shot!

What caused this flickering effect? Blame the hertz! (not really). The hertz is a unit of frequency that defines cycles per second. So, if the lighting in the school is running at 60Hz, this is just a fancy way of saying that the electricity flowing into the fluorescent lighting is cycling ON-OFF 60 times per second. While the human eye does not detect it, there is a subtle dimming of the light during each of these ON-OFF cycles. It is this dimming that our camera is seeing, and recording.


It all comes down to synchronization. If you synchronize your camera to the electrical frequency of the lighting, you are basically telling your camera to only take pictures of the ON portion of each cycle within the frequency. So how do we do achieve synchronization? There are two options:


Thankfully, many cameras today have the option to change frequencies between 50Hz (PAL) and 60Hz (NTSC). If your camera has this option, simply match your camera’s frequency with the electrical frequency of your environment. Once set to the correct frequency, you can safely use any of the frame rates or shutter speeds your camera offers. If you’re not sure what the frequency is where you are, here’s the Wikipedia link!


If you can’t change your camera’s frequency, or if your client requires you to shoot in a specific frequency, as is the case for us, there is a workaround. You can sync your shutter speed to the electrical frequency of your environment. I created a couple tables below with some commonly used frame rates and corresponding safe shutter speeds/angles. If you don’t see what you need in the tables, you can use this handy shutter speed/angle calculator courtesy of the team at Red.


Use this table if you're shooting under 60Hz lighting.

Your Frame RateSafe Shutter SpeedSafe Shutter Angle
50p/50i1/60, 1/120300, 150
25p1/40, 1/60, 1/120225, 150, 75


Use this table if you're shooting under 50Hz lighting.

Your Frame RateSafe Shutter SpeedSafe Shutter Angle
30p1/33.3, 1/50, 1/100324, 216, 108
24p1/33.3, 1/50, 1/100259.2, 172.8, 86.4

The sample footage below was shot on the same day, under the same 60Hz lighting, as the sample footage above. The camera was still in 50Hz mode (1080i50), however we adjusted our shutter speed from 1/50 to 1/60 to match the frequency of the fluorescent lighting. As you can see, the results are much better!


59 Responses

  1. Great article. It’s worth noting that LED lights can also be particularly problematic since they have a refresh rate similar to computer monitors which is a different problem than just the AC cycle. Also, different lights can flicker at different rates, so if you’re not confident about the quality of your lights, it’s really important to do tests and view them on a monitor (as your article points out).

    If you do have footage that suffers from flicker, we develop a plugin that removes most types of flicker including the flicker shown in the example caused by the camera being out of sync with the electricity. It’s called Flicker Free and you can find more info here:

    Jim Tierney
    Digital Anarchy

    1. Hello,

      I’m researching flicker rates of different light sources for the common use. I found several studies that provide correlation between flickering light bulbs and health problems. Could someone suggest how to tell which bulb is made from a higher quality materials, flicker free? How to test which bulbs are flicker free? Is there a way of reducing this flicking? Does electromagnetic interference most highly generated by CFL correlate with the flicker rate?

      1. Hello Jim, I apologize for the late response. I would look into Remote-Phosphor Lighting. As far as I know, it’s a relatively new lighting technology, at least in the video production world. Remote phosphor lighting is virtually flicker free due to its extremely high cycle. I believe it ranges somewhere around 250,000 Hz and up. Hope that helps with your research.

      2. Hi, i do have hack for checking high quality flicker free bulbs in department store. Get a smartphone with decent camera with high frame rate like 120 or 240 fps. Higher = better. Points the camera at the bulbs powered on. You will see flickering on smartphone screen in your camera app if there is low quality bulb. You can often pinpoint which bulb is that if there are multiple available. Check for yourself and experiment with frame rates. P.s. The only shop I known which flicker free leds is Ikea.

        1. I am very sensitive some of the new lighting out there. There are a couple of shops I can not spend more than 10 minutes in and Ikea is one of them. Last time I was in an Ikea it I had to close my eyes and be walked out of the shop with my family steering the cart.

  2. Just returned from Ukraine, shooting 23.98 fps but in one interview we accidentally let the shutter speed default to 1/48 instead of setting it at 1/100. Now of course we have a slow rolling light/dark area through the picture.

    Is there a program to correct for that?

    1. We just shot a sequence in a fabrication shop for a corporate video and the welding machines must have been on a different frequency because we ended up with some bad flickering. We used the Flicker Free Plugin by Digital Anarchy and it took all the flicker out beautifully. Can’t say enough about this plugin. It’s great. We just dropped it on our footage, left all the default settings, rendered, and the flicker was gone. It didn’t degrade the footage either. The plugin is $149 but well worth it. You can try the demo version first to make sure it works, which is what we did. Hope that helps!

    1. Yes, PWM (Pulse Width Modulation), another term for the on-off cycling of current to an electrical device (i.e. computer monitors), causes flicker if its frequency is out of sync with your camera’s frequency/shutter. Match your camera’s frequency/shutter and flicker goes away.

  3. Had a similar issue while shooting a live event. The flicker was very bad. Used the Flicker Free plugin and it worked perfectly. Took a long time to render but it was worth it.

  4. Awesome post! I found this out the hard way too after doing a shoot in Australia and shooting under florescent lights while shooting NTSC. Thanks for sharing your experience – I’m going to share this with the team as it’s a great description of the problem in general.

  5. I think you should add that 50hz wasn’t a problem for incandescent bulbs since they have rather high persistence, but the flicker from a 50hz CRT display is easy for most people to notice, even without interlacing. 60Hz, while better, still flickers enough to be annoying to people who spent long hours working on computers, thus the preference for some to set their vertical refresh rate to 72 or 75Hz.

  6. HI
    I’m planing to shoot in Pal area in few days. most my gears are NTSC. I wanna keep the same sittings i usually use here in the USA and also use the same lighting system i used in the USA. Do you think this idea will help me to avoid Flicker?

  7. Hi! We have a DP shooting a story for us in Japan where light bulbs work both at 50 and 60 hertz. However, we’re shooting at 23.98p, will she have the same problem or the flicker only affects when shooting interlaced?


    1. Hey sorry for the late response, hope it’s not too late. Shooting interlaced has nothing to do with it. If there are any 50 herts bulbs in the room she’ll definitely need to adjust her shutter speed to avoid flicker.

  8. Hi there – I’m afraid my experience doesn’t match your table. I recently shot an event here in Australia (50Hz cycle) on 25p, using 180.d shutter angle. The rolling horizontal banding was TERRIBLE. I tried adjusting the shutter both up and down and the effect was still visible, so I came away with awful footage. What caused this and what should I have done? Thanks for any tips!

    1. Hi Sarah, my apologies for the late reply. I’ve been working out of town. Is there any way I could see a sample of the footage? To be honest, if you were shooting in the correct frequency and tried various shutter angles with no luck, then I’m at a loss. The only guess I can muster up is that there were some lights at the event running on another frequency.

  9. Hi great info. Wonder if you could help? I’m wanting to design some DIY LED camera lighting that I can dim, but I can’t get my head around how to avoid lowering the duty cycle frequency without causing camera flicker. Is there a min frequency where syncing is no longer important or relevant say for eg above 26Khz? I guess I’m wanting to find out the minimum frequency I can dim down to (eg 10% duty cycle) without risk of flicker on camera across it’s various most common settings ? Thanks for any guidance.

    1. Sorry I didn’t get back to you sooner. Unfortunately, I literally know nothing about that stuff. I just know what settings to use in-camera to avoid flicker. Beyond that, I’m pretty useless. Good luck with the DIY project though!

  10. hi,
    i got a flicker with 30fps, 1/25 shutter speed and 50hz light. and the flicker effect reduced when i changed shutter speed to 1/50. but still flickering is there slightly, how can i avoid it completely.
    I changed the sensor ROW TIME for getting fps properly on live stream earlier.
    is it have any relation for this row time because this was the relation between ROWTIME and eshutterspeed
    regAddr = AR0331_COARSE_IT_TIME_A;
    regValue = (float)(eshutterInUsec/ROW_TIME);
    does it have eny effect on flickering in video

    1. Hi, are you referring to flicker coming from the lights or is it flicker from a TV or computer screen? Screens can be a bit harder to deal with.

  11. i coudn’t connect the logic behind selecting shutter speed at 1/25. it was there already i am new this feild.

  12. i will shoot in basel (switserland, europe). my client lives in the US. they asked me to deliver in NTSC. what should i do?
    greetings Peter

    1. I would need more specific info to give you proper advice (i.e. what frame rate your client wants you to shoot in and what kind of lighting you’ll be using), but I think a good starting point would be to put your camera in 60Hz mode and change your shutter speed to 1/50. If that doesn’t work, just experiment with different shutter speeds until the flicker is gone. Hope that helps!

  13. I would like to add one thing to this already excellent article by saying that fluorescent lights near the end of their life will flicker at slower and slower speeds before fully breaking down. It is actually possible to see the flickering of the light at the very, very end of the life of a fluorescent light with the human eye. The light in particular needs replacement at this point.

    It can be very frustrating when you are tinkering with your camera to get the best video quality while it is actually one or multiple of the fluorescent lights which are in dire need of replacement.

    Just wanted to put that out there.

    Source: They thought me this in electronics class in school.

  14. Great article, thank you. But I am confused about something:
    I adjusted the settings as you suggested and my room lights and monitors are perfectly synced. But my backlit keyboard is totally out of sync. How can this be possible? Thank you.

  15. This is a helpful page, but I have a stupid questions.
    Is it possible that If I synchronize your camera to the electrical frequency of the lighting, and camera to only take pictures of the OFF portion of each cycle within the frequency, because the frequency of the light is keeping light and dim cycle. I may have some knowledge misunderstanding if so please tell me. Thanks a lot!

  16. Hi thanks for the article. Some camera offer both flickering reduction (to be set to 50/60Hz) AND the choice of PAL/NTSC. Do you think both 50/PAL 60/NTSC should be aligned or is there something I miss ?

  17. Hi there. I want to confirm this – I will be traveling to Italy from the US for vacation. For my trip, I should change to PAL and the corresponding fps options (I like 60fps in the US to be able to slow footage down – so 50fps in PAL, right?). When I come back, I can put all of this footage into Premier Pro and it will work well together? If I happen to video some clips at the US airports – then I need to keep my shutter speed at 1/120 for 50fps to prevent banding, right? And, can you please explain what the shutter angle is – ie, you recommendation is: 300, 150. Thank you.

    1. Hey Kelley,

      You are exactly right. One thing to consider though. If you’re planning on just throwing the project on Youtube it would be easiest to shoot the whole thing in PAL mode since Youtube takes both NTSC and PAL. However, if you want to be able to watch the final video on your 60Hz TV then you might consider shooting everything in NTSC mode and just changing your shutter speed accordingly, i.e. if you shoot at 60fps, use a shutter speed of 1/100 (216-degrees). If you shoot any 24fps stuff, you would use a 1/50 shutter speed (172.8-degrees). As far as I know, there aren’t many issues viewing PAL content on an NTSC TV but it’s something to consider I guess.

      Regarding the US airport, you are right. If you’re in PAL mode at a US airport, a 1/120 shutter speed will work perfectly for 50fps stuff. If you shoot any 25fps, a shutter speed of 1/60 would be best.

      Here’s a great video explaining shutter speed vs angle. He says it way better than I ever could.

      Here’s an updated link to Red’s shutter speed/angle calculator. I noticed the link in my article wasn’t working.


  18. As a freelance documentary maker, the video flicker has always been an issue. In Pakistan, we mostly get our lights from Chinese brands and the cheapest ones don’t have the option to switch the frequency hence giving a lot of trouble when working for a Western client. Thank you for mentioning the video “What is Shutter Speed, Shutter Angle and How to get the Film Look”. It has been a great help.

  19. I’m a hobbysist and sometimes shoot in 4K @30fps NTSC on a Panasonic FZ2000. I have been keeping my shutter speed to the recommended double frame rate of 1/60th. I shoot mainly in the UK/Europe but prefer it in NTSC mode to get the extra frame rate at 30fps (25fps looks awful in most conditions). obviously I get flicker with indoor 50Hz lighting but most of my recording is outdoors. My question I guess is is it normal to only change the shutter when shooting to eliminate flicker and by default leave it at the doubled shutter of 1/60th in my case?

    1. Yes. If you cannot or prefer not to change the frame rate, you can adjust for flicker by adjusting your shutter.

  20. Hey! Nice post, thank you so much.
    I usually record at 30 frames 1/60, but now I bought a LED and if I use 1/60 it does flicker, but if I change the speed to 1/50 it doesn’t.

    Is there a big difference between recording at 25 frames 1/50 or 30 frames 1/60? Or the quality and the look is the same?

    Thank you!

    1. Thanks Bernat. Sorry for the delayed response. We were on vacation for a couple weeks out of country. As far as I can tell there is no discernible difference between the two. If you’ve ever watched any of Philip Bloom’s stuff, it’s mostly all shot at 25fps and always looks amazing.

  21. Wow, this article is gold. I always appreciate when technical questions are answered in ways that are accessible and interesting (not dry and intimidating). Very interesting and easy to understand. Big thank you!

  22. Hi, very interesting article!

    I am a professional photographer /videographer and for the first time i had really bad impossible flicker experience happened to me, I knew the the technics to avoid the flickers and also some good technics how to fix them on editing.

    However, I am getting nuts trying to understand why that happened, I am in Australia and used 50HZ in 50p, and….. that day i was trying ALL THE SETING 60hz (after no success) with all exposure frequenzes and shutter speeds angle or seting unimaginable but couldn’t get rid of this flickering!

    I was using a D750 full fram DSLR for short online videos production. I tried to find if the dslr itslef has a direct or occasional related issue on this concerne ( wich I don’t believe so) but couln’d find it…

    Was I maybe in another planet with a different frequence? or did i miss something?
    The shots was for real estate and house was braind new..

  23. Great article!!!
    I recently filmed an exhibit in the museum of fine arts in Boston. They had flourcent lighting which cause lots of flickers and black bars that would move across the screen especially at 120fps / shutter 250. From what I researched if your dropping slow motion footage into a 23.97 timeline is it true that we dont have to necessarily follow the 180° shutter rule? If so will this work and is there a recommended shutter speed boundary to stay within that wouldn’t comprise the quality. Thanks

    1. Hey Jonathan,

      Thanks for connecting! The only thing your shutter speed will affect is the amount of motion blur in your footage. Faster shutter speed will give less blur, and slower will give more. The reason the 180° rule exists is because most people find the amount of motion blur at 180° to be the most pleasing — it’s totally subjective. With that said, there are times where it makes sense not to shoot at 180°. For example, if you’re shooting something with a lot of motion and you plan to extract still images from the footage as well (something our clients ask for all the time so they don’t have to hire a photographer haha), you might want to shoot at a faster shutter so every frame isn’t totally blurry. I’ve found that you can still shoot at faster or slower shutter speeds and capture great looking footage as long there isn’t a whole lot of fast moving stuff going on, so I’m guessing you’d be safe to break the 180° rule in a museum. I’ve been on a few shoots over the years and forgot my ND filters so had to rely on shutter speed to control exposure — shooting as high as 1/4000 outside on a bright day. Most people don’t even notice — just don’t do it on an important shoot haha. Sorry I can’t give you specific shutter speeds to stay within. When it comes to controlling flicker, you just have to cycle through different shutter speed options on your camera until you find one that works. Like I said, if you’re not shooting stuff with a bunch of fast movement, you can move pretty far away from 180° shutter, either up or down, without noticing much. Personally, if I have a choice, I always opt for a slower shutter just so I don’t end up with that soap opera look. I know I didn’t really answer your question but hopefully there’s something in here that helps!

  24. Just a Few notes. 50hz electric actually means lighting goes on/off twice in each cycle. Ie 100 hz.
    Also, you forgot to mention that all of Europe uses 50hz. In fact, most of the world use.
    As being from the UK, It’s only recently we’ve even have had an option on the iPhone to record at a suitable non flicker 25fps. It seems a shame it doesn’t offer 50fps however, since the 60fps is offered.
    Being that these phones are sold all over the world, and as said above, most of the world works on 50hz,
    it can’t be rocket science to include it.
    It’s also important for broadcasting this footage in our 50hz countries, although less important for
    online streaming.
    I’m going for a pint of beer now….. yes a pint……the pub is a mile away… We’re a metric/imperial mixed bag here in UK.

    1. Thanks for the comment. That’s the first I’ve heard of the lighting going off “twice” in a cycle. Can you share where you learned that? Also, I did mention that the UK uses 50hz — at the top of the article in the History section, I said “In the UK, Africa, Australia, most of Asia and Russia, the frequency of AC (alternating current) running through electrical mains is 50Hz (Herts).” You must have skimmed over that part 🙂
      We’re in Canada here, so also on the metric system. Enjoy your pint!

  25. What shutter speed should be used for a 60Hz CCTV camera located in a 50Hz lighting environment?

    1. That depends on the frame rate you’re shooting in. If you’re shooting 24p, then these would be safe shutter speeds: 1/33.3, 1/50, 1/100. Check out the tables above for more info.

  26. There is a lot of misunderstanding in what I read. 50Hz means that the alternating current sinusoid repeats 50 times per second. During each cycle, the voltage is first + on wire A and – on wire B, then – on wire A and + on wire B, so that the lamp goes off and on again twice per cycle , which is 100 times per second. The camera must be perfectly in sync with this 100 Hz, so 25 or 50 or 100Hz is OK. But there is another big problem: the refresh rate of the video monitor must also be in perfect sync with the FPS of the video, which is almost never the case with a computer monitor. it’s not possible to display 25 or 50 FPS video on a 60Hz monitor without repeating some frames 2 times. The only good solution is to put a dedicated video output card (such as a Blackmagic Intensity Pro) un a PCI slot of the computer and using a TV or A multi sync compatible monitor plugged on this card. Now, instead of going trough the computer graphic card, the video is directly send to the external monitor with the correct frame rate and un the original YCbCr signal. Setting the refresh rate of the graphic card on 50Hz is not perfect, because the it’s never exacly 50Hz an the signal is send in RGB or in in a YUV format that was computed from RGB with very often a bad gamma curve. The gamma curve of RGB is not the same as in YUV and there can also be a mismatch of the video signal levels

  27. Please excuse my poor English. I wrote the previous post forgetting important details. A LED lamp is always DC powered. The alternating current is first rectified. If there is no capacitor after the rectifier, the lamp will strongly flash 100 x per second (cheap lamps) on a 50 Hz source. If there is a large enough capacitor, the lighting will be perfectly stable. With filament and fluorescent lamps, the flickering is less because the filament is never completely cold then completely hot and the phosphors of fluorescent tubes have an afterglow (just like in CRT monitors).

    I wrote in my previous post that the camera must be synchronized with the mains (25, 50 or 100 Hz for 50 Hz). This is true for a CCD sensor. With a CMOS sensor, there is rolling shutter. The sensor is progressively read from top to bottom, so not at the same time. During this time, the lighting on the subject will change, which will cause a kind of vertical vignetting. There is no solution to this uneven exposure issue.

    I also forgot to say that in many top cameras, there is a settig which allows to automatically synchronize the frequency of the camera with that of the mains, but the problem of the rolling shutter will not be solved.

    About the edition of the video on PC. The editing card for external monitor mentioned in the previous post can obviously only be used with a pro editing software that supports the card. The output will also be in the x.v.YCC colors workspace (an extension of the REC.709 specs used by almost all cameras), which contains color video levels that cannot fit in RGB and that cannot be output by a RGB computer monitor. Eg VLC or Windows Media Player cannot communicate with this (or other) video output hardware.

    If you read the Resolve manual, you will read in several places that it is impossible to do a good work without a dedicaced external monitor connected ton the appropriate hardware.

    Hope it was helpfull.

  28. I recently came back from Ukraine where I filmed at 23.98 frames per second. However, during one interview, we unintentionally left the shutter speed at the default setting of 1/48 instead of adjusting it to 1/100. As a result, there is now a noticeable slow rolling light/dark area throughout the footage.

    Is there a software program available to correct this issue?

    1. I have no idea, sorry. 400 is divisible by 25, so I think you shouldn’t have a problem finding a workable shutter speed when shooting at 25fps. For 30 fps, I suggest cycling through all the shutter speeds until you find one that doesn’t have flicker, or at the least minimal flicker. You should be able to get something pretty close. Good luck!

Leave a Reply

Your email address will not be published. Required fields are marked *


11749 156 St. Suite 100
Edmonton, AB
T5M 3N4