7D II Flicker setting question(s)

Hi, for those of you that have a 7D II, have you tried the anti-flicker mode under fluorescent (or sodium vapor) lights? How has it worked for you? Interested in hearing any specifics you can provide. I occasionally shoot indoors in halls or auditoriums that may have many fluorescent lights, or a few in combination with incandescent, LED, or natural light. These situations can be very tedious to try and correct in post. I'd like to hear opinions (good or bad) of anyone whose tried the camera under those difficult mixed lighting scenarios.

http://www.the-digital-picture.com …News-Post.aspx?News=13866

Eccentric M wrote in post #17271247
http://www.the-digital-picture.com …News-Post.aspx?News=13866

Although I typically shoot landscapes I find this to be interesting technology!

I've seen the flicker icon come up while pointing the camera around inside the hose. I moved the setting to my menu to be able to get to it quickly when needed.

It was also mentioned here.

It does occasionally come on when there aren't any flickering lights. I also think some LED backlights from TVs can set it off as they often pulse at different speeds to adjust the main backlight brightness level dynamically.

Very cool indeed.

Most of my "flicker" issues involve multiple lights cycling at different times. Is it really able to fix that?

eigga wrote in post #17272129
Most of my "flicker" issues involve multiple lights cycling at different times. Is it really able to fix that?

My understanding of the issue is the alternating power source of the lights, and if all the lights are on the same 60Hz source shouldn't the "flicker" rate all be the same?

The rate would be the same, but in areas of the world where the electrical system is reasonably developed, it's common practice to connect lights in large buildings to three-phase supplies. This is to even out the load on the three phases. Thus approximately 1/3 of the lights flicker at 50 Hz rate (100 times per second), the next 1/3 also at 50 Hz and the same for the last 1/3. But their phase is 120 degrees apart, so the total flicker will be less, but will show peaks corresponding to 150 Hz, or 300 peaks/s.

Thus the flicker effect would be far less, and perhaps not detectable by the camera, had the light sources been interleaved. But often the 1/3 that runs from L1 are at one side of the building, those on L2 in the middle and those on L3 at the other side. Thus you'll have the normal flicker effect everywhere, but the camera can't fix more than one area of it at a time.

apersson850 wrote in post #17272448
The rate would be the same, but in areas of the world where the electrical system is reasonably developed, it's common practice to connect lights in large buildings to three-phase supplies. This is to even out the load on the three phases. Thus approximately 1/3 of the lights flicker at 50 Hz rate (100 times per second), the next 1/3 also at 50 Hz and the same for the last 1/3. But their phase is 120 degrees apart, so the total flicker will be less, but will show peaks corresponding to 150 Hz, or 300 peaks/s.

Thus the flicker effect would be far less, and perhaps not detectable by the camera, had the light sources been interleaved. But often the 1/3 that runs from L1 are at one side of the building, those on L2 in the middle and those on L3 at the other side. Thus you'll have the normal flicker effect everywhere, but the camera can't fix more than one area of it at a time.

Thanks. I wasn't thinking a 3 phase panel. I guess we would have the same issues here but at 60Hz. I'll pay attention to that and the flicker indicator the next time I'm in a commercial building with the 7D2.

All that is above my head but I can tell you at the gyms and football fields I cover they cycle at different times. I often have images with lights cycling at different times and thus the image is split on exposure and white balance.

eigga wrote in post #17272739
...the image is split on exposure and white balance.

This happens even when they are cycling at the same rate and time.

Anyone have real world examples of this feature working? I don't need basement light samples. I need a high school gym or middle school football field

rrblint wrote in post #17272761
This happens even when they are cycling at the same rate and time.

Tom_D wrote in post #17272461
I guess we would have the same issues here but at 60Hz.

If you by "we" mean the US in general, then it's not for certain. The US power supply system lacks quite a lot compared to continental Europe. Here we had the "advantage" of the different existing systems being badly damaged by 1945, so when they were rebuilt, the design was based on experience dating back to the late 1800's. Thus many of the mistakes and bad decisions which still paluge the US system were removed and replaced with a better design in Europe. The 230/400 V 3N~ is clearly superior to the common US distribution system, and also lends itself much better to even load distribution in the way I described above.

As you perhaps understand electrical stuff is my profession, but I don't have the same detailed knowledge about how this is solved in the US.

I can comment on the anti-flicker mode. I have been evaluating a 7D2 for the past week, comparing its performance in a variety of situations with the 7D I have used for 5 years. One of the shooting situations I have tested is dimly lit gyms with bad discharge lighting.

Both cameras are used in manual mode. With the 7D typically 25 per cent of the shots would be underexposed by 1 to 1.5 f-stops, 25 per cent overexposed by an f-stop, and the other 50 per cent would be about right. With the 7D2 in anti-flicker mode, all of the shots have the same exposure, so the anti-flicker feature works as advertised.

In addition, the 7D2 is about 1/3 f-stop more sensitive at equivalent settings ( f/2.8, 1/200, ISO-6400) than the 7D; i.e. the 7D2 images are about 1/3 f-stop brighter -- this is in RAW.