[biz-engineer]

Looks like you are capturing the flicker of florescent and HID stadium lights. They basically cycle 60 times a second (50 in Europe) . Any light source that has a ballast will do that. The human eye puts it together so you don't notice it. You will see it in TV slo-mo replays if the camera is pointed at the lights. The newer Canon high end cameras automatically detect and eliminate this.

Ah ah !!!! That's right. When I received my K-3, I tried a few shot in living room and the same happened... I first through the camera had a problem... but no, depending on the time of the shutter opens, you get one of the two half period of the 50Hz (Europe) sine wave.

[eddaytona]

Canon 7d II (aps) and 5Ds (full frame) can compensate for this. Pretty cool. Pentax, are you listening?

[biz-engineer]

Canon 7d II (aps) and 5Ds (full frame) can compensate for this. Pretty cool. Pentax, are you listening?

K-3 also, you have to read the manual :-)

[BrianR]

K-3 also, you have to read the manual :-)

Where is it in the manual or what name does it go by so I can search for it? (I don't have a K-3, so I'm not planning on reading the manual cover-to-cover)

Canon claims to have had the First ever anti-flicker technology (this is dated after the k-3 was released).

[LensBeginner]

K-3 also, you have to read the manual :-)

Well my K-01 has a 50Hz-60Hz setting as well, but how effective it is I can't say, never tried...

[stevebrot]

Yeah, makes perfect sense, I understand the electrical principles of it all, I am just shocked that I've never encountered this issue before, or at least noticed it.

It has come up before on these forums, though not as often as one might think given how common HID and fluorescent lighting is. Even LED and tungsten lamps may fluctuate with line frequency. Here is an interesting and entertaining article on the subject. The intended audience is video production, but it still covers the basics.

Flicker-Free Lights, and Why They are Important to You | explora


Steve

[stevebrot]

Where is it in the manual or what name does it go by so I can search for it?

I believe he is misreading the intent of the 50/60 Hz setting for screen flicker.

Canon claims to have had the First ever anti-flicker technology (this is dated after the k-3 was released).

Yep, the way it works on the Canon product is to introduce additional shutter latency and/or adjust drive rate to correspond with the lighting peak. So much for timing the shot, eh?


Steve

[Brooke Meyer]

Canon 7d II (aps) and 5Ds (full frame) can compensate for this. Pretty cool. Pentax, are you listening?

Went and read Page 185 and 186 of the Canon 7D II Manual. A few caveats. It necessarily introduces some shutter lag which makes perfect sense, it waits for the right time of the light cycle. But it may get confused. Useful throughout an event but in my case, shutter lag is an issue. It's why I'm shooting DNGs, rear AF focused and everything that will slow response is off.

[willskywalker93]

well guys, thank you all for the information. I did some more reading and read that most stadium lights are wired in three phase systems so it isn't too big of a problem. Either I'd just never noticed the problem in that particular stadium or they've rewired everything into the same phase for some reason. I know it isn't an issue in my college stadium and some of the high school stadiums I've been to, so they all must be wired in offset phases.

Also, excellent shots, Brooke.

[BrianR]

Yep, the way it works on the Canon product is to introduce additional shutter latency and/or adjust drive rate to correspond with the lighting peak. So much for timing the shot, eh?

I dunno, I've never used it but it seems like a pretty cool option. It shouldn't need to delay the shutter by more than one cycle of the light, which is much faster than I'm able to react. It can also be turned off if you found it messed with the timing too much for your purposes.

What's pretty neat in any case is the cameras have a "FLICKER" warning light up in the viewfinder when it detects the flickering lights, which should either prompt the user to look up what's going on in their manual or misread it and think their next photo should be uploaded to flickr.

Here's some dull test images of it in action as well as anecdotal claims of the usefulness and the hit to response time:

Does the Canon EOS 7D Mark II's Anti-Flicker Mode Really Work?

[stevebrot]

It shouldn't need to delay the shutter by more than one cycle of the light

1 cycle = 0.017s for 60Hz or 0.020s for 50Hz*. The advertised shutter lag time for the 7DII is 0.055s, so the delay would only be a maximum 36% increase in latency. I would expect that that there would be some degradation in FPS as well. Whether either of these would upset a user who was unaware of how the system works is anyone's guess.

The Anti-Flicker detection and correction feature is interesting. I have friends that shoot the 7DII and will have to ask their opinion.


Steve

* For perspective, the additional latency on the K-3 for P-TTL that has some users on this site in a froth is 0.018s.

[BrianR]

1 cycle = 0.017s for 60Hz or 0.020s for 50Hz*.

According to the Canon link, it only works on lights that are 100Hz or 120Hz, so the delay may be even less. These are common flicker frequencies for fluorescents, due to the physics magic that happens inside the ballasts for the lights (I may have understood it 20 years ago, but now I'll call it magic).

The delay of my trigger finger is an order of magnitude larger than the shutter lag of most dslr's, but it would definitely be interesting to know if the added delay is noticeable in real use. Not being a predictable delay may set off the ultra skilled action photographers. Given that Canon's default is to have it disabled, I'd bet that either the delay or lowered fps is noticeable or at least easy enough to measure and that Canon users are just as froth prone as Pentax users about these things