Horizontal Distortion in High Shutter Speeds

Anthonyb

Anthonyb

Well-known member
So I was shooting a test with my friend at the mall tonight, and when I turned up the shutter speeds past 100 three fat horizontal bands showed up. When I lowered the shutter to 1/100 they mostly disappeared.

I attempted the same test when I got home, everything was fine. Does the mall have some kind of voodoo lights? Anyone ever experience this? :violin:
 
Yes, it is caused by a couple things from what I've read. One being the lights used and the other being either the pixel binning or refresh rate of the sensor or something.

It's usually caused by Flourescent lights.
 
It's fluorescent lights. Don't turn the shutter speed faster than 1/60 unless you have a really, really good reason.

And if you're shooting under fluorescents, don't turn the shutter to 1/50 either, you must leave it on 1/60.

*unless you know for a fact you're shooting under high-frequency electronic ballast fluos.
 
Don't listen to these people !

They have not even bothered to ask you which country you are in.

And that is very important.
 
It's important in that you need to know whether to go for 1/60 or 1/50, true. But everything else is directly applicable, and hardly warrants a "Don't listen to these people!"
 
its interesting thay rebel t1i/500d doesnt have problems with banding and those darkened lines dont appear with different shutter speeds ,they appear on 7d but why not on 500d - i dont know.I was in the same room with 7d and 500d and went through all shutter speeds in 500d - no banding at all.
Its something else,not fluorescent lights.Or 7d has some flaw in design if 500d doesnt have this.
 
Barry_Green said:
It's important in that you need to know whether to go for 1/60 or 1/50, true. But everything else is directly applicable, and hardly warrants a "Don't listen to these people!"
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Thanks Barry! I guess the refresh rates of these type of lights goes with the power: 60hz. I'm in Canada so it's 30fps, 1/60.
 
Barry_Green said:
It's important in that you need to know whether to go for 1/60 or 1/50, true. But everything else is directly applicable, and hardly warrants a "Don't listen to these people!"
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Hmmm . . . . 'everything else is directly applicable' - what is this 'everything else' ?




Just look at the information you are supplying:

" . . don't turn the shutter to 1/50 either, you must leave it on 1/60."

If he or she were in a SECAM or PAL country this would be very very bad advice.

Only recently someone here on DVXuser asked much the same question** - the person who replied also didn't bother to enquire as to where the camera would be used - this is especially a problem amongst those in the US who tend to assume the internet is America - this person was given similarly unqualified (in that the context was ignored) advice, the result was of course ruined footage.


** http://www.dvxuser.com/V6/showthread.php?p=1811883#post1811883

. . . so if someone were to advise the use of 1/60th (or for that matter 1/50th) without ever asking as to where the footage is going to be shot, I would advise the enquirer: "Don't listen to these people!".
 
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I'm saying that you can't shoot under magnetic-ballast fluos or HMIs with a high-speed shutter. That part is directly applicable. You have to use the appropriate shutter speed for your territory, yes -- but that's a matter of "er, check that -- if you're in a PAL territory, use 1/50" instead of a "DON'T LISTEN TO THESE PEOPLE!"

That's all I'm saying.

Yes it was my mistake for assuming. But you also didn't offer any corrections in your post, you just said to ignore us, when the info we were giving (while perhaps not 100% complete) was absolutely correct in diagnosing what the problem was and would certainly have put the shooter on the right track.

So you had a choice of how to respond -- you could have said "1/60 for NTSC countries, but 1/50 for PAL" or you could have said "these folks don't know what they're talking about." One is helpful and friendly, one is not.
 
Barry_Green said:
So you had a choice of how to respond -- you could have said "1/60 for NTSC countries, but 1/50 for PAL" or you could have said "these folks don't know what they're talking about." One is helpful and friendly, one is not.
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Maybe a few more smilies and a couple of more exclamation marks might have made my post appear less unfriendly, but regardless I stand by my basic point.

I suffer from a terrible affliction - I can only either explain things is exacting, painful, boring and tedious detail (in the hope of clarity) or not at all - in this case I chose the later option, perhaps a failing of mine.

No worries, it turned out you were right in the end anyhow !



. . . . but it is an ongoing issue, here is another piece of similarly blind advice I have just spotted:

http://www.dvxuser.com/V6/showthread.php?p=1820284&posted=1#post1820284

. . . the very first reply advises 1/60th shutter speed - again without asking about geographic location - and as we have seen (the example in my previous post) this can lead to people ending up with ruined footage. The very nature of someone who asks for such basic advice - like shutter speed - necessarily means that they are unlikely to be au fait with the technical side of things and will simply follow any pointers they are given. I would also say that someone asking basic questions (about shutter speed) might not know what "magnetic-ballast fluos or HMIs" are.

I think the problem stems from a presumption - on the part of our American members - that the world consists of the US and the ocean, when the fact of the matter is that there are vastly more PAL and SECAM countries than there are NTSC countries - so it is very important to check out where the poster comes from - in fact absolutely essential.

Like I say it is an ongoing issue, and I see it time and time again here on DVXuser, someone clearly new to the subject (by the nature of his or her question) asks for the 'correct' shutter speed and is told to stick to 1/60th.

:bath:

Which side of the road should I drive on ?

:happy:
 
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Lee Wilson said:
I think the problem stems from a presumption - on the part of our American members - that the world consists of the US and the ocean
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Well, since I have traveled this globe, and spent plenty of time in all sorts of overseas countries, in both northern and southern hemispheres...

... I'm still guilty as charged. Sometimes we just don't think about 50Hz. I try to be better about it, I certainly cover 50Hz thoroughly in my books and DVDs and stuff, but sometimes in the posts I just blow it.

Sorry. It was my mistake, and I should have been more thorough.
 
That in mind, I would also say that it behooves a poster to state what equipment they are using accurately. If the original poster doesn't specify, then people are likely to tend to give less specific information.

In both examples that Lee cited, there was no information in the original post, or under the poster's username to indicate a specific location.

In other words... I agree, but it's something that we all need to be cognizant of... not just Americans. :) Detailed questions tend to facilitate more detailed responses. More generic questions get more general answers. Particularly from a guy (Barry) who has been making something like 15 posts a day for however many years now :)
 
Barry_Green said:
Well, since I have traveled this globe, and spent plenty of time in all sorts of overseas countries, in both northern and southern hemispheres...

... I'm still guilty as charged. Sometimes we just don't think about 50Hz. I try to be better about it, I certainly cover 50Hz thoroughly in my books and DVDs and stuff, but sometimes in the posts I just blow it.

Sorry. It was my mistake, and I should have been more thorough.
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. . . and I will try and be a little less curt and little more helpful

:):beer:
 
Jason Ramsey said:
That in mind, I would also say that it behooves a poster to state what equipment they are using accurately. If the original poster doesn't specify, then people are likely to tend to give less specific information.

In both examples that Lee cited, there was no information in the original post, or under the poster's username to indicate a specific location.
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I think it reasonable to assume the camera is the Canon 5D. All example are posted in the Canon 5D forum - one even states "I'll borrowing a brand new 5D".
 
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