Ask David Mullen ANYTHING

[Emmanuel Decarpentrie]

i think you didn't understand me very well .

That's always a possibility :)

i am wondering why is that happened becuase it happened while i were changing my location and lenses .

You should NOT have to change your shutter speed because you changed your lens. Therefore, I maintain there is probably something wrong happening...

[BASSAM MSSALATIE]

That's always a possibility :)



You should NOT have to change your shutter speed because you changed your lens. Therefore, I maintain there is probably something wrong happening...

when i change my shooting situation , (lens ,iris, light), i didn't change my framerate
those waves show's up , that is what force me to change the shutter speed.
to get rid of them .
IS it because i was using normal light (sun light + neon lamps)
ARE neon lamps wave lenght will change during frequency change caused
those waves (difference in HZ frequency, or something)

[Emmanuel Decarpentrie]

ARE neon lamps wave lenght will change during frequency change caused those waves

If I'm decrypting this sentence correctly, you still are not convinced of what I answered you 2 times already... Yes "neon lamps" do flicker! No: this should not _force_ you to change the shutter speed every-time you change your lens or your iris!

If you want to keep talking about this issue, maybe you should consider opening your own discussion because this one is already very long on its own and it is dedicated to David and the questions we could have relating to the field of cinematography, not technical issues like synchronizing shutter speed to flickering fluorescent lights...

[Harry Clark]

Bassam,
I'll jump in here.
The colored bands moving up or down are a result of the Red One's rolling shutter. It's something we all need to be cognizant of.
You may, from time to time, have an issue with the Red One's rolling shutter and discharge lighting (HMI, flouro, neon) Yes, you will have to adjust the shutter. Yes, the bands can be subtle and colored, and move up OR down. You may notice them more depending on the lens (wider lens that renders the wall behind the actors more in focus and thus shows the bands from the HMI outside the window more readily) It's not that a particular lens itself creates the issue, just makes it show up better.
Arkham,
While I agree Bassam might have more appropriately posted a technical question elsewhere, the title of the thread IS "Ask David Mullen Anything" Give him a bit of a break.
David,
Sorry about my hijack. Please continue.
Cheers,
Harry

[Emmanuel Decarpentrie]

the title of the thread IS "Ask David Mullen Anything" Give him a bit of a break.

I understand that and would like to apologize if my suggestion was rude, it wasn't meant to be...

The fact of the matter is that I thought I did answer Bassam's questions in my first answer... even though it wasn't as detailed as yours ;) The initial question was a bit puzzling though: how could the focal length or the "f-stop" possibly be related to the "need to change the shutter speed", especially to shutter speed values that are so different from the typical current frequencies?? But now, thanks to your explanations, I understand a little bit better where it came from.

I never faced this issue so far though...

[BASSAM MSSALATIE]

Thanks Harry , now i understand what is happening .and sorry Arkham
If i couldn't explain what i am facing ,sorry again for David . it was mistake posting here .

[Lena]

Hello David,
I really appreciate all your posts, they have helped me a lot over the years. I work in the seminar and workshop business and have a small studio in which we conduct live seminars and film the lectures (usually one main trainer and a translator). Since a lot of the workshops are very long, we have quite a challenge with the heat that our lights are giving off, so I am thinking of switching to Litepanels.
Since I am not very familiar with Litepanels, I am not sure whether it would be a good idea or not. Do you have any suggestions?
I know that LED's have some downsides, but the fact that they are cool may make up for that.
I have also heard that I can mix Litepanels with Kinoflo's/dedo lights (for background lighting etc.).
Is this a common procedure? I always thought that the color of the lights are pretty different, so I am not sure if it is a good idea. I would appreciate any help on that topic.

After talking to some experts, I came up with the following solution:

4 Litepanels (one key light and one fill light per person)
2 Kinoflo's & 2 Dedo lights (backlights & background lights)

All lights will be daylight. Does this make sense?

Thanks for your help.

[David Mullen ASC]

LED's and daylight fluorescents mix pretty well, though it depends on the particular LED and particular fluorescent tubes as to whether they need some Minus Green correction or not.

[Lena]

Thanks, that is good to know. I am thinking of Litepanels and Kinoflo's. Any suggestions which fluorescent tubes match best with Litepanels (...and don't need a minus green correction)?
If I do need to correct them, how would I do that?

Also, do you have any experience with Litepanels? Would you recommend them or do you think it would be better to only use fluorescent lights?

So far, we have worked with tungsten lighting, but I don't think that it makes sense to use Litepanels for tungsten lighting since that will involve a filter. Do you agree with that?

Thanks for your help.

[David Mullen ASC]

I haven't used anything myself other than the little Litepanel over a camera lens but the color seemed to match HMI's and Kino 55 tubes.