Build 20 varispeed

[Thomas Wright]

ahoy,

it was my understanding that with normal shutter selected the exposure time remained the same through a ramp. I tested this and ramping from 25 fps to 100 fps the shutter angle went from 180 to 90 !?! when I'm sure it used to go to 360. the displayed angle is still red. the image gets darker and i'm sure it never used to do that, has anyone tried this?

additionally, some fellas were shooting in a studio with tungsten lights (filament) at 75 fps and no matter what shutter angle they dialed in they got flicker; it was more of a pulsing really.

and has anyone managed to get phase to work?

thanks for your time.

[Kip Kubin]

Just did a successful ramp from 5 to 24.

We had to change the shutter tp 1/60 because of the HMI flicker.

Once we did that all our picture was smooth and consistant

It was not at 1/48 flicker and darkness showed up.

All on build 20

[Thomas Wright]

thanks Kip,

was your shutter mode set to normal? did you see what the shutter angle changed to as it ramped?

could someone else try 25 to 100 fps or 75 fps under 50hz; the pulsing was quite obvious on the RED LCD if there was fall-off from bright to dark in image as it was evident in the graduated banding where luminosity decreases.

[Thomas Wright]

anyone...?

[Errol Afed]

Hi Thomas, same problem here. I was shooting last sunday and the dit for the Red camera approached me and asked me to check her camera settings. Everything was set right, 24 to 60 fps but we had the same problem with the shutter. I shot with ramping before and have not encountered this. Has anybody else experienced this?

[Cody Cuellar]

I've got a question about the flicker thing. I was shooting a 120 frame and was getting a little bit of flicker from a tweenie and from my understanding, lights about 1K and less don't get hot enough to stay consistent for high speed shooting. Since the light is powered AC at 60hz, I understand that if there is any amount of dimming between phase cycles (inherent on the smaller units) you will get flicker as you increase shutter speed over 1/60 (which will increase as you shoot higher than 60fps. What are some workarounds to this when using smaller lights when upping the power of the rest of the lights is not an option?

[Tony Bacak]

we had the same problem but it is because of the lights!
you have to use hmi with a nonflicker pulp and powesupply!!!
most hmi run at 50 hz in europe or 60 hz in us
so in europe 100 fps works fine with 50 hz or you use flickerfree lights then yoou can go up to every framrate you want

[Errol Afed]

We always use flicker free lights during shoots, the problem we encountered was with the ramp settings. the ramp would start at 24 fps/180 shutter and end at 60fps but the shutter would go down to 70 degrees, shutter was set to relative. Weird part is I've done it before and it worked fine. Is there a setting on the the camera (build 20) that I may have missed?