Shutter angle with HVX Letus

[mrbrycel]

I know this subject has been covered on this forum before, but I couldn't find the posts I was looking for.

I'm shooting a short tomorrow on my HVX/Letus Extreme, and I wanted to shoot at a 45 degree shutter angle. I did some tests today outdoors in the shade at 45 degrees, and the GG didn't give any bad effects or anything. But I just read on anther forum that if you close down the shutter angle with the Letus in daylight, the GG effects the sky in a weird way. When I did my tests I forgot to include the sky. I won't have time today to do another test, but now I'm worried. I don't want to mess up tomorrows footage. Has anyone tried this?

 

[Phenixone]

I have never tried anything similar this but my guess would be :
If you put your shutter to 45 degree, that means you a closing it to get a crisper image (ala Save Private Ryan). That means that you are removing the motion blur between the frames (correct?)

Then as you are using a Letus system you are actually shooting a vibrating/rotating (depending on the lens adapter you are using). This glass has a grainy look and that's why you are making it vibrate/turn go get a motion blur on it.

As you are reducing the shutter angle, this motion blur is disappearing (that's what I'v deduces earlier). The result will be that you will be able to see the grains quite clearly in your footage.

Why the sky ? - Answer is simple : The sky is a BIG PLAIN BRIGHT BLUE SURFACE, and it is easier to see the grain of the viewing glass on this big plain bright blue surface.

Conclusion :
- YES ! it will give a weird looking sky.
NO, the sky won't be the only thing affected, the whole image will have this grainy look, but it will be easier to notice it in the sky.
What you can do :
- Check your tests and pay a particular attention to the plain surfaces, a white wall would be good (if you still have time you can still film a well lit white wall tonight to make sure you'r alright)
- If possible have your vibrating/spinning glass to vibrate/rotate as fast as possible to reduce the grainy look.

/!\ AGAIN, I have NEVER used a mini35 kit with a variable shutter (other than 180deg) everything I've said is only a DEDUCTION /!\

Good Luck !

V.

 

[Joe Calabrese]

Well, It goes down to the way the adapter works.

As explained above, your camera is shooting what the film lens in projecting on the ground glass. If the ground glass grain is seen, it's recorded.

The reason you may see grain would be because you are losing light, not because more detail of high motion objects is being captured. The grain on any lens adapter will stand out in low light because the grain is just not "overpowered" by the light. Basically, when you have enough light, the grain becomes invisible because the spaces in between the grain is filled with light. When you dont have enough light, the spaces in between the grains become black or darker colors, and the actual grains become visible because they are illuminated, in a sense. Simply, if you have enough light, you could use a 1 degree shutter angle and not have a problem.