Letus Loss of light test footage

cousinavi7

cousinavi7

Well-known member
Hey Guys,

I've got a DVX100 and a Letus flip and am really having a hard time with how much light is lost with the adapter. I absolutely love it otherwise! The bokeh is awesome, the depth and rack focusing is amazing.

But its nearly useless indoor even with extra lighting. I'm willing to bet i'm doing something wrong but dont know what. Any ideas? Check out this video of test footage to show the difference with the adapter on and off.

http://vids.myspace.com/index.cfm?fuseaction=vids.individual&VideoID=35514239


I shot this with:
1. camera wide open
2. 24p
3. canon fd 28mm 2.8 lense wide open
4. ND filter off (haha wouldn't that be easy...)


Thanks for taking a look. Hopefully you guys have some great ideas. Otherwise I'll be melting my actors in front of the LAPD helicopter search lights to get them lit...
 
what is the f-stop on your dvx set to? Do you have nd filters on? I usually have to keep mine all the way open and keep my lenses on the letus wide open as well when shooting inside without lots of lights..
 
just take the space out of the two groups of numbers at the end of the url.
i am personally experiencing the same thing, but i just think it is a part of having the letus, unless of course i am doing something wrong as well....
 
It looks like a lot of loss. Are you sure the iris is actually ass open as it reads on the side?


I was going to say that you are shooting with an f 2.8 35mm lens. That's the biggest source of light loss. Get a faster 35mm lens for your Letus, or get a Brevis so you can get low light with an f2.8 lens.

- However that still looks like too much light loss. - wish i could help more.
 
sorry guys, there was an unnecessary *space* in the link. Try this one

http://vids.myspace.com/index.cfm?fuseaction=vids.individual&VideoID=35514239



Yeah I hear you. The camera was set to wide open iris, no ND filters, The canon lens is wide open at f2.8. I'm hoping its not just supposed to be that way...


 
That was not the the Extreme.

That is the first flip that ate a lot more light than the Extreme (1/2 f)

Anyway the light loss has more to do with the zoom and your f 2.8 35mm lens.
 
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Yeah thats a good point. I've got a few 35mm f1.8 lenses (50, 85).

So basically your saying that we always have to shoot wide open with a very narrow DOF. (which is fine most of the time, but occasionally you want more in focus in the scene...)

It does blow me away that it is so dark. Is any of it the ground glass? Really stupid question but has anyone ever replaced the ground glass with clear glass? I realize the vibrating glass adds a nice grain texture for a more film-look, but I'd rather have the Light and narrow DOF. Honestly I shot a short in 24p and some shots I used the Letus, and some I took it off and used only the DVX. As far as a "film grain look" you couldn't even tell much of a difference between shots! (Obviously the DOF looked incredibly better...)
 
cousinavi7 said:
Yeah thats a good point. I've got a few 35mm f1.8 lenses (50, 85).

So basically your saying that we always have to shoot wide open with a very narrow DOF. (which is fine most of the time, but occasionally you want more in focus in the scene...)
Click to expand...

NO, I like to shoot camera and 35mm lens both at f 4.0. You use different lenses to achieve broad or shallow DOF.

What I was talking about was the difference you see in you comparison were not apples to apples. Do your light loss test with the camera @ f 5.6. Use a white card board or a wall adjust light so you get the right exposure. Add the adapter without lens and adjust camera f stop to compensate. That is your adapter's light loss. You will loose some more when you ad a lens (unless you own an f 1.0 lens :grin:)
 
Good info Douglas I'll give that test a go! Which adapter do you have? If I shot camera and lens both at 4.0 i think the screen would be black! Or broad day light...
 
cousinavi7 said:
Good info Douglas I'll give that test a go! Which adapter do you have? If I shot camera and lens both at 4.0 i think the screen would be black! Or broad day light...
Click to expand...

I have the Extreme and yes you need more light to use a 35mm adapter. It is a tool to get an effect and like medicine it has side effects. :embarasse
 
the "letus flip" lost about 3 stops of light form memory....
the "letus flip enhanced" lost about 1.5 stops.
the "letus Extreme" and "Letus Economy" loses 0.5 stops.

that's your problem.


the only thing you can do is use faster lenses and turn on more lights or sell your adapter and buy an extreme or an economy.

you have to be aware that a f1.4 lens is NOT 2 stops faster than a 2.8 lens on an adapter. it's more like 1/2 to 1 stop depending on the GG... so using faster lenses will only help so much...
 
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