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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

My biggest wish from Red or the team behind Revolva...

Agreed they need to implement it!
The fact that RED is a cinema camera company (not eng) does't esclude the need to add nd filters in their bodies. Even the Alexa Mini LF has.
As a C200 owner I'm in l ove with up to 10 stops of filters and I think that RED should go as high as their highlight rollof images perform better with high ISO
 
we're using the revolva on our Monstro and so far...no problems...but we only tested it with the sigma art lenses, till 20mm....the 14mm vignettes even without the revolva.
 
I'd actually prefer to see some form of official "speedbooster" that's compatible with both DSMC1 and 2, to be honest...
 
A NEW motion mount would be good but with a CLEAR setting so there's no stop loss. Don't care about global shutter or that stuff. Just want a good internal ND system.
 
I very much care about a global shutter so I would love to see a motion mount with a zero light loss setting. This should have been made years ago.
 
Patrick Tresch said:
Sony Fs 5?
Click to expand...

I guess you are NOT well versed in physics. NO glass filter on earth is a "zero light loss" optical apparatus.

optical-properties-figures-RI2.png


Light that is incident on a glass surface will be reflected at an angle equal to the angle of incidence and transmitted according to Snell’s law. For normal incidence, approximately 4 % of the light is reflected; this value is determined by the refractive index of the glass.

The refractive index (n) of a material is defined as the ratio of the speed of light in a vacuum to that of light in the material.

Glass Refractive Index
Light that is incident on a glass surface will be reflected at an angle equal to the angle of incidence and transmitted according to Snell’s law. For normal incidence, approximately 4 % of the light is reflected; this value is determined by the refractive index of the glass.

When a beam of light hits a glass surface, part of the beam is reflected and part is transmitted. The index of refraction of the glass determines not only how much light is reflected and transmitted, but also its refracted angle in the glass. The angle of transmission can be calculated using Snell’s law:

equation-01.png

Snell’s law

Larger indices of refraction in glass result in greater differences between the angle of incidence and transmission of light. The reflection of light at the surface occurs due to an instantaneous change in refractive index between glass and its surrounding medium. For normal incidence (Θi = 0°), the amount of light reflected is found by

equation-2.png

glass normal incidence of light

For most glasses with a refractive index of 1.5, reflection losses at the surface result in an approximate 4% decrease in light intensity.

Absorption

When light travels through a glass, the intensity of the light is typically reduced. This absorption happens when the energy of a photon of light matches the energy needed to excite an electron within the glass to its higher energy state, and the photon is absorbed by the glass.
 
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I am not sure why Bobbys question deserves such a terse response but while Neil is correct in saying that all glass suffers from some light loss this is not really relevant in the context and spirit of Bobbys question. In the old days before modern low dispersion coatings this light loss would add up in multi element lenses but again this is not relevant to the ND question. If I use a clear filter in front of a lens I do not bother compensating for the @4% light loss but maybe that's just me.

Patrick as I understand with the Sony FS5 the electronic ND is physically switched in and out of the optical path. It has a minimum two stop loss when engaged. While a zero loss variable ND would be awesome I have not seen any practical technology yet that can do this? I like the Sony system and would love to see Red emulate it even if they used the existing Motion Mount technology and design it to work in a similar way. Check out this video at the 2min 48sec mark to see the Sony internal ND system in action. https://youtu.be/A9muBcF_QPw
I admit I don't know how Sony adjusts for the change in back focus when the rear ND is engaged? I would guess a clear glass replaces the ND. It is telling that they did not use their variable ND system in their top of the line Venice camera.
 
Tom Gleeson said:
What lenses were you using on the Monstro with the Motion Mount? Thanks
Click to expand...

Testet the Celeres, shot with K35/FDs, LOMO anas, Elites primes 50,75,100,135 and Speed Panchros 40,50,75,100, just from memory so maybe a few more.
 
There is a reason why the red motion mount is named motion mount and not ND mount. its not really built to use as ND filter but to give the shutter a nicer more sinus wave look. That kind of tech is not really suited to use as an ND as there is quite a bit of colorshifts that comes in play when dialing it up. Somthing that needs to be counter steared in color sience.
 
Manfred Baulig said:
we're using the revolva on our Monstro and so far...no problems...but we only tested it with the sigma art lenses, till 20mm....the 14mm vignettes even without the revolva.
Click to expand...

Are you shooting at 8K with EF type lenses and not getting any vignetting at all with the monstro?
 
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