DIY adapters for RB645 and 35mm lenses

[Ben Winter]

Originally Posted by Ted Ramasola

The primatte also has a lightwrap feature that when activated, allows you to sample the background image and gradually "smears" for lack of a better term, dominant colors of the backplate and apply it to the edging of the keyed image.

Its like simulated radiosity. A term i use in CGI and photography often. When colors of the surroundings affect the color of the subject.

I've often seen that "blooming" in real situations and have wondered who would finally implement it in a keying solution. Glad to see it's there.

[Bob Hart]

With any other than shooting through the real propellor, lighting is limited to directly overhead or to sides otherwise the shadow of a static greenscreen painted prop on the engine cowling has to be removed by CGI as well.

Frame rate could be anything if a single frame grab of the composite was taken. Strobing of prop blades is not a real problem at 1/50th sec or 1/60th sec shutter speeds at climb or cruise rpm as the prop is a blur.

The prop is not intended to be sharp in the shot and for safety reasons, the cam will have to sit off well in front of the aircraft in case brakes fail and it rolls forward before the pilot can cut power. So it is likely to be a long lens and selective focus on the humans inside the cabin.

The MINI35 or my own AGUS35 is best at slower shutter speeds although I can get away with 1/400th sec on my own if the light is right.

An entirely different story with CMOS cams though when shooting through a propellor disk.

The blades create these interesting close grouped horizontal ascending arcs in the image.

[Rich Hibner]

Teddy,

Where did you get your box from?

[Ted Ramasola]

Rich,

Its an electronic hobby enclosure thats available in most electronic shops in my country.

Its made of hard plastic. It comes apart at a seam and held together by 4 screws.

I've heavily reinforced the inside with aluminum brackets so it can hold the weight of heavy lenses without flex and vibration.

box dimensions 11cm width 12.4/10 cm height 7.3/10 cm depth.

Ted

[Ted Ramasola]

Bob,

I'll be posting that fan test you wanted. I got a little spare time after testing my cam and adapter.

I shot the fan at speed 1 with a nikon 50 mm at f1.4. Hd100 was at 24P mode at 60 shutter speed.

Also shot it at 60 P at 60 shuuterspd.

Gimme a moment at i'll post stills.


Ted

[Ted Ramasola]

Here are the 24P shots bob.

First, fan is off. Then start up. Third is full speed. The fourth is full speed with motion blur filter applied.

Shot this against a green screen wall in our studio with DIY flourescent softboxes as lighting.

Hope you find these useful.

[Bob Hart]

Ted.


Thank you very much for conducting that test for me. It raises some very real possibilities.

Also, reading up and learning more of a horror rolling shutter problem with CMOS cameras, it would create an option for dealing with those artifacts on dynamic objects in a fixed position.

In an ironical twist for those of us who obsess about the film look, the same artifact can be apparent with film cameras, though not as aggravating as a CMOS set to a high shutter speed. So with prepation and some effects work, a propellor shot with a CCD cam could be overlaid onto a CMOS origination.

I have discovered that views through operating aircraft propellors when originated on CMOS cams are really bad, no real issue for reality or documentary but not good for drama, until the artifact is more commonplace and accepted.

An aircraft could be filmed with the prop removed and a correctly oriented spinning propellor could be layered over.

[Ted Ramasola]

I experimented with a relay lens using a tamron 17mm. I dont like the lensbut it showed me that there is another way.

The test proved that another relay is doable using a wide lens and that CA caused by the achromat was eliminated since the achromat was also removed.

[Ted Ramasola]

Bob,

I just recieved a new achromat from Wayne kinney. The improvement in edge to edge sharpness and elimination of CA is VERY significant. I told wayne that the secret alchemy behind his adapters sharpness is in his achromat! And as a DIYer, i believe using his achromat on a diy adapter or even replacing the achromat on some branded adapters could significantly improve the image!

Ted

[Ted Ramasola]

Replacing the cinevate achromat with one from SGPRO sent by Wayne gave my adapter a significant improvement in removing blue and yellow CA from the image.

Edge to edge sharpness was also achieved using SGPRO achromat even at wider openings on the fujinon relay lens.

Attached are some clips from a recent shoot last thursday.
Images are unsharpened and no cc.

Food and chart shot with nikon 50mm f1.4
Dinner with sigma 20-40mm f2.8

[Bob Hart]

Ted.

There seems to be an improvement and this might be an option for hacking adaptors for the EX1 which has a wider imager (1/2"). I observed a little corner softness in the hack I did using my 58mm 4+ Century from Agus35 to match up a Mini35 to the EX1.

The front element of the EX1 lens is wider and the 58mm Century whilst "adequate" up to the Z1 and able to pass the Mini35 and Agus35 images to the EX1 may not be ideal for this camera's wider optics

[John Yamamoto]

TEd
thanks for ur post and seems the latest with SGPRO achromat is very good
I wish to know the making of GG as i m think to buy brevis GG to have less light loss.
1/ R u using spinning disc? or vibrating?
2/ how to grind the texture? DIY or use any material? tracing paper or any?
3/ speed of spinning? do u have different control?

thanks in advance
JY

[Ted Ramasola]

John

first, let me apologize as i didnt see this post of yours, apparently this thread got buried after i took a long vacation.
I hope my reply still helps.

1. I use a spinning GG
2. I use a frosted texture plastic cut into a circle and mounted on a CD motor.
3. The motor is 5.9 volts but underpowered with 2x 1.5 volt AA batteries. I have two battery holders and the other holds 3x 1.5 batts for a 4.5 volt power.

The 3 volt power gives me a quiet operation with max shutter speed of 60.
4.5 volts gives a humming sound but allows me to go to 100 shutterspeed.


Ted