Redrock adaptor owners can you help at DVinfo.net

Go Back   DV Info Net > Special Interest Areas > Alternative Imaging Methods

Alternative Imaging Methods
DV Info Net is the birthplace of all 35mm adapters.


Reply
 
Thread Tools Search this Thread
Old March 20th, 2009, 12:42 AM   #1
New Boot
 
Join Date: Feb 2007
Location: Koh Samui, Thailand
Posts: 22
Redrock adaptor owners can you help

I built a cine-adaptor from Redrock's DIY kit for use with my Z1U. It works fairly well.

I've been using a cheap achromat and now I'm thinking about getting their 72 mm dia achromatic diopter to get a better image. I'm trying to find out how far I'm going to need to put the ground glass from the new achromat to achieve focus, but I can''t seem to get an answer from their support.

I believe my rig approximates the production model, so I'm hoping a Redrock (non flip) production model owner can give me this distance to within a few millimeters, my measuring it in their rig.

Thanks.

Martin
Martin Amada is offline   Reply With Quote
Old March 20th, 2009, 09:42 AM   #2
Trustee
 
Join Date: May 2005
Location: Allen, Texas U.S.A
Posts: 1,117
Martin,

Put the distance at 69mm measured from surface of gg (facing the achromat) up to the achromat rim.

This assumes you are getting the achromat from either cinevate or redrock. They have the same power. (the original versions or M2 and brevis.)

Ted

P.S. The weaker the power of the achromat, the farther the distance.
Ted Ramasola is offline   Reply With Quote
Old March 20th, 2009, 10:17 AM   #3
New Boot
 
Join Date: Feb 2007
Location: Koh Samui, Thailand
Posts: 22
Hey Ted,

Funny, after getting vague answers from the manufucturers I started thinking about who might be able to help with this, and you were one of the people I thought of!

Have you used either of these with your DIY rig and would you recommend one over the other?

BTW, someone at Cinevate support told me focal length of their achromat was 20 cms. That seems very long to me! What do you suppose that was about?!

Martin
Martin Amada is offline   Reply With Quote
Old March 20th, 2009, 11:20 AM   #4
Inner Circle
 
Join Date: Dec 2003
Location: PERTH. W.A. AUSTRALIA.
Posts: 4,356
Martin.


The 8" or approx 200mm sounds about right for a flip adaptor with an approx 4+ achromatic dioptre.

The Brevis and SGPro were originally made as non-flip adaptors. It might be worth enquiring if they still have any of their more powerful achromatic dioptres for non-flip adaptors in stock or where they sourced them.
Bob Hart is offline   Reply With Quote
Old March 20th, 2009, 06:58 PM   #5
Trustee
 
Join Date: May 2005
Location: Allen, Texas U.S.A
Posts: 1,117
Martin,

Bob is correct. He actually provided me the chart for diopter power and the equivalent distances from the GG.

Correct me Bob if I'm wrong, it went like;
Power - Distance frm GG

3+ - Approx 10 in. - this may vignette.

4+ - Approx 8 in.

7+ - Approx 5 in.

10+ - Approx 3 in.

In my development, I used the Indian made which wasn't good.

The Cinevate (pre flip) similar to the Redrock (pre-flip) - ok but not optimal for my camera.

The SGPRO - very good for my set up.

I think when adapter makers incorporated a flip module they when for lower power achromats since the flip "shortens" the overall length because the path is bent to a "Z" pattern. if your straighten the Z to a straight line its gonna be a long set up.

Hope this helps.


Ted
Ted Ramasola is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Special Interest Areas > Alternative Imaging Methods

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 01:20 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network