Cosmicar lens in Beaulieu 4008 ZM4

[Jorge Rondao]

11 September 2005 - 10:24 PM, said:

 

Hi, cosmicar i think you'll find is a c-mount cctv lens with manual aperature, designed for use with cctv/security cameras. Possibly ok optically around f5.6, forget it around f2.0.

 

Sorry I am disagree here: I have tested fully the 12.5mm/f1.4 Cosmicar/Pentax lens to my RX5 super16 and I can tell you that it's absolutely sharp even at full open!! This lens is, with the Kinoptiks 5.7mm and 9mm (A-Cam) and the Cooke Kinetal 12.5mm (rare en c-mount), the only wide angles c-mount that I know which cover plenty the super16 area, because it was designed for the old 1" tube video cameras. Next week I am going to test the Computar 12.5mm/f1.3 lens, also a 1" TV lens. These lenses are selling in ebay by insignificant bucks... (I am not the seller)

 

If you intend to use such a lens on a beaulieu/bolex be carefull the c-mount thread is longer than switar,angenieux and schneider primes. May force the turret away from the camera body.

 

The Cosmicar 12.5mm doesn't have this problem. It's posible to use it at infinite (shortest distance to the gate) moving the turret.

 

All the best

 

 

 

Hi, Sorry but I had to lift this old post, I bought a cosmic 6mm to use in a beaulieu 4008 ZM4, just as you said I think I have to turn the screw to have the sharp focus, does anyone know how many laps have to take to stay back with the correct focus? I think with the experience that I did get 1 / 4 back less.

Regards

Jorge

[Jorge Rondao]

Hi,apparently there is no physical problem of fitting the lens, but when working with very closed f-stop do not noticeable but when I work with it fully open apparently is out of focus, and the solution according to experiments that did is unscrew 1/4 turn of the screw to get focused fine.

Then I think I have to add a washer on the threads of a certain thickness to that screw least 1/4 back.

 

Does anyone know anything of this situation or have a similar solution?

 

Regards

Jorge

[retoxproductions]

I just got the cosmicar 4.8, but the threads are way too long to fit on my beaulieu 4008zm4 without hitting the inside. do you know which cosmicars will work on this camera?@robertellsworth/twitter

 

 

Hi,apparently there is no physical problem of fitting the lens, but when working with very closed f-stop do not noticeable but when I work with it fully open apparently is out of focus, and the solution according to experiments that did is unscrew 1/4 turn of the screw to get focused fine.

Then I think I have to add a washer on the threads of a certain thickness to that screw least 1/4 back.

 

Does anyone know anything of this situation or have a similar solution?

 

Regards

Jorge

[Jorge Rondao]

Hi, There are only a few c-mount cosmicar lenses are designed to be used in sensors of 2 "and 1" that are compatible with the beaulieu 4008.

 

You have to be aware that they have to be of standard c-mount and not c-mount to cctv, because the back focus goes far of 1mm beyond the rear ring and not enter in the body of the camera.

 

After this all they have to do the Collimation (how to: http://lavender.fortunecity.com/lavender/569/lenscollimation.html ) to your camera with a brass spacer rings

fit for that purpose and they are put in back into the rear thread to achieve infinity focus.

( this rings you can get here: http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productid=2012 )

 

The lenses compatible with beaulieu are those marked with the red circle in the pictures below.

All the others are not because the backfocus goes back far beyond the rear ring and does not allow infinity focus.

 

For a rare 16mm lens I've found

that just came out from behind 1mm screw back, I had to make a small change in the ring of the lens fix on the camera.

 

I had to remove the small black ring inside the lens mounting ring as the pictures show

 

 

 

,and so allows infinity focus without hitting anything inside the camera, just like the others I have to put the ring in the back screw to get the infinity focus.

 

The lens:

 

 

 

 

This is compatible a backfocus

 

 

With this backfocus is not compatible

 

 

Regards

Jorge

[Dom Jaeger]

Thanks for sharing your research, Jorge.

 

One thing I thought I'd mention though - I wouldn't recommend removing the mask from inside the camera mount as you have done.

 

The mask helps to prevent light that falls outside the gate aperture from reflecting off shiny surfaces and fogging the film. This is especially prone to happen when using a 16mm format lens which has a much larger image circle than a Super 8 lens.