Bronica 30mm PE Fisheye Lens

[craig_tomash]

The ETRSi 30mm PE lens comes with 4 small (32.5mm) filters which screw into

the base/rear of the lens (bayonet side).

 

Does anyone know what these filters are for and when one should be using them:

 

The four are marked:

 

LA-40 and it has a slight blue tinge.

 

LB-40 which has a slight orange/yellowish tinge.

 

L-1B has a slight magenta or pinkish tinge.

 

Fourth filter appears to be clea and has no designated number.

 

I would like to do Infrared B&W photography and would like to use this lens;

any ideas if this size filter is available in the IR range of filters (ie.

#25, #29, #87 & #89B)

 

 

thanks

[john_papandreou]

The filters are as follows:-

 

LA-40 Evening light corection

LB-40 B&W -makes Sky Darker

L-1B B&W - Makes Sky Very Dark - Best option for IR Film

Clear - UV filter

 

This is my Best Guess, most fish Eye Lenses have a similar set.

 

Hope this helps.

[craig_tomash]

John:

 

Thank you for the clarification on the 32.5mm filters.

 

I am considering ordering Wratten #25, #29, #87 & #89b filters so that I may cut the 29mm size to fit into the Bronica filters; thus allowing me to use IR film with the filter in place on the 30mm lens.

 

thanks for your assitance.

[ilkka]

The optical system has been designed so that one filter should always be in place. If not the coloured ones, then the clear should be used.

[craig_tomash]

Folks:

 

I heard back from Bronica; and your comments are accurate.

 

The Neutral filter (with no imprint on filter frame) is for general photography.

 

L-1B filter provides even color tones by subduing the blue cast of a clear sky - no filter exposure variance.

 

LA-40 changes the color temperature to provide even color tones by subduing the blue cast under cloudy skies and shade - 1.4x exposure variance.

 

LB-40 changes the color temperature provide even color tones by subduing strong red light at dawn or dusk - 1.6x exposure variance.

 

There must be a filter in place at all times to allow for proper focusing and to obtain infinity.

 

 

Thanks for everyone's input....