ARTICLE: MINOX Enlarger Illumination System : LUSENET : Minox Photography : One Thread

-- martin tai (, April 02, 1999


Difference between Dr. Fishcer 6v6a lamp vs Replacement bulb

All made in North America RP11 bayonet mount lamps (INCLUING 12 V automotive tail lamps )have their filament perpendicular to the bayonet pins. European bulb has its filament parallel to the bayonet pins.

Dr. Fischer 6V5A lamp has such a filament; also its filament to base distance = 30 mm, same as Fischer 6v 6A lamp. The 6V5A lamp was used in MINOX enlarger I; if used in Enlarger II, it has the right orientation and right centering, but not the right focus.


Minox Enlarger , for information about sources for Dr. Fischer 6v6a lamp

-- martin tai (, April 14, 1999.

I am using A Dr. Fischer 6v 3A Bulb in my Type 2201 Minox enlarger with good results. I find that I had to put a ND.6 filter in to get slower exposure times. (with out ND.6 on low switch 2-4 sec: to fast!) I put the filter on the back of the condenser ring under the lens so I wouldn't degrade the lens in any way. heat seams minimal. Anyone have other thoughts?

-- Ralph Linhardt (, August 14, 1999.

I have a Dr. Fischer 6V 5A lamp, tried it on Minox enlarger II, it is workable, but not as even as the 6V6A bulb.

-- martin tai (, August 14, 1999.

Diffuser/collimator of Minox Enlarger II

It seems to me that there are several variations in Minox Enlarger II. Some with a diffuser/collimator, some has a diffuser only.

The diffuser/collimater plate is made of metal, diameter 94mm, with eight ventilation holes surrounding the center collimator lens: four large holes 18mm in diameter and four small ones 10mm diamter

The collimater/diffuser lens assembly is at center, the glass lens is 25mm diameter, the side facing the light bulb is flat and frosted, the side facing down towards the condensor is clear and convex. The function of this collimator/diffuser is to convert the light from Dr. Fischer special bulb into parallel beams towards the condensor. (The condensor in turns focus this parallel beams into the image of filament at inside the lens )

This collimator/diffuser plate is amounted at the top of the lower part part of the enlarger, right on the rim. On the rim of the lower housing, there are three small screws matching the three notches on the collimator plate . Align the three notches of the collimator plate with the three screws, turn clockwise to lock.

There is only one way to mount the collimator, because the collimator lens tube tube itself is about 20mm height, can only mounted face down, otherwise will get in the way of the Fischer Bulb. When I have time I shall post a picture of this collimator here

-- martin tai (, February 23, 2000.

  1. The collimator/diffuser disk may be missing in some Minox enlarger model II. Take off the top lamp house and check the rim of the lower housing, if there are three screws, but there is no collimator/diffuser, then that part is missing.
  2. Later model II replaced the collimator/diffuser with a piece of heat isolation glass, and move the diffuser (not collimator down on top of the negative carrier.
  3. For Minox enlarger without the collimator, you don't need a a Fischer bulb with offset filament; in this case, a Fishcer bulb or non Fischer bulb makes no difference.( You may turn the filament upside towards the reflector, and use it as a collimating reflector )

    -- martin tai (, February 27, 2000.


Disk 94mm diamter

Plano-convex collimator 25mm diamter, focal length ~ 20mm

Plano side frosted

Note: The big circle at center is the collimator lens, the eight smaller circles are the ventilation holes; the three notches at the rim engage the three screws on the lamp house to lock the collimator in place.

-- martin tai (, March 02, 2000.

Collimator Lens

On closer examination, the collimator lens is a compound lens of two element two group, the first element is a plano-convex, the second element is a biconvex lens. The plano side of the plano convex is frosted and closest to the Fischer Bulb.

-- martin tai (, March 02, 2000.

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