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  Condenser Heads


 
Most Omega enlargers came with the same condenser head throughout their production run.  An exception is the D series.  The D2 enlargers were fitted with no less than 4 variations during their time, so here we concentrate on the differences between those heads.

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Basic

D Type 2 Consenser Lamphouse
"Color"

D Type 3 Condenser Lamphouse
Filter Drawer

DV Condenser Lamphouse
DV

D6 Zoom Condenser Enlarger
Zoom

 

Condenser Head Basics


 
Most users of condenser enlargers give little thought to the lamphouse beyond occasionally changing the lamp and perhaps cleaning the dust off the condenser lenses.  In fact, the condenser enlarger is a precise optical projector.

The optical system must efficiently project the light from the enlarging lamp evenly across the negative and approximately focus the image created to the rear of the enlarging lens.  The design of the condenser lenses must take into account the size and shape of the enlarging lamp, the size of the negative, and the focal length of the enlarging lens with which they are to be used.  Although it is possible in limited circumstances to use just a single condenser lens, only one Omega enlarger, the B635, used this design.

Most Omega enlargers, and  most condenser enlargers in general, are based on the double condenser system, which usually utilizes a pair of plano-convex (simply meaning one side is flat and the other rounded) lenses mounted in a housing which, in use, will rest on the negative carrier.  Because the light is focused to the enlarging lens, that single set of condensers will work efficiently with only a limited range of focal length lenses.  For a 4"x5" enlarger with its standard condenser set, that would be about 135mm to perhaps 160mm lenses.  Attempts to use the same condenser set with shorter focal length lenses will result, as some users have discovered, in considerably reduced light output and much smaller enlargements than they expect.  

A variation on the double condenser system is the reflex lamphouse in which the light is projected horizontally through the first condenser, then is angled down off a 45 mirror or reflector to the second condenser.

In order to provide users with the ability to use the same enlarger for smaller formats, the initial approach was to provide accessory condenser sets.  For the condenser lamphouses fitted to the DII, for example, there were three additional condenser sets available - one for 90-105mm lenses, one for 75-80mm, and another for 50mm and shorter focal lengths.  The problem with this approach is that the extra condenser sets are a significant expense, are somewhat clumsy to change, and require cleaning and storage when not in use.

With that in mind, alternate solutions were devised.  Most involve the addition of a third condenser lens.  In general, the extra condenser is added to "prefocus" the light from the lamp before it reaches the main condenser set.  How that third lens is used does vary.  For medium format enlargers like the B22, the third lens is most often a supplementary or auxiliary condenser, added above the double condenser set when the user is working with smaller formats.  In the C67, the third lens was inserted in place of the upper condenser of the standard pair.  The 6x9cm format B7/B8 condenser lamphouse had two supplementary condensers - one used for 2"x2" negatives and the other for 35mm and smaller formats.

Because 4"x5" enlargers must accommodate even more negative sizes than medium format enlargers, the approach is different again - the third lens becomes a "variable" condenser.  It is adjusted for different formats by raising and lowering it relative to the main condenser set.  With the DV lamphouse, the user simply inserts the lens into different slots provided in the lamphouse.  The D6 Zoom lamphouse accomplished the same thing, but used a mechanism to raise and lower the third lens by means of an adjustment knob on the side of the lamphouse.  In both cases, however, the auxiliary lens must be removed when working with 150mm lenses.

While the supplementary and variable condenser solutions are not quite as efficient as specific condenser sets, they do provide excellent performance at a more reasonable cost and greater convenience.

Since different condenser lamphouses have different designs, it's important for the user to understand the design of the unit they have and ensure that they have the accessories required so that lamphouse can be configured correctly for the negative sizes and lenses to be used.  It's even more important for anyone about to purchase a used enlarger to be aware of these requirements.

 


 

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