Minolta Uniomat (Ansco Uniomat)

Setting the exposure is simplicity itself. First you need to set the ASA rating of your film (no DIN option) by lifting the inner ring on the lens and moving the red dot on the inner right of the lens to the correct ASA number (there are FOUR red dots on this ring for different purposes but it is fairly clear which one you need to use at a given moment). You then move the inner ring on the lens until the needles in the exposure window are superimposed. That is it. This sets both shutter speed and aperture – you have no control over either. There is a scale on the lens of standard EV numbers and a red dot indicating which one is in use, but you cannot influence the setting other than to move to a different EV if you want to increase or decrease the exposure. 

Wallace Koopmans has produced a chart to show the aperture and shutter speed you get for each EV value.  You can see the original and read Wallace’s comments on the Uniomat at Wallace Koopmans Artlog.  My thanks to Wallace for his permission to use his chart.

Copyright Wallace Koopmans

Once the exposure is set, there is another red dot on the right of the lens which indicates which shutter speed has been selected. These go from 1/8 to 1/1,000 seconds. That last, 1/1,000 seconds, is very fast for a leaf shutter. It is worth mentioning how Citizen (the manufacturer of the shutter) have achieved this. In most cameras, there are separate diaphragm and shutter blades.  You set the diaphragm to the required aperture and when the film is exposed, the shutter blades open to the maximum aperture (which on this camera is f2.8). This means that for smaller apertures, the shutter is spending time moving beyond the diaphragm blades and achieving nothing. In this Citizen shutter, there is only one set of blades in the lens (five blades in all) and the shutter blades double as diaphragm blades. So, at f2.8, the shutter blades open fully and offer a maximum speed of 1/60 seconds. At f5.4, the shutter blades do not open so far and the speed is 1/270 seconds. At the smallest aperture, f16, the shutter blades do not have to move very far at all and the shutter speed is an amazing 1/1,000 seconds.

There are other controls on the lens that are not obvious. First is the depth of field scale.  It is always nice to have one of these but this one is different. Because you cannot set the aperture, the depth of field scale does not use f numbers but EV numbers. In use it is much the same but slightly confusing to start with. Maximum depth of field is at EV18 and the depth of filed scale goes down to EV9. Below EV9, the aperture is always f2.8.  The are two scales to make using flash easy – one for electronic flash (x) and one for flash bulbs (M).  to use these, you line up the distance to the subject (taken from the focussing ring) against one of five letters (A, B, C, D and E).  This sets an appropriate EV and thus both shutter speed and aperture.  There is also a red dot that will tell you if you are too far away to use flash.

Other controls on the lens barrel are a flash selector – X (electronic) or M (bulb).  The difference between these (as on all cameras) is the timing of the flash and shutter.  With X, the flash fires as soon as the shutter is completely open and will synchronise at a speed somewhere between 1/250 and 1/500 seconds which is quite fast; faster than you will get with a focal plane shutter.  With M, the flash fires just before the shutter opens to allow the bulb to reach maximum intensity as the shutter is fully open.  In this case the flash will synchronise at 1/1,000 seconds which is extremely fast.  The last control here is the delayed action lever marked V (Vorlaufwerk, the German for ‘delay’).

The lens is a Rokkor 1:2.8 45mm lens about which I know nothing as yet – I will share when I do.

1-11-2012:   

Just got the test film back from the lab.  Fairly impressed with the results.  Only downside is that I managed to get flare on a very overcast day.  Some examples:

Busker, Lincoln city centre

Path in Lincoln’s Arboretum

Pottergate, Lincoln