Old cameras have probably lain in a draw for a considerable number of years. As they lie the lubrication dries and the moving parts get settled into one position. Dust collects inside and out and has a tendency to reinforce the settled position. The dry lubricant means that moving parts are likely to be sticky and will resist moving.
The first thing I do with a “new” old camera is clean it. I tend to use spray lens cleaner on all exterior parts – there is nothing in it to damage either lens or case, but take care around gaps in the shutter housing. There has to be holes and slots for the controls to access the insides and we do not want the cleaner getting into the mechanism. First I brush off dust and lose dirt. In some ways, the more dirt the better- it indicates the no one has used inappropriate methods to clean the camera for sale.
I also carefully brush the insides – Care! With some cameras, the shutter is exposed (always with SLRs). Shutters should not be touched at all. Leaf shutters are very delicate and will stop working if touched. Focal plane blind shutters are not quite so delicate but still should not be touched.
When clean, I try the controls – but carefully. It is rare for an old camera to come with its manual – not unknown but rare. Sometimes there are specific ways to carry out adjustments. For this reason, I always obtain a copy manual from the internet – there are several sites that have them available. Fed cameras, for instance, must have the shutter cocked before the shutter speed is adjusted and some Voigtländers have a release that must be pressed before setting the shutter to B. In the absence of a manual, use common sense. Never force anything – if a camera part will not move easily, it probably won’t move at all.
When I have tried all the controls and seen that there is nothing drastic wrong, I try to shoot a dummy picture. The shutter will not fire unless it is cocked and there are various ways in which the shutter is cocked. In most modern cameras, the film advance will cock the shutter but older cameras have a variety of methods. If the shutter will not fire, assume it is not cocked before you assume it is broken.
In addition to cocking the shutter, many cameras have interlocks to prevent double exposures. My Zeiss Ikon Ikoflex II must have the shutter mechanically cocked, have a film in the camera AND have the film wound on after the last shot. An empty Ikoflex II will not fire! My Voigtländer Vito B has the shutter cocked by the film moving past a sprocket wheel. An empty camera will not fire – but you can rotate the sprocket wheel by hand to cock the shutter.
Do not force any controls as cameras are delicate, sophisticated devices. Yet some controls will need a firm touch if the camera has not been used for 30+ years. Older shutter mechanisms have two separate timing systems. Short shutter speeds are usually easy to set but 1/30 down to 1 second (or sometimes 2 or 5 seconds) have a separate mechanism with a bigger spring – these resist the touch much more than the short settings do – but still do not force them. You should be able to feel the difference between mechanical resistance and mechanical seizure.
If the controls are stiff, I find it helps to pretend to take pictures – cock the shutter, release the shutter, repeat – repeatedly. Do this for various combinations of shutter speed and aperture. I might spend 20 minutes doing this repeatedly and this frees the shutter and aperture well. Not only does this dislodge any dust it also redistributes the remaining lubrication.
Once the camera mechanisms seem to be working as they should, it is time to try a film in the camera. It is possible to get 135 (35 mm) and 120 (6×6) films from most camera shops and 127 films can be obtained over the interweb. You need to used the common shutter speeds (1/60 up to the maximum available) and a variety of apertures – but avoid using the timer function if one is available. It helps when the time comes to assess the resulting pictures if you have kept notes on the settings for each frame.
When assessing the pictures, there are a number of things to look out for. Before looking at the actual pictures, check the shutter is fully opening (I have had a focal plane shutter that only exposed half of each negative) and the film is advancing as it should. If the film is not advancing as it should, that is either a faulty film advance or a faulty photographer. I have inadvertently taken pictures on 120 film as 6×6 but advanced the film as if it was 6×9 – that was an option I had not understood and is possible on my Zeiss Ikon Ikoflex II, Zeiss Ikon Nettar and Franka Solida II.
Assuming that the shutter and film advance are both working ok, it is time to look at the pictures. If you have used a reliable external light meter the pictures should all be exposed correctly – look at the negatives to assess this as the prints will have been adjusted as well as possible by the printer. I always use an external light meter even when there is a built in meter as this checks the built in meter as well. If the negatives have a good density then you can assume that the shutter and diaphragm are working at least reasonably well.
Is there anything else to look for? Yes. Focus, for starters. If the camera has been dropped or if someone has fiddled with the lens, then the lens might not be capable of proper focus. If the lens is mechanically ok, then you can see if there is a problem with dirt or moisture inside the lens – both will cause the image to be softened. If that is ok, then compare the sharpness with the lens wide open (i.e. with the largest f number) with the sharpness with the lens closed down. Most lenses work best with the lens stopped down a couple of stops and a poor lens will work best with the lens stopped down considerably.
One last thing – colour fringes. Old lenses (pre-1930) were designed to work with black and white film that had no sensitivity to red light. That made lens design very simple as the lens only had to focus blue light. When used with colour film, a very old lens will often produce noticeable colour fringes around objects and some softening when used with modern black and white film.
So, you have cleaned the camera, tried a film and found that the camera is actually very good. What now? Use it! Using a vintage film camera is very different to using a modern digital camera. They are not point-and-shoot – you need to establish the exposure, set the controls, focus the lens, cock the shutter and then take the picture. It is much slower and has the advantage of making you consider what you are doing to a much greater extent than is true for using a digital camera. Also, it is so much harder to manipulate the picture once it is taken so the need to get it right in camera is much greater. I find this much more satisfying than using my digital camera and should be improving my technique.