Hi and "saludos desde Perú",
The AE-1 was my first "serious" SLR and I still like the model. The camera's electronics are among the most reliable ever put on an electronic camera so if you don't see any corrosion traces, everything should be fine. The "weak" part is an internal string that runs across the camera top from one side to another, but if you move the shutter speed dial gently all the time, everything should be fine.
The advice above regarding checking the shutter speeds apply, particularly check the speed at 1/1000 and 1/500 by looking through the camera towards a white wall, with no lens mounted. The exposure should be an uniform white. Any lack of exposure uniformity (i.e. a white line at the side, when shooting) indicates a problem. But before worrying, shoot several times to see if the problem solves itself (sometimes it does).
As for the lens, i would discard that lens and start with any of these good (or great) standard lenses:
Canon FD 50/1.4, any version
Canon FD 50/1.8, bayonet mount version (known as "new FD" or "FD new" or "FDn" version)
Canon FD 55/1.2 or 50/1.2, any version
Canon FD 35/2.0,
any version
Canon FD 35/2.8
Canon FD 35/3.5
Most of them are available for cheap out there. Cheapest are 35/3.5 and 50/1.8, both are nice, sharp lenses (the 35/3.5 is a sleeper!). Best bokeh is on the 55/1.2, best overall is the 50/1.4, highest contrast/deeper colors are on the 50/1.4 new version (black barrel), and perhaps 35/2.8.
The 35/2.0 SSC with a concave front element has the reputation of being one of the sharpest FD lenses out there, but all of them will give a yellow/green coloring to the images due to radioactive decay of one of the elements. But the other 35/2.0 versions seem to test just beautifully, from what i've seen on the 'net. In all honesty, all the lenses listed are sharp enough so don't worry.
If you want a zoom, the Canon FD 35-105/3.5 is not expensive and it is one of the best zooms made by
any manufacturer in the 80s. Just make sure it does not rattle when you shake it. If it rattles, that means the internal mechanism that holds the zooming groups is tired, and the lens will not perform good at all. An alternative test is to focus it to a specific distance at, say, 35mm and then zoom slowly to 105mm. The focus point should not move... or at least just slightly. This test needs to be done with any Canon FD zoom in "new version" (bayonet mount) you want to buy.
Finally, if you want to build yourself a kit for little money, these three lenses will are inexpensive and excellent performing:
* Canon FD 28/2.8 or 35/3.5 or 35/2.8
* Canon New FD 50/1.8
* Canon FD 135/3.5 (any version)
As you may have noticed, i'm a big fan of Canon FD (and FL) lenses, so here are my favorites if this information is relevant to you:
- Canon FL 19mm f3.5 R
- Canon New FD 24/2.8
- Canon FD 55/1.2 S.S.C
- Canon New FD 50/1.4
- Canon New FD 85/1.8
- Canon New FD 200/2.8
All Canon 85mm, 100mm, and 135mm lenses are great to
fantastic, so you can't go wrong with any of these.
The camera will probably shoot with new battery, but if it makes a squealing noise when shooting, the mirror mechanism lubrication has dried. Either you can keep shooting until it breaks or alternatively disassemble the whole camera to remedy the situation. The camera is basically built around the mirror mechanism, so there is no easy way to reliably re-lubricate it.
There is an easy way to relubricate it and i have posted it way back in 2005 or so. It involves using WD-40 with the included straw, applying a small amount of WD40 in a strategic place. I have received a lot of patronizing and criticism for this, but it has worked perfectly and my A-1 is still working just fine after 11 years or more (of using this fix).
There are tons of variations on this, but basically this method is to take down the bottom plate of the camera and apply very light lubricant (or WD40 which is solvent with a tiny bit of lubricant) with a syringe (or the WD40 tube) (or whatever you want to use) on the exact point where the mirror mechanism that squeaks is.