This is a trip

Me and Olys Trip 35 by RaúlM.

Olympus Trip 35 by RaúlM.

Olympus Trip 35
Auto exposure, viewfinder, 35mm camera
D. Zuico 40mm 1:2.8 lens
Manual zone focus, pictograms on top of the lens barrel, the corresponding distances, in feet and meters, on the opposite side. 
Two speed, 1/40 and 1/200", central, leaf shutter
Selenium light meter ring, surrounding the lens. ASA range 25 - 400

Trip 35 viewfinder 
by Irish Light

The viewfinder has bright guide lines, with parallax correction indicators and a very small window, on the right bottom corner, aka the "Judas window", showing the aperture and distance chosen on the respective rings, in the lens barrel.            
Red flag when there's not enough light.
Additive exposure counter

The auto exposure is controlled by a needle trap. There's a small needle that is controlled by the selenium cell. When the shutter release is pressed half way, the needle rises and get trapped, by a double system, selecting the aperture and shutter speed.
Probably to avoid diffraction effects, common in 35mm cameras, when the aperture is greater than f8, the program uses the 1/40" shutter speed from f2,8 - 8, then increases the speed to 1/200 in order to enlarge the aperture, to keep it, as possible, under f11.

Olympus Trip 35 Program Graph by Irish Light

When there is not enough light a red flag is displayed in the viewfinder and the shutter is blocked.
This is a nice feature because it also avoids shooting with the lens cap in place. A common mistake with viewfinder and rangefinder cameras.

There's a manual mode to use it with flash. The shutter speed in this mode is 1/40".

Although there's a familiar look with the Pen series, this is a full frame, 24 x 36mm, camera.

The Olympus Trip 35 was produced by the millions, way over five millions, from 1967 to 1983.
There's a thread in the  Olympus Trip 35 group on Flickr intending to make a census of the serial numbers.

You can tell them apart by the serial number, the smaller the older or, very quickly, by the shutter release button, in the older models it's silver and black in the newer ones. The silver button model was produced until June 1978.
If you want to know precisely when yours was manufactured, remove the pressure plate, inside the back door, you'll find a Japanese character or Latin, in the newer models, that designates the factory, a number, for the year, and a another number or Latin character standing for the month (1-9 Jan-Sept, X-Y-Z Oct-Nov-Dec).
i.e. G9X = 79 / Oct

Opened back door   

Pressure plate removed revealing the manufacture code

      
                                           
If you are in doubt of the year go for the colour of the shutter release button.


They were made in two flavours: black and chrome and all black.

It's unjustified underrated by some and a cult camera to others.

I have two, one with the black button (Oct / 79), that came from €bay. The other with a silver button, that I found in a flea market (Nov / 73).

Two of the kind by RaúlM.

Both looking gorgeous but afflicted with the same disease, frozen shutter. Luckily I found this great tutorial and brought both back to life. It's work for a winter afternoon.

They are both very competent shooters. Light and small. It's an everyday camera.
The only caution that I advise is to always be careful and adjust, as best as you can, the focus distance. As it likes large apertures, the DOF tends to be shallow.

An example of what they are capable:

Mine...Mine...Mine...by RaúlM.

I been shooting with them. Soon I'll post some pics on Flickr.

Stay tuned (o;