OM 20 body

Recently I acquired a OM 20 body cheaply following a major metering fault on my beloved Om4 .

The OM20 also known back in North America as the OM-G, originally came out in 1982 being the second of that double figure secondary series of cameras Olympus had out.
The main differences between it and the OM10 models lies in that fact it was designed from the the get go as a camera with TTL-OTF Autodynamic  metering with built in manual over-ride with the shutter ring around the lens throat just like the OM2 models of which the OM2n came out around the same time rather than relying on the optional manual adapter the OM10 did.
In some respects then it's more a cut down OM2 losing that models TTL-OTF flash metering, the interchangeable focusing screens, backs although it kept the ability to use a power winder .
The focusing screen fitted was brighter than the OM10's and displayed the camera system information in a easier to see and less obtrusive way.

The above picture shows the OM20 in front of 1983's OM30 which Pop briefly owned which in truth was a more a focus confirmation with a 'auto focus' 35-70 zoom version of the OM10  that many found less than reliable at that. 
The failure to come up with a truly efficient auto focus SLR in many ways was what lead to Olympus losing it's place in the SLR market and dropping out of making its last film slr, the OM4Ti in 2002.

Tamron 35-70 standard zoom, small, fast and convenient

In for a penny, in for a pound they say and while on the look out for a cheap standard zoom to match the 75-150,  I spotted this in a bundle

This is actually really good a seven element, seven group Tamron type 17A 35-70mm constant F3.5 zoom with a 1:2:8 reproduction ratio at the 70mm end complete with Olympus OM mount and even a Hoya 1A filter fitted.
Serial # 556389
It only weighs in at 330 grams which isn't bad while the viewfinder image is fairly bright making it handy for quick picture taking where changing lens isn't so easy.
Making quick changes to how you frame the image is something that's easy to achieve with a zoom lens without having to move around a lot.
It came attached to a OM40 body that appears to be fully functional and both came in their original packaging with the OM40 having instructions and foam too.

75-150 Zoom

For more years than I really care for  arguments have raged over the qualities of lenses that cover several focal lengths  over fixed focal length ones.

Olympus themselves had manufactured a good number during what might in hindsight  be called the "Golden Era" of the OM system  in the late 1970's and 1980's that met their exacting standards.
Just what is the argument against them?
I think the first is for serious landscape photography they are harder to use with filters, specifically those square ones like Cokin's that screw on the filter thread of a lens because most zoom lenses have front elements that rotate when you focus whereas on fixed length ones they do not.
The other is during that era many cheaper zoom lenses came on the market that weren't so well designed spoiling their image. 
It was said at the time you needed to spend two to three times as much for a zoom lens of a similar quality to two or more fixed length ones and many amateurs just were not prepared to spend that.
This said, a good one has real uses like being able to easily control the final image you take very precisely not least on transparency film and this example I own, the 75-150mm F4 is a good example as it provides a very high image quality, offers a wide range of telephoto lengths and yet weighs little more than single 200mm lens which is comfortable for hand hold usage. 
I find its coverage is a good match for what I want in the field saving me carrying the 90mm and 135 and rarely need the 200mm as it's top end of 150 is adequate while saving me from changing lenses frequently.
It also uses a 49mm filter thread just like the regular standard and wide angle lenses which makes working with polarizers and square filters more straightforward for not having to double up on attachment rings and screw in filters.
As the OM system in the early 1990's moved very much toward  advanced amateurs and professionals with the OM4Ti being the only 'new' body available, while only a  few fixed length lenses went from the lens range such as the 135mm, all the Zooms did until they introduced the 35-80 F2.8 in 1995 issued with the OM3Ti.

300mm

I was thinking early on about getting a longish telephoto lens but it's taken now to find an affordable quality option for my OM10 and 40 bodies as most of the independent options from the late 1970's and 80's were rather so-so at best and you are normally talking of around £100 upward for Olympus's own.

Shopping around I found something that would work, the Tamron Adaptall 300mm F5.6 which was originally introduced  in 1976 and phased out in 1979 for the later Adaptall 2  close focusing version.
The early Adaptall lenses do take the later mounts and although this as bought came mounted for the old M42 screw fitting, changing to Olympus OM is quick and easy and for £36 was a bargain.

Technical notes

Lens construction: four group 4 elements

Minimum aperture: 22

Minimum focusing distance: 2.5m

Filter diameter: 58mm

Weight: 580g

Going further out

For a long time I had considered  the advantages of so-called ultra wide angle lenses as I found the 24mm lens a focal length  that didn't seem to offer too many advantages over a 28mm  for the inevitable extra weight of lugging it about without offering some of the advantages  in terms of getting heaps more into the frame or its creative uses building on the perspective distortion when shooting subjects such as cars close.

Around  2000 Vivitar and Cosina had out a 19 through 35mm ultra wide-angle zoom lenses in a variety of manual focus camera fittings including Olympus OM that appealed but tracking down the OM fitting proved difficult and some other options such as the Centon/Sirius 18-35 while plentiful used had terrible reputations for image quality.

As had been a while since I'd bought a 'new' lens, I ordered the Tamron 17mm F 3.5 Adaptall 2 in the high performance SP series

This is the later 151B version that dispensed with the built in black and white photo filters to simplify construction as well as reducing costs and adding a more modern feel to this longstanding lens.

Independent lens tests put this at the same quality as the Zuiko 18mm F3.5 which is some 60% more expensive used and exceeding it's equivalent by Minolta in the MD system.

As with all Adaptall 2 lenses, armed with the appropriate attachable mount they can mounted on nearly all manual focus bodies.

200mm

200mm lens are not the sort of thing you use everyday that's for sure but they have their place in the photographic scheme of thing such as Landscapes - mountain images - where their stacked perspective is easily recognizable 0r for sports photography.This is the Zuiko F4 which as such lenses go is quite light so you can use it handheld although support in the form of Monopods or Tripods really is best as the greater magnification increases the risk of camera shake.I bought mine in May 1997 and really like it's quality.

Moderate telephoto

This is the classic Zuiko 135mm F3.5 moderate telephoto lens good for sports, isolating people at events and air shows.
Although this is half a F stop slower compared to the regular F2.8 version the viewfinder is such you can't notice it and you save quite a bit of weight together with the advantage of using the same size filter thread (49mm) as your wide angle lenses. It makes for an easy to use lens handheld as well as on the tripod.