There is a lot of information available on vintage cameras and lenses on the internet, way too much for anyone to properly list, rate and catalogue. So here I've added places that I've found to be useful as my interest in vintage lenses has developed. They are in no particular order and I have no connection with any of the sites or people listed below. I have found them to be very useful and interesting.
Luton Camera Repair Services Luton Camera Repair Services have been around as long as I can remember. They have always been an Olympus specialist, but also deal with other makes. They also service and repair vintage cameras and lenses and their prices are very reasonable. I have been visiting them over the years and moreso now since I've been interested in vintage lenses. They have a very good stock of both vintage cameras and lenses too. Too many to list on their web site and stock turns over so give them a call if you want to find out if they have something of interest to you. Very friendly and helpful staff. What's not to like?
Vintage Optiks is also found on YouTube. This channel is not as big as Zenography and the videos here follow the exact same format and layout. The first section deals with the lens in general and shows all of the versions that were produced. This is useful if there were improvements or develpopments during production, or if later models are considered less or more desirable that earlier ones.
Lens adaptors are an essential part of using vinteage lenses. It is great being able to pick lenses from different makers which opens up a huge range of choices. I've found a great supplier of good quality adaptors that are around half of the price of adaptors found in the UK. The company is Rainbow Imaging in New York. They can be found on ebay in the UK, and anywhere else, I guess. Their prices, incuding the on average $2 postage are around 50% of the cost of a good adaptor bought in the UK. Delivery times do vary though. It usually takes 4 days to get from placing an order to it arriving at Heathrow, then up to two weeks to get the 30 miles from Heathrow to me! My last order however was in my hands just 7 days from ordering. Their ebay seller I.D. is rainbowimaging_us.
Rainbow Imaging on ebay (ebay UK)
They have their own website, but the checkout only allows dispatch to the USA. If you are not in the USA they should be on your local ebay, UK link above