Well, the whole benefit to it is utilizing lenses you may already own, thereby saving you money. Where some people go wrong is by going out and finding film era glass to buy specifically for their mirrorless camera. Ok, let me back up, because buying an old lens on its own isn’t a bad idea, but there is a point where the cost of that old manual glass starts to come really close to native glass you can get for your camera and at that point, it makes much more sense to just save a little longer and get the native glass for your camera.
I recently ran into this issue when I was looking into buying an old film era lens, and I discovered that in order to get a lens with the focal length I wanted with the aperture I was after, I was actually going to be paying about as much as I would for a native lens but without AF, weather sealing, and modern coatings. Simply put, it made absolutely no sense.
You usually run into this issue the most with fast glass: F2 and better. These lenses generally retain their value well and in the case of buying old film lenses, you may be able to find an F1.4 or F1.2 lens for the price of a native F1.8 or F2 lens. Obviously, the film lens will net you more light, but at the cost of no AF, weather sealing (in some cases), and modern coatings. For some people, going with the film era lens can still make sense, but for most it just makes sense to go with the slower (but still fast enough for most uses) native lenses than the older lenses.
Where buying film lenses makes the most sense is when you get into lenses with an F2.8 or slower aperture. These lenses are often still fairly cheap and can save you a lot of money over native modern lenses. You just need to be ok with using slower glass and stopping down in order to achieve the best results. This is great for people just looking to play with a new focal length, figure out if they like it or not and how to work with it.
For example, you can pick up a film era 28mm F2.8 lens on the cheap, and while that may be slow for a prime these days, it would give you the ability to play with the focal length and see if it is really one that you want to add to your kit.
So, if after all of this you still feel like buying some film era manual glass is the right decision for you, we highly recommend checking out your local exchanges – places like craigslist. This is so you can go and see the lens in person before committing to it. If you can’t find the lens you are looking for locally, then Ebay is where we suggest checking next. Just make sure to purchase from a reputable seller with good feedback. For lens adapters we suggest [amazon_textlink asin=’B00LECYGW6′ text=’buying from Amazon’ template=’ProductLink’ store=’thephobl-20′ marketplace=’US’ link_id=’3b722632-2b64-11e7-affd-930eb5599890′], you can find a great selection of affordable adapters and you can get them faster than buying from somewhere like Ebay.