Why use Manual focus lenses on a modern camera?
* With adapters available for any using any lens on almost any camera body, you can easily use any old manual focus lens on your camera. On eBay, some sellers from Asia sell many adapters for around 2-10 dollars!
* Old manual focus lenses some of them are very fast are available for 1/3 of what an AF lens will cost today.
* Most modern cameras offer focus peaking or auto enlarge which make it pretty easy to focus. Pentax K-01 is my favorite.
* Many cameras like Olympus and Pentax have image stabilization built into camera body, so you get same image stabilization with those old lenses too.
* Though AF is very useful, in certain situation where the object is moving fast, unless you have an expensive lens, most probably you will miss the shot. With use of Manual Focus, you can preplan the arrival at some point and adjust focus for that. Then when the subject hits that spot, just press the button fully. No need to press half-way for the AF to focus and when AF is done, the subject might have already moved on.
* Sure, AF is fast and convenient but sometimes it is a hit and miss. I took a photo of the Sigma 30mm AF lens with a Manual focus Chinon lens on my Panasonic GF3 camera. I was able to manually focus on the lens blurring the box. It worked. Then I put the Sigma 30mm lens to take photo of my Panasonic FZ22. I use auto-focus. I thought it worked fine but when I downloaded the photos to my computer, I noticed that it instead had focused on the box!
Compare the background blur and bokeh with manual focus fast lens vs AF Sigma!
(You guessed it right. I am trying to move these camera and lenses to some new hands where they can be used more often)
Want to take a look of a pack of old screw mount lenses that I bought on Craigslist recently. 10 or so lenses for $170? Sold one Takumar that I got for $95 so I am left with 9 lenses for $75! The Chinon is one of them!!