Luctantem wrote:1. What exactly means controlling electronic iris? (Sorry, I've read around, but not getting idea)
Canon EF lenses (and many other stills lenses) have apertures that are controlled electronically by the camera. There is no physical ring to control the aperture/iris. So the camera needs compatible electronics to control the lens.
Luctantem wrote:2. So how we control the iris , IS and focus in manual MFT lens?
Manual lenses are, as the name suggests, manual. You focus by turning the focus ring, adjust the aperture by turning the aperture ring. Manual lenses don't have IS as they have no electronics.
Luctantem wrote:3. Are manual lens used mostly in cinematography or electronic lens?
True cine lenses are all manual. Arri Master Primes, Zeiss CP.2, Angenieux Optimo zooms and many more are all manual.
Luctantem wrote:4. Are electronic MFT lenses costly or manual MFT lenses costly or electronics lens costly ?
"How long is a piece of string?"
You get cheap electronic lenses and expensive electronic lenses. You get cheap manual lenses. You also get extremely expensive manual lenses.
All depends on what they are and how costly they were to develop.
Luctantem wrote:5. Now my important question, I'm on my tight budget and important thing is I do not have any lens in my kit, I will buy new from scratch. So now which is best choice and what are negatives of that choice and how to overcome it?
Personally I would look at Carl Zeiss ZF.2 (I have cine modded 25mm f2.8, 35mm f/2, 50mm f1.4) and hire more expensive cine lenses when needed.
On the BMCC MFT you can add a Metabones SpeedBooster and those 3 lenses become 6 lenses.
But even Carl Zeiss ZF.2 are not affordable for some.
You could look at classic 2nd hand Nikon AI or AIS lenses.
Rokinon cine lenses. They are affordable and many people rate them very highly. I've not used them but I've seen the results and they look good.