Thank you Guys for your help. I have searched in RFF and found a lot of information. I have checked the bellows and painted it. I hope the next result will be OK.
I don't think that is a bellows problem. It looks more like a shutter problem. I think the little leaf blades are not closing immediately when you trip the shutter. What it looks like to me is called a sticky shutter and it is what happens when lubricant spreads onto the shutter blades and dries. It is quite common on old cameras, and in fact more older cameras have it than don't. Fortunately, it is relatively easy to fix and there is quite a lot of information on how to do this on the internet. For example:
Cleaning shutter blades: there are three methods in common use. (1) The best is to disassemble the shutter and clean every part individually, then reassemble. However, that is well beyond the skill level of most people, and the mere idea of doing that scares the hell out of them. (2) the next best method is to remove just the glass and then submerge the shutter in a solvent in an ultrasonic cleaner. It is important to remove the glass first because vibrating cleaners are known to cause micro-fractures of the surface of the glass. Most people don't have access to an ultrasonic cleaner though and so they won't be able to use this method either. (3) And so we come to the most frequently used method. Something like nine out of ten amateur collectors use this method; it isn't the best, but it does work. Use a lens spanner wrench to remove the front or rear lens element, so you can see the aperture iris and the shutter blades. Set the aperture on it's widest setting and clean the blades with a cotton swab soaked with naphtha (Ronsonol lighter fluid). Work the shutter a few times, get a new swab, and clean it again. Alternate between wet swabs and dry swabs, mopping up the lighter fluid (and dissolved oil) with the dry swabs. Keep doing this until there is no hint of oil or grease left on the blades and they look completely clean, with no streaks. The blades working together will transfer grease and oil from the side of the blades that you
can't reach to the side that you
can reach, so you should be able to eventually get it all. It takes a while. Figure on doing this about a hundred times. As long as you're at it, clean the aperture blades too. When done,
DO NOT LUBRICATE THE BLADES!!!!! Leaf shutters are designed to run dry (no lubricant). The blades will stick together and the shutter won't work at all if they are lubricated.
