Introductory preamble. I have just got myself a Canon 200D DSLR. The last (apart from a cheap & cheerful digtal camera I got in Lidl's about 12 years ago) camera I had was a Olympus OM4, which I had substantial kit for, mostly stuff for macro photograhy. Haven't keept up with developments in camera technology for about 25 years - the manual for my OM4 is 60 pages A6 size, in English, German, French & Spanish. The manual for the 200D is 400 pages A5 size and entirely in English. Learning curve: straight up into the clouds! The matter at hand. I have a lens mount adapter Olympus OM lens to Canon DLSR body. What should the camera settings be to close the apeture down when taking a photo. I've tried various things myself, checked youtube videos etc. I'm rather out of my depth at the moment. Thanks!