The sweet spot
All lenses have different levels of sharpness depending on the F-stop that you use. There is a common misconception that lenses are sharpest at F8, in reality this is simply not true. I test every lens I own and in my experience lens tend to be sharpest at F4 or so. I always say don’t trust me, do the experiment for yourself 🙂
I find that some people have either never heard of focus breathing ot they have a misunderstanding about how it works. Focus breathing means that at close distances some lenses are not actually as long as they say. A classic example of this is the Nikon 70-200mm vs the canon 70-200. When you take a tight head shoot with the nikon it more like a 130mm or 135mm even when it is zoomed all the way in. Don’t misunderstand this, both lenses are really 200mm you’re only going to see this effect at close distances when you focus on an object nearby, its just a fact how the lens works, to focus it needs to move the lens away from the camera, that results in you getting less distance. If you using this lens to shoot objects far away you’re never going to see this effect. If you test these lenis side by side then you’re really going to see this effect.
This is a term used when you set your focus all the way to the end. First thing to note is many lens will allow you to focus past infinity this is to compensate for different levels of heat. Setting a lens to infinity focus doesn’t mean that everything in your photo will be in focus, in fact really it means nothing will be in focus. Keep away form infinity focus and just focus on your subject
I would like to clear up a common misconception about depth of field, depth of field doesn’t actually exist. Depth of field is a an area that will be sharp to a level that you camera is unable to have the detail to see. All the calculations that you find online are from the film days, when people had unshape lens shooting on film, now that we have access to 50 megapixel or more you can forget about the calculations been correct.