There is no official responsible body that administers the term "normal lens". It is just a "rule of thumb" type, informal idea. We can argue about what we think the term means but there is no inherent reason why it has to objectively mean anything real at all. Say one or another "normal lens" explanation had arisen from a competely fallacious meme: say all of them had: then we would waste our time by discussing it.
Not when you are looking at your fingers, but the monitor is in focus when you ARE looking at it.
Correct, and some people get real hot & bothered when you try to correct them.
As in open both your eyes when you look through the viewfinder. The image through the camera will be the same size as the image in real life. That's what makes a standard lens "standard."
Prints don't enter into it, mate! We're talking about lenses, not prints.
What's a viewfinder? It's simply a screen onto which the image is projected (so your eye can see it). You could rig up a device to allow you to look directly through the lens, but the viewfinder works much the same way so there's no need. If you hook up a microscope to your viewfinder, you won't get any more information from the scene than what's already there. The lens determines what you see, not the viewfinder.
Well, it pretty much does (notwithstanding the different size "film" format to lens ratios as was already pointed out).
You mean make a lens that works in a similar fashion as does your eye? Yeah, I'm sure it can be done, but why bother? The human eye is quite flawed. It can only really focus on one small percentage of the scene. You may think other things are in focus, but that's just your brain compensating. You have lots of peripheral view, but we can make lenses that have 180° peripheral view already.
A human eye lens would have lots of peripheral view, but only a narrow degree of sharp focus. The lens has to be moved to all the other areas to bring those into sharp focus. Software would give the perception of additional sharpness and clarity.
IT IS NOT A FCN OF THE VIEWFINDER. you are thinking in today's gear. yrs ago when this started the interchangeable viewfinder did not exist in most slrs. in any event, even in slrs with interchnageable viewfinders, at the time the standard was at or near a .95-1.00X finder. not .5 or any other number you wish to make up.
i repeat again the fov has NOTHING to do with this compasrison. it is ONLY the apparent visual size that was being compared.
noone 30-40-50-60-70-etc yrs ago was talking about print size. that has nothing to do with this. when the film shooters of a 1/2 or 3/4 century ago said that the 50 was the standard they refered to apparent size. when i started in slrs 40yrs ago, apparent size was what they refered. to. heck, that was why i many many many others who bought slrs and lenses included the 50mm in the selection of lenses purchased. just we would have a lens that would render the object as real apparent size.
You do realize that 1.0 by definition is measured against a 50mm lens? The 50mm lens isn't standard because it shows the same magnification as watching the scene without the lens, it's because it was chosen as the standard that the magnification is the same. Huge difference.
No, but they were still wrong.
The size matching that has been described here IS merely a function of the viewfinder. Other viewfinders, with different magnifications, will match at different f-lengths.
No, it's because the lens is defined as standard that the image is the same, not the other way around.
I agree with u. The field of view of normal human being is very close to that of a 21mm lens ( using both eyes) or about 42mm with one eye. U can easily test this using a camera with 100% view finder coverage. The reason for the 50mm being called a normall lens is because 50mm is the equal to the hypotenuse of the 35mm format film which has the dimensions of 35mm and 24.6mm.
Maybe you do, but it is meaningless...(sorry) [shrugs]
When the objects appear to be the same size and overlap with a 1.0 viewfinder magnification, you have achieved 50mm, because 50mm was chosen to define 1.0 magnification, nothing else. If 24mm had been chosen, you would have claimed 24mm was normal. Suggested reading about viewfinders:
Why doesn't the moon require any extra exposure than a bald head in daylight then? (Actually I know the answer, but the point is it can be ignored can't it.)
This whole line of reasoning is circular. We can't learn anything useful about a 50mm lens from the evidence that a viewfinder of 1x magnification gives a same-size image.
