ok, i've got a question about something which has me stumped. to reproduce this you need:
1) to be short sighted
2) a camera with an lcd viewfinder
point your camera at something and look though your camera viewfinder with your glasses. what do you see? a perfectly clear image.
now, try it with your glasses off. you should see a blurry mess, no different to if you were looking at the subject without using the viewfinder.
i can't understand why this is so, the lcd panel in the viewfinder within camera is a few centimetres (at most) away from my eye - i can see things clearly with no glasses at such distances. i can understand this happening with an old style optical viewfinder, but not an lcd one.
anybody know why this happens? if it's complicated i'll need the big writing explanation.
Optical confusion
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Dr Lobster*
- Posts: 2123
- Joined: Sat 30 Aug, 2003 20.14
Yep, and by contrast those cheap digital cameras that put a little high-res screen in the viewfinder ACTUALLY make you focus to a point a few centimeters away from your eye - they get incredibly uncomfortable to use after a while
Basically: if you're short sighted, anything in the 'infinity' focal point (more than a specific focal length) appears with the same amount of blurriness. The lens in the viewfinder refracts the rays without adjusting for your lack of adjustment - it appearing closer is an illusion caused by the way the light is condensed. Fancy cameras (and binoculors) have a little slider on the lens that allows you to adjust this - this works by moving the front plane toward the back one (i.e. what your eye should be doing but can't). But not the binoculars they have in theatres which are bloody hopeless for that, ugh.
NB: this is based on what I vaguely remember from GCSE physics. i never found it very intuitive and i learnt the confusing diagrams all by rote rather than understanding the things.
Basically: if you're short sighted, anything in the 'infinity' focal point (more than a specific focal length) appears with the same amount of blurriness. The lens in the viewfinder refracts the rays without adjusting for your lack of adjustment - it appearing closer is an illusion caused by the way the light is condensed. Fancy cameras (and binoculors) have a little slider on the lens that allows you to adjust this - this works by moving the front plane toward the back one (i.e. what your eye should be doing but can't). But not the binoculars they have in theatres which are bloody hopeless for that, ugh.
NB: this is based on what I vaguely remember from GCSE physics. i never found it very intuitive and i learnt the confusing diagrams all by rote rather than understanding the things.
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Dr Lobster*
- Posts: 2123
- Joined: Sat 30 Aug, 2003 20.14
this does make a degree of sense, thank you.
i have come across those cheap digital cameras which don't have those optics in the way of the viewfinder now you mention it (or rather it was an ancient samsung or sharp hi8 camcorder i used to have access to) , the pixels in the viewfinder a really apparent and used to cause my horrible eye strain type headaches whenever i used to use it (it was a friends, i think it was purchased around 1997 when they just started becoming affordable)
i have come across those cheap digital cameras which don't have those optics in the way of the viewfinder now you mention it (or rather it was an ancient samsung or sharp hi8 camcorder i used to have access to) , the pixels in the viewfinder a really apparent and used to cause my horrible eye strain type headaches whenever i used to use it (it was a friends, i think it was purchased around 1997 when they just started becoming affordable)
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