K-50 suddenly stopped focusing with viewfinder; still focuses with live view????

i am so sick of useless technological mysteries. one day my camera works, i put it away, then i take it out, the SD card is now not formatted... OK... format the card, lose all saved photos... OK... try to focus manually, can't focus through viewfinder... OK... does focus with live view... so. does this mean i have used my allotment of viewfinder focuses and now i have to buy more??? seriously. WTF. how do i reset it ( i did reset if three times already to factory defaults) but... is there some magical useless setting to cause the viewfinder to stop working? how handy smart!!!!! yeah smart. stupid smart tech. this camera works WORSE that my 10 year old K-10. oh well, 21 st century all crap all the time. guess i;'m supposed to throw the camera away and buty a new one every 500 shots, right? whatever.

I think a step at a time. The viewfinder image is a purely optical one, so it can't stop working as such, but if the AF isn't functioning properly then I'd suggest checking the AF/MF switch is clicked fully home and then wiping the electrical contacts on lens and camera body with a soft, dry cotton cloth. Finally, new or fully charged batteries and we should be good to go.

To make sure we are focusing properly using the viewfinder, it's also essential to set the dioptre for our eyesight. Point the camera at a uniform, light coloured wall or similar and adjust till the etched lines in the viewfinder are sharpest. The image does not have to be in focus to do this, in fact better if it isn't. Then your eye is relaxed when looking at the focusing screen, which has a virtual distance of about 1 metre.

SD cards can become corrupted, but this can be avoided by making sure that images are regularly transferred to the computer and that the card is formatted in the camera it's going to be used in, not in the computer. Only change cards when the camera is switched off. Don't resave from the computer back to the card.

If all else fails, then a faulty camera needs to be returned, and hopefully with only 500 shots it isn't very old so will be under warranty. And cameras do fail sometimes I'm afraid, although to be fair it does seem they are generally very reliable.

Hope that helps!

I agree with what John says, the dioptre switch can slip - I have been there, got the t shirt and nearly booked an opticians appointment 'til the penny dropped. One practical thought though, is the mirror stuck in the up position, 'cos you would not see much through the viewfinder if it is!!!

Probably a number of coincidences. As to the SD card, sounds like it's gone bad, try a different one!