@tonyzee wrote:
I'm having the same problem with the viewfinder of my Rebel EOS T31. The camera is taking crisp photos when I use the digital screens but I prefer to use the viewfinder to shoot -- which is blurry. It does not change depending on the angle the camera is held, there is no rattle from a broken piece, and when I look my reflection mirror doesn't seem to be scratched or damaged in any way. The only solution I have found is doing a quick clean swab with the cleaner. That only fixes the problem for a short period of time. It looks like the cost of repair isn't worth the cost of the body (which is only 1+ years old).
Does anyone have any other suggestions?
What "cleaner" are you using and where are you applying this?
You should generally never touch the reflex mirror nor the focusing screen -- including if it appears dirty. The focusing screen has a frosted finish that can be damaged by cleaners and, worse, can throw off the accuracy of the metering system if damaged. When you say using a cleaner "only fixes the problem for a short period of time" this makes me worry that your "cleaning" solution is drying to a haze and may be the problem.
When you look through the viewfinder, it's best to look at a plain white wall and deliberately de-focus the lens. Just look at the focus on the focus points displayed through the viewfinder. You want those to be crisp and sharp.
If they aren't sharp (ignore what the lens can see -- that's why I suggest a plain white wall which is deliberately not in focus) then the standard things you should check are:
#1 - The diopter adjustment wheel that you see on the top corner of the viewfinder. Does adjusting this have any effect on focus (it should)? If you need prescription glasses and your eyes require significant correction, then it's possible your eyes are beyond what the diopter can correct for. Normally just wearing your glasses is enough but if you don't like to wear glasses you can get a replacement eyecup that alters the diopter adjustment range even more.
#2 - Is the focusing screen loose? This is a piece of frosted glass located in the roof of the mirror-chamber (directly above the reflex mirror.) Some camera models allow for replaceable focusing screens (my 5D II body has such screens.) It's possible your focusing screen is lose or the door-frame that holds the focusing screen isn't properly closed.
#3 - Somewhat less likely (though I'll mention it anyway) is that your reflex mirror isn't settling into the correct position. But this is unlikely because if that were happening, then not only would you not get a focused image on the focus screen (through the viewfinder) it is unlikely that the camera itself could focus. That's because there is a secondary mirror hiding behind the primary reflex mirror. The seondary mirror bounces light "down" to the phase-detect AF sensors. The secondary mirror is attached to the primary reflex mirror. If the primary mirror were not returning to the correct position then the secondary mirrors would not be aligned to the phase-detect sensors and it's unlikely the camera could focus at all in normal viewfinder mode.
Was your camera ever dropped or taken some type of hard knock?
Tim Campbell
5D III, 5D IV, 60Da
