Dark viewfinder, only can see when pointed at a light

It could one of a few problems:

1. The viewfinder is pulled out and "PRIORITY" is set to "FINDER".

Push the viewfinder back in or set "PRIORITY" to "LCD".

2. The LCD monitor's brightness setting is too dark.

Adjust the brightness of the LCD monitor.

3. If the monitor is tilted upward 180 degrees, open the monitor fully.

Download the manual for more info:
JVC GR D290 Manual

I am assuming it is a TTL (Through The Lens) Viewfinder meaning a mirror, Prism and screen gives you the image. This is based on reality and not any settings. This question confuses me. If something gets in the way and the viewfinder darkens AND the image you take is dark this means there is something very wrong with the lens and possibly with the camera. The Viewfinder image is what bounces off a mirror and when you take the photo the mirror flips out of the way. What is left is the lens, some air space and the sensor. It may be that one of the aperture blades may be moving when it should not. I am close to saying send the lens in and ask for a quote..

First, the "r06" message is NOT an error code. It indicates the number of shots remaining in the internal memory buffer, before the camera must prevent additional shutter actuations so that it may transfer those images already in the buffer to the memory card. This "r" number will decrease with each shot taken in rapid succession until it reaches 0. The shutter release will no longer work until the buffer is transferred to the memory card, then shooting may continue again.

As far as not being able to even see through the viewfinder, it sounds like something may be obstructing the light from reaching the meter and viewfinder. The problem is most likely the position of mirror inside the camera body. With the lens off the body, the mirror should be plainly visible at about a 45 degree angle to the opening. A side view drawing of this is below. The solid red line is the mirror in the normal position. The red dashed line is the up position of the mirror when the shutter is released.



When the mirror is in the "normal" position, the light from the lens is projected on a screen so that the image is visible in the viewfinder for composing and can be metered. When in the "up" position (when the shutter release is fully depressed), the light from the lens is projected on the camera's sensor for as long as set by the manual settings or program; based on ISO, aperture, etc. At the end of this time, the mirror returns to the "normal" position.

If your D100's mirror is not in the lowered 45 degree angle position, the image seen in the viewfinder is inside the camera - not that which the lens would project. Hence, the dark viewfinder, long exposure times and - I'm guessing - severely overexposed pictures because way too much light is striking the sensor because the meter is only seeing darkness.

If the mirror is ok, with the lens removed from the body, look for the aperture lever as shown in the yellow circle in the picture below:



By default, the aperture is at minimum. The camera moves the lever from this position to full open (and anywhere between) as needed. You should gently move the lever to the other end of its travel to open the aperture to maximum. Point the lens away from a light source but preferably at a light colored background. Look through the lens. There should be no obstructions and be clear. Next, look at a dark colored background to find the same results. If you want, you can even allow sunlight to shine through the lens onto a sheet of paper (like a magnifying glass). The result should be a bright circle with no obstructions. Obstructions in the lens will prevent the meter in the camera from getting accurate information about the scene and if significant enough, prevent viewing through the viewfinder.

You may wish to have the camera & lens professionally cleaned and serviced to repair a mirror or lens issue.

If this was helpful, please rate it as such. Good luck!

Hi tin_080 , the aperture actuating lever was bent or loose and is ahead of the control mechanism of the diaphragm opening in the camera body.
Check this: point the lens towards you notice that the diaphragm is closed.
To avoid more costly damage you take it to a workshop for servicing.
Best regards

Open your aperture or lower your shutter speed. That should let more light in to the camera.

I'm unfamiliar with the F80 but on models like the f65 and f75 the viewfinder screen has an lcd overlay and when the battery is exhausted or removed the viewfinder goes dark and blurry.

Looking at a picture of the f80 it looks like it's just an update on my f75 so it strongly suggests that you just need to insert a fresh battery. The lcd does draw power from the battery even with the camera turned off.

I hope that you found my answer useful, once you've tried another battery to confirm what I've suggested I'd appreciate it if you return the favour by rating my answer.

Please also ignore this answer, (see askers comment above). I've only posted it so that this question doesn't continue to appear as an unanswered one.

If anyone else has this problem please go to
http://www.fixya.com/support/t2637498-image_nikon_f80_dark_cloudy
for an answer.

It sounds as if there is a problem with aperture blades not fully opening.

A quick test...

With a known good lens on the camera, set it to shutter priority mode. Point the camera at a plain wall or ceiling, half press the shutter button and note the aperture reading suggested by the camera. (Play around with the shutter speed settings until you get something around about f11.)

If possible, switch to another good lens and do the same. (You will need to point the camera at the same wall or ceiling!) You should find that without altering any settings, you will get the same, or very similar, aperture reading as before.

Now try the suspect lens. If there is a a fault with the aperture, the camera will almost certainly suggest that a significantly different aperture setting is required.

Hope this helps!

Here's a link to the N75 / F75 user guide. The troubleshooting section / lens compatibility area might point to the problem. If the viewfinder is dark, the mirror is likely stuck in the UP position. This is usually due to a lens compatibilty issue, or the fact that the lens is not set to its smallest aperture (ie 22). The camera needs that to control the full range of aperture openings

That would explain the darkness if the lens is stopped down. It would seem the aperture control is faulty on the camera body. Normally, the aperture remains open until you take the picture. It is only closed down while the shutter is open.