How do I switch Viewfinder Info Light off?

I do a lot of astro work meaning 20 to 30 second exposure times at ISO 800 or higher and then need to push the ISO in post. I also sometimes need to underexpose parts of the pics and also then push for detail (eg no tripod, or windy day with plants and want to freeze motion in blue hour).

Problem is when I add, say, 4 stops exposure in Lightroom I often get a magenta cast down the edge of the image where the Viewfinder Info Display shines and so I am concerned that this does not switch off. How can I switch it off completely since I am shooting in Manual with Manual Focus and use the LCD screen to change settings. How can I switch off the internal light in the viewfinder?

TIA

The magenta cast is due to light leaking in through the viewfinder. If it were anything in the viewfinder, it would be on the opposite side..... all images projected onto the sensor are rotated 180° due to the optics of the lens. What you see in the viewfinder has been rotated back.

Thanks Sparky, is the viewfinder supposed to automatically close when the shutter is pressed?

Basilisk said:

Thanks Sparky, is the viewfinder supposed to automatically close when the shutter is pressed?

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The viewfinder doesn't 'close'. When you take a photo, the mirror that directs the image up into the viewfinder must raise up to allow the image to reach the sensor.

For those long exposures you need a view finder cap or cover... It just slips on in place of the standard cap and keeps any light from entering. You can get them from Amazon if you did not get one with your camera.

480sparky said:

The viewfinder doesn't 'close'. When you take a photo, the mirror that directs the image up into the viewfinder must raise up to allow the image to reach the sensor.

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The mirror lifting cannot have and has no effect on light entering through the viewfinder. I was told once that Nikon cameras have an automatic blind or shutter that blocked off light from entering the camera body through the viewfinder when the sensor curtain was open. The method described was that on pressing the shutter it activated the mirror lift, the sensor blind opening and the viewfinder blind closing. Perhaps my informant was mistaken because you and Danno are both suggesting that is not the case. Quelle domage. I do have one of those shutter blinds somewhere too. They're so easy to lose though.

Basilisk said:

The mirror lifting cannot have and has no effect on light entering through the viewfinder. I was told once that Nikon cameras have an automatic blind or shutter that blocked off light from entering the camera body through the viewfinder when the sensor curtain was open. The method described was that on pressing the shutter it activated the mirror lift, the sensor blind opening and the viewfinder blind closing. Perhaps my informant was mistaken because you and Danno are both suggesting that is not the case. Quelle domage. I do have one of those shutter blinds somewhere too. They're so easy to lose though.

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This is incorrect. Light leaks through the viewfinder is always a possibility. For most short-duration exposures, light leak is not an issue, especially when your eye is at the VF blocking 99% of the light. But for long exposures, especially when your eye is not at the VF, it can become an issue. If there's an 'automatic blind or shutter', there's no reason for the little plastic eyepiece covers to be included, and no reason for top-end DSLRs have manual eyepiece shutters built into them.

It's kind of standard operating procedure to block the view-finder when taking long exposures.

I usually toss a lens cloth over the top of the camera but use whatever works for you.

Thank you for the explanation, I must have been confused with the manual blind inbuilt to the higher end models. I had it happen on a shot with a 1/30th second exposure last week too. Here's a sample from that shoot:

Check out the bottom of the frame, and the left hand corner. On this shot I don't need the black to show detail, but it's a good example of how the problem occurs even with faster shutter speeds.

Here's a detail of the left lower corner:

The 'bottom' of the image is actually recorded by the sensor closest to the viewfinder... the 'top' of the sensor.

Basilisk said:

Thank you for the explanation, I must have been confused with the manual blind inbuilt to the higher end models. I had it happen on a shot with a 1/30th second exposure last week too. Here's a sample from that shoot:View attachment 239980

Check out the bottom of the frame, and the left hand corner. On this shot I don't need the black to show detail, but it's a good example of how the problem occurs even with faster shutter speeds.

Click to expand...

This also happens when you underexpose a photo. The higher ends do have a lot more features than the lower end DX cameras like the D5500 but the even my D750 does not have a shutter blind. I have to cover the viewfinder when doing long exposures to keep stray light out.
But underexposing a shot and raising it post is going to be a problem with your camera.

480sparky said:

The 'bottom' of the image is actually recorded by the sensor closest to the viewfinder... the 'top' of the sensor.

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Thanks, Sparky, that's my point. The Viewfinder Info is quite bright and does not appear to switch off. If it continues to glow, INside the viewfinder, won't the light from it reflect internally downwards and appear to come from outside of the camera because it came through the viewfinder window. I really don't need the info that is displayed in the viewfinder to be displayed anyway.

Basilisk said:

Thanks, Sparky, that's my point. The Viewfinder Info is quite bright and does not appear to switch off. If it continues to glow, INside the viewfinder, won't the light from it reflect internally downwards and appear to come from outside of the camera because it came through the viewfinder window. I really don't need the info that is displayed in the viewfinder to be displayed anyway.

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I'd think the light output of the VF display is so minimal I think it would be difficult for it to register in the image. I'd still bet the rent it's stray light coming in the VF.

480sparky said:

I'd think the light output of the VF display is so minimal I think it would be difficult for it to register in the image. I'd still bet the rent it's stray light coming in the VF.

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It's brighter than starlight. My favourite spot for astro shots has no background light as it is shooting from the edge of a forest on the top of a cliff. Pretty creepy in the pitch black with a slight wind rustling the branches behind you! There are shots I do where it could be viewfinder light, but since it also happens where there is no light (I suppose there is the starlight and reflected light pollution, but when my eyes have adjusted to the dark the light from the viewfinder (not the LCD) is enough for me to navigate by (if shows where the camera is at least).

Basilisk said:

It's brighter than starlight. My favourite spot for astro shots has no background light as it is shooting from the edge of a forest on the top of a cliff. Pretty creepy in the pitch black with a slight wind rustling the branches behind you! There are shots I do where it could be viewfinder light, but since it also happens where there is no light (I suppose there is the starlight and reflected light pollution, but when my eyes have adjusted to the dark the light from the viewfinder (not the LCD) is enough for me to navigate by (if shows where the camera is at least).

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If is that dark then I bet what you are seeing is underexposure especially when you are having to bump up the exposure in post. That camera does not have the range as some of the high end cameras do. Not designed for extremely high ISO. You are going to have to use a longer shutter speed and lower ISO. This should be ok if it is used on a telescope with tracking.

Don Kuykendall said:

If is that dark then I bet what you are seeing is underexposure especially when you are having to bump up the exposure in post. That camera does not have the range as some of the high end cameras do. Not designed for extremely high ISO. You are going to have to use a longer shutter speed and lower ISO. This should be ok if it is used on a telescope with tracking.

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Currently at the limit on shutter speed for avoiding Star Trails (Rule of 500/600). 10mm x 1.5 for DX = 15mm (35mm equivalent) divided into 500 = 30s and despite the camera is supposed to be OK up to 12,500 ISO I never take it beyond 1600 for astro work. I'm not after close ups of stars, galaxies and nubulae but landscapes with recognisable elements with the stars as background. That's why I need the ultrawide angle lens and a very wide aperture.

Basilisk said:

Currently at the limit on shutter speed for avoiding Star Trails (Rule of 500/600). 10mm x 1.5 for DX = 15mm (35mm equivalent) divided into 500 = 30s and despite the camera is supposed to be OK up to 12,500 ISO I never take it beyond 1600 for astro work. I'm not after close ups of stars, galaxies and nubulae but landscapes with recognisable elements with the stars as background. That's why I need the ultrawide angle lens and a very wide aperture.

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Your camera will not handle to much over 3200-6400 without being way to grainy. I do shoot the milky way and stay below 20 seconds to keep the stars pin sharp. your problem is going to be getting a good exposure without the underexposure. Underexposure is where you are going to get grain and color noise when you try and up the exposure especially in the underexposed areas.

Don Kuykendall said:

Your camera will not handle to much over 3200-6400 without being way to grainy. I do shoot the milky way and stay below 20 seconds to keep the stars pin sharp. your problem is going to be getting a good exposure without the underexposure. Underexposure is where you are going to get grain and color noise when you try and up the exposure especially in the underexposed areas.

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Clearly. As I said for astro work I rarely go over 1600 - in fact, I rarely go TO 1600. more commonly sticking to the 800 to 1250 range. There are a couple of Astrophotography groups on Facebook with some pretty good information if you want to improve your astro technique, one of the photographers there uses my camera and settings to get exceptional photos but I haven't quite mastered his post processing techniques yet (I have Lightroom but not Photoshop so cannot do layers or masking). According to DxO Mark the D5500 has a max reliable low light ISO of 1438 and a dynamic range of 14 EV, or 9 EV with 18% s/n ratio. They say it has "class leading low noise".

But of course, investment is needed when you are up against the barriers, and with astro work there are time constraints, with modern Nikon lenses there are aperture constraints, and with digital work there are sensor constraints. I really need a full frame camera with better low light (eg D750) but first I shall get a brighter lens which will also work on my DX camera until I can afford the FX model.

Basilisk said:

Thank you for the explanation, I must have been confused with the manual blind inbuilt to the higher end models. I had it happen on a shot with a 1/30th second exposure last week too. Here's a sample from that shoot:View attachment 239980

Check out the bottom of the frame, and the left hand corner. On this shot I don't need the black to show detail, but it's a good example of how the problem occurs even with faster shutter speeds.

Click to expand...

Can you show us an unedited image with exif in it please.