Dark Image Jpg

[Ceumar Pee]

Notethat the screen brightness does not change when ambient lighting changes in the room (I already turned off adaptive brightness from the Control Panel). The issue is that it changes when I am viewing dark contents/images (e.g. viewing a nighttime photo, or visiting a website with a dark background) on the screen. This is a big issue for me as I do a lot of video and photo editing and I need the screen brightness to remain the same at all times.

On Dell Vostro 5490 with Windows 10, I solved the problem by disabling "Eco Power" in the Video settings and also setting the screen brightness on Battery power to 100%. (Screenshot is from an Inspiron, but Bios screen is the same on my Vostro).

I found information online about doing this change in Windows settings, but the described settings were missing on my machine even after updating the Graphics (Intel + Nvidia) drivers and the Bios. For example, in Edit Power Plan -> advanced settings, under Display, I only have the option "Turn off display after".

Another possibility would be to set it to manual mode, crank it up to a 5 second exposure and with a f/8 or so, and see if the image comes out really bright or not. With nothing but a single lamp and the TV on, the image came out almost completely white. Sure, it'll come out REALLY blurry, but it'll give you an idea if it's getting light in or not.

ages ago(permalink)

Does your viewfinder look somewhat darker than usual?

My guess is that your lens' aperture servo is stuck on a very small aperture. If you can try another lens, that would either prove or disprove that theory.

I arrived at that thought because of the fairly deep field on the one image you posted that is reasonably exposed.

ages ago(permalink)

Scott has a point. What did the camera say you were shooting at in the aperture priority mode? In that kind of light, f4.5 just isn't wide enough open. Your lens is capable of f3.5, so if you can't turn it down that low, something is indeed wrong.

ages ago(permalink)

You might also carefully take a look at your lens' aperture lever.

Nikon lenses that don't have aperture rings are spring-loaded to their smallest aperture. This lever is controlled by the camera to set the aperture to the correct size prior to taking the picture.

When you look through the lens and gently push this lever with your finger, you should see the aperture open. If the lever is stuck, don't apply any force at all - your aperture blades could be stuck, and forcing will just bend them. If the aperture lever's stuck, and you can't see anything (dirt, etc.) physically blocking it, you need to have the lens looked at by a competent camera repair guy.

The camera end of the aperture mechanism could be at fault, too, of course. Swapping or checking the lens just narrows the problem down.

ages ago(permalink)

I have the same problem now as well, all the solutions have failed, and it doesn't seem anything is stuck, including the aperture lever. Tazdpro, did you figure out what that defective part was?

ages ago(permalink)

I'm having the same problem as well. I had the Error:press shutter release button again. I fixed that problem but for some reason the camera won't actuate the aperture correctly.

I can get properly exposed images when I use a completely manual lens like a 50mm AI-S. However as soon as I put anything at all with a CPU on the camera, it underexposes. This happens whether I'm in manual mode or not with a lens like a D or G lens. Oddly the meter and sensors still meter correctly.

Any help would be very much appreciated.

ages ago(permalink)

I'm having the same problem wiht my D40. So let me explain this and see what anyone might suggest. Here are the settings.

On Manual i"m using a remote floods and strobes - I'm using a remote/wireless sensor to trigger the flashes.

Never had a problem wiht this camera but then every ohter or every 3rd picture would be totally black. I thought the light system i bought or the wireless sensor was a problem. My friend brought over his cannon and it worked fine so i new it wasn't the lights.

Then i thought well the lens must be off. So i replaced the lens and still the same problem. I have not updated firmware or anything like that. But the problem is not consistent. I don't see a pattern on which pictures are correct and which ones are pitch black.

I'm thinking about just replacing the camera - i've had it for a while but i've only been using the strobes for 6 months or so. The camera works perfectly fine with it's own flash on all the ohter settings. It's just the manual mode - and yes i've tride setting all the settings different ways and it doesn't seem to matter.

The thing that gets me is if there was a bad setting wouldn't every picture be bad - why would some be perfect.

I think Nikkon should recall these cameras if htey have that faulty of an issue.

ages ago(permalink)

Take a picture of a uniform white wall lighted with a cold lamp (not an incandescent or warm white compact fluorescent, but a straight fluorescent tube with 3500K or more or sunlight are ok). Nothing except white wall should be visible in the picture. Generate a JPG (basic). Open it in Photoshop or equivalent and check the histogram. The middle of the peak should be about gray 18%, that means RGB 46, 46, 46. Small deviations are acceptable (40-51, it's a +-2%).

If not within that range, send to calibration or experiment with manual compensation until the value falls in the range and consider that compensation as the offset to always use as zero.

ages ago(permalink)

Nikkits4, your problem is almost certainly a flash trigger issue because of the fact that it is happening when using wirelessly triggered flashes. The dark shots are ones where, for some reason, either the flashes did not go off at all, or they went off out of sync with the camera. If you are shooting close to the max shutter sync speed (1/500 on a d40), it is likely that it is a sync problem. Try shooting at 1/200 or slower and I'll bet the problem goes away.

ages ago(permalink)

I had the similar problem with my Nikon D40 as most of the people mentioned here, my camera was taking good photos, i didn't change any camera setting but it started taking photos very dark.

I just tried changing lense twice and it worked, i had this problem before also but wasnt sure how it worked later, this problem is annoying and dont know the exact reason of the problem.

ages ago(permalink)

ditto here for the dark D40 problem.

My thinking is it may be corroded contacts? Mine was sitting in my attic for the last couple years without a lens on it (just the Nikon plastic cap) and it's possible the contacts got corroded. I will try when I get home to clean them.

ages ago(permalink)

i found solution, remove the lens while still on, put the dial to manual, put conpensation to -5, while holding the lever of aperture opener press the shutter facing on super bright light on the sensor, it will capture white picture, its ok, put back the lens, put dial to p,put the conpensation to 0.0 and test it. then adjust to your specs, this should bring back the light in your photos...

79 months ago(permalink)

Damn, arthur arago, I was really hoping that that would work for me. Do you or anyone else have any other solutions. All things considered I really can't complain. My shutter count is over 120,000. This dark picture problem just suddenly appeared.

79 months ago(permalink)

I had the same problem with underexposed images. I tried arthur arago's solution, but it didn't work for me. I ended up taking my D40 to a repair shop and they said it looked like the metering sensor was miscalibrated, probably from a drop.

72 months ago(permalink)

I would like to know how to write a function in Python 3 using OpenCV which takes in an image and a threshold and returns either 'dark' or 'light' after heavily blurring it and reducing quality (faster the better). This might sound vague , but anything that just works will do.

Personally, I would not bother writing any Python, or loading up OpenCV for such a simple operation. If you absolutely have to use Python, please just disregard this answer and select a different one.

You can just use ImageMagick at the command-line in your Terminal to get the mean brightness of an image as a percentage, where 100 means "fully white" and 0 means "fully black", like this:

However, if you really want Python/OpenCV code, I note none of the existing answers do that - some use a different library, some are incomplete, some do superfluous blurring and some read video cameras for some unknown reason, and none handle more than one image or errors. So, here's what you actually asked for:

You don't say why you want to do this. If your use-case is for a website/app 'dark mode', because you want to invert images which look better inverted rather than dimmed, none of the solutions given here will work perfectly - because they will all have false positives/negatives, like images which are grayscale photographs (which will have few colors / histograms, but will look awful when they contain a human and are inverted, like a photo negative). These can't be fixed by hacks like blurring because it is inherently based on the semantics of the image, like whether it contains a face or not.

For the latter approach, it is is easily handled with CV methods like finetuning a small neural network; you can find a FLOSS model & API at InvertOrNot.com (using PyTorch & Onnx to train an EfficientNet CNN).

what file format did you use, If you used a 32-Bit per channel image format like .hdr or .exr some tonemapping maybe ignored and you can have similar results to what you are showing.

also check the color profile below:

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