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When enabling the flash (by deploying the built-in, pop-up flash; or by using the hot shoe with an external flash device) the apparent brightness of the image displayed on the LCD monitor (LiveView) and/or electronic viewfinder (if it has one) automatically increases dramatically.

In some situations, the frame will be too dark to compose a shot, so I will pop up the built-in flash, and straight away I can compose a nice, sharp image. And then of course the flash fires as the shutter actuates, and it ruins the shot.. Cover up the flash, and it turns out darker than the preview.

But the thing is, I already had the desired image in the buffer, and displayed on the screen. It already existed. I saw it. The camera saw it. But I was unable to keep it. How do I get that exact image, as is? It's like it's trying to do some fancy exposure simulation business, and shooting itself (and me) in the foot.

  • 4
    Is there a reason you just don't switch to manual mode and increase the exposure? – Mike Dixon Mar 6 '18 at 19:02
  • @MikeDixon Manual mode is all I've ever used. I think you misunderstood the question. – voices Mar 7 '18 at 3:14
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That image is bright because it is boosted electronically. You don't really want to have that image, as it's extremely noisy. It only looks (somewhat) ok on the camera's LCD because you can't really judge image quality on that tiny screen.

But if you want to create an image like that, turn up ISO and aperture to maximum and select a sufficient shutter speed.

Addendum: in addition to the usual photography parameters mentioned above, it's likely that the camera also digitally increases brightness of the picture for LCD display. You can't recreate that in-camera, but in post processing with any image editor on a computer. This will, again, considerably increase noise and, in case of JPEG captures, make horrible compression artefacts visible which were formerly hidden in the shadows.

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First a point of clarification:

  • The images you see on screen aren't in the buffer. They are a live video stream at 1080p coming from the sensor.

You say that the issue happens when its pretty dark in your image, so you pop the flash. What is happening when you do this is that the camera says "Hey I know there is going to be another 3 stops of light in this scene [as provided by the flash]. Lets make it that much brighter." This results in the image looking the correct on the screen, but when the take the photo with the flash covered as you described, it doesn't get that light so it becomes darker.

To fix your issue:

  • Use live view
  • Do not deploy your flash
  • Look at the exposure bar:

The exposure bar used on Canon cameras, showing different exposures.

Addendum: Learn how to use the histogram in live view for your camera (try searching "[camera name] histogram live view"). This will allow you to nail the exposure every time.

  • I highly doubt the LCD preview is 1080p. Probably more like 750x500. The "pixel" count for most rear LCD screens in the specs include each RGB set as "3" pixels. 750x500=375,000 pixels x 3 dots = 1.1MP rear LCD screen. – Michael C Mar 7 '18 at 17:18
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    @MichaelClark I agree that the LCD preview is that quality, but on most Canon cameras you can port the live view out to a 1080p panel over HDMI, so I am guessing that it captures in 1080p. – Hairy Dresden Mar 7 '18 at 18:27
  • Popping up the flash does not add 3 stops of light. All it does is disable exposure simulation. – Mike Sowsun Mar 8 '18 at 0:14
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You don't mention what body you're shooting with. Does it have a feature called "exposure simulation"? That would explain the brightness change with flash enabled.

Mike Dixon is right, though. Don't rely on a crutch like that to establish your shot configuration. Take a shot with your best guess and adjust from there.

I shoot 99% of my work in AV, and exposure compensation is a critical tool in my kit. Bump EC a stop or more and see how it goes.

  • Canon EOS cameras in general, I think. Maybe other brands, I'm not sure. I just tried it with a 650D, which has no configurable exposure simulation/compensation features (although I've noticed these features on other models); but the display does change as I adjust the aperture, shutter speed, ISO, DOF preview, and so on. I use manual mode 100% of the time. – voices Mar 7 '18 at 3:55
  • @tjt263 The reason there is no exposure simulation setting for your camera is that it is permanently turned on when you are in Live View. no setting needed for that. – Michael C Mar 7 '18 at 16:52
  • According to the user manual, the 650D does have exposure compensation. – Caleb Mar 7 '18 at 19:36
  • @Caleb yep, but Exposure SIMULATION can't be turned off. Thus, no need for a menu item. If Live View is on, so is Exposure SIMULATION. Totally different thing than Exposure COMPENSATION. – Michael C Mar 8 '18 at 1:47
  • @MichaelClark Agree. I was responding to tjt263's assertion the the 650D has no configurable exposure compensation. Sorry for any confusion--I could've been more clear. – Caleb Mar 8 '18 at 2:16
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Live-View on Canon cameras is Exposure-Priority which is one of the best implementation out there. As you noticed though, it is not possible to get this working with flash since the camera has no idea which pixels in the scene will be illuminated by how much. Flash falls off with the square of distance, so not all pixels get the same amount of light.

What you see in Live-View when the flash is off is exposure simulated by the exposure parameters. If you expose the same way, without a flash of course, you will get the same result as what you see on screen, without being 100% accurate, Canon DSLRs do a rather good job.

  • I'm talking about capturing the live, raw frame; exactly as it's displayed on the screen. – voices Mar 7 '18 at 6:52
  • @tjt263 To get what is on the screen you cannot use the flash. It is impossible for the camera to preview the effect of flash since it would need to know the distance of every pixel and reflectivity of the surface there. What you see on-screen when the flash is active, is a boost of the image, so you could get something close by applying positive exposure compensation, again without the flash. – Itai Mar 7 '18 at 15:33
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The default for Canon cameras is to use exposure simulation while in LiveView.

Higher end cameras like the 80D, 6D, 7D, 5D, etc. have the option to turn off exposure simulation. The Rebel series of cameras are more basic and have no option to turn off exposure simulation.

There is no way to “capture” the image displayed on the LCD screen. Having exposure simulation turned on is about as close as you can get.

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If you really want to capture the contents of the screen, then connect your camera to a computer and use EOS Utility to control the camera. EOS Utility lets you see the same image that's displayed on the camera's screen. Once you've got that set up, you can capture the screen using a screen grab utility on your computer.

Other's have explained that this probably isn't what you really want. You're going to get a noisy, low resolution image that's not good for much beyond illustrating how to use the camera. If you really want a photograph, then you should adjust your exposure settings accordingly. Use the histogram to judge exposure, not the brightness of the image as displayed on the camera's screen. If the image on the screen seems darker than the image you capture, you might need to tweak the camera's display brightness.

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