What post-processing tricks can be used to improve the quality of photos taken with the on-camera flash?

Question

I know that the on-camera flash tends to produce poor images in general (the subjects are washed out, and the light from the flash isn't very powerful). But... sometimes there's no other choice but to use the on-camera flash and hope for the best. So I'm wondering, what is the best way to recover these images are in post-processing?

My question is similar to this question about fixing blown-out highlights; however, I'm interested more in things I can do to improve the entire image quality -- so this might include things like better color balance, ways to make the subject look less flat, etc.

I'm interested particularly in answers that use tricks or techniques that aren't necessarily "obvious", but might be considered "tricks of the trade" by professional photographers (I assume they have to deal with this problem sometimes, too?) -- I have both Lightroom and CS5, and am reasonably proficient with their basic use, but I know I'm probably just scratching the surface of their power. So nothing's off-limits for this answer -- if you have a solution, but it requires 20 layers and 15 different brushes, I'm all ears!

Edited to add: Note that I'm asking about photos that I've already taken, so any preprocessing tips are not helpful to me. Additionally, I do have a bounce flash, but there are certain settings in which it's not useful (if, say, there's nothing to bounce off of!), and the only way to get any light into the frame is direct hard light. My question is about how to make the best of these less-than-ideal shooting conditions in post-processing.

Asked by David

Answer

Here are a few ways I have fixed washed-out photos be it from the flash or just in general.

• Adjust levels - I will slide the black slider to the right to darken the photo. Sometimes if only part of the photo is washed out I will use a mask on the levels to darken only what I want to. This masking can get complicated and I recommend looking up some tutorials.

• Curves is another tool I have used but can be a bit tricky.

• High Pass Filter to bring details into the image and sometimes helps the washed out look. For a tutorial on the high pass filter check here.

• Shooting in RAW and adjusting the sliders sometimes is all that is needed

• Burn to image to darken where needed. You can do this in Photoshop non-destructively by creating a new layer, filling the layer with 50% Gray (Hex is #808080) then change that layers Blend Mode to Overlay, Then Burn on that layer (Dodge will also work on the same layer)

• Create a black layer and change the blend modes to soft light.

• Duplicate photo and change blend modes to see what helps darken the photo. Again advanced masking is sometimes involved and experimentation is required to see if this will work for your photo and what blend mode will work.

• Use a plugin like Topaz Adjust to change the photo.

• PS Photo Filters can help.

• I will sometimes use a combo of the above.

• The biggest trick is experimentation with filters, settings, etc in PS to see what happens. But always remember...HAVE FUN! =>

These are all done in Photoshop CS5/CS6. I do not have any examples I can currently post or I would.

I hope some of these help!

Answered by Lynda

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Without modification, is the built-in pop-up flash EVER appropriate?

Question

You can't use a diffuser, you can't redirect it, you can't adjust intensity, you can only pop that little sucker up and blast away.

Is there ever a situation where having this built-in pop-up flash is beneficial?

You don't own any other flashes/lights so using it to trigger something else is not a valid response. :-)

Asked by Andrew Heath

Answer

The pop-up flash produces notoriously bad results if it is allowed to overpower any ambient light and is used as the main light. This is because it is a small, hard light, and it is directly on the camera axis, so you can get a washed out look, particularly if you're photographic a human face - no light and shadow areas.

If you use it as fill, it can enhance your images, not harm them:

• it will add catchlights to the eyes
• it will fill in shadow areas, preventing dark eye sockets or dark shadows in the neck area. Portrait photographers often place a fill lights behind or above the camera, on-axis (true, it's a larger, softer light, but the idea is the same)

To us as fill, you simply have to dial down the power (using flash exposure compensation). As long as there is reasonable ambient light, and you only fill in shadows with the pop-up flash, you can obtain fine results.

You wouldn't want to rely on it for portrait work, but for general snapshot, with exposure dialled back a bit, it's far better to use the on-board flash than to have blurry, underexposed and noisy images.

Not all photographs are made of human faces however. Pop up flash can be very useful in macro work for example to allow you to take hand-held shots at a faster shutter speed or lower ISO.

Answered by MikeW

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Why does the exposure vary in these Nikon flash photos?

Question

The following 4 photos were all taken with a Nikon D300 at 1/250s, f/5.3, ISO-400, in shutter priority mode, with the on-camera pop-up flash. The only difference between them is the exposure bias, which varies from -4EV to +2EV. You can clearly see that the four pictures get brighter, despite having the same exposure settings.

Can you explain how/why this is happening? I have come up with a few possibilities, but I don't know which (if any) is actually correct:

• Is the camera adjusting the output of the flash to compensate for the exposure bias? This seems like the most likely solution to me, based on how the images look, but my understanding is that exposure bias was supposed to control the amount of ambient light in the scene, while leaving the flash alone, whereas flash exposure compensation is supposed to control the power output from the flash. (Flash exposure compensation remained constant for the four images).
• Alternately, is the camera applying some sort of automatic lighting correction in post-processing after the images were shot? (These images were all taken in JPEG mode, not as Raw).
• Is there some other effect at play here that I don't understand?

Edit I've copied-and-pasted the relevant exif data, extracted by exiftool, for the photos. The data is identical in all important fields (I checked using diff), except for the Exposure Compensation and Exposure Difference fields (I don't know what the latter means):

Camera Model Name               : NIKON D300
Exposure Time                   : 1/250
F Number                        : 5.3
Exposure Program                : Shutter speed priority AE
ISO                             : 400
Flash                           : On, Return not detected
Flash Type                      : Built-in,TTL
Flash Exposure Compensation     : +2/3
Active D-Lighting               : Normal

The Exposure Compensation and Exposure Difference fields for each image, from top to bottom is as follows:

Exposure Compensation           : -4
Exposure Difference             : -0.3Exposure Compensation           : -2
Exposure Difference             : -2.5Exposure Compensation           : 0
Exposure Difference             : -4.4Exposure Compensation           : +2
Exposure Difference             : -6.6

Asked by David

Answer

With Nikon, Exposure Compensation affects the overall exposure, including any automatically metered flash, while Flash Exposure Compensation (when available) affects only the flash's contribution to the overall exposure.

If the scene weren't essentially a flat plane (there isn't much depth to the scene at all), you could use Exposure Compensation to bring down the entire exposure, then boost the flash exposure to correctly expose your main subject. That would isolate the subject from the background. (The opposite can be set in theory, but it won't work unless and until somebody invents a "flash" that subtracts light from the ambient exposure.) More often, though, you'd use the Exposure compensation to compensate for the tonality of the scene (bumping it up for scenes consisting mostly of lighter tones or lowering it for predominantly dark scenes), then independently adjust the flash (usually downward) to add the desired amount of fill.

Note that with these pictures, there isn't much contribution to the exposure from ambient light at all, so if you had set the Exposure compensation to -1 EV and the Flash Exposure Compensation to +1 EV, you would have gotten pretty much the same picture as the normal exposure.

Answered by Stan Rogers

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Why is the shutter speed so long when using Flash in Aperture Priority on a Nikon D40X?

Question

I'm trying to get the background out of focus (bokeh) and using Aperature(A) mode and setting aperture to lowest value.

Update: I'm shooting in dim light and the flash goes off but the shutter speed incredibly slow (1-2 seconds), even slower than if I put it in full auto (where, presumably, the Aperture would be no wider than in Aperture mode with maximum Aperture .

I did find something in my Nikon Df0/D40X Digital Field Guid (by Busch) that said that in Aperture priority, the shutter speed is limited to 1/60s up to Syc speed. So I assume that means no slower than 1/60s

Here are the photos:

Aperture Priority with Flash (2s Shutter time)

• Exposure : 2s
• F/5.6
• Focal Length: 120mm
• ISO: 100

Full Auto

• Exposure : 1/60 s

• F/5.6

• Focal Length: 135mm (Ok, that's a little different)

• ISO: 200

Asked by Clay Nichols

Answer

This is called Slow Sync, which is a technique that allows you to combine flash with an ambient light exposure.

You probably turned this on by mistake. Generally, that's by holding the flash button (the one that pops up the flash) and turning the control wheel.

Your manual is here, see page 47 (in the PDF, technically pg 35 in the actual manual).

Answered by Instantkamera

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HF-DC1 flash light for Canon EOS 400D

Question

I want to buy an external flash light for my Canon EOS 400D. Is HF-DC1 good enough or is it designed for more compact cameras?

Any suggestion on alternatives?

Asked by Don

Answer

Canon HF-DC1 is designed for Canon PowerShot product line only and incompatible with DSLRs. You can get Canon 270EX which is about the same price range. Other relatively expensive options will be Canon 430EX II and Canon 580EX II.

Also there are 3rd party (non Canon branded) flashes, which are cheap. But most of them do not have automatic (TTL) mode and all settings have to be done manually.

Answered by ShutterBug

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I cannot open the internal flash on my Canon 60D camera; how do I fix it?

Question

I tried opening the internal flash on my Canon 60D camera the other day and it didn't open at all. I couldn't understand why. After messing around in the menus, I found out that the camera thinks that an external flash is attached. It gives the message "This menu cannot be displayed. External flash is attached."

How do I fix this?

Providing a few photos to explain what happens here. Sorry for the low quality, obviously I couldn't use my 60D to shoot photos of my 60D :))

Asked by RiMMER

Answer

There is a little microswitch in the hotshoe that detects an external flash -- this may have become stuck, or got a piece of grit blocking it. If you cannot see anything under the rails, you may have to take it to your local friendly Canon authorised repair centre, but if you can see some grit, you may be able to carefully remove it with a cocktail stick or similar.

Answered by Rowland Shaw

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Are there any tricks to make a pop-up flash suck less in low light?

Question

I'm taking a lot of low-light indoor shots of moving subjects. I hate a the default flip-up flashes of most moderns DSLRs (in my case, a Canon 60D), but this is typically a point and shoot situation (so, no external flash or setups).

Are there any tricks to make the flash less stark/harsh and contrasty, in the settings or by using some external trick?

Answer

I'm going to say no. MikeW's advice on using a high ISO and longer shutter is good, and you can do little bounce card and diffuser gimmicks, but the absolute difference these make just isn't enough — the built-in flash still will suck.

Most importantly, these gimmicks and other tricks and techniques run against one of your fundamental requirements: no setup. You're going to have a thing to fiddle with, and something to worry about. In many situations it'd be less hassle to do something which will make a big, positive difference: use a hotshoe flash, or use a wireless-TTL flash off-camera triggered by the built-in flash. For the latter, you can put your flash somewhere convenient and out of the way in the room (on a bookcase, say, pointed at the ceiling). This is some setup, but not really very involved. I do it all the time for pictures of my family.

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Why is the D7000 commander mode flash firing during exposure when the manual says it won't?

Question

I'm wondering if I'm using the D7000's Commander mode incorrectly. Page 225 of the Nikon D7000 manual says

The built-in flash does not fire [in "--" Option], although remote flash units do.

Yet what I've found is that the built-in flash in fact does fire, adding ugly on-camera, direct flash to my photos especially for short-distance subjects. I present Exhibit A below, where it is seen that both the remote SB900's and the on-camera's flash are captured, even in "--" Commander option. How do I fix this?

Answer

They lie.

It does, it just not supposed to fire enough to matter. The flash is how it communicates with external units.

You can get an SG-31R unit to block it and let the IR only through.

Your other option is to ditch CLS and go with radio triggers - of which, if you search, we have various questions about.

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Can you use the built-in flash in a Canon EOS 450D with a hot shoe GPS geo-tagger?

Question

As far as I can see, the answer is no, the flash cannot open if anything, is plugged on the hot shoe of a Canon EOS 450D:

Can anyone confirm that I wouldn't be able to use something like the Jobo photoGPS and the flash at the same time?

Answer

There is a sensor in the hotshoe to detect a flashgun; this inhibits the pop-up flash from coming up (or even firing, even if you trick it). You might be able to chip off the relevant part of the slide so the camera doesn't detect the hotshoe flash, but I wouldn't personally recommend it.

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Why is the D7000 commander mode flash firing during exposure when the manual says it won't?

Question

I'm wondering if I'm using the D7000's Commander mode incorrectly. Page 225 of the Nikon D7000 manual says

The built-in flash does not fire [in "--" Option], although remote flash units do.

Yet what I've found is that the built-in flash in fact does fire, adding ugly on-camera, direct flash to my photos especially for short-distance subjects. I present Exhibit A below, where it is seen that both the remote SB900's and the on-camera's flash are captured, even in "--" Commander option. How do I fix this?

Answer

They lie.

It does, it just not supposed to fire enough to matter. The flash is how it communicates with external units.

You can get an SG-31R unit to block it and let the IR only through.

Your other option is to ditch CLS and go with radio triggers - of which, if you search, we have various questions about.

Check more discussion of this question.