External Flash

[birds604]

I have a Cannon EOS T3i and shoot automatic.  My interior pics seem to be yellowish.  Would an external flash help and if so what model

[TCampbell · Accepted solution]

There's really two different questions here:

1)  Will flash help with interior shots? 

2)  Why are the interior shots yellowish?

Let's talk about the "yellowish" problem first.

I'm going to guess that your interior shots have traditional incandescant lighting (traditional tungsten filament light bulbs).  This is normal as those bulbs put out a rather decidedly yellow/orange color cast.

You can adjust the white balance to the "Tungsten light" setting (icon looks like a typical light bulb).  Just don't forget to change it back when you're done or your outdoor photos will end up looking much too blue.  You can use "custom white balance" to fix it as well (custom white balance involves taking a photo of a neutral gray card held in the same light you plan to shoot in.  When you pick custom white balance, it'll ask for the reference image, you pick that photo of the gray card, and the camera will adjust the white balance to neutralize any color cast caused by the light.  There are tutorials and YouTube videos to demonstrate how to do this.)

Now about the flash...

A flash has a "color temperature" designed to match daylight (outdoor light).  A wonky thing happens when you mix "daylight" with "tungsten".  If the flash appears "white" then any traditional incandescant lighting will look particularly orange.  If you set a white balance to remove that, then those lamps will look normal, but light from your flash will seem "cool" and blue.  

The "fix" is to use something called a "CTO gel" on the flash.  CTO stands for "Color Temperature Orange".  The colored gel (you just tape it over the front of the flash) tints the light from the flash to match the color of the lamps.  Then when you set the camera to use "tungsten" white balance, the entire scene looks normal.

You can do a Google search for "CTO flash gels" and find lots of information as well as companies that sell the gels.  

Canon's new Speedlite 600EX-RT comes with a CTO gel and a darker orange gel (which more approximates the color of sunlight at sunset).  

I happen to think everyone should own an external speedlite flash.  There are two or three issues with built-in flashes.

First... they tend to not be very big and not very powerful.  They're good for working distances of about 10'... maybe 12' -- but beyond that they don't have the power to illuiminate a large area.

Second... they don't offer diffuse or angled light.  When the light comes from the same direction as the camera lens, it hides all shadows.  To have great light, you actually do want shadows.  Shadows allow three-dimensional objects to show off their dimensionality.  Textures look "flat" when there are no shadows.  Also, it's a tiny pin-point source so it doesn't create soft diffuse light (diffuse light is light which appears to originate from a broad area -- not a pinpoint source.)

Third... light has a "fall off" problem (all light does).  As the distance from the light source increases, the light spreads out.  The rate at which it spreads out is called the "inverse square law" and it applies to lots of things besides light.  But the inverse square law says that the light will effectively become half as bright each time to the distance from the source increases at a well understood rate.  That rate is based on the square root of 2 (which is a number very close to 1.4).  

Assume you have a subject at 5' from the light.  It gets some amount of light and you've set the exposure for a nice exposure with that light at that distance.  An object which is 1.4 times farther away (which would be 7') would get HALF as much light.  An object 1.4 times farther from that (10') would get half as much again (or 1/8th).  At 14' it'd be half as much again (1/16th) and at 20' it would be 1/32nd as much light.  

If you "bounce" the light off the ceiling, then it all comes raining down from above... there's still a fall-off problem but due to the new path the light is taking it wont be as drastic.   You'll get room lighting which is a little more even.  But the built-in pop-up flash cannot be pointed up at the ceiling to "bounce" the light.  An external shoe-mounted speedlight has a head which can be tilted up to "bounce" the shot -- and they tend to be significantly more powerful.

Today I use 600EX-RT speedlites, but I own and have extensively used the 430EX II and found it to be a great workhorse flash in a nice size package.  

[ScottyP · Accepted solution]

Tim makes good points. I would just add that odd color casts are going to be a recurring problem. Besides the CTO fixable problem there are a lot lot more and there are often lighting mixtures or reflections off of colored walls you and the camera won't be able to anticipate or deal with except by fiddling with it in post processing.
White balance issues like this are one huge reason you want to be shooting in the RAW format, or RAW + JPG. Raw keeps the whole image file so you can fix these problems easily. Jpg brows out a lot of the data in the image and kind of burns in the white balance so there is less you can do to fix the image in post.
Also, Adobe Lightroom is an excellent post processing program. Easier to use than Photoshop. And it makes working with RAW files so easy you dont know any difference because there is nothing extra to do. It converts the raw files automatically.

Good luck!

[TCampbell · Accepted solution]

There's really two different questions here:

1)  Will flash help with interior shots? 

2)  Why are the interior shots yellowish?

Let's talk about the "yellowish" problem first.

I'm going to guess that your interior shots have traditional incandescant lighting (traditional tungsten filament light bulbs).  This is normal as those bulbs put out a rather decidedly yellow/orange color cast.

You can adjust the white balance to the "Tungsten light" setting (icon looks like a typical light bulb).  Just don't forget to change it back when you're done or your outdoor photos will end up looking much too blue.  You can use "custom white balance" to fix it as well (custom white balance involves taking a photo of a neutral gray card held in the same light you plan to shoot in.  When you pick custom white balance, it'll ask for the reference image, you pick that photo of the gray card, and the camera will adjust the white balance to neutralize any color cast caused by the light.  There are tutorials and YouTube videos to demonstrate how to do this.)

Now about the flash...

A flash has a "color temperature" designed to match daylight (outdoor light).  A wonky thing happens when you mix "daylight" with "tungsten".  If the flash appears "white" then any traditional incandescant lighting will look particularly orange.  If you set a white balance to remove that, then those lamps will look normal, but light from your flash will seem "cool" and blue.  

The "fix" is to use something called a "CTO gel" on the flash.  CTO stands for "Color Temperature Orange".  The colored gel (you just tape it over the front of the flash) tints the light from the flash to match the color of the lamps.  Then when you set the camera to use "tungsten" white balance, the entire scene looks normal.

You can do a Google search for "CTO flash gels" and find lots of information as well as companies that sell the gels.  

Canon's new Speedlite 600EX-RT comes with a CTO gel and a darker orange gel (which more approximates the color of sunlight at sunset).  

I happen to think everyone should own an external speedlite flash.  There are two or three issues with built-in flashes.

First... they tend to not be very big and not very powerful.  They're good for working distances of about 10'... maybe 12' -- but beyond that they don't have the power to illuiminate a large area.

Second... they don't offer diffuse or angled light.  When the light comes from the same direction as the camera lens, it hides all shadows.  To have great light, you actually do want shadows.  Shadows allow three-dimensional objects to show off their dimensionality.  Textures look "flat" when there are no shadows.  Also, it's a tiny pin-point source so it doesn't create soft diffuse light (diffuse light is light which appears to originate from a broad area -- not a pinpoint source.)

Third... light has a "fall off" problem (all light does).  As the distance from the light source increases, the light spreads out.  The rate at which it spreads out is called the "inverse square law" and it applies to lots of things besides light.  But the inverse square law says that the light will effectively become half as bright each time to the distance from the source increases at a well understood rate.  That rate is based on the square root of 2 (which is a number very close to 1.4).  

Assume you have a subject at 5' from the light.  It gets some amount of light and you've set the exposure for a nice exposure with that light at that distance.  An object which is 1.4 times farther away (which would be 7') would get HALF as much light.  An object 1.4 times farther from that (10') would get half as much again (or 1/8th).  At 14' it'd be half as much again (1/16th) and at 20' it would be 1/32nd as much light.  

If you "bounce" the light off the ceiling, then it all comes raining down from above... there's still a fall-off problem but due to the new path the light is taking it wont be as drastic.   You'll get room lighting which is a little more even.  But the built-in pop-up flash cannot be pointed up at the ceiling to "bounce" the light.  An external shoe-mounted speedlight has a head which can be tilted up to "bounce" the shot -- and they tend to be significantly more powerful.

Today I use 600EX-RT speedlites, but I own and have extensively used the 430EX II and found it to be a great workhorse flash in a nice size package.  

[ScottyP · Accepted solution]

Tim makes good points. I would just add that odd color casts are going to be a recurring problem. Besides the CTO fixable problem there are a lot lot more and there are often lighting mixtures or reflections off of colored walls you and the camera won't be able to anticipate or deal with except by fiddling with it in post processing.
White balance issues like this are one huge reason you want to be shooting in the RAW format, or RAW + JPG. Raw keeps the whole image file so you can fix these problems easily. Jpg brows out a lot of the data in the image and kind of burns in the white balance so there is less you can do to fix the image in post.
Also, Adobe Lightroom is an excellent post processing program. Easier to use than Photoshop. And it makes working with RAW files so easy you dont know any difference because there is nothing extra to do. It converts the raw files automatically.

Good luck!

[birds604]

thank you, great information. Now, one more question. I am an amature and only use automatic features. Do I still need a speedlite 430ex11 or 600ex-rt

[ColinGlover]

Yongnuo make great flashguns. Much cheaper. Check out the Amazon reviews. Get an ITTL or ETTL model.

[TCampbell · Accepted solution]

Do NOT get an iTTL model.  That is Nikon's proprietary dedicated flash communication system (their counterpart to Canon E-TTL).  If it doesn't do E-TTL (or better yet... E-TTL II) then it wont support automatic flash with your T3i.

[ScottyP]

A 430 would be a good bargain. A 600 makes little sense unless you get 2 or more, or 1 plus the transmitter, because the big claim to fame for that unit is the radio control feature. You want to get the flash off the camera with one remote firing method or another (sometimes) because it gives nicer light than head-on lighting. I would not hesitate to get Yongnuo flashes if 1.) the savings is the only way you will get multiple flashes, and 2.) you verify you are getting a model that does ETTL with your T3i.