ClioSport.net

Register a free account today to become a member!
Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Indoor Flash Photography Tips...



Perrinho

ClioSport Club Member
Any indoor flash photography i have done in the past (limited) i have done with the auto settings. Im after some advice for shooting indoors with a canon 40d and 430ex to achieve photos that dont have a lit subject and dark background...Im using a stoffen diffuser...
 
High ISO to expose the image with ambiant light and lower power on the flash to boost the subject should work. Will you be able to bounce the flash off the ceiling?

There is a fairly comprehensive guide on POTN.. borrowed some of it for you:

THE BASICS
Before you venture into the world of flash shooting, you need to first understand the basics of exposure. This guide assumes that you understand how shutter speed affects exposure and motion blur, how aperture affects exposure and depth-of-field, and how the ISO setting affects exposure and digital noise. If you don’t yet have at least a theoretical grasp of these concepts, then it’s best to learn about them before venturing into the flash world.

LESSON 1: FACTS THAT EVERY FLASH SHOOTER MUST UNDERSTAND

The first four facts are universal, whether you’re using the camera’s built-in flash, a hotshoe-mounted flash unit, or studio strobes.
Flash fact #1: Every flash photograph is two exposures in one – an ambient light exposure and a flash exposure. This is a critical fact to remember. The shutter opens, the flash fires, the shutter closes. During this time, both ambient light and flash will contribute to the recorded image. Flash photography requires managing both exposures.

Flash fact #2*: Flash exposure is not affected by shutter speed. The entire burst of light from the flash begins and ends while the shutter is open, so keeping the shutter open longer won’t help with flash illumination. The flash exposure and the effective range of your flash unit will be affected by aperture and ISO settings, but not the shutter. Of course, the ambient light component in a flash photograph is affected by shutter speed. So changing the shutter speed is one way to manage the amount of ambient light that contributes to a flash photograph.

Flash fact #3: Flash illumination is dramatically affected by distance. This is known as the inverse square law. Think of it this way: Suppose you’re using a lens that gives you a 4 x 6 ft. field of view at a distance of 10 feet. That same lens will give an 8 x 12 ft. field of view at a distance of 20 feet. So when you double the distance, the same light is covering an area four times larger (96 square feet vs. 24 square feet)! So you need four times as much light to get the same illumination. This phenomenon, sometimes referred to as “flash falloff”, will affect any image with more than one subject at different distances. Whenever your subject distance increases by a factor of roughly 1.4 (the square root of 2), the flash illumination will be cut in half. Suppose you’re taking a large group portrait. The people in the first row are 10 feet away, and the people in the back row are 14 feet away. With on-camera flash as the primary light source, the front row will be a full stop brighter than the back row!

In the image below, each cup is one stop brighter than the one behind it, and one stop darker than the one in front of it. It would take 16 times as much light to properly expose the cup at 11 feet verses the cup at 2.8 feet. Do those distance numbers look familar? They're the same as standard f/ stops for aperture settings, and the relationship is identical. This thread from PhotosGuy gives an example of how to use this relationship in the field.




Flash fact #4: Your camera measures ambient light and flash illumination separately. In Av, Tv or P modes, it will attempt to expose properly for the ambient light by adjusting either the shutter speed, aperture, or both. The fact that you have your flash turned on has no effect on this** ( one exception is that in P mode it will not use a shutter speed slower than 1/60 with flash). The camera’s metering system cannot predict how much illumination will be gained by the flash, so it doesn’t try. In manual mode, the meter in the viewfinder measures only ambient light, because that’s all it has to measure.

Fact 5 refers to any form of automatic flash metering, including older “auto thyristor” flash units, TTL film cameras, and E-TTL or E-TTL II digital cameras.
Flash fact #5: With automatic flash metering, the flash illumination is measured after the shutter button is pressed, and the flash output is adjusted accordingly. There are technical differences between the various types of flash metering, but all of them operate independently from the camera’s metering of ambient light, and all of them work by adjusting the output of the flash, not by changing the camera’s exposure settings.

Facts 6 and 7 apply to any camera with a focal plane shutter (all SLR cameras with a mechanical shutter).
Flash fact #6*: Every SLR camera with a mechanical shutter has a maximum flash sync shutter speed (1/200 or 1/250 on current Canon DSLRs). This has to do with the way focal plane shutters work. At slower shutter speeds, the first curtain opens, the flash fires, and after the specified time duration, the second curtain closes behind it. At shutter speeds faster than flash sync, the second curtain begins to close before the first curtain is completely open. The second curtain follows the first across the frame, exposing only a slice of the image at any given moment. Firing a flash during this process would illuminate only part of the image.

Flash fact #7*: (Applicable to modern electronic cameras only) If you set your shutter speed faster than flash sync, or use Av mode with an aperture setting that requires a shutter speed faster than flash sync for proper exposure, the camera will automatically revert to flash sync speed when the shot is taken if a built-in or hotshoe-mounted flash is turned on. Usually this results in overexposure (unless you have a “safety shift” custom function enabled). If you’re getting overexposed images when using flash outdoors, this is probably the reason. The image is not overexposed because of light from the flash. It’s overexposed from ambient light because the shutter speed was too slow. If you’re using flash for fill in bright situations, it’s necessary to stop down the aperture or lower the ISO setting to get the shutter speed below flash sync.

* The exception to facts 2, 6 and 7 is FP Flash, sometimes referred to as “high-speed sync.” That topic is covered in Chapter 4.
**With some Canon cameras there is a poorly-documented phenomenon called NEVEC (negative evaluative exposure compensation) which will adjust the ambient exposure by up to a full stop when the flash is turned on, but that’s also a topic for another chapter.
 

Perrinho

ClioSport Club Member
Thanks for the response...just founf that guide and im reading it now...it is very detailed though...

I wont be able to bounce the flash really as the ceilings are very high...

How high an ISO setting do you recommend? I dont really fancy using too high a setting as i dont want noisy photos...

Also, do you recommend using shutter priority?
 
  1.2 Dynamique billabong
yes mate you will need to use shutter speed priority or full manual mode because if you put the shutter speed up higher than the flash sync speed the flash wont have fully fired before the image is captured depending on your camera it is normally 1/200 or 1/250 which is the fastest you can go
 
High ISO isn't necessarily the problem you think it is, providing that you get a good exposure.

I've played about with my 40D and 430EX II, shooting in manual mode, exposing for the ambient light less approx. 1 stop and then letting the flash and E-TTL do it job. Notably you can also risk a slower shutter speed than normal since the flash will help freeze the subject and therefore any minor movement will be masked.

Try a few test shots in manual, messing primarily with the ISO and aperture settings and then just using the shutter speed to get to the ambient light minus 1 stop. Notably shutter speed has no impact on flash exposure.
 

Ian

  Focus TDCi
I can't help with the flash settings, but what I will say is don't be afraid to use higher ISO settings. If I need to use ISO1600 on my 450d then I will and, unless a heavy crop is needed, the image is perfectly usable. Frame your shots well and high ISO isn't a problem.

OT, whereabouts in Manchester are you from pal?
 

Ian

  Focus TDCi
Ashton-under-lyne...

Think ill have a play at lunch then, cheers for the advice...:cool:

Wrong side of Manchester :( Lol. If you ever want to meet up/try a lens I wouldn't mind, everyone else seems to be darnn Sarff.
 

Ian

  Focus TDCi
Aye near enough, I'm within a few miles of the Trafford Centre. Canon 450d, 18-55mm IS (kit), 50mm f/1.8 and 70-200mm f/4 L USM. Hopefully be getting either 50mm f/1.4 or 85mm f/1.8 in December too. If you're going to the next meet I'll probably be there anyway. :)
 

Perrinho

ClioSport Club Member
I have the 40d (sold the 450d to get it) with 18-55mm IS (kit), 50mm f/1.8 and 70-200mm f/4 L USM...my 17-85mm IS lens has just broke, so i need to replace that with a decent walkaround lens...

What is the next meet?
 

Ian

  Focus TDCi
I have the 40d (sold the 450d to get it) with 18-55mm IS (kit), 50mm f/1.8 and 70-200mm f/4 L USM...my 17-85mm IS lens has just broke, so i need to replace that with a decent walkaround lens...

What is the next meet?

Hmm appears our equipment overlaps somewhat lol. They've not decided where the next meet is going to be, but it's either near the Trafford Centre, or in Warrington at the end of the month. Thread here.
 


Top