Toilet paper diffuser

[AaronBBrown]

Originally Posted by baldmountain

I'm not sure I agree. An on camera flash has a mirrored parabolic reflector that blasts all light straight out the front of the flash in a tight beam. The TP is white so some of the light will reflect around inside the flash before exiting and also be diffused going through the paper. I don't imply that it is an ideal solution, but will do in a pinch and is far better than the normal harsh flash.

Light is light. All that matters to the subject is the intensity, direction, and apparent size of the light source. Covering the light source with TP does nothing but decrease the intensity. It might *very* slightly increase the apparent size, but it is by such a fractional amount that it is unrecognizable in a photo.

Diffusers soften shadows by increasing the apparent size of the light source. Toilet paper does not accomplish this. Try it for yourself for the proof - take a picture with TP over the thing. Now bring your flash down a 1/2 stop or so and take a picture with the same f/stop/shutter/ISO without the TP...I can't tell the difference except for the white balance being slightly different.

Part of what makes the portrait of your son appear "softer" is that it is quite a bit underexposed. I'm not entirely certain how Nikon's built-in flash exposure works, but the TP probably fooled the internal light meter in the camera somehow. There is no doubt thatthe same exact effect can be had by manually adjusting the flash exposure compensation....and your batteries will last longer.

I did determine that I drastically need a shave and a haircut, though!

To better understand this, I'd suggest going thru Lighting 101 and Lighting 102 at http://strobist.blogspot.com.

What seems to confuse matters is that people call the Stofen Omni-Bounce a "diffuser" -- it is not a diffuser - it just directs some of the light that would be going straight in a different direction, thus using walls and ceilings as diffusion sources. Because of this, the Stofen Omni-bounce is totally useless outdoors or even in large rooms.

I'd agree that the film canister would be better, but being digital it has been ages since I've seen a film canister.

Heh, yeah, when I did the light canister mod, I had to actually go out and buy a roll of film!

[AaronBBrown]

Because I was really curious about this, I decided to do an experiment:

One of these shots is with a TP over the flash head, one is not. I had to do this with an external flash because even in manual mode, it appears that my Canon DSLR automatically adjusts the built-in flash

I found that a piece of TP was worth about 3.3 stops of light. Because my flash is only adjustable in 1 stop increments, I had to adjust the f-stop slightly to get similar exposures. I white balanced both techniques separately. I shot off camera at a 30 degree angle in order to show shadow edges.




No editing was done except for a crop and a very slight raising of the exposure on one shot to get them even closer together in overall exposure.

Settings were
ISO 200
1/200"
30mm

With TP:
f/8
Flash at 1/16 power, 24mm

Without:
f/9
Flash at 1/2 power, 24mm

The flash was approximately 3 feet from the subject, 30 degrees to camera right

What I did notice, which is expected on an external flash especially, is that the paper acted to increase the area of coverage slightly, but did not alter the softness of the light much at all - were the flash moved back even more, the edges would become indecipherable between the two.

[sk66]

Hmm, guess I can remove the TP from my Nikon's built in flash and just set it lower...
I always have a couple layers of TP on my built in flashes because I HATE the harshness of them bare. I'll be leaving it on my P.S. since it doesn't have fstop or flash comp adjustments.
I might mess with adjusting the exposure comp with fill flash on it, but I don't expect much.

[baldmountain]

Well I consider myself corrected and chastised for spreading falsities about flash photography. Thanks for setting me straight and teaching me something new!

[AaronBBrown]

Originally Posted by baldmountain

Well I consider myself corrected and chastised for spreading falsities about flash photography. Thanks for setting me straight and teaching me something new!

I'm sorry if it came across as chastising - that wasn't the intent. It's always worth trying something new!

[prince]

Thanks AaronBBrown and baldmountain, this discussion has been very informative. I took the pleasure of adding tags. If someone else can add few more that would help others.

[baldmountain]

Originally Posted by AaronBBrown

I'm sorry if it came across as chastising - that wasn't the intent. It's always worth trying something new!

No troubles. Too often I lecture like a know it all and need to be set straight. It happens often enough that I don't mind anymore. Looks like it is finally time to pick up that copy of "Light Science and Magic".

[sftl99]

This whole thing got me curious. A while back I had a point and shoot that had a terrible harsh flash (and no custom settings at all). I took some white Scotch tape (white = the cloudy but still clear kind) and put it over the flash and it seemed to improve the pictures quite a bit. After reading the technical jargon here it seems that I probably wasn't doing anything but bringing down the intensity and perhaps changing the white balance a bit. I guess my thought at the time was that the cloudy transparency might kill the harshness of the light, but now I really have no idea what was actually happening. What do you think?

[sk66]

Originally Posted by sftl99

This whole thing got me curious. A while back I had a point and shoot that had a terrible harsh flash (and no custom settings at all). I took some white Scotch tape (white = the cloudy but still clear kind) and put it over the flash and it seemed to improve the pictures quite a bit. After reading the technical jargon here it seems that I probably wasn't doing anything but bringing down the intensity and perhaps changing the white balance a bit. I guess my thought at the time was that the cloudy transparency might kill the harshness of the light, but now I really have no idea what was actually happening. What do you think?

What I got is that since there is really no "extra room" for the light to disperse/redirect before "leaving the flash" the result is really just a reduction in light from the flash...and that makes sense. That said, I'm still using this technique on my PS since it doesn't have flash adjustments....

[JRGould]

I'll echo what some of the strobists have been saying here: ditch the tp, it's just wearing out your battery and increasing your risk of spontaneous combustion, instead think about the relative size of your light source to the subject. The film canister thing is pretty good, makes the light a bit bigger, but also mimics a "bare bulb" sending light around the room somewhat evenly - another trick I used to use was just to grab a white business card, fold 2 of the corners down on one of the short sides, slip that under the pop up flash, and then fold the card up so that it is in front of the flash - I only use this indoors, basically it bounces the flash up and back, using the walls and ceiling as your diffuser whilst still giving a bit of fill as long as you're using white cards that aren't very thick.

here's some pics to explain:
http://jrgould.com/uploads/8389afc43...142aa5d9ac.jpg
http://jrgould.com/uploads/b3024eb5a...66c822b15d.jpg
http://jrgould.com/uploads/5e1dbea31...e72e2aaa75.jpg