[Zafar Iqbal]

Can someone explain what's going on in these photos?

1.


2.


3.


The photos are more or less SOOC.

I shot using K-30 on manual and YN-560 always at a fixed power output.

I get the obvious light falloff in portrait mode a tad too often. It seems as if the YN-560 might be spreading light sideways more - so, when I tilt the camera for portrait format, the flash, now resting sideways in relation to the subject, might be casting a bit too much in the forward direction.

Other than that the flash was always rotated so it was pointed straight up for the ceiling.

#1 shows the rapid light falloff.
#2. Does not - I don't understand what I did differently.
#3. Landscape, just for reference.

I get this rapid fall off in portrait mode many times - #2 photo is a rare exception tbh.

I noticed this the first time about 2 months ago - I was photographing in a large room. the ceiling was higher and walls were further away. I'd get the same thing while taking pictures in the middle of the hall - but not always.

Ps. I don't have anything attached to the flash.

[SOldBear]

Note that when you bounce, light fall-off depends largely on where the light hits and reflects from (the particular spot(s) on the ceiling in this case). In (1), it looks like this spot is closer to the wall than in (2). The camera tilt angles in (1) and (2) may be different.

The light travels from the flash (attached to the camera, I assume), to the ceiling, and to the scene. If you sketch the light paths, you'll see that in (1), the difference between the path to the top of the photo and the path to the bottom of the photo is much larger than that in (2).

[joe.penn]

It could also be a CB issue (in the case of these pictures). Was there any ambient light in the scene? Also, what was your shutter speed on these?

To overcome ambient light, shutter speed should be on the faster side while the flash power should be set to higher power. [Assuming there was ambient light] -> If you gel'd the flash to match the ambient lighting, then shutter speed wouldn't come into play.

[joe.penn]

To add to this, @SOldBear is right about the bouncing (angle, etc.) - it sounds like you were trying to flash for fill, if that's the case to properly do it in that environment is a little tricky with the subjects that close to the background. Again, gel'ing to match the ambient lights would allow for you to do a simple color balance in post and the whole scene would have matched, then a little work to curves would have fixed the lower halves and (or) left/right of the scene.

[Zafar Iqbal]

Those were my first thoughts as well and you might be correct.

This is a test shot from when I was re-adjusting my settings:


You can see a gap along the sides of the ceiling. Same gap was present by the wall furthest away, which is the wall I shot up against. The gap might have been as wide but I remember it as being a tad narrower. I was conscious about it, though I did move slightly back and forth a bit, and as you said, tilted the camera.

The ceiling is so high in the gap part that I didn't think it would affect too much - even though I know the lowered part of the ceiling is darker, which is what the flash was set for.

The guests shot camera was set to a fixed setting @ 1/50, ISO 1600 and f5.6 while the flash was at full or half power output. If this helps to nail down your previous conclusion then fine - I'll take it. If not, then I'd love further input of what may have been going on.

Ps. Super nice lighting to shoot in - not :P

[Zafar Iqbal]

Joe, your posts crossed mine

The lighting you see in the latest photo is pretty much all there was, and as you can see, the wall is very evenly lit. theres some coming from the enstrace, but that didnøt affect my exposures at all.

the colorcast you saw earlier, and as you might have guested by now, is caused by the ceiling.

[maxfield_photo]

I suspect you've had a run in with our old friend (or foe, depending on how you see it) the inverse square law.

Imagine, for simplicity's sake, that you shot two photos in two different room. Both rooms are white and have white ceilings. In room 'A' the ceiling is 4 meters tall, and in room 'B' the ceiling is 6 meters tall. You have the flash mounted on the hotshoe in both situations pointed up, regardless of whether the camera is in landscape or portrait orientation. In both shots your subjects, roughly 2 meters tall, are the same distance from you, let's say 4 meters. Get the picture? The only difference is the ceiling height. Although the light is being emitted from your flash gun, basicly we can think of the ceiling as being the light source.

So in room 'A', the light travels from the halfway point on the ceiling between you and your subject, and hits your subject's face, with an intensity of, I don't know, f/5.6. If you do the math, you can figure out that the distance from the point on the ceiling to your subject's face is about 2.8 meters, but that means that the distance to their feet is about 4.5 meters. So the inverse square law tells us that light will fall off by a factor of four when we double the distance, meaning that your subject's feet will be about a stop and a half darker if you expose correctly for their face.

Now in room 'B' with 6 meter ceilings, we'll again assume that you want to expose properly for your subject's face. The distance from the point on the ceiling from where the light is being reflected to your subject's face is about 4.5 meters, and the distance to his feet is 6.3 meters. So in this example, your subject's feet are 1.4 times further from the point on the ceiling (6.3/4.5) resulting in only a 1 stop underexposure. The taller the ceilings the closer in brightness your subjects head and feet will be.

So what's the solution? Well unfortunately light behaves the way it wants to, there's not much we can do about it. You can A) learn to live with it, B) get a light modifier that sends some of the light towards your subject like a Sto-fen, a GF Lightsphere, or a Lumiquest 80/20, or C) add a second flash to your setup, or use something like the Metz 58 that has a secondary reflector that always points towards your subject. Oh, and there's D) shoot in a room with taller ceilings, but sometimes we don't have that luxury.

[amoringello]

What mode are you shooting in? Manual, Av, Tv, P modes? If you are leaving the camera to adjust its own settings (not in Manual mode), any movement of yourself, the camera or the subjects may affect total tonal/brightness of the scene and affect the resulting metering. I.e. the camera may be increasing exposure when three people wearing black are in the photo and reducing exposure when more of the white background is visible with only one or two people wearing black. To my eyes, the first image has about 50% black. The second and third much less than that.

The celling is also multi colored. If your flash centered on a white v.s. blue v.s. orange stripe by only a slight variation in camera or flash angle, it will affect the color balance and brightness. That exact issue may not affect other shooting locations, but flash angle is also going to have more of an effect when bouncing because of the further distances to travel.

You are playing with a LOT of variables. Without actually seeing a third-person point of view of exactly what was happening at the time it may be difficult to truly diagnose the exact cause.
Light fall off, angle, surroundings, subject matter... they all have a potential to affect the end result.

[amoringello]

er, um, oh, sorry... looks like I missed where you mentioned settings were fixed. Throws out most of my theory.

Another question, is the YN-560 output stable/consistent?
It sounds like a decent flash for the money, but it may be worth doing some controlled test shots (stable environment, on a tripod, etc...) to make sure it isn't actually causing the problem.
My Pentax PTTL flashes will not always fire consistently at all apertures. And not always 100% consistent with the same settings. But usually not very far off.
Although I've had test shots be more than 1/2 stop off at times.

[Zafar Iqbal]

I suspect you've had a run in with our old friend (or foe, depending on how you see it) the inverse square law.

I do think your point makes sense and even though I "understand" the inverse-square law, I didn't expect it to have such an impact. This could be because I have limited experience with flashes and also because it didn't feel like I moved that much between shots.

I haven't done too many tests since I started this thread but I do not think the light is being spread in an odd pattern. The light fall thing must be what has been going on - I need to experience it again, and then try to work with it to better understand it.

Another question, is the YN-560 output stable/consistent?
It sounds like a decent flash for the money, but it may be worth doing some controlled test shots (stable environment, on a tripod, etc...) to make sure it isn't actually causing the problem.

the amount of shits with flash, and the YN-560 on top of that, is relatively ery low compared to none flash exposures. But it¨'s still a great enough number, and diverse enough usage that I do not think that is the problem. I've plenty of times had the camera of a tripod while also using a single or more flashes and never experienced output consistency issues - even when I later look though the photos, I might have trouble telling the YN apart from the Metz as they are very close in output capabilities.

[maxfield_photo]

I do think your point makes sense and even though I "understand" the inverse-square law, I didn't expect it to have such an impact. This could be because I have limited experience with flashes and also because it didn't feel like I moved that much between shots.
I haven't done too many tests since I started this thread but I do not think the light is being spread in an odd pattern. The light fall thing must be what has been going on - I need to experience it again, and then try to work with it to better understand it.

I'm with you, although I understand in theory exactly how it works, coming to terms with the ramifications of it can sometimes be a humbling thing. Another closely related variable that could be affecting the shots is the angle of elevation of your lens, assuming you have the flash on the hotshoe. If you tip the camera forward just a few degrees for instance, it would change the location of the bounce on the ceiling, moving it closer to your subjects, and thereby increasing the rate of falloff.