C&C for a newbie please...

[danpak]

This discussion is a contiuation of this thread...
http://www.photocamel.com/forum/ligh...pear-tree.html

At any rate, I had a chance to test out my set up before the real shoot in about two weeks. The following are the set up and the results - at the expense of my brother-in-laws family. (Now, the equipment in the set up is all I have - with the exception of a small ubmrella I can attach to my SB600 flash) I will eventually do more with the images (level, touch-up, background etc.) in photoshop but just wanted to get your feedback without too much post-processing.

I know there are things I could do to improve this with what I have. Your candid feedback is greatly appreciated. One thing that was frustrating for me was that the pictures were underexposed for the reasons I did not know. I was forced to shoot at ISO 400.

Thanks in advance for your feedback!

[WayneF]

Originally Posted by danpak

One thing that was frustrating for me was that the pictures were underexposed for the reasons I did not know. I was forced to shoot at ISO 400.

I thought the result was a very good picture. A second fill flash at half of key power, just left of camera lens, could help remove the shadow of boys heads on chests, and under necks, but still a fine photo.

I didn't understand about the SB-600 on the floor, since I didn't see any evidence of it on the background or on the mans pants leg? Other than some some odd shadow back there? Are you sure it was firing?

About the underexposure, how far was the key light from the subject?

The flash distance is from the flash to the umbrella fabric and back to subject. Making up all the rest, but the umbrella shaft is probably about 2 feet, round trip on the shaft 4 feet, and if light stand pole to subject were say 6 feet, that is 10 feet total trip that affects the light from the flash.

GN of SB-800 at 24 mm zoom is 98 ISO 100, or 2x at ISO 400, which is GN 196. (24 mm width spec is 78x60 degrees, needed to fill the umbrella).

So GN 196 / 10 feet computes f19. There is a good stop loss at the fabric reflection, so maybe roughly f11, but still a couple of stops more than f5.6. Lower ISO should have done it too.

I assume you were in CLS TTL mode, due to using the SB-600.

[WayneF]

Oops. Very sorry, the SB-600 confused me into assuming B800 said SB-800, which of course, I realize now it doesnt. Please forget all of that. Always embarrassing to go down the wrong trail.

The B800 meters two stops stronger than the SB-800 that I computed (both at full power), so yes, it is very strange. What power level on B800? Depending on all the small details like distance, 1/4 power ought to give over f/16 at ISO 400.

[danpak]

Originally Posted by WayneF

I thought the result was a very good picture. A second fill flash at half of key power, just left of camera lens, could help remove the shadow of boys heads on chests, and under necks, but still a fine photo.

I didn't understand about the SB-600 on the floor, since I didn't see any evidence of it on the background or on the mans pants leg? Other than some some odd shadow back there? Are you sure it was firing?

All I have is the AB800 strobe and the SB600 flash. And the SB600 flash was sitting on the ground, filling the background.

Originally Posted by WayneF

About the underexposure, how far was the key light from the subject?

The key light was only about 3-4 feet away. This mystified me. I had to put it at the full power and get the ISO up to 400 in order to get the right exposure. I was firing the AB800 using my off-shoe SB600 flash on the background. And I was at manual setting on my camera for the aperture and the shutter.

[WayneF]

Originally Posted by danpak

All I have is the AB800 strobe and the SB600 flash. And the SB600 flash was sitting on the ground, filling the background.

The key light was only about 3-4 feet away. This mystified me. I had to put it at the full power and get the ISO up to 400 in order to get the right exposure. I was firing the AB800 using my off-shoe SB600 flash on the background. And I was at manual setting on my camera for the aperture and the shutter.

The picture really doesn't show any evidence of light from the SB-600 back there on the floor. Should be visible to the photographer, or there wasnt much point. The background would be much brighter in that corner, closer to the light, and no effect at far corner, away from it.

How did you trigger the SB-600? It has no PC connector, so were you using chained SC-17 cords to trigger it? Or a third party flashshoe/PC cord adapter? Was the SB-600 in its Manual flash mode? I think the SB-600 was the problem. It is not built to do this job.

I'm also fearing there was a CLS preflash involved, triggering the B800 early, so that most of its light peak was over with by the time the shutter opened. I cannot explain why yet, wouldnt assume it in manual flash mode, but full power from B800 at 4 feet should have knocked your subject down. Closer to f/32 for sure.

I would suggest setting up the lights again, the test not needing subjects or background or reflector boards, just the lights. A wooden chair with a vase or kids teddy bear on it, anything, in front of a wall is adequate test subject for this. Use only the B800 by itself first. Trigger the B800 directly with its sync cord. 1/4 power will surely be too much for f16 at 4 feet. Get that resolved first. This is how it should work.

The SB-600 doesnt have any manual capability to work with studio lights. The SB-800 does, and then some. The only way I know to use the SB-600 with studio lights is with a third party shoe adapter with an optical trigger in it, to trigger the SB-600 in manual mode from the B800 light. Or there are third party shoe adapters fitting a PC cord to it too. But the SB-600 surely must be the source of this problem.

Your camera should be in M manual mode, with shutter speed not faster than the cameras sync speed - cameras vary, but like maybe 1/200 second. Then set aperture to get the right exposure from the light present.

Still a good picture, I dont meant to knock the picture at all, but the procedure isnt right if you get no light from either flash.

[danpak]

Originally Posted by WayneF

The picture really doesn't show any evidence of light from the SB-600 back there on the floor. Should be visible to the photographer, or there wasnt much point. The background would be much brighter in that corner, closer to the light, and no effect at far corner, away from it.

How did you trigger the SB-600? It has no PC connector, so were you using chained SC-17 cords to trigger it? Or a third party flashshoe/PC cord adapter? Was the SB-600 in its Manual flash mode? I think the SB-600 was the problem. It is not built to do this job.

I'm also fearing there was a CLS preflash involved, triggering the B800 early, so that most of its light peak was over with by the time the shutter opened. I cannot explain why yet, wouldnt assume it in manual flash mode, but full power from B800 at 4 feet should have knocked your subject down. Closer to f/32 for sure.

I would suggest setting up the lights again, the test not needing subjects or background or reflector boards, just the lights. A wooden chair with a vase or kids teddy bear on it, anything, in front of a wall is adequate test subject for this. Use only the B800 by itself first. Trigger the B800 directly with its sync cord. 1/4 power will surely be too much for f16 at 4 feet. Get that resolved first. This is how it should work.

The SB-600 doesnt have any manual capability to work with studio lights. The SB-800 does, and then some. The only way I know to use the SB-600 with studio lights is with a third party shoe adapter with an optical trigger in it, to trigger the SB-600 in manual mode from the B800 light. Or there are third party shoe adapters fitting a PC cord to it too. But the SB-600 surely must be the source of this problem.

Your camera should be in M manual mode, with shutter speed not faster than the cameras sync speed - cameras vary, but like maybe 1/200 second. Then set aperture to get the right exposure from the light present.

Still a good picture, I dont meant to knock the picture at all, but the procedure isnt right if you get no light from either flash.

I triggered the AB800 using the built-in optical trigger - sb600 fires AB800. I used the "lengthened" SC-28 from my camera to sb600.

I think you are right. I don't think the sb600 was effective. I think this is because I did not have it at manual mode - duh This is why I don't see any trace of the flash on the background.

Also, you may be right that the pre-flash is triggering the AB800 prematurily - although I have my camera set at the manual mode. Maybe the flash and the camera both should be in manual mode.

This studio lighting thing is not easy...

I thank this forum and people like you for taking the time to give me feedback. I will test the AB800 this week. I did think it was wierd that AB800 4 feet away was not enough...

Thanks!

[WayneF]

Originally Posted by danpak

I triggered the AB800 using the built-in optical trigger - sb600 fires AB800. I used the "lengthened" SC-28 from my camera to sb600.

I think you are right. I don't think the sb600 was effective. I think this is because I did not have it at manual mode - duh This is why I don't see any trace of the flash on the background.

Also, you may be right that the pre-flash is triggering the AB800 prematurily - although I have my camera set at the manual mode. Maybe the flash and the camera both should be in manual mode.

Yes, I'd bet this was the entire issue if the SB-600 was not in Manual mode.

The SB-600 manual page 26 says you WILL get preflash except in Manual flash mode. And any preflash will trigger the B800 early, so it will be virtually finished and done before the shutter ever opens. The only surprise was that the B800 had a percent or two still left then. Its light will be less red and more white then too, if you use more than just the weak tail of it.

I think that fully explains the exposure problem. The B800 simply didnt have any light left when the shutter finally opened. However even if you had to use ISO 400 and f/5.6 and full power, it was enough for a decent picture, but just was not the easiest way to do it.

The lengthened SC-28 cord sounds just right, your only way to use the SB-600 for this. It ought to work well that way, triggering the B800 too, but it will have to be in Manual mode to prevent the preflash which triggers the B800 too early. Maybe start with SB-600 at 1/4 power Manual and adjust a step either way as needed in results, to brighten the background more or less. White backgrounds can use a stop or two more light than other colors. You can make it bright white, but dont overdo it to where its excessive reflection lights up the subjects too. Use more spacing back there if you need it bright.

Then I bet you see a huge change from both lights. Maybe ISO 100 at f/8 with B800 at 1/4 power if it is not too far (very approximate, but not far from ballpark). Should see a tremendous difference, a whole new world. And should see some effect of the background light too. That lower left corner of background will get bright white, as you showed it.

If you want to light the background more evenly, just put the SB-600 in the center, behind the subjects, close to them, hidden by the subjects, up behind their chest if you have a stand for it, pointed up slightly towards the central area behind their heads. Chest is close to head, but wide to hide it. If lower and pointed up a lot, you will see a strong gradient, to dim gray towards the top because that is far from the light (which might be a goal). SB-600 24mm zoom setting for the width, and you will need maybe 6 feet of room back there for this (for the width of the group - 4 feet works for head/shoulders of one person).

Its flash will still trigger the B800 from there, no problem at all.

[danpak]

Yes, It was the flash - not being in manual mode. Did a quick test to confirm. After all this, I do feel a little more confident than when I first started... Thanks!

[Uncle Frank]

Originally Posted by danpak

Yes, It was the flash - not being in manual mode. Did a quick test to confirm. After all this, I do feel a little more confident than when I first started... Thanks!

Glad you worked it out, Dan. I'd like to see your result after getting the sb600's output included, but I'm guessing it won't contribute enough light to represent the background properly. Gray isn't too complementary to the subjects, but it's easy enough to adjust in Photoshop afterwards. I hope you don't mind me using your picture for this example, and will remove it as soon as you've had a chance to check it out.

Btw, while I was at it, I removed the yellow cast from throughout the frame.

[WayneF]

Originally Posted by Uncle Frank

Glad you worked it out, Dan. I'd like to see your result after getting the sb600's output included, but I'm guessing it won't contribute enough light to represent the background properly. Gray isn't too complementary to the subjects, but it's easy enough to adjust in Photoshop afterwards.

I'd like to see it too, but I'm thinking the Nikon speedlight should do it. If it is centered. May be close however if it is an ISO 100 camera.

I use a SB-800 for background all the time, typically about 1/4 power at 5 feet for f/10 camera exposure, on colored backgrounds, for a one person 1/2 length frame. That is ISO 200, it would be 1/2 power at ISO 100. The SB-800 is nearly a stop stronger at the long end, but they are more equal at the wide end for this... GN 85 instead of GN 98 at 24mm, which is only about 0.1 stop difference.

White backgrounds do need one or two stops more light, to insure bright white instead of gray, but the SB-600 should about do it. Its GN85 should meter f/17 at 5 feet, which with its 78x60 degree coverage at 24mm, should cover 7 feet width back there, and still be a stop stronger than a camera at f/11. Or two stops more if the AB B800 is turned down further to say f/8, which effectively makes the white background two stops brighter than camera, and should be plenty.

That is all assuming ISO 100. But if it is a ISO 200 camera, then all the better. GN is 1.4x greater, or one stop greater, at ISO 200.

And of course the light closer than 5 feet works wonders, but 24mm may not be wide enough then for multiple people, to avoid a falloff at the edges. Which is not always bad.