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02-13-2011, 12:02 PM   #1
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Sigma flash problems

My wife and I had a game night last night to celebrate her birthday. I was running around like a bandit taking pictures of everyone. One thing I noticed was my pictures were turning out way over exposed. (see first few examples) I tried adjusting the settings on the flash to take it down 1 ev, that didnt work. I set on the camera to take the flash down 1 ev, that didnt fix it. I adjusted all kinds of other settings (Shutter speed, aperture, ISO etc..), and I never could find that constant "sweet spot" I would take the same picture 2 or 3 times before it had the right flash output. I tried shooting in X, Manual, and even "green" (Pentax K20) all had the same issue. Is there something I am doing wrong? or should I just keep practicing?

Examples....








Also, my other problem is that several pictures were turning out with a big black line across the bottom/side. It was just happening at random, I deleted most of them before I thought about submitting the problem to the experts here, but I do have one example.
(excuse the swirl edit. Someone was giving the salute)


All the pictures taken were with a Pentax K20, Sigma 530 Super, and a StoFen omni bounce. Most of them were bounced off the ceiling as well, not directly aimed... and most were with the 10-20mm (small house, need the exta wiggle room)

My apologies for the pictures, sometimes even grown adults act like children... hehe.

Thanks all

EDIT:
Found some more of the "black line"






Last edited by SlickYamaha; 02-13-2011 at 12:27 PM.
02-13-2011, 12:53 PM   #2
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were you using a diffuser? and was the flash pointed directly at the people? I have the same flash, but usually I try to point it at the ceiling to have the light bounce back to the subjects instead.

Never seen the black line before...but possibly your 10-20mm is too wide for the flash? Were all the black line ones 10mm?
02-13-2011, 01:06 PM   #3
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QuoteOriginally posted by hawk1500 Quote
were you using a diffuser? and was the flash pointed directly at the people? I have the same flash, but usually I try to point it at the ceiling to have the light bounce back to the subjects instead.

Never seen the black line before...but possibly your 10-20mm is too wide for the flash? Were all the black line ones 10mm?
Yes, the omni bounce was on all night, 99% of the time it was pointed at a 60 or 75 degree angle. and the 10-24 was on almost all night, with only a handful of the pictures having this line.

Just now tested at 10mm... no issues...
At first with the vertical shot, i thought that it may have been the camera strap in front of the lens, but there is no way the camera strap could go horizontal...
02-13-2011, 01:52 PM   #4
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hmmm, you'll have to wait for advice from the experts then...sorry. =)

edit: oh, sorry, just saw the blurp you wrote in between the pictures where you basically answered all of my questions already.

02-13-2011, 03:42 PM   #5
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I don't have any experience with the lens or the flash but...

1. It Looks like your flash was firing full power, with the camera thinking you have a non A type lens.

2. The black line has a curve to it suggesting a hood or something like that may have been blocking the light. I know you said you were bouncing the flash but even when bouncing, with a diffuser light will travel past the front of the camera.

Probably not a cure but it may give some ideas of what to look at.

02-18-2011, 12:22 AM   #6
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For the black-bar at the bottom see this video link below. Looks like you have a Problem with Sync speed. I hope this video helps, If not I tried .

02-18-2011, 06:03 AM   #7
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I beg to differ with some of the opinions expressed before.

The black area means that some of the light from the flash did not reach your subject. You said you aimed the flash at around 70 degrees tilt. When subjects are close, shoot the flash strait up instead to avoid this.

Even with a diffuser, most flashes will not cover the field of view of a lens wider than 17 mm. By bouncing the flash strait up you will mitigate this problem.

Adjusting the aperture of shutter speed will not help with a flash. You need to modify the exposure compensation if your images turn out too bright or dark. (clarification: it will work in manual mode, but in that case your flash will fire at a fixed power ratio).

Make a few tests by experimenting with the angle of your flash head and with EV compensation. You'll get the knack of it.
02-19-2011, 12:19 AM   #8
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OP did express that most of the flash was bounced off the ceiling.

I have the same Sigma 530 Super, but shot with the flash off camera, wireless. The flash would be bounce flash off of ceilings or walls, and test shot would be made. I have had best results that way, rather than attach directly to the hotshoe of camera.

02-19-2011, 12:44 AM   #9
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Strange, I was examining your photos EXIF's and found that the images you posted with black bars at bottom was fired with the Sigma and the rest of the images that were over exposed (no black bars) seem to be fired with the pop up flash?
02-19-2011, 07:12 AM   #10
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That is strange, I never looked at the exifs. 100% of the pics were fired with the sigma or no flash at all. I never use the pop up since getting the sigma.

I did however do some testing and think I figured out the problem. It seems when I don't tighten the flash quite tight enough that it does the black bar thing. Its almost as if the front pin wouldn't make a connection. Not sure how that would produce a black bar though..

QuoteOriginally posted by pixelKore Quote
Strange, I was examining your photos EXIF's and found that the images you posted with black bars at bottom was fired with the Sigma and the rest of the images that were over exposed (no black bars) seem to be fired with the pop up flash?
02-19-2011, 09:48 AM   #11
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QuoteOriginally posted by SlickYamaha Quote
That is strange, I never looked at the exifs. 100% of the pics were fired with the sigma or no flash at all. I never use the pop up since getting the sigma.

I did however do some testing and think I figured out the problem. It seems when I don't tighten the flash quite tight enough that it does the black bar thing. Its almost as if the front pin wouldn't make a connection. Not sure how that would produce a black bar though..




How tight does the flash fit on the shoe? Could it be tipping?

02-19-2011, 10:10 AM   #12
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QuoteOriginally posted by JeffJS Quote
How tight does the flash fit on the shoe? Could it be tipping?

After doing some testing, i think it may have tipped just far enough to not make a firm connection. but how would that cause teh black bar?
02-19-2011, 10:24 AM   #13
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Glad you figure it out. If you like try shooting with a off camera set-up indoors, with a wireless trigger if you have one. I usually find in a tight confine space it is difficult to bounce with on camera hotshoe.

The only time I ever shot with the the flash on the the hotshoe is usually with some type of newspaper/magizine reporting look, if that make any sense. Or in a setup where are to many people around and no way to place a off cam setup. Paparazzi.
02-19-2011, 11:38 PM   #14
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The 530 Super sometimes has a problem with timing when you have the cam on max sync speed. With my cameras (K20 and K7) it seems to be fine on the hotshoe and wireless but if I use my Cactus triggers I'll get the black bar 100% of the time at 1/180 and 80% of the time at 1/160. At 1/125 and slower its fine. Now, for me, its only when I use wireless triggers. Any other way and its fine at max sync. It may just be the design flaw of the Sigma because my other flashes (Af360, AF540, Metz 48 & 58) are fine at any speed.
I concur with JeffJS' assumption that maybe the lens wasn't on the A setting. I have that same lens and I know it has an aperture ring. The flash fires full power when it thinks you have a manual lens. Changing Ev settings are useless because it won't change anything since it doesnt know what F stop youre at. BTW, did you see "F--" on your LCD? Thats the dead giveaway that youre not on "A"
Also, did you have your cam on TAv? Avoid that with flash because it makes your exposure settings with the assumption of just using ambient light. A flash will give you "supernova" pictures.
Also, you say it was in a small room. The Sigma is a strong bright flash. I can't be closer than 1.5ft away from a subject to ensure it wont overexpose it. And in all honesty, the Sto-fen isnt much of a diffuser, you may be better off just bouncing off the ceiling. You'll get a better spread of light, just make sure the ceiling's white or youll get a color cast.
I hope at least some of this helps, and that nobody got hurt playing Twister. :-)
02-21-2011, 01:29 AM   #15
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The black bar may have several causes:

- synch speed problem, happened sometimes at 1/180 sec, even 1/160, and especially with radio triggers. Don't worry about 1/125, the flash burst will freeze the movements, unless you want more ambient light.

- bouncing direction of flash. I m not using diffuser, just bounce straight up or a bit backward/reverse. A bit tip forward with the widest flash focal will 'polute' the picture.

- Rule of light fall off. The distance to the floor is too far away relatively to the faces. You have correct face exp but light drop to 1/4 by reaching the lower part of the frame. Typical when the ceiling is relatively low and the photographer is tall. Try to get a bit lower eg. on your knees. For a large group using flash, this rule is the first I consider.

As jboyde said, this is a good flash in small/medium room generally, but bouncing have to count in. A white matte surface: reduce 2 steps, you got 1/4. Light gray/beige wall/ceiling can easily reduce to 1/8 of original beam. Closer distance stronger light but less even.

Hope this helps.
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