Dark backgrounds when using high speed sync w Tv mode on rebel (550EX)

suemccartin · #1 11-24-2004, 08:53 AM

Hi all
I've shot a number of pictures using my 380EX speedlight and my 550EX speedlight. I shoot heavy action (karate demo) so I need to keep the shutter speed up for better pictures.

Using both these flash units in Tv mode I get decently lighted subjects but really dark backgrounds (Rebel body). With the 550EX I have high speed sync available and it happens with that too. Any thoughts on why this is happening? I get better backgrounds with full program mode but the shutter speeds are too slow, haven't tried program mode yet, think that might work better? I just find it strange that full program has decently exposed backgrounds while Tv mode doesn't. I suppose the camera in program mode is boosting up the ISO speeds or somesuch like that.

LoveOfSelene · #2 11-24-2004, 12:17 PM

Quote:

Originally Posted by suemccartin

Hi all
I've shot a number of pictures using my 380EX speedlight and my 550EX speedlight. I shoot heavy action (karate demo) so I need to keep the shutter speed up for better pictures.

Using both these flash units in Tv mode I get decently lighted subjects but really dark backgrounds (Rebel body). With the 550EX I have high speed sync available and it happens with that too. Any thoughts on why this is happening? I get better backgrounds with full program mode but the shutter speeds are too slow, haven't tried program mode yet, think that might work better? I just find it strange that full program has decently exposed backgrounds while Tv mode doesn't. I suppose the camera in program mode is boosting up the ISO speeds or somesuch like that.

If you have the manual for the 550EX pages 28 to 30 will somewhat explain how to balance the background and the subject.

If your in Tv mode, press the shutter halfway, if the aperture numbers are blinking in the viewfinder then you will have to adjust the shutter, or you will probally get a over or underexposed picture. Av mode is much better wen it comes to balancing the background and the subject, but for doing karate demos that won't cut it, i know this b/c i do a similar art hap-ki-do. Most of the time when shutter speed goes up the background gets more and more underexposed. I get balanced backgrounds and subjects using a shutter speed of 100-500 and a aperture of f/2.8 at ISO 400 +.

Hope this helps
~loveofselene

suemccartin · #3 11-24-2004, 02:04 PM

Yeah I expect I'm just going to have to go to iso 800 to get the light needs down because I sure can't afford those fast L series lenses at least not right now. I saw the blinking aperature in the view finder but I guess I was expecting the flash to deal with it but there's only so much the little guy can do, perhaps some slave units would also help but the action is all over a good sized gym so I'd have to have four to six + slaves to make it all work. Do you have problems with strangely colored backgrounds in mixed lighting conditions? I think maybe I just need to set the saturation down but I'm also having a problem with really yellow backgrounds in the same gym when shooting with the flash. My G2 doesn't do what I'm seeing with the Rebel in the same gym when taking flash shots.

glennp · #4 11-24-2004, 02:18 PM

Quote:

Originally Posted by suemccartin

Hi all
I just find it strange that full program has decently exposed backgrounds while Tv mode doesn't. I suppose the camera in program mode is boosting up the ISO speeds or somesuch like that.

You didn't say what your shutter speeds are but I'd guess that the shutter speed is slower in program mode than what you set in Tv mode. At the slower speed, more light is hitting the sensor which is resulting in better exposed backgrounds. The downside, as you mentioned, is that the shutter speed is too slow to stop action. When you use Tv mode with a higher shutter speed, the action is stopped but the background is being underexposed. It's a tradeoff.

Another factor is the distance of the background and the flash power. If the background is out of range, the flash won't help and you'll only get the benefit of ambient light. Again, slower shutter speeds will provide more exposure.

When I've shot in dim situations like yours, I've shot manual. I set the ISO, shutter speed, and aperature for the effect I want and let the flash fill in the blanks. For some situations when you can't have it all, you just have to pick what elements of the shot are most important and work from there. In your example, I'd boost the ISO, go with the slowest shutter speed you feel comfortable with to stop action and then try a little Photoshopping to bring back some details in the background.

PS - If you pick up a 420EX, you can use it as a remote slave and have a multi-flash setup. Use the 520 as your main flash and set up the 420 for help with the backgrounds/additional lighting.

suemccartin · #5 11-30-2004, 08:27 AM

If you had the money to buy a bunch of slave flashes and tripod setups how many would you think you'd need to properly light your typical basketball court sized small gymnasium?

I'd think at least one at each corner and perhaps one in the center on each of the long sides of the rectangle. So that would be 6 slaves to the main one on the camera. I don't know much about slave setups, I probably wouldn't have enough wireless range/capacity even indoors to operate that many at once. I'm also thinking there would be some more hardware involved than just the camera and the 7 flash units. Does the camera and the flash units do all the work to balance all those slaves? Like I said, pretty ignorant about slave setups.

stephe · #6 12-01-2004, 03:10 PM

hello, if I were you, I would make the background blurr instead. just like what you see on basketball cards, they all look cool no matter how they pose

I'd get 2 quantaray MS-1 ($20 each) and set one high up pointing down and one to either side. Does anyone have experience with the MS-1?

stephe

LoveOfSelene · #7 12-01-2004, 07:32 PM

Quote:

Originally Posted by stephe

hello, if I were you, I would make the background blurr instead. just like what you see on basketball cards, they all look cool no matter how they pose

I'd get 2 quantaray MS-1 ($20 each) and set one high up pointing down and one to either side. Does anyone have experience with the MS-1?

stephe

...the MS-1s from Quantaray, IMHO they are not that great, first they don't fire all the time when you want it too, and you don't have any control over the flash
i prefer to save for a real slave as in a 420ex

Just in my honest opinion
Loveofselene

stephe · #8 12-01-2004, 09:23 PM

well, I dont have much experience on flash photography
but can you really see a big different if using a 420ex and a bunch of MS-1?
what kind of "control" you talking about?

stephe

LoveOfSelene · #9 12-02-2004, 12:33 PM

Quote:

Originally Posted by stephe

well, I dont have much experience on flash photography
but can you really see a big different if using a 420ex and a bunch of MS-1?
what kind of "control" you talking about?

stephe

Well for starters the MS-1 only has one output for the flash, so if your not careful you can over expose your shot

Control as in settings: FE Lock, FP flash (high sync), Flash exposure compensation, exposure bracketing, full manual, ect. If you set the 420ex as a slave, you still have the E-TTL compatiblity as if it were on the camera. The only thing that it won't do is a second curtain flash.

For example, if you use a 550ex or 580ex flash as the master, settings that you set for the master (550 or 580ex) will also be set wirelessly for the slave (420ex). If you have more then one slave, they all can be set at the same setting or they can be set different for each slave (up to four slaves).

Hope this helps.
~LoveofSelene

suemccartin · #10 12-15-2004, 11:09 AM

Thanks for the comments about the slaves--the 420's are down to about 150 on ebay right now can't do much better than that for a real speedlight--the 380 doesn't have the wireless slave stuff. I've heard from professionals that I'm really jumping into some difficult shooting conditions with the karate stuff but someone did tell me something interesting that I wanted to pass on.

The reason I'm having the funny colored background issue is probably related to white balance and the difference in the color of the flash lighting and the background lighting. I've read a couple of things that talk about what focus point the camera is using to set the flash and white balance etc. all of which makes sense. My friend who shoots professionally (and uses a 10D) says I need to get the flash the same color as the surrounding lighting and manually set the white balance to cure the problem. So far, I'm not finding any filter kits specifically for the 550/580 (which is silly--they're made for every professional sunpak flash I've ever owned), so I'm probably going to have to rig something using a gel or I think I can maybe come up with a temporary way to make my sunpak filter set frame fit the 550. So in the case of the mercury vapor lighting I'd need to get a yellow filter on the flash. I'm going to try this out and I'll let you know how it goes.