A quick flash.

Janice

Janice

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Janice
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Sorry to bang on about flash, but Ive just received my Sigma 500 DG Super.
Bloody hell....it is SO difficult! (and this is from someone who has mastered manual exposure with spot metering!!) :D

I have read all the tutorials I can muster on all the sites I can find...but I still have a few questions:

1. When in ETTL mode, when you adjust the power of the flash ( +1, -2 etc) how come the bar below in the flash readout panel which appertains to the distance, gets higher in ft/mtres ...ie further away, when you turn the flash down..........and vice versa, when you increase the flash power, the marker gets closer in ft/meteres. ISnt this the opposite of what shOuLD HAPPEN?
Doesnt increasing the flash mean that the object is further away and needs more flash, and if you decrease it its because it is close and doesnt need as much flash?


2. The instructions say.........".. either turn the wheel in AV mode to stop the aperture flashing.... " etc. my numbers never seem to stop flashing, either the aperture or anything......I never seem to have an adequate setup of combinations. I feel I have paid all that money and will never be able to handle it.

the only thing that works is in the "GREEN AUTOMATIC MODE" or "P" mode, neither of which I have ever used in my normal photography.

God, it doesnt take much to dishearten me! :help:
 
Janice... are you reading that bar wrongly? The flash distance bar refers to the range within which TTL can operate. In other words you have the limits of automatic operation indicated by each end of the bar... the close limit at one end and the far limit at the other. TTL flash should be fine anywhere in between those two distances, i.e., anywhere along the bar.

There's nothing wrong with using 'P' mode btw for balanced flash pics out of doors and it's the simplest way of getting good balanced exposures of flash and combined daylight. Obviously just keep an eye on aperture and shutter speed and their suitabilty for your particular subject.

HTH...
 
Ah I think I see now. I am using the bars like they are intended in manual flash mode....where they show the distance the subject is away from the camera.

Nothing in the manual says it doesnt mean the same thing.
In fact I have never seen such a rubbish manual for anything, let alone something as complicated as a flashgun!
 
Congrats on the new toy.......now lets see a flash (picture) ;)
 
Flashguns make us all scratch our heads sometimes. The fact is modern guns are so automated, it's difficult to see the wood for the trees sometimes, particularly with all the camera modes at our disposal. Regardless of what mode you operate the camera in, as long as the flash is in ETTL Mode, the onboard chip will do it's best to get you a proper flash exposure, and even if it isn't bang on or to your own particular taste, you're usually in the ball park. If anything they tend to overflash a little, so my approach is usually to start out with no flash power reduction, then suck it and see. :)

I rarely use Manual Mode on the camera, but for macro it's great to use pretty well any aperture or shutter speed combination you like (as long as you don't exceed the max shutter sync speed) without a meter reading and let the flash and camera combination worry about outputting the light to meet the commitment. If it shows under-exposed with a very small aperture then just open up a stop or two or up the ISO.

Matching the flash to prevailing ambient light is a different matter of course, but it's never been easier than it is with modern kit. :)
 
Thank you. I still seem to have a blind spot as far as the compensation goes.
When I put it on +3 the range bar below says the range is only up to 5 feet.
When I put it on -3 the range bar says the range is 60 feet!

How can a stronger flash of +3 only have a range of 5 feet while a -3 which is obviously lighter have a range of 60 feet? :thinking:
 
Janice said:
Thank you. I still seem to have a blind spot as far as the compensation goes.
When I put it on +3 the range bar below says the range is only up to 5 feet.
When I put it on -3 the range bar says the range is 60 feet!

How can a stronger flash of +3 only have a range of 5 feet while a -3 which is obviously lighter have a range of 60 feet? :thinking:
Click to expand...


You tell the flash to push out +3 more light to do the job it thought it could do with no compensation..... so to go further it needs even more power so the max range is reduced.

Tell it that it can do the job with -3 and it finds it easy to reach out further.

(don't be fooled that I really understand this stuff though)
 
Janice said:
How can a stronger flash of +3 only have a range of 5 feet while a -3 which is obviously lighter have a range of 60 feet? :thinking:
Click to expand...

I'm not familiar with your Sigma flashgun Janice so I can't really comment. I'll tell you what though, I rarely if ever look at the scale anyway unless I use the flash in manual Mode. Stick a bit of tape over the scale for a while and stop worrying about it. At the sort of close to moderate distances we take most flash shots at, (macro to group shot distances) and as long as the flash is set on ETTL, the flash/camera electronics are more than capable of delivering a good result as long as you're not going too extreme with apertures and shutter speed. ;)
 
That's a reasonable explanation by Robert. Modern flashguns are just about the most powerful units you can mount in the camera hot shoe, but to increase power by +3 stops is obviously imposing a huge drain on the flashguns power and it's ability to output at that level, so there's a limit at what distance it will be effective. Conversely, on reduced power it can output that level of power far easier and for longer, so will have a greater working range.

Cover that scale up and just go and take some pics. Adjust the flash output if you need to, but it will almost certainly be reduced power anyway. Time to worry about a more technical approach as and when you really need to. ;)
 
Just did a check on mine and CT/Robert are right.

The flash can send it's maximum power a certain distance (i.e. 50m @ iso100) to increase the effective power the range needs to be shorter.
 
Even I understand that! Well explained guys, thank you.
 
Another black art of photography.

I'm currently on a mission to learn flash as it has to be one of the most difficult things to understand in photography. Mostly because it really makes you think bout the quality, direction and volume of light and ultimately that's what we, as photogrpahers are all about, light.

It ultimately depends on whether you're using flash for fill or main light, but I would suggest reading reading the guides I posted last night, especially the one I posted on this sub-forum (flash 101 or something similar), A lot of good reading about different techniques and ideas. We're lucky these days that we have a lot of experience from people who've learnt the hard way using film and money to find the best ways to use flash. Fortunately, the techniques translate well to digital.
 
On the one hand we say it's easier than it's ever been, which is true as long as you understand the basic principles, but us wrinklies have seen these innovations and come to grips with them gradually over time. There was a time when an SLR had the apertures in the proper place.. on the lens barrel, a dial with the shutter speeds on and an ASA (ISO) dial. That was all you got and all you really needed in the way of exposure control. The flash had a guide number from which you calculated the aperture needed.

For a newcomer to be confronted with a modern multi mode DSLR and flashgun must be really intimidating, and flash is one of the most difficult things to explain without writing a novel.
 
Well I THOUGHT I had it covered with Robert's explaination.

Now Ive thought more on the subject I STILL think I disagree!!

If a flash of light is made brighter, then its the sheer brilliance of the light which makes it cover things further away.

If a flash of light is made duller, it wont light up things to a satisfactory degree unless they are closer to it.

I cant see it has to do with the fact that if the unit uses more power to make a brighter light, it hasnt got as much power to get it to travel as far....the sheer brightness of the extra light will do this wont it?
 
Well - that's perfectly true in a 'normal' situation and you've hit the nail on the head! It boils down to the "inverse square law of light"; double the distance and you only have a quarter of it's power at that new distance. So, you need more light if you want it to travel further and correctly expose ......

But, (if I've read your enigma correctly) you're talking about exposure compensation whereby you want/need 3 stops overexposure which means, at full flash output [therefore maximum distance] the light needs to be 3 times brighter still! You can't get any more light so the only recourse you have to achieve overexposure is to reduce the maximum flash to subject distance. In this instance the cube root of the previous maximum distance [ie. if it was previously 27 metres it is now reduced to 3 metres].

If you've followed my ramblings (and if I've made sense!) then the converse is true! 3 stops under exposure means you need 3x less light therefore the distance is increased by the power of three. (Simple sums.... 3 metres becomes 27 metres).

As you so rightly say - it means the gun is putting out less light (or more, depending upon which way you want to compensate). The clever flashgun re-computes the compensation to enable the correct maximum distance to be displayed on the LCD if you so desire to shoot that far! :)

Phew .... I think... ;)
 
chuckles said:
But, (if I've read your enigma correctly) you're talking about exposure compensation whereby you want/need 3 stops overexposure which means, at full flash output [therefore maximum distance] the light needs to be 3 times brighter still! You can't get any more light....
Click to expand...

Good post Barry! The above would be true in a situation where you were using the flash in Manual Mode at full power with wide open aperture trying to (say), pick out a performer on stage from the back of a huge darkened auditorium. The flash is pushing out full power and that's your lot, you can't increase it any further. You can only up the ISO (possibly) to increase the sensitivity of the sensor.

However in TTL Mode, although the flash display may be indicating the flash will fire at full power, the on board electronics will decide to what extent that power is utilised. This is particularly true where the flash is combining flash exposure with ambient light, and you may well be able to give + exp compensation. You're not increasing max flash power, simply overriding the calculation made by the flashgun as to the most desirable level of output.

I think Janice needs to set the flash on ETTL, the camera on P and go and take some shots at varying distances without altering any settings at all.. shutter speed or aperture. As I said earlier I think the system will cope extremely well and she'll be able to make any adjustments to flash output based on those results.
 
I have followed your ramblings.... you explained it very well indeed.

(I can see the attraction, Marianne!! ;) )

Thank You Barry.
 
S'ok, no problem - Happy to help....
 
Thanks Dave. I have already read those, it is a wealth of info, although it didnt address this particular problem. It isnt really a problem, its just that my mind has to fully understand how things work before I use them. I cant use something blindly without knowing whats going on!
 
Nothing in the manual says it doesnt mean the same thing.
In fact I have never seen such a rubbish manual for anything, let alone something as complicated as a flashgun![/QUOTE]

I have just taken delivery of the same EF-500 DG flash and I agree with your comments about the quality of the manual - lousy at best. This thread has helped me alot.

I am going to start googling (dangerous I know!) to see if I can find any better links to help me use this with my Nikon. Does anybody have any stored away in the favourates folder?

Cheers,

Bob.
 
Well I still aint got my head around the Sigma flash with a Canon EOS 350. Why in Av mode does it not think ah you have a flash connected therefore the numbers stop flashing? How do I know what settings to use? Does the flash compensate for any setting?

My pics often come out too bright if there is something in the foreground- what would i change to stop this ?

Thanks
 
Keltic Ice Man said:
Well I still aint got my head around the Sigma flash with a Canon EOS 350. Why in Av mode does it not think ah you have a flash connected therefore the numbers stop flashing?
Click to expand...
Well I don't use a Sigma flashgun but it sounds like you're making hard work of this Alan. ;) Set the flashgun on TTL Mode and the camera on AV or TV and you shouldn't be far away with your results at all.
How do I know what settings to use? Does the flash compensate for any setting?
Click to expand...
Pretty well - yes!! In fact the easiest way to use it is to set the camera on P Mode and the flash on TTL. As long as you don't exceed the max flash sync speed of your camera or go ridiculously small with your apertures, the flash will adjust it's output accordingly.The results wont be far away at all, but if they are - simply reduce (or increase) the output power of the flashgun until you get the result you want.
My pics often come out too bright if there is something in the foreground- what would i change to stop this ?

Thanks
Click to expand...

I take it you mean that objects between the camera and main subject are over-flashed and too bright Alan? That's just the way flash is when it's mounted directly on camera - it's very linear, firing a beam of light straight out, the light hits your foreground subject first, and by the time it reaches your main subject, the foreground bit is alteady over-exposed.

Either remove the offending foreground bit or try bouncing the flash from a wall, ceiling or other reflector.

Try the simple approach mate - Programme Mode with TTL selected on the flash and see what happens. :)
 
Iv just got a sigma 500 dg super. Don't us it as a creative tool , just for bounce flash on my 20d in auto or p mode, less harsh than the on-board flash and at half the price of the canon a pretty good deal. Must say using it in auto i never look at the display just leave the camera flash combination do its bit and so far never been disappointed with the results. Only thing i found i have to consistently overexpose one stop to get good results.
 
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