flash overexposure and blowout

[Carl_Constantine]

While trying to take pics of my Mossy Mopalia, I removed the flash from the shoe and powered it up. Lined up the flash with my lens and hit the test and shutter at the same time. This produced a completely WHITE image, no detail. It was like I took a picture of a piece of paper.

I later added back to the hotshoe and put a diffuser on the flash and got some decent results (this due to the fact that the flash couldn't be pointed at the subject, so the diffuser provided some bounce lighting). However the inner shell shot I had to not use the flash because parts of the shell were over exposed.

I can't really seem to get a good handle on how best to use my flash. I'm really having a hard time with this.

I have a Sigma 500 DG Super for a flash, so it has lots of power, but no real handle on how to really use the functions of the flash particularly with macro work where everyone suggests the flash has to be close to the subject.

HELP. Can anyone recommend some good resources on flash use, guide numbers and so forth? I'm stuck

[lauriek]

I would imagine the test button fired the flash at full power while the camera did not have the flash connected (so was not expecting any help from the flash!) and had metered exposure from the natural light available, so when it received a full power close up burst of flash it completely overexposed the shot...

With the flash mounted on your camera does the flash meter automatically (TTL)?

Assuming so, what you probably want to do is get an off camera flash cable, capable of transferring the necessary signals from/to your camera, this would probably be made by the manufacturer of your camera (which you don't mention so I can't comment further!).

Then you can hook up the camera to the flash with this cable and hand hold the flash where you want. TTL communication should occur between the body and the flash so allowing the two to work together properly. It would be better go get some sort of macro flash bracket so you don't have to hold the flash in place but you could do without it for a bit if funds won't stretch that far for now...

[Carl_Constantine]

Thanks for your response. I have a Canon EOS 300D (original Digital Rebel). The off shoe cable for these is $120 or so Canadian, so I just don't have the funds right now. Was experimenting, but your reply makes complete sense to me.

I do need to get some more equipment so I can do a better job of my macro shots. Yes, the flash does TTL and E-TTL.

[Mike B in OKlahoma]

Depending on how you want to use your flashes, you may want to consider a Canon ST-E2:

http://www.amazon.com/Canon-Speedlite-T ... 955&sr=8-1

It costs more than the off-shoe cable, but you aren't tied to a camera by the cable. I find mine works wonderfully indoors. Outdoors it is not as reliable, and I would have to describe it as spotty at best. But for indoor shooting it can't be beat, and you have much more freedom to move the flash around.

Also, the Canon off-shoe cords have a bad recommendation for breakage and failure without warning. I have one that still works, but I don't use it that often (mostly for bird photography rather than macro).

[rjlittlefield]

Carl,

Consider pure manual operation.

Set your camera on its lowest ISO number and a shutter speed that's slow enough to work with flash (1/200 second or longer on your camera). Lock in some fixed low power on the strobe, set a fixed f/stop on your lens, and pick a flash-to-subject distance. Take a test picture. If it's too bright, then adjust something(s) to make it darker --- reduce the power level, raise the f/number, increase the flash-to-subject distance, introduce a diffuser, or use a different one, or some combination of these. If it's too dark, go the other way.

You will quickly learn what settings are needed to give good exposures.

This may seem hopelessly crude, but in fact it's the way that all of my flash pictures get shot. Explaining exactly why that is would be a long story. Suffice to say that when I first bought my Digital Rebel, I purchased, tested, and returned three new highly automated flashes that looked great but wouldn't actually work for what I wanted to do. Finally I realized that with the immediate feedback provided by digital imaging, pure manual operation was actually not very painful. Since manual operation is also extremely reliable, in the sense of "no surprises", I just kept doing it.

Manual operation is definitely not the right approach for grab shooting under varying conditions -- auto exposure is far better for that -- but in your situation, it might be just the ticket.

--Rik

[DaveW]

See:-

http://www.naturephotographers.net/arti ... 703-1.html

http://photonotes.org/articles/eos-flash/index2.html

http://www.dcmag.co.uk/Close_up_flash.Y ... 9cnPg.html

DaveW

[Carl_Constantine]

Thanks for the tips guys. I'll check into these and try them out.

[cannyman]

While trying to take pics of my Mossy Mopalia, I removed the flash from the shoe and powered it up. Lined up the flash with my lens and hit the test and shutter at the same time. This produced a completely WHITE image, no detail. It was like I took a picture of a piece of paper.

I later added back to the hotshoe and put a diffuser on the flash and got some decent results (this due to the fact that the flash couldn't be pointed at the subject, so the diffuser provided some bounce lighting). However the inner shell shot I had to not use the flash because parts of the shell were over exposed.

I can't really seem to get a good handle on how best to use my flash. I'm really having a hard time with this.

I have a Sigma 500 DG Super for a flash, so it has lots of power, but no real handle on how to really use the functions of the flash particularly with macro work where everyone suggests the flash has to be close to the subject.

HELP. Can anyone recommend some good resources on flash use, guide numbers and so forth? I'm stuck

Shame on you , pointing your camera directly at the flash Luckily sensors seem to take this in their stride with no damage. If you are taking macro shots at 1:1 the front element is about 1" away from the subject, so a flash mounted on the camera is a non starter. Front flash is the answer, but the prohibitive price for say a Canon model is beyond the average photographers purse. I decided to give it a go and made my own, which worked out OK. 1/ twin strobe flash head for mounting onto the lens barrel. 2/ A free standing twin flash with a mini tripod and flash diffuser. If this forum allows down loading of shots ,I will put a couple on

[augusthouse]

Hi cannyman,
Welcome aboard. Upload those pics. When replying to a post or creating a new topic, you will notice an 'upload picture' button above the post editing box. Just need to click on that and a small, separate window will open that allows you to browse to the images that you want to upload. There is a 200kb limit per image. There is also a 'send' button, which adds the image to your post and then allows you to upload another one if applicable.

Craig

[cannyman]

Hi cannyman,
Welcome aboard. Upload those pics. When replying to a post or creating a new topic, you will notice an 'upload picture' button above the post editing box. Just need to click on that and a small, separate window will open that allows you to browse to the images that you want to upload. There is a 200kb limit per image. There is also a 'send' button, which adds the image to your post and then allows you to upload another one if applicable.

Craig

Hi, I attempted to send a couple of shots. I thought I did everything correct, but nothing showed Will try another.

[augusthouse]

cannyman,
Here is a link to the proceedure.

http://photomacrography.net/forum/viewtopic.php?t=7

Craig

[cannyman]

Hi cannyman,
Welcome aboard. Upload those pics. When replying to a post or creating a new topic, you will notice an 'upload picture' button above the post editing box. Just need to click on that and a small, separate window will open that allows you to browse to the images that you want to upload. There is a 200kb limit per image. There is also a 'send' button, which adds the image to your post and then allows you to upload another one if applicable.

Craig

Hi, I attempted to send a couple of shots. I thought I did everything correct, but nothing showed Will try another.

Tried another, still nowt. (Thats lancashire for nothing )

[DaveW]

Carl,

I use a Manfrotto dual flash bracket because my 70-180 Micro Nikkor is their one micro lens they don't advocate hanging their dual macroflash onto because of the overhang when extended, plus plastic filter threads on the lens which the dual macroflash would be fixed to.

See:-

http://www.amazon.com/Bogen-Manfrotto-M ... B00030DLA8

The dual arms are extendable and can be swiveled to put the flashes at the front of the lens. The thing standing vertical in the illustration is the camera platform that swings up from horizontal to vertical then slides sideways to allow the camera to be used in either landscape or portrait orientation without altering the lighting. With the macroflashes if you turn the camera up, unless you reset them, your flashes go from one each side to one top and one bottom.

Obviously you need either slaves on the flashes set off by the cameras pop up flash, or a cord from the hotshoe to at least one flash and a slave on the other.

Just found a better picture with the camera attached:-

http://www.calumetphoto.com/item/BG4290/

DaveW

[cannyman]

Well here goes.

[cannyman]

Well here goes.

The reason for this shot was to check the sync between camera shutter and flash. Took it up to fastest speed and the sync was OK.