Need help on exposure problem

I have recently switched over to Canon's 5D after using Nikon systems for the past 15 years. I use Canon's 24-105mm f/4L IS USM lens and the 580 EX II as a complete kit.

Though I don't earn my living off photography, I do make extra money on wedding photography. I have been experiencing under exposure problems in low light conditions; and have even increased the metering exposure compensation to + 1 1/3 and flash exposure compensation to +1/3 - Shutter speed 40 @ f4 [Though in my mind a constant increase in flash exposure would not be advisable].

Though I am not at sea with the Canon system, having adequately mastered Nikon's metering, I wonder what I am missing out on here with my Canon kit. I have to practically edit/correct almost all images shot in low light @ Adobe Photoshop. I've also noticed that exposure differs for practically each frame clicked; my methodology of clicking snaps, e.g. exposure settings, distance from subject, etc is the same with what I've done with my erstwhile Nikon system and what I'm now doing with my Canon system [Though I used Sigma's f/2.8 lens with my Nikon F80 and SB 28]. I've compensated an extra amount considering that I'm using an f/4 lens. I know that using an f/2.8 lens will make a positive difference, but at the moment my budget has been exhausted by the kit I'm presently using.

I've also noticed that a couple of other members on this site are experiencing battery drain with the 580 EX II. I too have noticed this with my 580 EX II - a fully charged set of Sanyo 2100 mAh NiMh batteries lasts for only about 150 - 200 exposures. As suggested by some members, I will buy Sanyo’s eneloope batteries and check the difference.

Will appreciate someone reverting with advice on the exposure problems.

28/12/2007

Weddings here in Goa are between a 4pm nuptial mass followed by the reception. It begins at the groom's residence, followed at the bride's residence with blessings, group photographs, a sprinkling of candids and then the nuptials [As they are mostly Catholic, like me ]. The reception follows, where lighting is very low, that's where an f/2.8 or faster lens comes in very essential [I miss the f/2.8 I used with my Nikons]. I have attached another picture I clicked on 22nd at 1/40Sec, F4.0, Exposure Compensation +1, ISO Speed 200 and FEC was around + 1 1/3. Image has been resized.

I noticed that in low light, the flash metering does not remain steady for moving subjects, say a couple dancing; as per observations on the photgraphs clicked. As mentioned by Curtis N, 'The key to getting predictable flash exposure is to learn how these various modes work, understand their strengths and limitations, then choose the most appropriate mode for the situation' stands and fortunately its a digital camera and an endless number of photographs can be clicked.

That's for now. Cheers!

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Welcome to the forums. The ETTL flash system does leave a lot to be desired and is very sensitive to bright, reflective spots in the image. I've read that switching to average flash metering on the camera helps considerably (or is it the other way around?).

I've read of folks pushing the FEC to over +1 to get properly exposed images. One thing you didn't mention was ISO - don't be afraid to push it up, especially with the 5D body. I shoot weddings with a 20D and 550EX flash and have not had the underexposure problems that many report with the EX flash. I also use f2.8 or faster lenses.

As far as batteries - 2600mAh NiMh work real well. I'm not sure how many shots you are used to but several hundred sounds good to me.

Here's a link that may help: https://photography-on-the.net/forum/showthre​ad.php?t=392233

And after all that - could you post a sample image? It may answer a lot of questions and will certainly be asked for by the flash gurus on the site....

Compared to other flash metering systems, Canon E-TTL is miscalibrated. Lots of people start with a "default" setting of +2/3 FEC and go up from there if there's much white in the image, like a bridal gown or a tablecloth at a wedding reception.

Keep in mind that with a Canon system, EC and FEC are completely separate, and EC has no effect when the camera is in manual mode.

Thanks Dave,

ISO equivalent used is 200, I will push up to 250 or even 320 and test - though I'm a bit worried about grains on enlargements; the maximum size that I print is 8" x 12".

I was very keen on Canon's 24-70mm f/2.8L USM lens, but the initial investment on the 5D was high. Will now have to opt as a temporary measure for Sigma's 24-70mm f/2.8 EX DG MACRO lens, which has got pretty good reviews.

With my Nikon system and using Sanyo 2100 mAh batteries I used to get about 400 exposures.

Will post a sample picture for the flash gurus .

Thanks for your post and wishing you 'Compliments of the Christmas season'

Derek

Titus213 wrote in post #4567003
Welcome to the forums. The ETTL flash system does leave a lot to be desired and is very sensitive to bright, reflective spots in the image. I've read that switching to average flash metering on the camera helps considerably (or is it the other way around?).

I've read of folks pushing the FEC to over +1 to get properly exposed images. One thing you didn't mention was ISO - don't be afraid to push it up, especially with the 5D body. I shoot weddings with a 20D and 550EX flash and have not had the underexposure problems that many report with the EX flash. I also use f2.8 or faster lenses.

As far as batteries - 2600mAh NiMh work real well. I'm not sure how many shots you are used to but several hundred sounds good to me.

Here's a link that may help: https://photography-on-the.net/forum/showthre​ad.php?t=392233

And after all that - could you post a sample image? It may answer a lot of questions and will certainly be asked for by the flash gurus on the site....

Thanks for your post.

Curtis N wrote in post #4567837
Compared to other flash metering systems, Canon E-TTL is miscalibrated. Lots of people start with a "default" setting of +2/3 FEC and go up from there if there's much white in the image, like a bridal gown or a tablecloth at a wedding reception.

Keep in mind that with a Canon system, EC and FEC are completely separate, and EC has no effect when the camera is in manual mode.

I don't think you'll see any difference between ISO 100 and 400 on a 5D, so don't be afraid to go there, certainly not enough to matter on a 12'' print. Compared to the grain you get when underexposing at ISO 200 (after bringing it up in photoshop) will be a lot more prounounced anyway. I routinely shoot bridals at ISO 800 or higher if I need to and they always look terrific, as long as I really get the exposure right.

Thanks for your post.

Wishing you 'Compliments of the Christmas season'.

Philco wrote in post #4569697
I don't think you'll see any difference between ISO 100 and 400 on a 5D, so don't be afraid to go there, certainly not enough to matter on a 12'' print. Compared to the grain you get when underexposing at ISO 200 (after bringing it up in photoshop) will be a lot more prounounced anyway. I routinely shoot bridals at ISO 800 or higher if I need to and they always look terrific, as long as I really get the exposure right.

I agree with Titus213. Increasing the FEC to over +1 to compensate for the white gown and its shiny surface would probably have helped improve the exposure. But the groom in his black suit would probably still have been lost in the dark background unless the ambient exposure was also increased (ISO 400 or 800).

Yonders, compared with a film camera's TTL reliable and consistent flash exposure, dSLRs' ETTL/ITTL/whateverTTL is a poor second. The world went BACKWARD in flash exposure automation, with the advance of the digital world! And Canon's system is especially perplexing. No matter how much you try to learn about it, it always seems to provide confounding results that puzzle even the experts from time to time. Dial in FEC +2/3 EV and your results should improve.

Wilt wrote in post #4570591
Yonders, compared with a film camera's TTL reliable and consistent flash exposure, dSLRs' ETTL/ITTL/whateverTTL is a poor second. The world went BACKWARD in flash exposure automation, with the advance of the digital world! And Canon's system is especially perplexing. No matter how much you try to learn about it, it always seems to provide confounding results that puzzle even the experts from time to time. Dial in FEC +2/3 EV and your results should improve.

Wilt, he already had +1/3 EV dialed in. I hardly doubt that another +1/3 would be enough of an improvement in exposure.

I absolutely agree with you on what you quoted on film camera's reliable and consistent flash exposure and dSLR's flash exposure. I have to check for each and every exposure before a picture is taken , unlike when I was using my Nikon film SLR and systems.

Wilt wrote in post #4570591
Yonders, compared with a film camera's TTL reliable and consistent flash exposure, dSLRs' ETTL/ITTL/whateverTTL is a poor second. The world went BACKWARD in flash exposure automation, with the advance of the digital world! And Canon's system is especially perplexing. No matter how much you try to learn about it, it always seems to provide confounding results that puzzle even the experts from time to time. Dial in FEC +2/3 EV and your results should improve.

PacAce wrote in post #4570493
I agree with Titus213. Increasing the FEC to over +1 to compensate for the white gown and its shiny surface would probably have helped improve the exposure. But the groom in his black suit would probably still have been lost in the dark background unless the ambient exposure was also increased (ISO 400 or 800).

Leo, was shooting at ISO equivalent 200, +1/3 to +1 metering compensation and +1/3 to + 2/3 FEC. Will now have to set at 320-400 ISO equivalent and juggle metering exposure compensatio and FEC.

I presume you'll guys must have been using Canon's systems for ages, unlike me who has switched over to Canon since June 2007, after using Nikon's systems for 15 years. I wonder whether this switch was in the right direction? Your opinion.

People complain about Nikon's flash metering system too. If you had purchased a Nikon DSLR you would likely still need to go through a process of leaning how their system works.

You actually have four flash metering options with the system you have.
1) and 2): You can choose between Evaluative and Average E-TTL mode via custom function on the camera.
3) You can use flash exposure lock, which is basically spot metering the flash exposure.
4) You can use the manual external flash metering mode on the 580EX II, which is traditional non-dedicated auto flash.

The key to getting predictable flash exposure is to learn how these various modes work, understand their strengths and limitations, then choose the most appropriate mode for the situation.

And this learning process is not something that happens overnight.

My take on Canon's ETTL system is that it latches on to the brightest thing it sees and exposes for it. I would do a bunch of practicing with situations similar to the ones you encounter using the various methods Curtis N suggested. Eventually you will find a method that works for you. I don't think there is enough money out there to get me to shoot a wedding, but I shoot cars all the time. When using a 580EX on a subject that has a reflective license tag or sticker, I can get pretty close to the right exposure using +2 FEC. If there is nothing reflective, I don't need any FEC.

yonders wrote in post #4569650
ISO equivalent used is 200, I will push up to 250 or even 320 and test - though I'm a bit worried about grains on enlargements; the maximum size that I print is 8" x 12".

Derek

There is no reason that you can not go to higher ISOs. The 5D handles noise almost better than any other camera out there. I was fortunate enough to get to use one at a friend's wedding, routinely shooting at ISO 800 and above. The noise was minimal at its worst. An 8x12 print should show minimal, if any, signs of grain.

I realize these are downsized versions for the web but all were shot at ISO 800 to allow maximum ambient light and flash for fill.

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