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Old Jan 19, 2005, 9:37 PM   #21
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Now thatI read up on similar information in other forums and canon's web site, it seems like it's just a matter of, like Bob has suggested, getting educated on the system.

Quite a bit of information out there. Until i read all of it, looks like I will simply be setting the flash to compensate indoors by 2/3rds or +1 at most.

Giving the system the right input. If the lens focusses on say a dark red sweater on a person standing in front of a white wall, does it, if set to default, comensate for a low exposure or will it automatically use the wall as a reference. Could you please point out Where I may obtainmore information on "average of 18% grey in the partial metering circle".



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Old Jan 19, 2005, 10:25 PM   #22
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Hiya Pascal,



You might find the following post with info from Chuck Westfall of Canon useful:

http://photography-on-the.net/forum/...ghlight=ettlii

The same site also has a flash info section:

http://photography-on-the.net/forum/...ad.php?t=46599



18% Grey

If you have your subject hold an 18% grey card to meter off of (you can get one at a good camera store), you can press the FE Lock button (* , the same as the AE lock button), while the grey card is filling the partial metering circle in the middle of the viewfinder, and you will getpretty consistent photos. See page 95 of the manual to see what I mean by the partial metering circle. FE lock isn't linked to an active focus point ... only to average metering of the partial metering circle.

I'm a noob at using a grey card, so maybe some of the other guys can pipe in ... but it seems to work pretty well.

Otherwise, if you have a picture that has a lot of tones, try taking test shots,adding FEC until the histogram is to the right without touching the right hand side. This doesn't work for shots where say there is tons of black, or tons of white, but works well for me when taking shots of the kids around the house.

You have to make sure that you don't OVER expose, because then you will lose detail that you can never get back. If you take some pictures in RAW then look at the RGB histograms (instead of luminosity) you can get a feel for how far you can go to the right without going too far. Again, you have to be careful relying on the histograms because it will, and should, look different depending on the scene. However, for me, I've been getting excellent shots of the kids doing this. For night shots, sunrises, sunsets, etc. this won't work.

Bob




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Old Jan 20, 2005, 12:21 AM   #23
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I just learned a few things ...

Fill flash supposedly only comes into play at 10 EV or 5 Bv, which is much brighter than typical indoors shots. So, fill flash and fill flash reduction shouldn't be what is causing the need to use FEC for indoor pictures.

10 EV or 5 Bv would be equivalent of getting a properly exposed picture without flash at 1/60 s and f 4.0 with ISO 100. For room light at 1/60 s with ISO 100 the cameras light meter would indicate that the background would be maybe over 2 stops under exposed at f 4.0 ... so, no chance that fill-flash (or auto fill flash reduction) is kicking in.

So ... I can see I still don't fully understand E-TTL II and what causes my need to have varying amounts of FEC, but I'm getting closer :-)



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Old Jan 20, 2005, 6:49 AM   #24
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I have the same problems using my 20D and 580ex. I don't really see why we should have to put up with from what purports to be 'quality' equipment. Has anyone considered sending this entire post to Canon?
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Old Jan 22, 2005, 6:01 AM   #25
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BobA has the right idea :idea:

Quote:
18% Grey
The camera's meter (just like anyreflectance light meter) is calibrated to a grey card! Don't blame the camera if you 'force' it to measurea 'wrong' value or FEL it on something that is not mid-tone!

"Because the card is 18% grey and your lightmeter is calibrated to 18% grey, you've now got a benchmark to work from. Therefore the camera will be able to get a precise handle on how much light is actually falling onto the card and advise the exact exposure setting you're after." http://www.naturespic.com/articles/a.../article4.html


The same issue is therewith natural light -> with a flash, the lighting is more limited since it only comes from one source and decreases as it travels and spreads proportionaly to the square of the distance traveled - This is why the problem is so acute when you only have afew stops to work with.

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Old Jan 23, 2005, 12:24 PM   #26
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I have a 20D and have the same problem. Correct the built-in flash exposure compensation by +1 stop in the "P" mode and that will solve your problem.

Phil

http://www.pbase.com/pyoung2493/coco_girls

The 3 photos with a prefix of "IMG" were all shot in this manner. The other 3 photos with "DSC" were shot with a Fuji S3 with Alien Bees studio strobes.
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Old Jan 26, 2005, 10:40 AM   #27
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I have the 20 D on the way to me, but when I read this post about flash photo's indoors makes me worry. I'm not a professional, just using this camera for armature photos. I would like to know this camera can take photos indoors in full auto mode with no problems if that's what I want to do, then also have fun with the settings when I want to take more time at getting a better shot. Is this camera no better then one of the point and shoot cams when just taking full auto shots?



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Old Jan 26, 2005, 8:58 PM   #28
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There are a lot of posts with people having problems using Canon digital SLR's with both E-TTL and E-TTL II complaining about problems with flash photography using a flash that supports E-TTL/E-TTL II.

There may be some very rare instances of equipment problems, but I am convinced that for most people reporting the problem, the issue is with a misunderstanding of how E-TTL II works, and is not a problem with the camera at all. One of the biggest problems is that there is little help from Canon in the form of technical bulletins, on-line courses, etc. Even their support staff have a hard time providing correct information to disgruntled customers (like i was! :lol.

However, without having a great understanding of E-TTL II you can still take great flash pictures with an E-TTL enabled flash. It has taken a bit of effort, but I'm pretty happy with the results I'm currently getting ... where at first the results were awful.

__________________________________________________ _______

Some of the things I've learned:

- Don't use focus lock then recompose. Even though E-TTL II is NEVER linked to an active focusing point, focus lock-recompose still messes things up. I don't know the details, but it does. If you need to recompose, use focus lock - FE lock - recompose instead. Canon also encourages users to select a AF point instead of recomposing.

- Using FE lock can improve consistency A LOT. However to use it properly the user has to understand that when you use FE lock the flash metering is set for thepartial metering zone in the center of the viewfinder (middle 19.5% of the area of the viewfinder). So, if you FE lock on a caucasian face you may be a bit underexposed ... because the face probably isn't the equivalent of 18% grey.

By practicing taking pictures of "faces" with FE lock you can get used to how much flash exposure compensation (FEC) you need to dial in to get great images.

- Taking digital pictures is much more like taking slide film pictures NOT like taking negatives. Using negative film there is a lot more "range", and sins are compensated for at the photo lab.

- It's ok if your pictures are a little bit underexposed ... they can be fixed up during post processing. However, don't overexpose because you will be missing detail that can never be brought back.

- I usually look at the histogram on the camera after taking a picture. I you are taking photos of the kids or anything that has a lot of tonality I've been happy with a histogram that falls off just to the left of the right hand side. If it is far from the right, I add flash exposure compensation and try the shot again. If it's piled up a bit on the right, go the other way with FEC. Using the histogram this way won't work for some pictures, but it seems to give consistent results for pictures of the kids.

-I never use direct flash because of the harsh shadows it creates. However I learned that since the rooms I am taking pictures in are reatively small, unless I point the flash directly at the ceiling I get pictures where the faces take on some of the colouration from the walls. If it wasn't for digital(near instant feedback) getting this right would have taken forever.

- I use Manual exposure mode for flash. This way I can set the shutter speed to whatever I want to avoid shake, and still have control over DOF. The other creative modes (Av, Tv, P-Auto) will give just as good a flash "exposure" result.None of the creative modes meter for flash exposure differently than the others as far as I can tell.

- For indoor shots under typical room light the picture will NOT be taken using fill-flash (it will be full flash). Fill flash is only used for much brighter situations, where the EV is greater than 10.

-According to Canon, fill flash is used the same way for ALL flash modes. As soon as the EV is >10 (BV > 5) fill flash starts kicking in, with maximum fill-flash reduction at EV=13. As an example, for the brightness to be equal to an EV of 10 for ISO 100 at 1/60s, you would need f-4 for a proper exposure without any flash.

- If you are taking posed pictures and you want them as perfect as possible, try using an 18% grey card. Have the subject hold the 18% grey cardAFTER you focus lock so that you can FE lock on it (it has the fill the middle 9.5% of the viewfinder). After they toss it aside, take the picture. A bit of a hassle, but it works.

- Be careful when you read posts referring to similar problems using E-TTL instead of E-TTL II. Some of the solutions given such as changing from Auto focus to Manual focus to change from Evaluative to Center focus metering are incorrect for the 20D. For cameras such as the 10D (using E-TTL) changing the focus from Auto to Manual DOES make the exposure for flash more averaged because it takes the focus point out of the equations. However since the 20D using E-TTL II NEVER (never ever) uses an active AF point, changing the focus mode has no effect.

- Canon tech support has informed me that in full auto the 20D has been designed to give results that are slightly underexposed. I have a hard time believing this one, but since I never use full auto for flash I can't dispute it.

__________________________________________________ ____



There also have been many posts (some from pros) saying that they get much more consistent flash photos without as much fuss when they use a non-E-TTL flash. I have a 420EX, so I have no experience with this.

I'm also an amateur ... and a digital noob ... so if anyone else has additional info that they have gleaned from Canon it would be great to hear about!



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Old Jan 27, 2005, 12:39 AM   #29
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FYI: 18% grey is exactly what human (caucasian) skin should be. At least in an average sense. That's why grey cards exist.
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Old Jan 27, 2005, 8:35 AM   #30
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Thanks for the info, but say my wife just wants to pick up the camera and take a shot of the kids indoors with a flash will she have to do all of this just to get a good shot ?or will the picture be good enough that we will not care. I would ope that for the With the price of this cam the full autoshould be just as good as most of the better point and shoot cams. I know most of you work hard to get a perfect picture, but to just get good pictures with full auto mode be a problem with this cam? I would hate to know that all my pictures indoors would be dark without all the effort above.



Thanks in advance

T
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