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Yakim Peled , Dec 21, 2004; 10:19 a.m.

Hi Photo Nutters :-)

This question is for those of you with experience in both metering systems.

1. Can you really spot the difference? For example, do you need less FEC with E-TTL II than with E-TTL? Are the results more reliable in difficult situations? Do you feel less the need to put a diffuser on the flash if you are in E-TTL II?

2. Is there any indication (e.g. in the flash and/or in the camera) when you switch from E-TTL II to E-TTL or vice versa?

3. E-TTL II does not work in bounce mode, in macro mode and in wireless mode. That means that E-TTL II is only useful when you have one flash and when it's pointed directly forward. Am I right? If that is so, it seems that it's benefits are limited.

Thanks for any answers, comments and enlightments.

Happy shooting, Yakim.

One last thing. Please don't direct me to NK Guy's article. I am looking for user experience, not theory.


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Jim Larson , Dec 21, 2004; 12:09 p.m.


I have not used both systems extensively, but I have researched enough to comment on a few of your questions.

1) I can't comment on "quality", as I have not shot E-TTL II more than a few times (with a film body).

2) A given camera body will use either E-TTL or E-TTL II exclusiviely. This is firmware/hardware configuration issue and is not user selectable. Kind of like if your camera has partial metering or a spot meter -> you get one or the other and that's the end of it.

There are no firmware upgrades to convert a 10D or Elan 7 to use ETTL-II.

3) E-TTL II refers to the *entire system* of flash metering. This system includes a correction factor for lens focus distance. This correction factor is not used in the conditions you describe (ie, bounce flash). This correction factor is also not used if you use a lens that does not provide distance feedback to the body.

I do not know the importance of this correction factor, but *I suspect* it is minor.


The primary difference between E-TTL and E-TTL II is that E-TTL is strongly focus point biased. ETTL evaluates the flash exposure primarily at the focus point. E-TTL II does not have this high focus point biasing, and the flash exposure is calculated using more of an evaluative metering pattern.

The primary benefit of E-TTL II is that you are no longer so reliant on Flash Exposure Lock to get correct exposures. Much better for shoot-on-the fly photography. E-TTL works very well in slow motion situations, where you can 1)press one button to do FEL, 2) press another button to focus and 3) mash the shutter to take the image.

Jacek Cwik , Dec 21, 2004; 03:12 p.m.

Yakim, I have switched from 10D to 20D. The flash I use is 550EX. I have never played with FEC. However I used to work with preflashes (FEL) almost all the time during weddings. HUGE difference. ETTL-II does not guarranty that every your shot will be dead on. But most of the images are correctly exposed. Finally! I am talking about high contrast (black/white vs. face) difficult situations.

BTW, I don't think ETTL-II does not work in bounce mode. It doesn't support distance info while bouncing, but there are other factors - improvements over ETTL that I think work even in bounce mode.

The only two things I wonder are: if the 580EX is any improvement over 550EX in regard to exposure accuracy (probably not), and if 580EX really helps to get better White Balance results.

Merry Christmas!


Puppy Face , Dec 21, 2004; 03:39 p.m.

I've used E-TTL and E-TTL II extensively shooting chromes with my EOS 3 (E-TTL) , Elan 7E (E-TTL) and Elan 7NE (E-TTL II). There is no discernable difference between results with on-camera flash, bounce or wireless. In fact, plain E-TTL always gave me good and consistent results, at least with chromes and with few user overrides. E-TTL implementation on my 10D isn't nearly as good and requires lots of user override to get consistent results. Perhaps E-TTL II has more perceivable benefits in the digital domain. Chromes are actually much more forgiving of small exposure errors than digital.

Jim Simon , Dec 21, 2004; 03:42 p.m.

My 2 cents. I use the 550 on an EOS 3 and now on my D1 MkII. On the 3 all the head shots had to have FEC so that the faces were not blown out (bounced or direct). On shots that were fill, I would often go all the way to minus 2. On the D1, using minus FEC indoors always results in underexposure. Outdoors as fill, it is a preference matter. The ETTL II seems to be very good virtually all the time.

Alexandru Petrescu , Dec 21, 2004; 04:20 p.m.

Are the results more reliable in difficult situations?

Yes to me. I used 420ex on E-TTL and E-TTL II bodies on similar reflective subjects (traffic signs) and results seem much better to me - they range from seeing only a little white circle on the sign to getting a clear sign as if it were non-reflective (E-TTL was almost always giving a too white too reflective unreadable sign). Slides. No exact measuring though, and it's only a few signs I've shot.

Alex, a happy shooter.

Amit Bronstein , Dec 21, 2004; 04:44 p.m.

Can anyone point me to a good technical article that explain these 2 methods in details. I came from the Nikon world and things there are different. Now I am imegrating to the 20D world and understanding the flash issue is important to me.

Thanks, Amit

Jason Kim , Dec 21, 2004; 04:58 p.m.

I will comment on 580EX with 10D and 20D.

1. I need +2/3 FEC on both cameras for my taste.

2. 20D seems to have more pleasing WB maybe due to 580EX and 20D E-TTL2 communicating better.

3. Difficult situations(white bridal gown/black tux) handle differently. On 10D, you need to point focus square to mid tone to get correct exposure but on 20D, I focus and reframe and get correct exposure. Very easy and fast.

4. Bounced flash is about equal.

5. Fill flash is more consistant on 20D.

I think best thing about E-TTL2 is that you are no longer tied to focus point to get correct exposure. Focus, reframe and shoot. It's that easy with fairly consistant results.

Jim Strutz - Anchorage, AK , Dec 21, 2004; 05:09 p.m.

Amit asked, "Can anyone point me to a good technical article that explain these 2 methods in details." Yakim asked us not to post it, but here it is. The answer to all your questions, and a starter for all your new ones. http://photonotes.org/articles/eos-flash/

Brad W , Dec 21, 2004; 06:06 p.m.

Direct responses to you qu's Yakim. :

1. Yes, to me there is a noticeable difference, ETTL-II gives much better results on my 20D than ETTL on my 10D (more consistent exposure, less over-exposure). Original ETTL seemed to work fine for me on my EOS 3, however. I still use a diffuser but more out of habit than as a result of 1st-hand testing.

2. You do not get a choice between ETTL I or II - it's fixed in the body.

3. ETTL-II works in all modes as far as I know. It's a totally different algorithm and method for estimating flash exposure. It is not simply a refinement of ETTL.

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