ETTL again....

When shooting film with classic TTL 2nd curtain makes some sense - with shutter speed below 1/20 (Due to the realtime evaluation, the resulting flash is a bit weaker then 1st curtain sync). When using ETTL I still can't see any advantage. For long shutter speed like 1/2 or 1 seconds you may freeze some blurred fish with the flash but at 1/15 and ETTL the results of 1st or 2nd curtain are identical. The 2nd curtain sync just starts the flash a bit later, the evaluation is already done with the preflash before the exposure. Somebody will correct me if I'm wrong

Nice picture, Julian!

Satura,

thanks, but I didn't take the pic :-)

I think Craig was talking about 2nd curtain sync with manual flash.

However, freezing the subject at the end or at the beginning of the motion line is the same, no matter if E-TTL or manually.

Julian

Yes, I don't want the TTL but rather manual strobe with 2nd curtain. The whole point is to get the blur going in the right direction, not to make minor corrections on the TTL flash automation. I don't see any reason for slow shutter underwater unless you specifically want motion blur and in that case you always want 2nd curtain.

Apparently with Canon you must have an E-TTL strobe to get 2nd curtain sync even when desiring manual strobe mode. Perhaps a converter to accomplish just that?

Apparently with Canon you must have an E-TTL strobe to get 2nd curtain sync even when desiring manual strobe mode.  Perhaps a converter to accomplish just that?

I don't know. But you can ask the converter's maker: http://www.muenster.de/~matthias/blitz/ettle.htm

The above link shows the converter is now upgraded to do the 10D as well beside the 300D and is ready for shipping. Order is already placed naturally :-)

As soon as I have it installed I will try 2nd curtain sync.

Julian

According to Matthias 2nd curtain sync is not currently supported with the converter.

The above link shows the converter is now upgraded to do the 10D as well beside the 300D and is ready for shipping. Order is already placed naturally

I have ordered my ETTL converter as well. Costs 174 Euros for ETTL converter, hotshoe cable and shipping. Must say I am a bit nervous about the installation. I had to file off a bit of plastic on the 10D hotshoe to expose the ground contact. Hope I dont bugger it all up! :oops:

Has anyone actually installed one of these for a 10D and can report back on its effectiveness?

Hi Andre,

I have had a try with the 300D converter some month ago to ckeck how it would behave on a 10D. It didn't work properly of course.

scratching off the plastic is necassary if you use the 300D hot shoe connector version as the ground contact is different between 10D and 300D. But I'm sure you know that already :-)

Have you choosen power supply with the onboard battery (no external)? So there is just the wiring converter <-> sync cord bulkhead left.

May I ask which housing do you use?

Julian

Julian, I have the UK-Germany housing for the 10D. It is a very neat and compact housing but for that reason there isnt much space to spare on the inside of the housing for additions - so its going to be tight!

I did choose the on board battery type as I figured the CR2032 will last forever and would be easy to replace when required. It does however add another 7mm thickness to the PCB for a total of 1.4cm.

I dont quite get the potentiometer thingy. I am not sure on what basis you would adjust it. Hopefully the manual will explain that or I will EM Matthias. The external version of the potentiometer would probably be a nice feature but that is clearly beyond my tinkering ability!

i just ordered my converter as well. i will be using it with my 10d in a jonah housing.

more news to follow when i receive it and can get it wet!

/paul

Andre,

the potentiometer is for calibrating the strobe control. Not really for flash exposure compensation. As I understood the converter is worked out with the supported strobes. Matthias stated that there is some margin with all those strobes in the manufacturing process. If there are slighty +/- results with certain strobes the potentiometer allows calibration.

the values (-3, ...) on the potentiometer are not f-stops. the whole calibration range is something around one f-stop. Might only be interesting for 300D users being afraid of installing the russian firmware hack offering FEC :-)

The usefull position underwater is the "M" setting. If you turn your strobe(s) into manual mode without the "M" setting you can only use the power settings 1/2 and below. Without "M" the strobe(s) fire a preflash as well. If the power setting is above 1/2 there is not enough flash energy left to drive the mainflash. So far I have understood things.

I will have a switch which disconnects one certain line (Matthias will point out which one :-) ) to have E-TTL and proper Manual available underwater.

Julian

Thanks Julian. I keep on learning more about this. And the more I know the more questions come to mind!

I did not realise that ( without changing the potentiometer settings ) you would be limited to ETTL only with no fallback to Manual if required. Thus putting the srtobe on manual setting will only permit half power output - am I right so far? So if you want both you will have to engineer an external switch or dial - have you got a plan on how to this?

As for calibrating the potentiometer ( assuming again that you dont have the luxury of an external control) it would be easy to set up the correct exposure beforehand by running some simple tests with a strobe. That would be fine if you are using the same one strobe all the time. But what about if you have two strobes or combintions of different strobes? - eg. I use S&S YS 120s, 90s and even a 30 in various combinations. Hopefully the adjustments required are small enough not to be very significant.

And finally, will flash exposure compensation dialed on the 10D work with the converter??

Yikes, this is complicated - maybe I should have stuck with manual flash exposure! I was just getting it right anyway!!

good things first: yes, FEC works. The camera realizes a E-TTL flash connected :-)

Bruder will install the switch in the housing for uw use.

I don't think the calibration should be a problem with different strobes. I guess it's an option if there are constant under-/over results in certain combinations.

I haven't try strobin manually without "M". So the 1/2 power limitation is just my personal thought how it would behave. :-)

Julian

Thanks again Julian.

I will report back once I have done the simple installation of the ETTL converter and done a few tests. If indeed the strobe M position only allows half strobe output, I will give serious consideration to doing a housing modification to install an external switch. Wonder if anybody can recommend someone for that kind of job in Canada??

I am delighted to hear that flash exposure compensation will work. That will probably then compensate for the previously mentioned different strobe responses and it will be possible to improve exposures for those difficult subjects that tend to fool TTL.

If indeed the strobe M position only allows half strobe output

welcome. just to confirm, the "M" setting allows proper manual control. Only when not set to "M" (one of the E-TTL positions of the converter like 0, -1, etc.) and selecting a manual strobe power, it results in max. 1/2 power due to the triggered preflash (in my opinion) :-)

would like to hear about your initial results.

thanks,

Julian

Got it!

sorry, you meant "M" with the strobe position (so I mixed it with the converter "M" position). I should learn to read more carefully :-)

Hi again

I can now report back on Matthia's ETTL converter fot Canon 10D:

Installation was actually quite simple. The bit of plastic I had to scratch off the 10D hotshoe to expose the earth is no big deal - just a few gentle strokes with a small screwdriver removes the extremely thin covering easily.

The converter works well. I ran several tests - initially I was a bit concerned as I was getting overexposures at large apertures and fast ISOs, but as Mattheus explained that will not be the case for typical underwater situations.

I am particularly impressed at how well the flash exposure lock feature works. ( the * button fires a flash and the correct exposure is memmorised) This is going to make CFWA shots very simple.

Flash exposure compensation also works very well.

Single or combination flashes all gave excellent TTL performance. ( I used S&S YS 120, 90 Duo, 90 Auto and 30 strobes)

Matthias has been very helpful with my questions and responded within hours to my EMails.

Overall I am thrilled with it. I will play with it in the pool shortly but the real test will have to wait for my February Fiji dive trip!

Andre,

Where in BC are you? I'm interested in the converter as well. Would like to see how you've got your's set up. I'm in the lower mainland.

Stu

I think the second-curtain synch can only be set through the Canon strobes. There IS a custom function for second-curtain synch with the internal on-camera flash. And the Canon Speedlites (550EX, anyway) enable setting second-curtain synch. I don't think it's possible in manual mode with non-Canon strobes. I'd like to be proved wrong, though.