Canon S50 questions

Hello,

I just got a Canon S50 and I have a Canon housing for it.

About 2 weeks ago I went to Florida and did a lot of diving and tried for the first time my new S50 underwater.

My setup include a Bonica reflective strobe and I try to shoot in automatic mode (big mistake) and in Tv mode with a time set of 1/125. I don't think my strobe got synced too good so I was wondering what settings everybody else use?

- Flasy sync (1st curtain or 2nd curtain)

- Exposure time?

Is the flash of th S50 TTL?

Does the camera turn off the flash or the shutter?

Any sugestions?

If you want to see the pictures I took you can go to www.pambucol.com and then Trips and then Key Largo Summer 2003

Thank you

Vlad

Hi I don't know the Strobe that you are using. Does it support TTL? As Far As I Know only hte Ikelites with a TTL Sensore does this with a PreFlash Camera (i.e the S50)

As Fra as I know you have to use the Strobe in Manual mode and this would probably lead to use the Camera in Manual Mode also. But I haven't done so until now.

Simon

Hi,

No, the Bonica strobe doesn't support TTL. It is a reflective strobe so the camera flash will turn it on and then the strobe flashes for a pre determined time (not settable), BUT, if the camera's TTL system is sort of like:

1) Turn camera flash on

2) Take light measurements on the reflection from the flash on the subject

3) Set shutter and time based on the light measurements

4) Turn off shutter.

... then it would not be a problem with a non TTL flash since it will fire at full power and it will fire a predetermined time but the camera would open and close the shutter based on its measurements.

Does anybody know what is the pre-flash timing?

Did anybody put this on a scope (oscilloscope that is)

Thnx

Vlad

As far as I know, The S Series do multible Preflashes (with different intensity) and does the main flash afterwards. To work with the preflashes your flash has to copy the Preflashes exactly. (The Iklite TTLSensor does this).

I think you have to use the Camera in Manual mode so it wont emit preflashes.

But please someony correct me if I'm wrong

Simon

I don't have the strobe or the camera you're talking about but I can try and give some input into what's (probably) happening.

Sounds like:

- the canon sXX cameras emits a pre-flash

- tbe bonica is a fixed output slave strobe and not pre-flash compatible

If the above are true then what's probably happening is that the strobe is trying to fire it's fixed output on both the pre-flash and main flash of the camera ie the bonica is treating the pre-flash and main flash as two separate 'triggers' to fire twice. It is firing it's fixed output on the pre-flash leaving it with no juice to fire on the main flash. This is what is looking like a 'shutter sync' problem to you.

To get your setup to work you will need to do the following (if at all possible):

- set the bonica to ignore pre-flash (which it sounds like it can't)

or

- disable the pre-flash on the camera

I think you have to use the Camera in Manual mode so it wont emit pre-flashes

I doubt if this is true but easy enough to determine - just shoot in manual and if you see more than one flash then it does not disable pre-flash. Make sure you don't have 'red eye reduction' turned on. Usually switching off pre-flash is a flash function e.g. on the Olympus C5050 you select 'slave' flash instead of TTL.

HTH

I have S40 based set up, and your questions got me looking into the matter. The S50 should be the same as the S40. My S40 will preflash once in all modes except Manual. Therefore, if you do not have a strobe that can account for the preflash (Ikelite DS125 w/ TTL sensor), then you will have to use manual setting mode. Basically this means that you must spend some time experimenting and adjusting your ISO speed, f-stop (apeture), and shutter speed untill you get the proper exposures based on depth and distance to subject. The good news is that with digital, you can take as many pictures as you want and get instant feedback and throw away the ones that you don't want. Also, Photoshop and similar programs can fix many of the otherwise bad exposure levels.

Hope this helps a little...

Dave Bush

Florida

Dave,

Welcome to Wetpixel.

Cheers

James Wiseman

Ok, looked at the S50 on the Canon site in more detail (pretty good detail on the site) and found this:

It seems like you can turn the pre-flash off (non-TTL) in Aperture Priority, Shutter Priority and Manual shooting modes (Av, Tv and M) by setting 'Flash Adjust' to Manual. See Flash Adjust and Features Available per Shooting Mode.

Looks like this is also available on the S45.

HTH.

A very late additon to this topic

The Canons (S30,40,45,50) emit ONE pre-flash if the flash is set to Auto mode.

No pre-flash if you set flash to manual mode ( which is available in Manual, AP, Tv at least)

It does not do TTL real time metering so unless you have a strobe with an inbuilt meter ( eg Inon...sea and sea??)...or a strobe that will copy your cameras flash pattern ( my interpretation of the Ikelite set up) you need to go full manual ....

Or am I repeating what everyone else has just said???

Tack

Yes, Tack, you made a good summary.

BTW, the model numbers in your sig file look wrong.

UWL-100 is the Wide Angle lens

UCL-330 is the new Close Up lens

Cheers,

lol

Thanks Mars.

Just amended it as I now have the Inon WA lens too!...maybe one day the dome?

QUICK...someone stop me!!!! B)

Remember...he who dies with the most toys...........

Tack