To TTL or not and what is the strobe

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Just got back from Grand Cayman, where I was attempting to use my new Inon D-2000s with my SP-350. Had lots of problems with sync, and inconsistent firing with the fiber optic cable. To be truthful, I was trying to slave it off my Oly ttl flash, as the Inon AD mount interfered with my Sea & Sea WA lens. Stopped in at Cathy Church shop at Sunset Divers, and they said, "Why did they sell you that? You should have bought the Z-240, and had hard wired true ttl." They strongly recommended the YS90, but said the Z-240 is also quite good, and better in some ways. They use both with the Heinrichs/Weikamp bulkhead, and have sold and used tons of them. They said they had some earlier teething problems, but the bad units were replaced by Mathias. All the current units are apparently reliable. Cathy Church rents these things to tourists, uses them for teaching, etc. and were sold on the H/W and ttl strobe combo. They had a big box of the H/W's to go with a wall full of SP-350's.
 
f3nikon:
I recommend Ike's as well the Substrobes/A35 from ebay or new from B and H photo. 95% of U/W flash photos are manual the other 5% bought all that "TTL" stuff, found out it does not work but are still in denial.

"minority of the time" all it takes is for it to not to work at that once in a lifetime moment! :rofl3:

I find the two sides facing off to be amusing. The manual control folks say that TTL may sometimes fail and you will miss those once in a lifetime photos.

At the opposite extreme, they say that the digital camera has instant review, so you can shoot, examine, adjust, and reshoot. Sounds to me like you just missed that once in a lifetime photo when you had to adjust and reshoot.

There are pros and cons to both sides. Try one for a while and then switch sides if you wish. If you wish, try whichever side is less expensive first.

David
 
AUTiger:
I find the two sides facing off to be amusing. The manual control folks say that TTL may sometimes fail and you will miss those once in a lifetime photos.

At the opposite extreme, they say that the digital camera has instant review, so you can shoot, examine, adjust, and reshoot. Sounds to me like you just missed that once in a lifetime photo when you had to adjust and reshoot.

There are pros and cons to both sides. Try one for a while and then switch sides if you wish. If you wish, try whichever side is less expensive first.

David

Actually it was the TTL user that said it could fail:
“Or join the 21st century and use TTL. It works fine for most of your shooting. It can be fooled, just as it can on land, but these are a minority of the time.”

The advantage of shooting in manual strobe control, which is its really semi auto mode, is that with the camera set at aperture priority, one of the variables is removed.

And that variable is the light intensity from the strobe, the intensity is fixed, you control the amount of light hitting the CCD sensor via the aperture opening, the background is controlled by a varying shutter speed, controlled by the camera’s exposure meter. The shutter speed is meant to “float” or adjust the background depending on the “manual” opening of the aperture.

The advantage to this is that you have a known or predetermine range of strobe exposure control. Meaning that at a give range (less than one or two feet or more) you know exactly what the exposure will be at a given distance, because the strobe power is fixed. I would just push or pull the entire rig (camera and strobe) into a known range and fire.

And this is where it gets hairy…

With TTL strobe control in film cameras (Digital PS cameras do not have TTL strobe control) the light intensity of the strobe is variable depending on what the camera’s electronics is telling the strobe.

The camera’s working end of the TTL system is a photo sensor mounted inside the camera looking at the center of the actual film plane itself. The electronics is programmed to make this area 18% of gray meaning that a white object should be light gray and a black or dark object should also be gray. So now, even if the TTL system is working as it should, we have the white or light colored objects UNDER exposed and the darker objects OVER exposed!

And it does not stop there! Remember that in a TTL system the camera only cares about the area in the center of the film. So what if the subject does not occupy this center area of the film, like that fast moving once in a lifetime subject? You guess it, that subject was just blown out to the overexposed ROUNDFILE, because now the camera thinks that the subject is much farther way than it really is and is now telling the strobe to pump out more power!

Let's fast forward to the digital age...TTL strobe control does not work with PS digital cameras because the CCD sensor cannot reflect the light to the photo TTL sensor as it did with film. So what does the camera maker do? Mount a photo sensor OUTSIDE the camera just above the lens, now the light hitting the outside sensor may or may not be the same intensity as the light hitting the CCD sensor inside the camera.

And to make matters worse we place the camera in an underwater housing so even if we cover most of the internal flash, some light still escapes, bounces off the housing and back to the photo sensor and telling the system to shut off the flash power even before the image is fully exposed. using the hotshoe for an Olympus strobe will help but the housing may now be blocking the out sensor and not blocking the CCD sensor inside the camera.

Well now you can say that one can always adjust the exposure compensation on the manual controller or on the cameras buttons…well I could have done that as well in manual mode, at less the cost! Plus you had better be sure that manual controller is pointed at your subject because if the controller does not see what the camera's lens sees, distance wise, the exposure could be over or underexposed. Because the manual controller is NOT a TTL (Through The Lens) system.

In conclusion we really have an auto exposure system that tells YOU how to shoot, your subjects better be in the center of your viewfinder or else! So much for that "artsy" off center subject stuff I guess thats why they call it a "slave"
 
Larry C:
Just got back from Grand Cayman, where I was attempting to use my new Inon D-2000s with my SP-350. Had lots of problems with sync, and inconsistent firing with the fiber optic cable. To be truthful, I was trying to slave it off my Oly ttl flash, as the Inon AD mount interfered with my Sea & Sea WA lens. Stopped in at Cathy Church shop at Sunset Divers, and they said, "Why did they sell you that? You should have bought the Z-240, and had hard wired true ttl." They strongly recommended the YS90, but said the Z-240 is also quite good, and better in some ways. They use both with the Heinrichs/Weikamp bulkhead, and have sold and used tons of them. They said they had some earlier teething problems, but the bad units were replaced by Mathias. All the current units are apparently reliable. Cathy Church rents these things to tourists, uses them for teaching, etc. and were sold on the H/W and ttl strobe combo. They had a big box of the H/W's to go with a wall full of SP-350's.

Sorry to hear about your problems on your rig, but did you not test your system on before the dive trip and "hardwired" strobe...what a novel idea. The question is for Cathy Church, how can it be "true ttl" when the SP-350 is not setup for "true ttl"?
 
Aperature priority takes away creative control of an important variable, depth of field. I control both speed and aperature, to freeze action and control depth of field, and let the strobe do the work of appropriately lighting the scene.
 
Another option was sugested to me at the dive show last weekend.
Mount a video flood / powerful torch and use that to light the subject, set exposure, aid to the autofocus, and as a night light.

This does appeal in many ways, particularly the autofocus, and I like to have a torch to look under all those rocks etc.

Has anyone tried this option?
 
victor:
Another option was sugested to me at the dive show last weekend.
Mount a video flood / powerful torch and use that to light the subject, set exposure, aid to the autofocus, and as a night light.

This does appeal in many ways, particularly the autofocus, and I like to have a torch to look under all those rocks etc.

Has anyone tried this option?

I've tryed it with my HID can light. It can be done but there were two problems - the main one being that the torch light output is not up to stratch when compared to even a basic dedicated strobe, and so required slow blur-incuding shutter speeds. It worked ok if lots of background light but forget about freezing action or getting a black background.

The second problem is when I used the torch in combination with the built in strobe - the HID light in my photos comes out green when the white balance is set for light from the cameras flash.

Cheers,
Rohan.
 
Tassie_Rohan:
I've tryed it with my HID can light. It can be done but there were two problems - the main one being that the torch light output is not up to stratch when compared to even a basic dedicated strobe, and so required slow blur-incuding shutter speeds. It worked ok if lots of background light but forget about freezing action or getting a black background.

The second problem is when I used the torch in combination with the built in strobe - the HID light in my photos comes out green when the white balance is set for light from the cameras flash.

Cheers,
Rohan.

I was hoping someone had tried this as I don't know anyone who shoots video to borrow a light from. I don't know what the temperature of a video flood is compared to an HID light.
Oh well back to the search for a strobe with a focus light that I can use on my PT-023
 
I'm looking to buy a ttl converter from mike-dive as I don't need to replace pt-023 bulkhead. So I won't be able to break my housing :) As c-8080 has problems focusing in low light conditions I'm getting one with a focus light. Did you find a list of supported strobes from mike-dive? My german isn't good enough or they didn't have a list available on their website. Now I'm leaning towards inon z-240 for it's high power/guide number, fast recycling time and guide light. There's also sea&sea ys110 that meets my requirements. Other than those (maybe inon z-220 but it's discontinued) I haven't quite found any goodies. Have you tried digital Diver (http://www.digitaldiver.net/strobes.php) to compare different strobes? If you come up with a solution please let me know since we both have same system and both are looking for a strobe.
Cheers!
 

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