Trays and Strobes

[bfisher]

I don't know if I'm in the right place but have a couple questions. I'm just getting into UW photography. I recently bought an Olympus SP-350 and PT0-30 housing.

My questions concern strobes and hookups. I see trays advertised for specific cameras. Considering that modt cameras have a threaded base for tripod use, would not most trays work on any camera? Secondly, are TTL connectors on cameras universal or brand specific. Is it necessary to go the TTL route?

I am looking to get a strobe or two in the future, but am somewhat budgeted out at the moment. Seven trips to the Caribbean this year doesn't leave much money for photo gear. Any advice you can give would be greatly appreciated.

And please don't tell my wife I'm looking. LOL

 

[f3nikon]

I would first build a wrap around frame/tray to help protect the housing, a good one is at this site:

http://kayakdiver.com/divephotos/camerasetup.htm

Check out the Thread by Sea Yoda about the Sunpak strobe, he has some very good information on this.

Yes the tripod 1/4-20 screw is standard and will bolt up to your housing. With TTL..don't even go there, start with manual mode.

 

[mddolson]

f3nikon,

Please elaborate on your advise to go manual vs TTL.

I have an Olympus C750 with Ikelite Housing.
I bought a Nikonos sb-105 strobe and have it wired to work in manual mode.

Since I am just starting out I made this choise for $ reasons.
I found a new SB-105 at a real bargain.

Mike D

With TTL..don't even go there, start with manual mode.

 

[RonFrank]

f3nikon,

Please elaborate on your advise to go manual vs TTL.

I have an Olympus C750 with Ikelite Housing.
I bought a Nikonos sb-105 strobe and have it wired to work in manual mode.

Since I am just starting out I made this choise for $ reasons.
I found a new SB-105 at a real bargain.

Mike D

I would suggest that there is some real advantages to TTL, however with your setup you don't have that option.

I'm not sure there is a strobe out there that does TTL with your camera other than to maybe house an OLY topside strobe in a housing, but I could be wrong

 

[f3nikon]

f3nikon,

Please elaborate on your advise to go manual vs TTL.

I have an Olympus C750 with Ikelite Housing.
I bought a Nikonos sb-105 strobe and have it wired to work in manual mode.

Since I am just starting out I made this choise for $ reasons.
I found a new SB-105 at a real bargain.

Mike D

Sure, in manual mode your strobe output is "fixed" so to get the correct exposure one would need to either vary the distance between the strobe and the subject or change the camera's lens opening (aperture) to decrease or increase the amount of light coming in to the camera or change the strobe power out. Manual lets you select what YOU think is the correct exposure and not what the camera thinks is correct. Bracketing the shots is the key and manual mode does this very well.

TTL is a closed loop feedback system, the strobe and camera talk to each other. As the light from the strobe strikes the subject and makes its way to the film, the light bouncing off the film is measured and a signal from the camera to strobe tells the strobe that there is enough light hitting the film so you can turn off now.

Notice I said film for the TTL example, TTL does not work with digital because the CCD sensor is not as uniform as 35mm film in bouncing the light. What most digital camera makers do is to place a photo eye near the lens opening outside the camera's body, this is not a real "Through The Lens" it's more of an automatic exposure. Which may or not work esp. when you place your camera in an U/W in which this sensor is then blocked due to the housing and port.

Just hardwire your SB-105 so that it fires all the time, then let the photographer in you take care of the rest.

I did try TTL mode on both land and U/W a great concept, but I always go back to manual.

The SB-105 is a very good strobe try ebay for some older Ikelite strobes.

 

[mddolson]

f3nikon,

Thanks for the explanation.
I have heard the same advise before but you are the first to explain why with any detail.

thanks again

Mike D

 

[RonFrank]

Notice I said film for the TTL example, TTL does not work with digital because the CCD sensor is not as uniform as 35mm film in bouncing the light. What most digital camera makers do is to place a photo eye near the lens opening outside the camera's body, this is not a real "Through The Lens" it's more of an automatic exposure. Which may or not work esp. when you place your camera in an U/W in which this sensor is then blocked due to the housing and port.

You seem to be lacking in understanding how flash TTL works.

There is no photo eye on the outside of the body.. at all. Where do you get this information? iTTL uses a 256 segment meter that reads light off the sensor plane to judge exposure. In addition iTTL uses something like up to nine pre-flashes to determine accurate exposure when doing flash.

PnS camera's while maybe not as advanced as Nikon's iTTL also use sensors at the focal plane and preflash to determine the flash exposure.

 

[Larry C]

As Ron said, you can use TTL with your set-up. There are three ways to do it. Easiest is go on e-bay and get an Oly FL-20 flash and FLE-01 Housing. If you're careful you can score both of them new for about $220.00 including freight. The flash isn't really strong (20 meter guide #) but it works really well topside and for macros and close up wide angle shots. You can buy a ttl conversion board for your housing from the German guy listed on many threads on ttl for Oly. That will let you use a standard Nikonos type wire which will work with your SB-105, S&S, etc. It'll cost you around the same $200 as I recall, + whatever you spent on the strobe. If you didn't already have the Oly housing, Ike has a set-up for his housings only to work with non Oly strobes on ttl. As I recall, I think I saw where Ryan will actually sell you the German unit and install it for a fixed price.(Don't quote me, it might have been somebody else-I couldn't find the post. If you talk the wife into more budget, and go crazy like I did, you can order the Sunpak strobe mentioned earlier for $179 at Helix or other online camera shops and use it for a slave strobe to get more power out of the Oly. I'm still waiting for my Sunpak, 5 week B/O so far as I think everyone who has read the threads went out and bought one. I'll post pictures of my set-up and some of my shots as soon as it arrives and my boat gets it's new $5000 transom. See, photography is cheap. It's those darned boats to get you to where the good pictures are that cost money.

 

[f3nikon]

You seem to be lacking in understanding how flash TTL works.

There is no photo eye on the outside of the body.. at all. Where do you get this information? iTTL uses a 256 segment meter that reads light off the sensor plane to judge exposure. In addition iTTL uses something like up to nine pre-flashes to determine accurate exposure when doing flash.

PnS camera's while maybe not as advanced as Nikon's iTTL also use sensors at the focal plane and preflash to determine the flash exposure.

More than you think Ron, more than you think... eyebrow

There is a photo eye in the poster's camera (see picture below) its in the 2 oclock position above the lens. In this case they should call it TTTL or Through The "Top" of the Lens.

http://www.nikonians.org/dcforum/DCForumID86/668.html

Because, Ron, why do you think Nikon has to fire a series of preflashes in order to make the iTTL work? And that is before the mirror is lifted in a DSLR, so the photo sensor cannot be reading off the CCD sensor (as in film) because the mirror is still in the way!

A true TTL system as we know it with film, has a sensor reading the light bouncing off the film in real time then turning off the strobe.

The iTTL does not do this, it has to fire a series of flash in order to gauge the correct amount of flash needed before the light even hits the CCD sensor.

Actually my Nikon Rep. told me the same thing:

"No, this is not red-eye reduction or low light AF assist. iTTL is a replacement mechanism for how film cameras read the light level off the film. Since the sensors in DSLRs do not reflect light like film does, the camera is unable to read the light level from the sensor directly. Therefore, the solution that Nikon came up with is to fire pre-flashes, read the results of those pre-flashes, then fire the flash and take the picture. If you are familiar with control system theory, one would consider the method used by film cameras to be closed-loop since it is reading the actual light level from the film prior while taking the picture and iTTL open-loop since all calcuations are done prior to taking the picture. The thought is that since so little time has passed since you did the pre-flash calculation, the light levels in the area are likely the same and your pre-caculated guess will yield a good result.
This is all well and good, except that the camera leaves the mirror down during the pre-flash period. It takes noticable time to raise that mirror, causing a brief, but noticable, delay. Coupled with the percieved brightness of the pre-flash, some people consistantly blink during the pre-flash and the main flash catches them with their eyes closed."

and another:

"Digital came later with sensors which reflect very little light and conventional mirror box sensors had big trouble. Exposure adjustment during exposure was dropped because it was not accurate in a short enough time with the low reflectance levels."

Anyone in the Nikon Club should have known about this a long time ago.

 

[f3nikon]

f3nikon,

Thanks for the explanation.
I have heard the same advise before but you are the first to explain why with any detail.

thanks again

Mike D

You're welcome.