Need advice on 20D/Ike system

Have new 20D, Ike housing and DS-125 system. Haven't gotten it wet yet, but trying to learn the system dry. With the stobe set on TTL and the housing set on TTL every picture is underexposed. Have tried with camera in P mode and also on manual using various combinations oF F-stops and shutter speed. Changing flash exposure compensation (even all the way) does not change the exposure levels. Pictures still come out underexposed.

Leaving the strobe in TTL and changing the housing to manual I can get the correct exposure levels.

Shouldn't I be able to get the correct exposures without having to manually control the strobe through the housing?

Lens is EF-S 60MM.

Your topic doesn't indicate if you have one or dual DS-125's. I've been using dual DS-125's on the same set-up with a Canon 100mm Macro and generally get pretty accurate exposures using manual settings and TTL. Wide angle is another story, however. Usually shoot with strobes on manual with my 10-22mm. If you shoot RAW, and if you don't you should, you can correct exposures when processing in Photoshop.

Set to manual, f8, s 1/100 at ISO 100 and take a picture with the rig aimed at a mirror. You should see the strobe flash in the picture. Do you?

fowlplay is supposed to get TTL. You MUST have the new digital sync cord with blue band to get TTL. Also check that the connector is completely into the hot shoe of the camera, and stays there as you slide back with camera into the housing. Moving out 1/16" is enough to loose the TTL contact connection.............

Have the new sync cord with blue band. Will check the connection, but am pretty sure that it is connected properly. Saw one time when I installed the camera in the housing that it wasn't fully seated, so I have checked that on susequent installations.

Have one DS-125.

Fowlplay,

Is your DS125 strobe set to TTL? Is switch under housing tray set to use DS125 versus DS50?

Finally, possibly grease on pins at either end of your synch cord connection (from greasing the o-rings) could prevent TTL signals from going back and forth between camera and strobe.

Hope this helps!

David Haas

Switch is set to DS-125. No grease on connections. Haven't put it in the water yet. No lubricant used on o-rings. Connections clean and tight. Made sure cable was seated all the way on the hot shoe. Checked before putting camera in housing. Took pictures, all badly underexposed. Took back off and checked connections. Still seated all the way on the hotshoe. Strobe is firing, but exposure is not correct. Strobe and housing both set on TTL.

Can you take the battery off the back of your strobe and look at the serial number stamped on the strobe head? What is that number?

Cheers

James

Number is 6603.

James is asking because older DS-125 require updates to work in eTTL mode. Here is the information copied from Ikelite's site:

"DS-125 SubStrobes with Serial Number below 2,500 require a $150 update to operate with the latest eTTL conversion circuitry. DS-125 SubStrobes with Serial Number between 2,500 and 4.999 operate well with the latest eTTL conversion circuitry, but require a $50 update to provide optimum performance. *"

Since yours is above 4999, you don't need an upgrade, something else is going on. Do you have a land flash for your 20D? Does it work ok? Can you get properly exposed pictures in manual mode (ie. with the DS-125 set to manual in full or 1/2 power)?

Broken wire in hot shoe or possibly a short between pins is a possibility. Does the strobe sync at 1/250 second with the housing in TTL and the camera in manual mode? The way to test this is to set the shutter speed higher than 1/250th of a second. Then press the shutter release half way. The shutter speed should drop to 1/250. Does the pushing the FEL button (asterisk) cause a preflash to fire? If one or both of these things is not happening, E-TTL communication is not taking place.

Strobe must be okay to produce different manual powers. This leaves a broken wire in the sync cord or hot shoe connection as probable cause of strobe not receiving TTL communication. We should look at both............

Fowlplay,

Can't believe I'm asking this, but here goes....Any chance you dialed in minus EV compensation on your camera and this is causing gross underexposure? Although this would only affect less flash if you were in P, Av, or Tv mode.........

Hmmm.........Thinking, thinking, thinking........Dirty connection on your hot shoe of the camera itself leading to no true eTTL2 communications between strobe and camera?

Do you have a Canon land flash you can try? Or do you get good flash exposures with the built in pop up flash? Even on "P" mode to make sure nothing is wrong with your camera itself?

Solving problems is what the board relishes, so keep posting.....

David Haas

Shutter speed reverts to 250 when set higher. FEL button causes the strobe to preflash. Hotshoe is clean. Do not have another external stobe to try. Using internal strobe gives excellent results. Have run the scale on exposure compensation when in TTL and always get extremely underexposed pictures.

Frustration level is pretty high. Appreciate all the suggestions. Making no progress. Should I return for testing?

Should be sent directly to Ikelite. There is no reason to endure the aggravation of a product that is not performing as intended. The 20D and eTTL2 have proven to be one of the best TTL systems...........