Common Questions about Strobe Firing, TTL, and Sync Speeds

Will my strobe operate TTL?

Most DS strobes will operate in TTL when set properly and attached to an Ikelite TTL system. We've tried very hard over the years to produce what we call "smart" housings and "dumb" strobes. By building sophisticated TTL electronics into our housings we can usually make sure even older digital strobes will be able to communicate according to the newest TTL protocols. So your strobe is still good long after the camera becomes obsolete.

Compatibility of DS strobes with TTL electronics varies per camera make and model. Some of our original older DS strobes may not work, or may require an update, to be used with the most modern TTL protocols. Refer to the web page or instruction manual for your housing model for complete details on strobe compatibility by serial number.

New strobes are compatible with all past and current Ikelite TTL systems.

Non-Ikelite strobes are not capable of powering or communicating with our TTL electronics. SEA&SEA, INON, and Nikonos strobes support manual exposure only.

Can I verify that TTL is working?

Set the camera at its widest aperture (like f/2.8) and trip the shutter while the camera and strobe are aimed at a very close, well-lit subject. The strobe should produce only a small blip of light. Repeat this with the lens covered and the strobe should produce a full power flash.

What causes my strobe to fire by itself?

Some strobes will emit a flash by themselves when turned on or switched between power settings. This is considered to be normal as long as the strobe does not continue to fire by itself when left in that setting. Repeated auto-firing or self-firing of the strobe is almost always caused by water in a connection or a bad sync cord. If the problem persists after replacing the sync cord, please return the strobe to Ikelite for evaluation.

An AF35 or DS strobe attached to an optical sensor may fire at very shallow depths or when they detect the flash from another diver's camera. This is normal and unavoidable. To conserve batteries the strobe should be turned off when not in use.

Can my strobes sync when shooting at shutter speeds faster than 1/200 (1/250)?

At this time, it is not possible with our strobes, nor with our competitors' strobes. The maximum sync speed is set by the camera. Surface flash units send a code to the camera telling it to use high speed sync (also known as focal plane flash). However, this dramatically reduces the guide number (brightness) of the flash, making these high speed sync modes virtually useless underwater. These modes also require the flash to fire in a series of pulses at a very high repeating rate, which is devastating to certain components in your underwater strobe, decreasing reliability and increasing failure rates!

Can I use Rear Curtain Sync?

It depends on the camera's flash protocol—i.e. when it sends a signal to the external flash.

For Nikon DSLRs, we accommodate rear curtain sync.

For Canon DSLRs, we do not support Rear Curtain Sync as it would preclude the use of non-Ikelite strobes. Most of our Canon DSLR systems can be updated to support Rear Curtain Sync for a nominal service fee. Contact us for more details.

For Canon G-series cameras up to and including the G16, we do accommodate rear curtain sync. However, Canon modified their flash protocol with the release of the Canon PowerShot G1X Mark II. At this time, we do not support Rear Curtain Sync with the G1X II or later models.

Why is the half of my image black?

This usually means you are shooting at a very fast shutter speed. Make sure high speed sync is turned off and that the camera reverts to a shutter speed of 1/200 or 1/250 when you take a photo. If the camera does not limit your shutter speed then either you have a bad camera setting or there is a problem with the TTL circuit.

Related Articles

Large Bore M24 Port Modifications for HDMI Monitor Bulkheads
Large Bore M24 Port Modifications for HDMI Monitor Bulkheads
The 200DL housing series now supports the attachment of third-party HDMI monitors via HDMI 2.0 through a dedicated large bore M24 accessory port.
TTL Testing and Troubleshooting
TTL Testing and Troubleshooting
Make sure you're set up for success. Here's the complete guide to TTL flash, whether you're setting up for the first time or diagnosing an issue.
Nikon Z6 II, Z7 II 200DL Underwater Housing Compatibility Update
Nikon Z6 II, Z7 II 200DL Underwater Housing Compatibility Update
The 2020 Nikon Z6 II full frame mirrorless camera is a perfect fit in existing housings engineered for the original Z6 with the addition of a simple upgrade kit.