A review of the new Cactus X-TTL cross platform flash trigger firmware with HSS and TTL

One of the reasons I love shooting with Sigma camera bodies is the combination of the Foveon sensor that delivers great color and image detail with high quality and large aperture lenses like the Sigma 50-100mm f1.8 “Art.” that let me isolate a subject while turning the background into dreamy bokeh-filled canvas like this shot of my daughter.

This combination can deliver some wonderful images however, if you’re like me and you enjoy using off-camera flash, having all that light entering your camera can quickly exceed the flash sync limit. The only two solutions are closing down the aperture – in which case you destroy potential for how creamy that background can be – or use ND filters to reduce the amount of light entering the lens.

The problem with ND filters is there are even more tradeoffs – it becomes more of a hassle to see and properly focus on your subject (depending on the strength of your filter), you are adding another layer of glass that diminishes the overall sharpness and image quality potential, and finally you need a more powerful flash to cancel out the strength of the filter. It blocks all light after all, not just the ambient.

Wouldn’t it be nice if we could just concentrate on the shoot without having to worry about sync speed limits?

Luckily, Cactus has been working hard to bring TTL and FP/HSS support via the existing Cactus V6 II radio transceiver with the soon-to-be released “X-TTL” firmware, which allows TTL for not just Sigma but Canon, Nikon, Pentax, and other otherwise proprietary systems.

We are delighted to offer firmware support for Sigma cameras and flashes. This includes remote power control, remote zoom control, wireless High-speed Sync, and wireless TTL with Sigma’s SA-TTL flashes. The same cross-brand support is also available on the Sigma X-TTL firmware.

– Cactus

I’ve had the opportunity to test this new firmware and not only does it enable me to exceed the camera’s flash sync speed limit but it also allows wireless TTL using Cactus’s own RF60x speedlight (with built-in transceiver). Additionally, you can attach a Sigma TTL flash like the wonderful Sigma 630 onto a second V6 II and enjoy wireless HSS and TTL along with the ability to remotely change flash settings.

For the below shot of my son I set my Sigma sdQ-H to 1/4000s, f/1.4, and ISO 100 and the camera automatically transmitted the power settings to the flash through the Cactus V6 II system to produce this image.

Being able to do this without having to worry about the 1/180 flash sync or installing ND filters is not only amazing, it’s a game changer enhancing my creative freedom to make full use of camera and lens without worrying about sync speed limits.

Here’s another shot similar to the above, however this time it’s using the Sigma 50-100mm f/1.8 “Art” at the long end of the zoom range and wide open.

Here’s a small BTS video from my Instagram.

Here’s a few more examples where I mix the large aperture of the “Art” lens with Strobe lighting to really isolate my subjects.

And lastly a little creative shot with Aranel Cosplay using high speed sync to turn day into night while using flash to light the subject.

For more information on the Cactus V6 II transceiver and/or the upcoming “X-TTL” firmware, please check out the Cactus website or the X-TTL microsite. For more information on the wonderful Foveon sensor and Sigmas own cameras then check out Sigma Imaging.

About the Author

Paul Monaghan is a portrait photographer based just outside of Glasgow, Scotland. You can find out more about Paul on his website, or follow his work on Instagram and Facebook. This article was also published here and shared with permission.