Godox TT685s and AD600TTL with Sony A7RII

What I’ve learned in the first couple of days

TT685s Notes¹:

The TT685 is a creditable Sony compliant TTL speedlite. One of the first questions asked is “how powerful compared to other speedlites?” So, here’s a picture of manny, along with a color checker to illustrate. ISO 100, 1/200, F11, 10 feet with auto zoom at 70mm. (clicking on the image will open it in a window that has the EXIF data captioned.)

Note: None of the images used to illustrate this report have been processed other than resizing and cropping.

As a comparison, I then put a Nissin Di700a in the camera hotshoe and did another image. The results are nearly identical. Certainly within 1/3 EV depending on where I took a reading in Lightroom.

The TT685s construction quality is comparable to other Godox products and looks and feels as hefty and well built as my Canon speedlites over the years. Its probably a bit heavier and bigger than the Nissin Di700a.

The flash head is the same size as a Canon 580EX II so any slide on modifier that works with a 580EX II will work with the TT685. The same is true for the v850 and I expect will be true for the TT860IIs when its released.

The external power plug is in the front of the flash body under the red focus assist light. It is a Canon plug on the Sony variant. While some may find that problematic, I like it. It means I can use a Paramount PM-CZ cable to connect to the  PB9600 battery pack. Paramount does not make this cable with a Sony plug.

When going through the various wireless selection options the Sony camera flash settings have to be set appropriately as well. When the TT685 is set to the optical (lighting flash symbol) wireless mode the camera flash mode has to be set to WL. If its not, the TT685 screen displays a message “Set your Camera”. Once the camera is set to WL flash the TT685 will only cycle through the wireless settings that work with the camera in WL.

All the other wireless options require the camera to be set to one of the three other flash modes. When the TT685 is set to TTL as an on-camera speedlite without off camera lights, and with the flash head aligned with the lens, there is a distance scale depicting the useful range. The range changes to accommodate the lens focal length when A zoom is activated. It also changes to accommodate shutter speed in HSS mode. Adjusting the shutter from 1/250 to 1/320 for F8.0 ISO 100 and a 35mm focal length, the distance scale drops from 10ft to 7ft. Test exposures at the two shutter speeds are nearly identical. Using Flash Exposure Compensation suggests that the flash is at about 1/2 power. i.e. Plus one EV results in an increased exposure, while plus 2 EV is the same exposure as +1.

There is no need, with the Sony cameras, to set the speedlite for High Speed Sync (HSS). Having the speedlite in the hotshoe releases the x sync shutter speed lock.

AD360 or V850 H mode via the XTR-16 and XTR-16s requires that the on-camera Master be in M mode. The remote lights have to be placed in H mode using the appropriate button press on the light. When the TT685 is in TTL mode on the camera it fires in HSS and the camera can access shutter speeds greater than x sync. However, the remote lights with XTR-16/16s receivers do not fire. My first thought was that H mode should work on the remote lights while the on-camera master is in TTL mode. Once I got it setup appropriately with the master in M mode and it worked as expected I realized its probably a TTL communications limitation. The camera communicates to the speedlite to permit FP sync but if its also communicating TTL information its not going to send the FP sync signal via the XTR-16. In my view, this is a limitation. I would like to be able to have the on-camera speedlite in TTL as a fill while using the AD360 or V850 as manual off camera units in H mode.

Here is a two frame gallery showing the difference between fill and no fill from an on-camera TTL speedlite. These were shot with the Master in TTL and Gr A in M with the power set appropriately for the camera settings. The speedlite head was aimed directly at Manny. Notice the shadow behind him on the image with fill? I’ve found, in practice, that the shadow isn’t a problem unless there is a wall or something directly behind the subject.

Invalid Displayed Gallery

The XTR-16 and XTR-16s do not support Multi. The lights have to be switched into multi via button press and then the parameters are set via button press and dial on the light. Apparently there is no means to translate those actions into radio messages.

Summarizing, the TT685s is a Sony compatible TTL speedlite that functions as one would expect. It delivers reasonable results and is well built. The only drawback is that the flash head has no detent locks when it is tilted or swiveled. This can be problematic if a modifier is placed on the head that has some weight. Since I use, at most, a “foamy thing” when bouncing on-camera flash its not a concern. Actually its kind of nice not having to grip the head in such a way as to press the locking button to move the head.

Now on to the capabilities that we are most interested in, the X system wireless radio.

When using the TT685 as a master the camera has to be set to fill flash, slow flash or rear curtain sync. If its set to WL flash the camera drives the TT685 to optical mode. With the camera set to one of the other three the LCD on the TT685 becomes the control panel for managing the on-camera master and three off camera groups.

The master can be set to TTL with the A,B,C groups set to TTL, M or – – -(disabled). The – – – option turns a group off by disabling it. When I first started working with the group function I used – – to turn a group off. I soon found that when reactivating the group the lights will stay in an off condition until the power is changed and the change is sent to the light via the set button. Thus, its better to use the power setting function to turn the light(s) in a group off. That’s accomplished by rotating the dial clockwise pasted 1/128 to off.

I discovered, through experimentation, that the A, B, C group is selected on the XTR-16 and XTR-16s receivers as A, B, C. I first thought it might be 0,1,2. Once I figured it out it makes sense that its A, B, C. That also means there are 10 groups from 0-9 available for other uses. Also, that D, E and potentially F are available as group identifiers for TTL with the X1-T controller.

Setting power on the remote light groups is straight forward. The one thing to remember is that the set button has to be pressed to sent the setting to the unit(s). The sequence is to press the Gr button to select the group, then press the mode button to get the group to TTL, M or – – -. If in TTL or M mode then press the power button and use the dial to set the FEC or M power. Once the power is selected, press the set button to send the setting to the remote lights.

The process is straight forward and quickly becomes second nature. Its been quite awhile since I used the Canon 600EX-RT as a controller for remote speedlites in Gr mode, but this seems quite similar.

Summarizing, Godox has delivered a TTL lighting solution for Sony cameras that is easy to learn and use for multi-source lighting scenarios. Its not perfect, but it offers the tools I have been hoping for to implement TTL lighting with my Sony A series cameras. I don’t have other Sony cameras with a multi-function-shoe, but I expect that they will all offer essentially the same results.

AD600BTTL² Notes:

This battery powered strobe comes with two modifier mount options, the version I received has a Bowens S mount. It is rated by Godox at 600Ws and the version I ordered has TTL firmware enabled. V2.2 firmware supports the Sony X1T controller so I tested it with the TT685s as a master. It works, although with some peculiarities. V2.2 firmware does not support Sony optical wireless. The strobe menu offers Canon and Nikon optical wireless.

I used the mode button to get the strobe set to use its radio and as a slave in Group A, channel 1. I used the TT685 to set group A to TTL. Changing the modes for Group A on the TT685 changed the mode on the AD600. As expected, power changes made on the TT685 were communicated to the AD600 when the set button is pressed.

When the Master is set to TTL and the shutter speed is in the FP sync range the AD600 in HSS mode does not fire at FP-sync. If the AD600 is not set to H mode it switches to H mode when the shutter is pressed with a shutter speed above x sync. However the light does not fire in FP sync.

When the Master group is disabled, or in M mode, the AD600 then fires in FP sync with a TTL pre-flash. This works with AD600 strobes in Gr A and B. This suggests there is something in the firmware implementation on the TT685s that is causing FP sync and TTL pre-flash to not be signaled to the AD600. Hopefully this is something that can be fixed in a firmware update. Its nice to have the option to use the on-camera speedlite for fill when shooting in HSS with an off camera strobe.

Here are two images that illustrate the impact Flash Exposure Compensation (FEC) can have for controlling fill light ratio. The first image has the FEC set to -3EV  for Gr B via the control function of the speedlite master. The second has it set to -2EV. The Gr A FEC was set to 0EV.



As can be seen in this BTS image, the fill light was positioned so it was lighting both sides of Manny’s face. Thus the lighting ratio for the image with -3EV was 1:4 and the ratio for -2EV was 1:3.

Its worth noting that, given the tight arrangement of my test setup, spill from one light source is polluting the shadow area of the other source. This makes the result visually different than the arbitrary settings on the lights.

I plan to redo these tests in a more realistic environment when I have an X1Ts to test next week.

These last three images illustrate the difference between TTL main with TTL fill and Manual main with TTL fill.

The left image is TTL main and Fill.  The center image is AD600 main at 1/16th power with TTL fill from TT685s. The right image is AD600 main at 1/32nd power with TTL fill from TT685s.











More to come.



end notes:

¹ I purchased the TT685s as soon as it was available from a Chinese reseller with direct connection to Godox. I ordered the XTR-16 and XTR-16s from the same supplier at the same time. The order was via Amazon. It took the TT685s about 4 weeks to arrive via international mail.

² I purchased the AD600 lights from Adorama. They brand them XPLOR600TTL/R2. The lights were shipped about 5 days after my pre-order. They also sell the manual version.  Cheetah Stand sells the manual version branded CL-600X.

Disclaimer: From time-to-time I do beta testing for CS. Most recently the V680IIs and X1Ts. Edward provides the equipment for testing and its then returned to him.