Using a flash is highly recommended with any Sigma camera for the best pixel quality and white balance, unless you only do landscape or street photography.
Sigma often lists the dedicated accessories only, so digging deeper into their websites is necessary to find all the compatible accessories.
So I finally found this in the official announcement of the DP3 Merrill (also applies to the DP1 Merrill and DP2 Merrill, needless to say):
The SIGMA DP3 Merrill is equipped with a hot shoe, allowing use of the dedicated external flashgun EF-140 DG (optional) as well as SIGMA electronic flashguns for SD series such as EF-610 DG Super (optional) and EF-610 DG ST (optional).
The EF-610 DG Super correctly receives the information from the camera, displaying the aperture and equivalent focal length, and confirms the through-the-lens metering.
Whatever the DPM model, make sure that you have the latest firmware installed. As explained by Sigma, it further improves the combination:
Improves the precision of bounce flash shooting when ELECTRONIC FLASH EF-610 DG SUPER SA-STTL and ELECTRONIC FLASH EF-610 DG ST SA-STTL are used.
Admittedly, the setup above will not win any conveniency award, but unbalance is a trade-off to get bouncing capabilities and significantly more power – two valuable merits both EF-610 DG flashes have over the little EF-140 DG.
But what does the EF-610 DG Super offer over the cheaper EF-610 DG ST ?
While the first difference is salient at first sight, the others require a bit more research.
The “Super” version has the following extra features:
- An LCD control panel.
- High-speed synchronization.
- Eight levels of power for manual control, from full power to 1/128 (the EF-610 DG ST has only two selectable levels: full power or 1/16).
- A wireless slave mode (a second, hot shoe mounted unit is required for off-camera triggering with the DP Merrills, since they have no built-in flash).
- A “modeling flash function” allowing the user to check for troublesome highlights and shadows before taking the picture.
In the end, the Sigma EF-610 DG Super is highly recommended.
Links to latest firmwares: