EOS R8: Dark pictures with twin flash

[TSB]

Hello all!

I am a keen beginner dental photographer looking to troubleshoot an issue. I am experiencing mostly dark images while taking shots with a mirrorless camera and twin flash set up. This same set up with an APS-C sensor camera takes the same images without an issue.

This is the set up where the issues occur:R8 (mirrorless)750D (APS-C)

EOS R8 (mirrorless)
EF-EOS R adapter
EF 100mm f/2.8L Macro IS USM lens
Meike TTL MK-MT42 ii twin flash (with diffusers)
Owl Bracket

When taking the pictures, as you can see, only the upper part of the image is visible and everything else is too dark.

HOWEVER, when I use exactly the same set up with an EOS 750D (APS-C sensor), the picture comes out completely fine.

While taking the pictures, both camera bodies have the same settings:

Manual Exposure Mode
Shutter Speed 1/200
F22
ISO 100

As you can see, when taking the picture using the R8, the images hardly appear. I have tried messing around with the shutter speed and iso but they still come out the same.

BUT when i take the pictures with the 750D, i can see the pictures at least.

I would truly appreciate any guidance and help!

[FloridaDrafter]

According to the EXIF data of your two images, the flash did not fire on the R8.

It may have indeed fired, but out of sync.

Newton 

[TSB]

It definitely did fire, but seems to be out of sync, no matter what I tweak!

[rs-eos]

A long shot here, but are there any settings you can try such as first curtain or rear curtain sync with these flashes?  It could be though that the Meike flash is just not compatible with the R8.

[p4pictures]

Can you try a shot with the shutter speed set to 1/125?

I wonder if your Meike Twin Flash is fully compatible with the EOS R8 so a little slower shutter speed might help and is not likely to make a difference to the ambient light part of your shot.

[TSB]

Hi Brian, thank you for replying!

I think you are correct regarding the compatibility. Although the Meike twin flash is working normally with the 750D, it does not want to play ball with the R8.

Meike 1/125 f22 ISO 100Godox MF-R76 Ring flash, 1/200

I have tested out other flashes like the Godox MF-R76 with the R8 set up and it is working fine. Unfortunately to get the most perfect intra-oral pictures, twin flashes are by far superior. 

Would you recommend any other setting changes or would it be obvious that I need to invest in other twin flash systems? (any recommendations as I use twin flashes with diffusers)

[normadel]

Your best bet may be to use a Canon Macro Flash....Macro Ring Lite MR-14EX II or Macro Twin Lite MT-26EX-RT.

Pricey, but they will provide full E-TTL capability and guaranteed camera compatibility.  You take a chance with an aftermarket flash.

I have a Godox MF-R76 for macro use. Since it is a fully-manual unit, there's no concern about camera compatibility. You just use camera in Manual Mode and fiddle with aperture and flash intensity settings to get what you want.

[normadel]

Oh yeah. A non-Canon flash will not fire when using Live View, unless you turn off a function called "Silent Shooting", if a camera has it. I have a Rebel that does not. My 50D, 60D, 7D and 6D do.

[ajm133]

I have an r7 and started with a Godox TT350c flash which usually worked but once in a while it misfired.  Turning off the AF assist lamp helped make it more reliable, but I still didn't have a level of confidence with it.  So I purchased a Canon EL100 which has literally been flawless.  Less power and twice the price of the Godox but it never let me down so the Godox collects dust. Based on various reading, it seems like many who have used 3rd party flash had some inconsistencies so my guess would be the flash and camera are just not communicating consistently which may be causing a problem