TTL Flash with M8 and SF20

[gerasdoc]

I have been unable to use my SF20 in TTL mode with my M8. A major caveat to include is that I am a newbie with the flash and I bought it used. The flash works fine in auto and manual modes on the M8 and an M6. Any ideas?

 

[barjohn]

I believe that the M* requires the newer Guide Number control for TTL so you need the newer flash, the SF24D. That is what I found when I was looking so I purchased the SF24D and ti works very well for me.

 

[dspeltz]

Right. the 20 will not TTL with the M8. You need the 24. No upward compatibility. why not? No idea.

 

[gerasdoc]

That is what I was afraid of. Thanks for the info.