The GetDPI Photography Forum

Great to see you here. Join our insightful photographic forum today and start tapping into a huge wealth of photographic knowledge. Completing our simple registration process will allow you to gain access to exclusive content, add your own topics and posts, share your work and connect with other members through your own private inbox! And don’t forget to say hi!

SB-700 and Auto ISO

Jan Brittenson

Senior Subscriber Member
If I shoot at auto ISO and pop up the built-in flash on the D800, with flash set to -1.5EV, I get a nice fill flash, with the ISO settings in the menus used. In fact, there's no difference with or without the flash popped open, except for a bit of fill. Everything else looks and works the same just like one would expect.

If I attach an SB-700 suddenly it gets very strange. The max ISO setting in the camera is ignored in A mode. Instead, it seems the max is whatever I had manually set before switching to auto ISO. If that was 400 while the menu says 3200, the 3200 is used until I turn on the SB-700. At that point it switches to 400! And as if that weren't enough, it refuses to drop the ISO until it gets to sync speed (1/250). Is this normal? It's driving me nuts. Is there a way to make it operate like the built-in flash? I need fill at low light (like streetlights) at night with a Zeiss 18mm lens. I want 1/20 f/4 ISO 400, not 1/250 f/4 ISO 3200! The SB-700 can zoom out to 14 with the diffuser while the built-in will result in a huge lens shadow. Am I stuck shooting with everything set manually - M mode, ISO, flash power? The problem is the lighting changes too fast and wildly to just keep changing it manually to match. (And this is why I have a camera with fancy electronics, anyway.)

I have the camera set to slow sync, flash to TTL BL. Nothing I do seems to be able to get this fancy-pants flash system to work right.
 

Jan Brittenson

Senior Subscriber Member
I think I figured it out - as usual the manual is useless...

While auto ISO is enabled, hold down the ISO button and turn the rear dial. This will actually set a "center" ISO. With the flash attached the camera will then only go two stops up OR two stops down in ISO. So if I set it to 800 the camera will go up to 3200 or down to 200, which is good enough for my uses, for shooting in low light. Setting it to 400 similarly yields a range of 100-1600.

Only problem is when the flash is removed the camera is now set to a min auto ISO of 800...

I'm really pleased with this, because the SB-700 is in all ways an excellent, solid little flash otherwise!
 
Top