Question about using flash at night

HI, i am a landscape photographer, recently I am trying to learn about using flash for portraits. I have D610, and recently got yougnou 685 + the transmitter. I have one question. If you are using external flash (off camera), at night, in manual mode, Same F and shutter speed. If you use ISO 1000 and take picture and flash fires. Then you change ISO to 3000 and take picture under same settings, will the flash fire with less intensity because you are using high ISO? Is the TTL flash that intelligent? (I don't care about noise).

If not, whats the best and easy mode to use external flash.?

Thank you

Is the TTL flash that intelligent?

Not when you set it to manual mode.

Also not when it wanted to expose stronger but hit it's capacity i.e. had only half or a quarter the power you would have needed.

Otherwise it exposes for the ISO you set in TTL mode.

Most convenient manual use of off camera flash should be dialing it down via a wireless remote on your camera. + Trial & error according to your histogram. That approach might be a bit better when the reflection characteristic of your model could vary from shot to shot. due to dark hair and pale skin, jewelry or whatever and you are after consistent exposure.

But in general TTL seems to be quite awesome.

If you mean that the camera is in manual mode and the flash in i-TTL mode, then yes, the flash TTL control should respond to a change of camera ISO. Provided you have the YN 622N i-TTL transceiver. The RF-603N transceiver doesn't support TTL.

I say should, because my experience of Nikon's I-TTL hasn't been very positive to date, with exposures being quite inconsistent. Plus there's an issue with using flash at high ISO speeds. In that a flash varies its "power" by shortening the flash duration, and there's a limit to how short this light pulse can be made. You may well find that overexposure occurs at a high ISO and short flash distance.

"If not, whats the best and easy mode to use external flash.?"

If the flash supports AA (auto aperture) mode, then try that. My experience has been that AA flash mode is far more consistent than I-TTL.

Yes I have the controller that supports TTL (622N).

Not when you set it to manual mode.

Also not when it wanted to expose stronger but hit it's capacity i.e. had only half or a quarter the power you would have needed.

 

Otherwise it exposes for the ISO you set in TTL mode.

 

Most convenient manual use of off camera flash should be dialing it down via a wireless remote on your camera. + Trial & error according to your histogram. That approach might be a bit better when the reflection characteristic of your model could vary from shot to shot. due to dark hair and pale skin, jewelry or whatever and you are after consistent exposure.

 

But in general TTL seems to be quite awesome.

Thank you very much for replying!

So if not manual mode, what mode is good so that the flash's intensity is changed automatically based on exposure/metering (changes in ISO or F number)?

If you mean that the camera is in manual mode and the flash in i-TTL mode, then yes, the flash TTL control should respond to a change of camera ISO. Provided you have the YN 622N i-TTL transceiver. The RF-603N transceiver doesn't support TTL.

 

I say should, because my experience of Nikon's I-TTL hasn't been very positive to date, with exposures being quite inconsistent. Plus there's an issue with using flash at high ISO speeds. In that a flash varies its "power" by shortening the flash duration, and there's a limit to how short this light pulse can be made. You may well find that overexposure occurs at a high ISO and short flash distance.

 

"If not, whats the best and easy mode to use external flash.?"

 

If the flash supports AA (auto aperture) mode, then try that. My experience has been that AA flash mode is far more consistent than I-TTL.

Thank you for replying! :)

I have the 622N controller, which supports TTL. So you are saying that even in manual mode the flash will change intensity depending upon exposure/metering (changes in ISO or F number)?

I will check if yougnuo 685 supports AA mode. Thank you

"So you are saying that even in manual mode the flash will change intensity depending upon exposure/metering (changes in ISO or F number)?"

Only if the camera is in manual mode and the 622 passes aperture and ISO information from camera to flash.

Obviously, if the flash is in manual mode, then TTL is overridden and the flash parameters won't change.

Also the shutter speed should be kept longer than the X-synch speed of the camera - >= 1/250th second.

"So you are saying that even in manual mode the flash will change intensity depending upon exposure/metering (changes in ISO or F number)?"

 

Only if the camera is in manual mode and the 622 passes aperture and ISO information from camera to flash.

 

Obviously, if the flash is in manual mode, then TTL is overridden and the flash parameters won't change.

 

Also the shutter speed should be kept longer than the X-synch speed of the camera - >= 1/250th second.

Ok, its a new flash for me (yougnou 685) I think its set to TTL. So if I leave camera to manual mode and flash to TTL then flash should control light intensity based on cameras light metering. I believe the camera is setting the shutter to 1/60 and the sync speed is 1/200. is there any other setting in Nikon camera for flash that I have to set or change?

In manual shooting mode (M), the shutter speed and aperture are what you set them to be. The camera shouldn't override the chosen shutter speed except in program (P) or aperture-priority (A) modes.

1/60th second is the camera default speed when a flash is attached in the automatic shooting modes.

I strongly suggest you read the sections in the manual relating to flash use.