TTL vs Manual flash

[Leonard Migliore]

I have the same camera and flash. I always have the camera in manual mode and the flash in TTL. If I have any exposure automation at all (aperture priority or auto ISO) things get weird. The D750 defaults to fill flash in aperture priority or P mode, which is usually not what I want.

Leonard- are there any other settings I need to check for TTL and the camera in manual mode? To me the flash in TTL seems weak but I have a hunch something is set wrong. The flash is basically new. Just played with it again in TTL mode, flash fires but is so weak it wont light any subjects up.

Note: Just played with it again, TTL seems to work fine when I crank it up to +3EV but if no compensation is set {0.00EV } the subject will come out dark and not illuminated at all.

Camera is set to 1/160 for both flash sync speed and flash shutter speed in the D750

I'm wondering if it's only the pre-flash that's actually firing in TTL

First, I strongly doubt that you're shooting with the pre-flash. Your camera or flash would have to be very strangely messed up for that to happen.

With respect to camera settings, I can only report on what I use, which is manual mode, matrix metering, and manual ISO. If you have auto ISO the camera/flash setup will obstinately set the exposure for the ambient light and add fill flash only. The only time you get standard TTL metering is when you set the camera metering to spot mode, which has its own problems.

I don't use my SB-700 much. I mostly use studio flash, which is completely manual, and I expose with a flash meter, which works pretty well. The only time I use the SB-700 is when I'm dragooned into taking snapshots at parties since the D750 is still better than a phone.

But I just stuck it on the camera right now and when I set the camera to M it exposes fine with bounce flash (direct flash is an ugly thing).

For parties, I set the shutter at 1/200 and the f/stop around f/5.6 unless I need more DOF. I do some test shots to see what ISO I need to get decent brightness for whatever light the reflection from the ceiling lets me have.

 

[Aberaeron]

I have the same camera and flash. I always have the camera in manual mode and the flash in TTL. If I have any exposure automation at all (aperture priority or auto ISO) things get weird. The D750 defaults to fill flash in aperture priority or P mode, which is usually not what I want.

Leonard- are there any other settings I need to check for TTL and the camera in manual mode? To me the flash in TTL seems weak but I have a hunch something is set wrong. The flash is basically new. Just played with it again in TTL mode, flash fires but is so weak it wont light any subjects up.

Note: Just played with it again, TTL seems to work fine when I crank it up to +3EV but if no compensation is set {0.00EV } the subject will come out dark and not illuminated at all.

Camera is set to 1/160 for both flash sync speed and flash shutter speed in the D750

I'm wondering if it's only the pre-flash that's actually firing in TTL

There may be two distinct flash compensation controls on your setup [a setup I know nothing about]. There could be compensations available on the flash itself and also in the camera menu and/or quick menu. Is it possible that you have one of these set to -2 or -3 EV?

 

[SoCalAngler]

Good suggestion as the body and external speedlight EC are cumulative.

I have got myself into a similar situation a couple of times when I sent negative flash EC for the built in flash and forgot to re set to 0 and then later put a speedlight in the hot shoe.

 

[pmgnut]

Great suggestion. Just checked EC on the camera, it is at 0.0. I was just playing with it some more. Took a picture of a white wall calendar at 4 feet away, the calendar was illuminated by the ttl flash at 1.8 and 1/15 sec. Took picture of open closet full of hanging clothes {dark colors} at same distance , same settings and pic is all dark. I'm stumped.



What does the "BL" stand for next to TTL??

 

[pmgnut]

Great suggestion. Just checked EC on the camera, it is at 0.0. I was just playing with it some more. Took a picture of a white wall calendar at 4 feet away, the calendar was illuminated by the ttl flash at 1.8 and 1/15 sec. Took picture of open closet full of hanging clothes {dark colors} at same distance , same settings and pic is all dark. I'm stumped.

What does the "BL" stand for next to TTL??

Just found my answer in the manual:

-TTL balanced fill-flash
The fl ash output level is automatically adjusted for well-balanced
exposure of the main subject and background. appears on the
LCD.
Standard i-TTL
The main subject is correctly exposed regardless of background
brightness. This is useful when you want to highlight the main subject.
appears on the LCD.
t Camera’s metering mode and i-TTL mode
• When the camera’s metering mode is changed to spot metering
while i-TTL balanced fill-flash is in use, the i-TTL mode automatically
changes to the standard i-TTL mode.
• The i-TTL mode automatically changes to i-TTL balanced fill-flash,
after changing the camera’s metering mode to matrix or centerweighted.

That said, maybe I should try the standard TTL mode?



Could it be simply that my iso is not high enough? I would think even at ISO 100 , 1.8 and 1/15 sec the ttl flash would illuminate a closet full of clothes at 3 to 4 feet away.

 

[PhotoTeach2]

EC should indeed be a "0" (at least for now).

But there should be something in your "menu" called Flash-Ratio (it will be under a "flash" setting). It should also be at "0" (at least for now).

We suspect that ("Flash-Ratio") is set to a -2 setting ... (note it may not be called exactly "flash-ratio" ... but something similar).

 

[Leonard Migliore]

Great suggestion. Just checked EC on the camera, it is at 0.0. I was just playing with it some more. Took a picture of a white wall calendar at 4 feet away, the calendar was illuminated by the ttl flash at 1.8 and 1/15 sec. Took picture of open closet full of hanging clothes {dark colors} at same distance , same settings and pic is all dark. I'm stumped.

What does the "BL" stand for next to TTL??

I played around with my camera some more after seeing the screen above. Note that your minimum flash distance is 9 feet. The only way I could get a number like that was to set my lens to f/1.8 and my ISO to 1250. Now, you also say that you're using 1/15 for an exposure time. So you don't need any flash. That is, in fact, pretty murky lighting.

Try using the flash under different conditions, like an ISO of 100 and an aperture of f/8. You may get more sensible results.

--
Leonard Migliore

 

[SoCalAngler]

EC should indeed be a "0" (at least for now).

But there should be something in your "menu" called Flash-Ratio (it will be under a "flash" setting). It should also be at "0" (at least for now).

We suspect that ("Flash-Ratio") is set to a -2 setting ... (note it may not be called exactly "flash-ratio" ... but something similar).

D750 has a combination of menu and control settings that affect flash exposure compensation.

On the D750 body it is menu item e4: Exposure Comp For Flash. There are two settings: Entire Frame and Background Only. This only affects camera exposure compensation, not flash exposure compensation (which changes flash output). Page 353 of the manual. I don't think this setting is the OP's issue

Flash exposure compensation for built in flash is controlled by pressing the flash button (same one that deploys the built in flash) and turning the sub command wheel (front command wheel). The flash comp value is displayed on the control window on top and on the main information display on back LCD, depending on how it is configured. Page 188 of the manual

If there is a flash in the hot shoe, the built in flash will not deploy but flash compensation can still be set this way and will apply to the mounted flash. It is also cumulative with any flash compensation set directly on the flash unit, if the unit has that control. The SB-700 does have that control. So, for example, of you set -0.7 on the body and -0.7 on the SB-700 you end up with -1.3 when the shot is made.

Hate to admit how many times I have fouled up a shot by forgetting to reset one, the other, or both to 0 before I start - or preferably when done for the day.

 

[SoCalAngler]

Great suggestion. Just checked EC on the camera, it is at 0.0. I was just playing with it some more. Took a picture of a white wall calendar at 4 feet away, the calendar was illuminated by the ttl flash at 1.8 and 1/15 sec. Took picture of open closet full of hanging clothes {dark colors} at same distance , same settings and pic is all dark. I'm stumped.

What does the "BL" stand for next to TTL??

Just found my answer in the manual:

-TTL balanced fill-flash
The fl ash output level is automatically adjusted for well-balanced
exposure of the main subject and background. appears on the
LCD.
Standard i-TTL
The main subject is correctly exposed regardless of background
brightness. This is useful when you want to highlight the main subject.
appears on the LCD.
t Camera’s metering mode and i-TTL mode
• When the camera’s metering mode is changed to spot metering
while i-TTL balanced fill-flash is in use, the i-TTL mode automatically
changes to the standard i-TTL mode.
• The i-TTL mode automatically changes to i-TTL balanced fill-flash,
after changing the camera’s metering mode to matrix or centerweighted.

That said, maybe I should try the standard TTL mode?

Could it be simply that my iso is not high enough? I would think even at ISO 100 , 1.8 and 1/15 sec the ttl flash would illuminate a closet full of clothes at 3 to 4 feet away.

At f/1.8, ISO 100 you should get full illumination and potentially over exposure with most subjects within range in the the TTL modes, even in a nearly pitch black room since the flash will engage its red focus assist light first.

It has come up earlier, I think you brought it up, if it is possible that only the pre flash is firing and not the actual exposure flash.

You can check this. Set control menu item e2 to something like 8 seconds or 15 seconds.

Put camera in to manual (M) mode.

Make sure you are in one of the I-TTL modes (not manual flash)

Set the flash mode to rear curtain sync. This will cause a pre flash when the the shutter button is pressed and the main exposure flash at the end of the exposure.

Set the shutter speed to something like 8 seconds to give you plenty of time to observe both flashes. For this experiment it doesnt matter what the aperture is. Dont care about the image. Just want to verify you are get both the pre flash and the final flash.

Press shutter button. You should see the pre flash when you press shutter button and the main flash at the end of the exposure. If you dont see two flashes then something is wrong with the flash or the communication between body and flash.

Set everything back to starting point when you have done this experiment.

 

[PhotoTeach2]

EC should indeed be a "0" (at least for now).

But there should be something in your "menu" called Flash-Ratio (it will be under a "flash" setting). It should also be at "0" (at least for now).

We suspect that ("Flash-Ratio") is set to a -2 setting ... (note it may not be called exactly "flash-ratio" ... but something similar).

D750 has a combination of menu and control settings that affect flash exposure compensation.

On the D750 body it is menu item e4: Exposure Comp For Flash. There are two settings: Entire Frame and Background Only. This only affects camera exposure compensation, not flash exposure compensation (which changes flash output). Page 353 of the manual. I don't think this setting is the OP's issue

Flash exposure compensation for built in flash is controlled by pressing the flash button (same one that deploys the built in flash) and turning the sub command wheel (front command wheel). The flash comp value is displayed on the control window on top and on the main information display on back LCD, depending on how it is configured. Page 188 of the manual

If there is a flash in the hot shoe, the built in flash will not deploy but flash compensation can still be set this way and will apply to the mounted flash. It is also cumulative with any flash compensation set directly on the flash unit, if the unit has that control. The SB-700 does have that control. So, for example, of you set -0.7 on the body and -0.7 on the SB-700 you end up with -1.3 when the shot is made.

Hate to admit how many times I have fouled up a shot by forgetting to reset one, the other, or both to 0 before I start - or preferably when done for the day.

Since he is getting sufficient on manual (flash), I suspect TTL is his problem, and the settings you mention above may indeed be his answer.

I do not have a D750 ... so can't help further ...

So my question is do you think your description above is "sufficient" for the OP to follow, (he seems very lost and I think it would help if you repeated the above in a more step-by-step procedure he may be able to follow).

 

[SoCalAngler]

Since he is getting sufficient on manual (flash), I suspect TTL is his problem, and the settings you mention above may indeed be his answer.

I do not have a D750 ... so can't help further ...

So my question is do you think your description above is "sufficient" for the OP to follow, (he seems very lost and I think it would help if you repeated the above in a more step-by-step procedure he may be able to follow).

My previous comments in this thread may be sufficient for some but I recognize they may not be for some too. I think the best way forward would be to purchase Thom Hogan's ebook on the D750.

Essentially, otherwise I would be copying almost directly from his book.

https://dslrbodies.com/books/bythom-complete-guides-/nikon-d750-guide.html

I have his ebooks for my other Nikon bodies. I dont have a D750 but, from looking at the manual, flash usage is very similar or identical to my D7100. Both bodies came out in 2014. The D7100 book has about 60 pages dedicated to using flash, including a section specifically on the SB-700. I presume the D750 book has the same level of detail and the summary at the link above does specifically mention the SB-700 speed light

The books are better than manual, explaining things that are not covered well, or even not at all in some cases in the manual. They run from around 800 pages to well over 1000, depending on the camera. Can seem overwhelming, but are not if you take them on in smaller chunks.

I have always found these at USD$29.99 funds well spent.

There are a lot of other sources of info on using Nikon speed lights, but these books are very specific to how the subject body behaves.

Since it is an ebook in PDF format I keep copies, as per his license agreement, on my phone, tablets, and computer. And I constantly refer back to them when doing something that I dont do regularly.

 

[pmgnut]

Great suggestion. Just checked EC on the camera, it is at 0.0. I was just playing with it some more. Took a picture of a white wall calendar at 4 feet away, the calendar was illuminated by the ttl flash at 1.8 and 1/15 sec. Took picture of open closet full of hanging clothes {dark colors} at same distance , same settings and pic is all dark. I'm stumped.

What does the "BL" stand for next to TTL??

Just found my answer in the manual:

-TTL balanced fill-flash
The fl ash output level is automatically adjusted for well-balanced
exposure of the main subject and background. appears on the
LCD.
Standard i-TTL
The main subject is correctly exposed regardless of background
brightness. This is useful when you want to highlight the main subject.
appears on the LCD.
t Camera’s metering mode and i-TTL mode
• When the camera’s metering mode is changed to spot metering
while i-TTL balanced fill-flash is in use, the i-TTL mode automatically
changes to the standard i-TTL mode.
• The i-TTL mode automatically changes to i-TTL balanced fill-flash,
after changing the camera’s metering mode to matrix or centerweighted.

That said, maybe I should try the standard TTL mode?

Could it be simply that my iso is not high enough? I would think even at ISO 100 , 1.8 and 1/15 sec the ttl flash would illuminate a closet full of clothes at 3 to 4 feet away.

At f/1.8, ISO 100 you should get full illumination and potentially over exposure with most subjects within range in the the TTL modes, even in a nearly pitch black room since the flash will engage its red focus assist light first.

It has come up earlier, I think you brought it up, if it is possible that only the pre flash is firing and not the actual exposure flash.

You can check this. Set control menu item e2 to something like 8 seconds or 15 seconds.

Put camera in to manual (M) mode.

Make sure you are in one of the I-TTL modes (not manual flash)

Set the flash mode to rear curtain sync. This will cause a pre flash when the the shutter button is pressed and the main exposure flash at the end of the exposure.

Set the shutter speed to something like 8 seconds to give you plenty of time to observe both flashes. For this experiment it doesnt matter what the aperture is. Dont care about the image. Just want to verify you are get both the pre flash and the final flash.

Press shutter button. You should see the pre flash when you press shutter button and the main flash at the end of the exposure. If you dont see two flashes then something is wrong with the flash or the communication between body and flash.

Set everything back to starting point when you have done this experiment.

Hi, thanks very much I will try this and report back. So in a dark room, that red focus assist light should automatically come on?

 

[SoCalAngler]

Hi, thanks very much I will try this and report back. So in a dark room, that red focus assist light should automatically come on?

Yes, but only if one of the focus sensors in the center vertical line or center horizontal line are used. Just try the center focus point. And I believe you need to be in AF-S focus mode with single point selected (it may work in some other settings like AF-A, but I don’t recall). and camera lens focal length needs to be between 24 and 135mm

if looking at the front of the camera.flash you will see that red plastic areas on the main part of the flash body light up while half pressing the shutter to focus ( or preening the AE-L/AF-L button if set up for back button focus) . If looking through the viewfinder you will see a red grid briefly appear on your target. There may be some other constraints associated with the SB-700 auto focus light covered in the flash’ manual. For example it can be disabled from the on flash menu - page B-22 of the flash manual

 

[PhotoTeach2]

Great suggestion. Just checked EC on the camera, it is at 0.0. I was just playing with it some more. Took a picture of a white wall calendar at 4 feet away, the calendar was illuminated by the ttl flash at 1.8 and 1/15 sec. Took picture of open closet full of hanging clothes {dark colors} at same distance , same settings and pic is all dark. I'm stumped.

What does the "BL" stand for next to TTL??

Just found my answer in the manual:

-TTL balanced fill-flash
The fl ash output level is automatically adjusted for well-balanced
exposure of the main subject and background. appears on the
LCD.
Standard i-TTL
The main subject is correctly exposed regardless of background
brightness. This is useful when you want to highlight the main subject.
appears on the LCD.
t Camera’s metering mode and i-TTL mode
• When the camera’s metering mode is changed to spot metering
while i-TTL balanced fill-flash is in use, the i-TTL mode automatically
changes to the standard i-TTL mode.
• The i-TTL mode automatically changes to i-TTL balanced fill-flash,
after changing the camera’s metering mode to matrix or centerweighted.

That said, maybe I should try the standard TTL mode?

Could it be simply that my iso is not high enough? I would think even at ISO 100 , 1.8 and 1/15 sec the ttl flash would illuminate a closet full of clothes at 3 to 4 feet away.

At f/1.8, ISO 100 you should get full illumination and potentially over exposure with most subjects within range in the the TTL modes, even in a nearly pitch black room since the flash will engage its red focus assist light first.

It has come up earlier, I think you brought it up, if it is possible that only the pre flash is firing and not the actual exposure flash.

You can check this. Set control menu item e2 to something like 8 seconds or 15 seconds.

Put camera in to manual (M) mode.

Make sure you are in one of the I-TTL modes (not manual flash)

Set the flash mode to rear curtain sync. This will cause a pre flash when the the shutter button is pressed and the main exposure flash at the end of the exposure.

Set the shutter speed to something like 8 seconds to give you plenty of time to observe both flashes. For this experiment it doesnt matter what the aperture is. Dont care about the image. Just want to verify you are get both the pre flash and the final flash.

Press shutter button. You should see the pre flash when you press shutter button and the main flash at the end of the exposure. If you dont see two flashes then something is wrong with the flash or the communication between body and flash.

Set everything back to starting point when you have done this experiment.

Hi, thanks very much I will try this and report back. So in a dark room, that red focus assist light should automatically come on?

I will say yes, but i dont think "focus" is your main issue, neither do i think it is a "flash-unit" setting.

I think it is a camera-MENU setting, (that controls flash-TTL power).

I suggest you ask the same question in the "Nikon FX SLR" forum, for someone with your exact camera (and flash).

 

[SoCalAngler]

Hi, thanks very much I will try this and report back. So in a dark room, that red focus assist light should automatically come on?

I will say yes, but i dont think "focus" is your main issue, neither do i think it is a "flash-unit" setting.

I think it is a camera-MENU setting, (that controls flash-TTL power).

I suggest you ask the same question in the "Nikon FX SLR" forum, for someone with your exact camera (and flash).

Yep. It would just be another possible indication of a failed bad flash or flash-body communication problem such as a slightly corroded contact.

Agree most likely problem is a combination of settings.

My D40 with a mounted flash started to do weird things after about 5 years of not having the contact cover in place. Misfires and poor exposure. Cleaning the contacts fixed that. I have seen some third party flashes stop working correctly too. Just something to rule out.