Favor to ask of owners with SB-700 or SB-910

I'd like to ask a favor from anyone with a current model Nikon flash (SB-700 or SB-910) and a hot shoe extension cord, such as old SC-17, or new SC-28 or SC-29. Any of the cords, it doesn't matter. Hearing from both flash models would be good.

Check out the effect at Review of the Yongnuo YN565EX Speedlight

I'd like to ask that you repeat that simple test and confirm or refute the result with the newer Nikon flash - which is Matrix and Center seriously underexposed, Spot metering Not. It dawned on me that my SB-800s are ten years old, and maybe the new models are different too? The new third party flashes have no head tilt switch to be reported, so oddly it is interpreted as tilted... so they do not have this fault. There is also a firmware difference, 1.01 old SB-800 vs 2.01 in the newer third party flashes, both of which says "(SB-800)", which must mean compatibility.

However, even the newest camera manual (D750) still says:
So that should be clear, but still, if you have the cord, this only takes a minute. Any small tabletop object and the one flash on the cord.

My situation had the camera at about 2 feet from subject (50 or 60mm lens), and the umbrella fabric is 4 feet, and 2 feet back to the flash is a 6 foot flash path.

It need NOT be an umbrella, all that is important is that if the camera is 2 feet, the flash should be 5 or 6 feet (flash held arms length on cord behind camera), just significantly farther than camera. Direct flash is fine, just should be behind camera.

Indoors, Spot metering actually works outdoors.

Two things are important:

The flash head is level, Not tilted.

The flash mode is TTL BL, which TTL is TTL BL (SB-700) if it does not have a specific TTL vs. TTL BL menu (SB-910).

Then just click, click, click, changing metering from Matrix to Center to Spot. A couple of minutes should do it.

I don't need to see the pictures, just wondering if everyone gets the same effect on newer Nikon flashes? Yes or No?

Thanks much,

If no one else takes on this challenge I'll see what I can do - have one of those Nikon cords somewhere and an SB-700. Also have a Metz 54 so could try it with that one too for comparison. But may not get to this until the weekend - if I do. hopefully someone with more time will try this for you before then.

Fortkentdad said:

If no one else takes on this challenge I'll see what I can do - have one of those Nikon cords somewhere and an SB-700. Also have a Metz 54 so could try it with that one too for comparison. But may not get to this until the weekend - if I do. hopefully someone with more time will try this for you before then.

Click to expand...

Thanks, I would appreciate that. Would like to know about the Metz too. I think the 54 has a menu selection between TTL and TTL BL, and it is important (to this test) that it be TTL BL. Spot and TTL are the same, in that they will not show this problem (Spot forces TTL).

Does it have to be a cord? What about remote control using the pop-up flash on my D7100 in commander mode? I have a SB-700, but no extension cord.

Any method will take the picture, but yes, the test has to use the cord, with camera closer than the TTL BL direct flash, for the test to be meaningful.

The system knows that the commander remote flashes are off camera, so are at an unknown different distance than the camera.

The hot shoe cord is on the camera, so to speak, no difference in the hot shoe itself. No way to know the cord is even being used. It is just a hot shoe extension cord.

The idea is that direct flash pictures are often overexposed, due to metering being affected by the dark background behind the direct subject. Black or dark subjects increase exposure. So the metering might be trying to light the dark background, when that is not the pictures goal about subject.

So TTL BL (direct flash) assumes a hot shoe flash on camera, and uses the D lens distance to compute a guide number, and if the metered TTL BL exposure seems too much for the guide number distance (due to dark background, etc), it backs the flash down, to agree with the safe guide number that it knows for the D lens distance. Good in theory, for a hot shoe flash (except zoom D lens distances are rather inaccurate, and can cause similar problems as in the test).

But in practice, if the flash is not at the same distance as the camera (specifically if the camera is closer than the flash), then it doesn't know where the flash is, doesn't even know there is an issue, and it may back off flash power when it should not. We can get severely underexposed pictures (the test case).

Switching to TTL (instead of TTL BL) overrides, and it forgets about D lens distance, and just takes the picture metered.
Spot metering forces TTL mode.
Also tilting the flash head tells it that is not direct flash, so again it forgets about D lens distance.

Or the Commander expects off camera flashes, and it forgets D lens distance too.

I see that the third party flashes (Yongnuo, etc) do not have the head tilt switch, and they also cause the metering to forget the D-lens distance, and we get good results in this test case. So which is a good thing when camera is closer than the flash. I was just wondering if the latest Nikons might have changed too? I suspect not, but don't know.

I repeated the experiment with a D7100, SB700 and a SC-29 cable. Results are the same you got, great exposure with spot, way under with matrix and center weighted. I used direct flash without an umbrella with the subject 2 feet in front of me and the flash held as far back as I could hold it a little above my head over my left shoulder. Hope this helps.

Thank you John, appreciate it. I figured as much, but just wanted to be sure nothing had changed. My Nikon SB-800s are ten years old, and now, the inexpensive Chinese flashes don't do that. They don't have the head tilt switch, but (making this up), the lack of it must signal same as tilted, so no D-lens "correction".

I wish Nikon would provide us a menu in the camera to ignore it too. My big complaint is not the cable, but that the zoom lenses often report really poor distance data. They can cause the same thing. Spot metering and TTL is the same fix for them.

No problem Wayne, a good thing to know for us Nikonites. Also good to know for us that get a Yongnuo as a second flash which I was looking into recently!!

Thanks Revet - save me the trouble of repeating the test.
This only happens when using the cord. And only if the head is not tilted. And only with the Nikon. Curious.
I suppose I should test my Metz 58 and see if the effect is the same. Will let you know.

and only TTL BL. Not actual TTL mode.

Not sure I understand that philosophy, except that TTL BL is system manipulated (balanced for example), where TTL is whatever the metering actually measures. I wish that were my own choice.

OK maybe I didn't fully understand but I don't see any exposure differences.

Used both my SB-700 and Metz 58 AF-2

Attached with SC-28 cord to my D610

Holding flash as far from camera as I could, it was up and back of the camera full arms length and camera held away with my other arm. Maybe five feet between camera and flash.

Both flash units set to TTL and then tried the TTL-B option on the Metz. No such setting on the 700

Took set of pictures Spot metering and then AF-C / S, AF-C / 9 and AF-C 3D

I see no exposure differences with any of the pictures? For either flash unit.
I did notice that the Metz pictures were a touch brighter - but then this was not scientific, maybe the angle at which the light bounced was a wee bit different? And the Metz is a more powerful flash (same as an SB-900).

Gave it my best 'shot'

Fortkentdad said:

OK maybe I didn't fully understand but I don't see any exposure differences.

Used both my SB-700 and Metz 58 AF-2

Attached with SC-28 cord to my D610

Holding flash as far from camera as I could, it was up and back of the camera full arms length and camera held away with my other arm. Maybe five feet between camera and flash.

Click to expand...

How far from camera to subject? If camera is like 2 feet from subject, and flash 5 feet behind camera, that's a big difference (2 vs 7) that should show up. But if like 10 feet and 15 feet, less difference (still maybe one stop difference).

Both flash units set to TTL and then tried the TTL-B option on the Metz. No such setting on the 700

Click to expand...

The SB-700 (and specifically the Nikon system) is TTL BL, unless spot metering. Menu says the generic TTL (Through The Lens metering), but the system specifically does TTL BL Balanced flash (unless Spot metering).

The Metz has the TTL vs TTL BL menu to override, TTL menu doesn't need Spot, but Spot will still change its TTL BL to be TLL.

Took set of pictures Spot metering and then AF-C / S, AF-C / 9 and AF-C 3D

Click to expand...

Test is about Matrix, Center Weighted, and Spot metering. AF-S/C won't matter. Of these, only Spot switches TTL BL to TTL

(Complications: Tilting head up also switches to TTL. And FV Lock is still TTL BL, but it switches out D-lens check. Not all cameras have FV Lock, but with TTL BL direct flash behind camera, the test could just specify Matrix metering, but with and without FV Lock ... same thing. I think it is a terrible flash design situation. We learn to use it, but I'd like a camera menu to disable D-lens meddling. TTL vs TTL BL ought to be a camera menu too, or maybe a button on back of camera.)

I appreciate the try, but I am guessing that your equal results suggest all tests were Spot metering? Switch to Matrix or Center, and at least the SB-700 ought to show a big surprise (in the test situation).