FV Lock isn't working as expected on my Nikon Z8.

[David H. Hartman]

FV Lock (Flash Value) isn't working on my Z8 as expected...

I've loved the FV Lock feature fond on my DSLR(s) D2H to D850 but it doesn't work as expected on my Z8. Nikon DSLR(s) have a dedicated flash sensor in the mirror box for TTL flash exposure. A mirrorless camera would need to create the same feature in software I'd guess. Maybe I'm missing something.

The way the FV Lock works on all my DSLR(s) is you press a dedicated button and the flash emits a monitor pre-flash. The flash exposure is automatically locked in. You can recompose and you can fire off several shots and the flash exposure will be the same in all shots. You do have to maintain the flash to subject distance to have correct exposure. To cancel the FV lock you press the dedicated button again. It's a toggle on, toggle off feature.

The way I've used this feature is in a PJ, PR, "Paparazzi" style of on camera flash. I put paparazzi in quotes because I don't badger subjects. At an event say a wedding reception I select a subject or subjects. The place is swarming with people taking photos so it's not a big deal. Subjects typically pose with a "say cheese" smile and when the monitor pre-flash fires they relax and give a natural smile. Then I'll fire a couple of actual photos and move on. If the subjects clown for the camera I'll take a few more. This technique works especially well with kids.

Now the Z8 is different as to how auto flash works and as yet I don't understand it. What is happening is I'm getting consistent over exposure of maybe 2 stops. So far I'm finding my FV lock, PR/PJ technique useless with my Z8.

Maybe someone here understands how TTL auto flash works on a Nikon Z camera. I hope someone here has suggestions.

Thank's for considering this!

Dave

I was experimenting with an SB-400. Just now I tried with an SB-800 and the results are the same. I'm also finding that the SB-800 doesn't expose correctly in the [TTL] mode, only the [TTL][BL] mode where [TTL][BL] is balanced TTL fill flash and [TTL] is standard iTTL flash that ignores the ambient light.

Asking here is probably a long shot as not much is disgust about flash here. There are several groups on Flickr that in years past would be a good place to ask this question but these days one needs a familiar spirit to bring up the dead to get a question answered.

[Ilkka Nissilä]

Do you also get overexposure when using the SB-800 on the Z8 without using FV lock?

I haven't had any issues using the SB-5000 on the Z8, but with one third-party flash the results at higher than sync speeds (Elinchrom THREE with Skyport Pro) have been not what I would have expected.

[Akira]

According to the manual of Z8 for FV lock function with SB-800:

Available only in i‑TTL flash control mode or when the flash is configured to emit monitor preflashes in Auto Aperture or Non-TTL Auto flash control mode.

The source:

https://onlinemanual.nikonimglib.com/z8/en/compatible_flash_units_377.html


Hope this would be of any help.

[David H. Hartman]

Do you also get overexposure when using the SB-800 on the Z8 without using FV lock?

No, the SB-800, SB-700 and the SB-400 all produce expected results when the FV lock is not used.

[David H. Hartman]

Available only in i‑TTL flash control mode or when the flash is configured to...

Aira, thanks for the link. I'll check it out tomorrow afternoon.

Dave

[David H. Hartman]

According to the manual of Z8 for FV lock function with SB-800:

Available only in i‑TTL flash control mode or when the flash is configured to emit monitor preflashes in Auto Aperture or Non-TTL Auto flash control mode.

The source:

https://onlinemanual.nikonimglib.com/z8/en/compatible_flash_units_377.html


Hope this would be of any help.

OK, the SB-800 performs correctly with the Z8 and FV lock in AA mode with monitor pre-flash but not in iTTL or iTTL BL so I've learn that much.

The SB-400 has a limited feature set offering iTTL BL or manual in from 1/1 to 1/128 in 1/3 stops. It's small and light, easy to carry but lacks the power for single shots in rapid succession.

Maybe FV Lock has lost it's usefulness with Nikon mirrorless cameras?

Yes, the link was helpful.

Dave

I don't care for the SB-700. I bought it because the D-800 had no popup flash to use as a Master or Controller and the SB-800 was discontinued. At the time I bought the SB-700, used SB-800(s) sold for $435.00 used where they SB-800 had recently closed out a $320.00. The SB-700 is almost identical to the SB-800 in size and weight but has about 1 ~ 1 1/3 stop less power compared to the SB-800. Further the SB-700 has 4 channels but only groups A & B. I think the latter is Nikon jerking around its customers.

The SU-800 is long in the tooth and does not offer 1/3 increments in manual mode.

---

Maybe in a year I can look into the SB-5000?

[Ilkka Nissilä]

OK, the SB-800 performs correctly with the Z8 and FV lock in AA mode with monitor pre-flash but not in iTTL or iTTL BL so I've learn that much.

The SB-400 has a limited feature set offering iTTL BL or manual in from 1/1 to 1/128 in 1/3 stops. It's small and light, easy to carry but lacks the power for single shots in rapid succession.

Maybe FV Lock has lost it's usefulness with Nikon mirrorless cameras?

Yes, the link was helpful.

Dave

I don't care for the SB-700. I bought it because the D-800 had no popup flash to use as a Master or Controller and the SB-800 was discontinued. At the time I bought the SB-700, used SB-800(s) sold for $435.00 used where they SB-800 had recently closed out a $320.00. The SB-700 is almost identical to the SB-800 in size and weight but has about 1 ~ 1 1/3 stop less power compared to the SB-800. Further the SB-700 has 4 channels but only groups A & B. I think the latter is Nikon jerking around its customers.

The SU-800 is long in the tooth and does not offer 1/3 increments in manual mode.

---

Maybe in a year I can look into the SB-5000?

It seems like there is a bug. I can check how FV lock behaves on my Z8 and SB-5000; I have not used this feature in recent years. In the early DSLR years I felt the preflashes were timed so that they caused a lot of eye closures at the time of the actual exposure, at least with the less expensive camera models, and so I would use FV lock to get the preflashes out of the way, wait for a moment and then get some real shots without eye blinks. However, in the higher-end DSLRs the delay between the preflashes and main exposure was so short that eye blinks were not a common issue for me (though they could still happen) but in the past decade or so, most of my flash work has been with Elinchrom flashes mostly in manual mode so I haven't had as much recent experience with this.

I am happy to do some testing if it helps to identify the problem. I think you should report to Nikon on their contact web page, give as much information as you can, and they will pass the information to Japan.