Shutter lag when using flash on Nikon D750

Nelsinki

Nelsinki

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Nelson
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Hi folks,

Whenever I use my flash, whether mounted on the camera or off camera using a transmitter, there is a delay of about half a second before it takes the picture. My D600 doesn't do this and I cannot find an answer to this. I've checked the camera settings but I cannot find out what it is.

Ant ideas please, or better, a solution? Thanks

Nelsinki
 
Do you have front or rear curtain sync turned on the flash?
 
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Front/rear curtain is set in camera, it's om front curtain. What happens is that when I press the shutter nothing happens, then about half a second later the picture is taken, it's more like shutter lag. It only happens when I mount a flash or transmitter in the hotshoe, pressing the shutter does nothing for half a second and then suddenly the picture is taken. I'm baffled and cannot find an answer to this....
 
Problem solved! Thanks for your input. I changed the flash sunc setting from 1/250s (Auto FP) to 1/200s (Auto FP) and it's all fine :)
 
Nelsinki said:
Problem solved! Thanks for your input. I changed the flash sunc setting from 1/250s (Auto FP) to 1/200s (Auto FP) and it's all fine :)
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Interesting, why would this make a difference? I don’t fully understand why there’s both a 1/200 autoFP and 1/250 auto FP tbh?
 
Nelsinki said:
Front/rear curtain is set in camera, it's om front curtain. What happens is that when I press the shutter nothing happens, then about half a second later the picture is taken, it's more like shutter lag. It only happens when I mount a flash or transmitter in the hotshoe, pressing the shutter does nothing for half a second and then suddenly the picture is taken. I'm baffled and cannot find an answer to this....
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You said it’s on front curtain? That is the lag problem then as that’s what it’s meant to do?
 
Isn't Auto FP what Nikon calls High Speed Sync (HSS)? Is that the function you actually want for your shooting scenario? Normally HSS is for fill in bright ambient e.g. daylight. Even so, there shouldn't be a lag whether using HSS or standard sync modes. I think the likeliest cause for the appearance of lag would be second curtain at a slow shutter speed, so mirror flips up, first curtain opens, silence for the time interval, then flash followed by second curtain. Are you only pressing the shutter release once? No mirror lock-up set? If there are no sounds at all for an appreciable delay, then either a timer is in operation or something wrong, maybe low battery power?

Edit: For clarity, just checked and apparently Auto FP modes use standard sync when possible and only switch to HSS if the shutter speed goes above normal sync range. This might all be well known to Nikon users, I usually shoot Canon. Above points still stand.
 
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AdamSi said:
You said it’s on front curtain? That is the lag problem then as that’s what it’s meant to do?
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Is there a setting for front curtain sync? I thought all flash within the camera sync speed was front curtain unless you specifically select rear curtain slow sync? There’s no setting for front curtain slow sync just slow sync, which assumes that it will be first curtain.

khakoo said:
Isn't Auto FP what Nikon calls High Speed Sync (HSS)? Is that the function you actually want for your shooting scenario? Normally HSS is for fill in bright ambient e.g. daylight. Even so, there shouldn't be a lag whether using HSS or standard sync modes. I think the likeliest cause for the appearance of lag would be second curtain at a slow shutter speed, so mirror flips up, first curtain opens, silence for the time interval, then flash followed by second curtain. Are you only pressing the shutter release once? No mirror lock-up set? If there are no sounds at all for an appreciable delay, then either a timer is in operation or something wrong, maybe low battery power?

Edit: For clarity, just checked and apparently Auto FP modes use standard sync when possible and only switch to HSS if the shutter speed goes above normal sync range. This might all be well known to Nikon users, I usually shoot Canon. Above points still stand.
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Yes auto FP automatically changes to HSS once you go above the camera sync speed. What I still don’t understand is why Nikon has two Auto FP modes, 1/200 auto FP and 1/250 auto FP. The camera can’t have two max sync speeds so what’s the other for?

HSS isn’t exclusively for fill in bright scenarios using fast lenses of course, you can also use it to eliminate background light (y)
 
snerkler said:
HSS isn’t exclusively for fill in bright scenarios
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Yes, the tools have multiple applications. Just noting the function was engaged but resisting my natural urge to provide a lengthy and tiresome contextual essay. :D Still curious about the underlying issue. The OP changed a setting and lag problem went away, but the cause remains undiagnosed.
 
snerkler said:
Yes auto FP automatically changes to HSS once you go above the camera sync speed. What I still don’t understand is why Nikon has two Auto FP modes, 1/200 auto FP and 1/250 auto FP. The camera can’t have two max sync speeds so what’s the other for?
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ISTR.. that the built in pop up flash can sync at 1/250 but the hot shoe can't. Could be wrong, though.
 
juggler said:
ISTR.. that the built in pop up flash can sync at 1/250 but the hot shoe can't. Could be wrong, though.
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Maybe, but I have two auto sync modes on the D850 and no in built flash :confused:
 
snerkler said:
Maybe, but I have two auto sync modes on the D850 and no in built flash :confused:
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From memory, some Nikons have a slightly higher X-sync speed (maybe only properly enabled with Nikon guns?) where you can shoot above the normal x-sync ceiling but there's a slight loss of brightness at full power. Basically the sensor is completely uncovered at this speed, but the second curtain follows so quickly that some brightness from a long duration flash pulse is lost. Something like that.
 
HoppyUK said:
From memory, some Nikons have a slightly higher X-sync speed (maybe only properly enabled with Nikon guns?) where you can shoot above the normal x-sync ceiling but there's a slight loss of brightness at full power. Basically the sensor is completely uncovered at this speed, but the second curtain follows so quickly that some brightness from a long duration flash pulse is lost. Something like that.
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Interesting, thanks. Which then begs another question, what benefit is that. The only downside I can see for HSS is that you get light/power loss from the flash, so it makes me wonder what x-sync offers above HSS? I’ll have to do some googling ;)

Ok so the wonders of google inform me that using the faster auto FP mode allows greater power and therefore range of the flash before going to the HSS pulse type flash that vastly reduces range. However, the trade off is that you may not get completely even lighting using the higher auto FP mode at the top speed due to the shutter closing too fast and darkening the bottom of the image.
 
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With Nikons HSS is only functional with an external flash. The x-sync speeds are available with either an external or the built in (even the higher settings if optional).
From what I understand, the rear curtain doesn't start moving before the front curtain has finished at SS's below ~ 1/400. But when the SS is faster than the total burn time (to include rise and tail) there is some loss of light. It is definitely dependent on which light is being used, but I believe that there can be some loss of light even at SS's above 1/100... that's probably with older units and why the camera likes to default to 1/60 with flash (the fastest min SS with flash setting).
Nikon notes that there is a loss of *range* as SS increases with the 1/320 x-sync setting (D8xx); I suspect that means it's starting to cut into the main peak burn at SS's above 1/250 (normal x-sync)... this can also cause a visible gradient. The loss of range/light/power due to SS's within x-sync is still much less than the power reduction HSS causes.

My best guess for the original issue is that red eye reduction was enabled, and in the process of checking/changing things it was disabled without recognizing it... changing the x-sync setting should not have an effect on shutter delay.
 
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snerkler said:
Interesting, thanks. Which then begs another question, what benefit is that. The only downside I can see for HSS is that you get light/power loss from the flash, so it makes me wonder what x-sync offers above HSS? I’ll have to do some googling ;)

Ok so the wonders of google inform me that using the faster auto FP mode allows greater power and therefore range of the flash before going to the HSS pulse type flash that vastly reduces range. However, the trade off is that you may not get completely even lighting using the higher auto FP mode at the top speed due to the shutter closing too fast and darkening the bottom of the image.
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Agree, it's a pretty useless feature as probably the only time you'd want fastest possible shutter speed would be to reduce ambient light when the flash is maxed out on power. In other words, at the very time when you can't afford to lose any flash brightness...

It makes a useful point about x-sync though, when not only must the sensor be fully uncovered, it has to stay fully uncovered while the flash dumps its full output. So it stands to reason that when your total flash duration/dump time extends to say 1/300sec or so (common with speedlights at full power, and many studio heads) there's no way the sensor can capture 100% of the light before the shutter starts to close. Correspondingly, Canon recommends 1/60sec or even 1/30sec with "large studio flash units". TBH that's unnecessary but my default shutter speed with flash in the studio is 1/125sec. Never had any problem with that, even with radio triggers that also introduce a tiny delay.

It's easy to test this simply by taking a flash picture of a plain surface, eg wall, in a darkened room with a flashgun at full power. Start at say 1/60sec, then increase shutter speed up to max x-sync. In theory, every image should be identical, but as shutter speed gets closer to max x-sync the brightness will reduce slightly and you may also notice a little extra darkening at the top of the frame, which is the shutter closing while the tail of the flash pulse is still putting out a small amount of light. Then do the same thing again with flash output reduced to say 1/4 power which significantly reduces the flash duration (raise ISO two stops to compensate). This time, all images will be identical.
 
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I would probably disagree a bit.
Using higher sync/shutter speeds has the benefit of causing MUCH less loss of power/light than the automatic drop to 1/4 power max (something like that) that HSS causes. Even using an extended sync speed like 1/320 will only cause a slight loss of power; and if the gradient falls somewhere off the subject the effect can be negligible (or even beneficial). I would agree that it is of limited use though...
 
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sk66 said:
I would probably disagree a bit.
Using higher sync/shutter speeds has the benefit of causing MUCH less loss of power/light than the automatic drop to 1/4 power max (something like that) that HSS causes. Even using an extended sync speed like 1/320 will only cause a slight loss of power; and if the gradient falls somewhere off the subject the effect can be negligible (or even beneficial). I would agree that it is of limited use though...
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It's only an opinion, so that's cool, but the facts are that an x-sync speed of 1/320sec vs 1/250sec is only one third of a stop, and there is a noticeable reduction in flash brightness at full power with a gradient at the top of the frame. The net effect varies by flash unit and by camera, but the benefits can never be more than marginal - say 1/4 stop at best? If that's a deal-breaker more than once in a blue moon, a different flash solution is needed.

You can also do this with any camera, by bypassing the automatic switch-over to HSS above the nominal x-sync ceiling, but in practise the best way of getting around x-sync limitations (without resorting to HSS mode with its inherent power loss) is to add an ND filter to pull everything down so x-sync ceases to be an issue.
 
Hi Folks,

I think some of you don't understand what I mean. The shutter didn't fire when I pressed the shutter button, NOTHING HAPPENED, for about half a second and then, the shutter fired. It wasn't second curtain sync as the first curtain would have fired instantly, I would have realised what the problem was if that had happened. There was a complete delay, with absolutely nothing happening at all and then the picture was taken, perfectly, but not when I pressed the button. It only did this when the flash or transmitter was attached.

I had the flash sync on 1/250s (Auto FP) as I wanted to use HSS. I changed this to 1/200s (Auto FP) and the problem disappeared. Now it works perfectly.

I have absolutely no ides why this is, I'm just relieved to have found a solution to the problem. I can now do HSS without any problem and the exposures are perfect, job done :)
 
Nelsinki said:
Hi Folks,

I think some of you don't understand what I mean. The shutter didn't fire when I pressed the shutter button, NOTHING HAPPENED, for about half a second and then, the shutter fired. It wasn't second curtain sync as the first curtain would have fired instantly, I would have realised what the problem was if that had happened. There was a complete delay, with absolutely nothing happening at all and then the picture was taken, perfectly, but not when I pressed the button. It only did this when the flash or transmitter was attached.

I had the flash sync on 1/250s (Auto FP) as I wanted to use HSS. I changed this to 1/200s (Auto FP) and the problem disappeared. Now it works perfectly.

I have absolutely no ides why this is, I'm just relieved to have found a solution to the problem. I can now do HSS without any problem and the exposures are perfect, job done :)
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As I said, that sounds like red-eye reduction was enabled and you didn't realize it... it's easy to miss that tiny symbol on the LCD. Combine red-eye reduction with TTL metering and all of the required pre-flashes can cause a notable delay. **Some Nikons use the camera's AF assist light for red-eye reduction, still causes a delay and may be less noticeable visually.

I have always set x-sync to the max available (auto FP) on every Nikon I've ever owned and I've never had the issue you're describing. I highly suspect that if you change *only* the x-sync setting back to 1/250* the issue won't return... if I'm wrong, then there is something odd/wrong with your camera.

**Edit: that may be only when the pop-up flash or a "dumb" flash is used...
 
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I appreciate all your comments and advice, it's been really useful. I used Canon for about 15 years and then moved to M4/3 using Panasonic for about 7 years so I've only recently moved to Nikon a couple of months ago and still finding my way around the menu system. I've made all the necessary adjustments and checked all the settings as you've advised and I reckon my Nikons are very well set up now. A few more shoots and tweaks and I'll store the settings. Thanks for your help :)
 
HoppyUK said:
It's only an opinion, so that's cool, but the facts are that an x-sync speed of 1/320sec vs 1/250sec is only one third of a stop, and there is a noticeable reduction in flash brightness at full power with a gradient at the top of the frame. The net effect varies by flash unit and by camera, but the benefits can never be more than marginal - say 1/4 stop at best?
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I think it is more significant when considering/comparing the max x-sync available between models... there are many cameras available that don't sync above 1/160, that's 1 full stop less effective power from the flash compared to 1/320. But yeah, 1/320 w/ a gradient vs 1/250 w/o isn't much to be excited about.
 
Nelsinki said:
I appreciate all your comments and advice, it's been really useful. I used Canon for about 15 years and then moved to M4/3 using Panasonic for about 7 years so I've only recently moved to Nikon a couple of months ago and still finding my way around the menu system. I've made all the necessary adjustments and checked all the settings as you've advised and I reckon my Nikons are very well set up now. A few more shoots and tweaks and I'll store the settings. Thanks for your help :)
Click to expand...
I wouldn't necessarily recommend setting x-sync to the extended range, that's just what I do. But when using flash I'm normally in manual (camera, and often flash) and well away from the x-sync/HSS change over point, so it doesn't really matter.
 
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I know this is a very old post (and this is also my first post here) and I don’t mean to bring up an old thread, however I was also having this issue with my Nikon D610 with my Godox AD400Pro and it was very frustrating! I have looked everywhere and stumbled upon this thread.

I noticed the OP said he changed from 1/250 AutoFP to 1/200 AutoFP and it fixed it. However, I’d like to add that the solution that worked for me was the red-eye reduction function. Changing my sync speed from 250 to 200 did not work, but my camera was set to red eye reduction flash setting. Turning that off gave me instant shutter fires!

Just wanted to add that for anyone searching for a solution and found this thread, that worked for me! Thanks for that suggestion!
 
cdphoto said:
I know this is a very old post (and this is also my first post here) and I don’t mean to bring up an old thread, however I was also having this issue with my Nikon D610 with my Godox AD400Pro and it was very frustrating! I have looked everywhere and stumbled upon this thread.

I noticed the OP said he changed from 1/250 AutoFP to 1/200 AutoFP and it fixed it. However, I’d like to add that the solution that worked for me was the red-eye reduction function. Changing my sync speed from 250 to 200 did not work, but my camera was set to red eye reduction flash setting. Turning that off gave me instant shutter fires!

Just wanted to add that for anyone searching for a solution and found this thread, that worked for me! Thanks for that suggestion!
Click to expand...

Thanks Cam. Welcome to TP. Great first post.
 
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