Flash Sync Speed

Ok no problem but I don't understand what you mean by 'so many sync settings' perhaps if I did I could answer your question more fully.
Ok
On my Nikon I go into the Custom Setting Menu>Bracketing/Flash>Flash Sync Speed and I have the following choices:
1/250 s (Auto FP) (This is HSS)
1/250 s (Max Sync Speed)
1/200 s
1/160 s
1/125 s
1/100 s
1/80 s
1/60 s

So why would I choose anything but either the top one if I want HSS or the second my max sync speed

I think Andy hit the nail on the head when he said
According to Thom Hogan, the reason for a slower sync setting is to improve compatibility as some external flash units might have a slower maximum speed. The other scenario is when working with 2 different cameras. If the sync speeds are different, then the images might look slightly different if the subject is moving. By setting a slower sync speed, shots taken from either camera should look consistent.
So I am now assuming that they are just old sync speeds from earlier days left in for compatibility reasons
 
That option determines the slowest shutter speed available when using front or rear curtain sync, or red eye reduction in programmed auto or aperture priority auto exposure mode.
Basically, you are setting the boundaries for when the camera is making decisions, rather than you.
When using manual, you may choose any shutter speed you wish, up to the maximum x sync speed of 1/250th sec, unless utilising HSS mode (FP).
 
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Ok
On my Nikon I go into the Custom Setting Menu>Bracketing/Flash>Flash Sync Speed and I have the following choices:
1/250 s (Auto FP) (This is HSS)
1/250 s (Max Sync Speed)
1/200 s
1/160 s
1/125 s
1/100 s
1/80 s
1/60 s

So why would I choose anything but either the top one if I want HSS or the second my max sync speed

I think Andy hit the nail on the head when he said

So I am now assuming that they are just old sync speeds from earlier days left in for compatibility reasons

Yes I completely misunderstood your question and I now know the menu you are referring to. I agree It probably is a legacy / comparability feature to allow compatible flashguns to work with the iTTL Creative Flash System. I previously haven't paid much attention to it as I generally use manual flash and set my own shutter speed. Glad we cleared that one up :)
 
I have heard people report this Phil but personally I've never had any issues with my Bronicas.
My ETRS had a max SS of 1/500 which is only 1 stop higher than many modern FP shutters. IIRC some of the new leaf shutter lenses have a max sync speed that's higher than 1/500 but still less than the max SS of the lens.
 
Max x-sync speed is just that - maximum, not necessarily optimum. Everything should work fine at that speed, but there is no margin for error.

The most common problem is radio triggers, all of which introduce a very slight delay. Mostly these days, that delay is insignificant, but not always. The other potential problem is with slower flash units, like some studio heads, where they take a millisecond longer to get up to full brightness. This is why Canon (in my 5D2 handbook) suggests testing at 1/60-1/30sec with studio flash.

I've never come across a flash unit that needs a shutter speed anything like that long, but it's common to find that you won't get 100% optimum exposure with studio flash at max x-sync speed. Try it, against a plain wall or similar, and you may well see some slightly darker shading at the bottom of the frame. This is the flash pulse ramping up to full brightness at the same time as the second curtain is closing. Drop the shutter speed down a click and it will disappear.
 
Ok
On my Nikon I go into the Custom Setting Menu>Bracketing/Flash>Flash Sync Speed and I have the following choices:
1/250 s (Auto FP) (This is HSS)
1/250 s (Max Sync Speed)
1/200 s
1/160 s
1/125 s
1/100 s
1/80 s
1/60 s

So why would I choose anything but either the top one if I want HSS or the second my max sync speed

I think Andy hit the nail on the head when he said

So I am now assuming that they are just old sync speeds from earlier days left in for compatibility reasons
Those settings only apply if you are in an automated/semi-automated mode... and in a semi automated mode the camera sets it's exposure first (just like always, but with an additional SS limit if not in FP), and then the flash sets it's exposure "on top" to make up for whatever is lacking in the camera exposure... they don't really talk to each other much (if at all).

In your case, setting the max to 1/125 means the camera will use one stop lower ISO, or it will use one stop smaller aperture. The first uses less flash power and battery, the second may be sharper and will have more DOF.

And as I said earlier, many wireless do best around 1/160 or so.

I leave mine set to auto FP (it's only HSS when SS goes above x-sync)... and if I don't like what's happening/going to happen I switch to manual.
 
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That option determines the slowest shutter speed available when using front or rear curtain sync, or red eye reduction in programmed auto or aperture priority auto exposure mode.
That's the flash SS setting, not x-sync. Nikon's max out at 1/60 for that setting...
 
Those settings only apply if you are in an automated/semi-automated mode... and in a semi automated mode the camera sets it's exposure first (just like always, but with an additional SS limit if not in FP), and then the flash sets it's exposure "on top" to make up for whatever is lacking in the camera exposure... they don't really talk to each other much (if at all).

In your case, setting the max to 1/125 means the camera will use one stop lower ISO, or it will use one stop smaller aperture. The first uses less flash power and battery, the second may be sharper and will have more DOF.

And as I said earlier, many wireless do best around 1/160 or so.

I leave mine set to auto FP (it's only HSS when SS goes above x-sync)... and if I don't like what's happening/going to happen I switch to manual.
Thank you Steven a very concise explanation and easy to understand
 
It was quoted directly from the D4 manual, word for word. Well, apart from any spelling mistakes :)
I wasn't going to post this, but just to prevent confusion I decided to.
In my D4 manual flash sync is on page 323...what you quoted is from page 324, flash shutter speed.
 
Yes I completely misunderstood your question and I now know the menu you are referring to. I agree It probably is a legacy / comparability feature to allow compatible flashguns to work with the iTTL Creative Flash System. I previously haven't paid much attention to it as I generally use manual flash and set my own shutter speed. Glad we cleared that one up :)

Nothing to do with legacy, it is just determining the point you want to use flash. Some can hand hold a lot better than others

Mike
 
Nothing to do with legacy, it is just determining the point you want to use flash. Some can hand hold a lot better than others

Mike
OK but let us say I decide I can hand hold steady at 1/60, why would I set my sync speed to 1/60, what is the point when I can just leave at 1/250 allowing me to alter my shutter speed at will without having to adjust sync speed every time I adjust shutter speed?
 
OK but let us say I decide I can hand hold steady at 1/60, why would I set my sync speed to 1/60, what is the point when I can just leave at 1/250 allowing me to alter my shutter speed at will without having to adjust sync speed every time I adjust shutter speed?

IF there is no ambient light, and you have tested your equipment to ensure that it's 100% right up to max x-sync, then there will be no difference to the image regardless of shutter speed right up to max x-sync. Use whatever shutter speed you like.

I tend to use 1/125sec, because I know that works fine with all my cameras and triggers, including Canon 5D2 with the slightly slower YN RF602 triggers that I have several of. Often I could go a click or two faster, but it would make no difference and it's one less thing to think about.

If you want to use 1/250sec, then that's fine, with the caveat that with some combinations of equipment it will not be optimum and could cause problems. The advantage is, if there is significant ambient light that you want to eliminate, the fastest speed will ensure it's knocked back as far as possible.
 
OK but let us say I decide I can hand hold steady at 1/60, why would I set my sync speed to 1/60, what is the point when I can just leave at 1/250 allowing me to alter my shutter speed at will without having to adjust sync speed every time I adjust shutter speed?
If you are altering the SS in S/Tv then it sets a limit to the SS choices you have. If the camera is controlling SS in A/Av then it sets a limit to the SS choices it has.

You only have to reset x-sync if the SS you want is higher than the chosen setting (in a semi/automatic mode). Having it limited to lower than max has the benefit of limiting flash output (battery power/ratio) and can additionally help ensure compatibility with radio trigger delays. Think of it as being the same as an auto ISO limit... it just ensures the automation doesn't do something you don't want it to.

If you are controlling the SS in M then it has no impact whatsoever... the setting is ignored.
 
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If you are altering the SS in S/Tv then it sets a limit to the SS choices you have. If the camera is controlling SS in A/Av then it sets a limit to the SS choices it has.

You only have to reset x-sync if the SS you want is higher than the chosen setting (in a semi/automatic mode). Having it limited to lower than max has the benefit of limiting flash output (battery power/ratio) and can additionally help ensure compatibility with radio trigger delays. Think of it as being the same as an auto ISO limit... it just ensures the automation doesn't do something you don't want it to.

If you are controlling the SS in M then it has no impact whatsoever... the setting is ignored.
Except for occasional use in TTL I work in M exclusively (when using flash) so this is perhaps why I have had difficulty getting my head round this, but your explanation makes a lot of sense. Cheers
 
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