June 24, 2013

comparing maximum flash sync speed – 1/250 vs 1/200

A comment that was posted in the photo gear section, asked about the relative merits of 1/250 max flash sync speed, vs 1/200 max flash sync speed.

Hi Neil, thanks again for Tangents, & your books which I refer to a lot. You have a gift in teaching and your passion is contagious. You’re probably my no 1 reference out there amongst the myriad of info now available. That’s why I’d like your opinion on the D600, particularly the 1/200 sync speed factor. I just bought one. Do you think it’s a big issue. Mr Hobby considers major enough to dismiss buying one. I couldn’t bear the thought of processing 36mp images from the D800 & couldn’t afford the D4. I got an ND filter hoping that would make up for it! What do you think about the camera other than that. Thanks again.

My first instinct will always be to go for the camera with the higher flash sync speed. It is especially valuable when working in bright light, to make it easier for a speedlight to match that bright ambient light. But it also helps with a (slightly) shallower depth-of-field when you can take the shutter speed higher.

But just how much of a difference does that 1/3rd stop difference in shutter speed make in the grand scheme of things?

Now, you have to hang in there a little bit. You’re going to need your calculator for this. But it will be worth the effort, because your choice of camera might just depend on the answer. And you may even save yourself some money. But you will have to work through this, and help figure this out. It’ll be worth it in the end. And you’ll understand your flash a little bit better.

Now, as mentioned in the tutorial: how to use the guide number of your flash
The Guide Number (GN) of your flash is a numerical indication of how powerful your flash is. It depends on the design of your flash, and also on how you zoom your flash’s head.

The Guide Number of your flash =  distance  *  f-stop

This means that there is a constant relation between the distance your flash can reach, depending on your choice of aperture.

Or conversely, a specific distance will imply a certain f-stop.

Great! So where does this all lead us?

 

an example: shooting with flash in bright sunlight

So let’s say we are working at the extreme end of what our (bare) speedlight is capable of in bright sunshine.

Now, the Sunny 16 Rule says that for bright sunshine, we have 1/100 @ f/16 @ 100 ISO,
which translates to:
1/200 @ f/11 @ 100 ISO, or
1/250 @ f//10 @ 100 ISO

So there is a 1/3rd stop difference in aperture. It is an incremental change in terms of Depth-of-Field. In comparing images, the difference would barely be noticeable.

So where else does the change in shutter speed have an effect?

Manual flash exposure is dependent on: (4 factors)
aperture / ISO / power / distance

This of course is encapsulated in the Guide Number.

So what is the difference in distance with 1/3rd stop change in aperture?

Well, the specs for the  Canon 600EX-RT Speedlite (vendor) is given as: 197′ (60 m) at ISO 100
(I assume this is with the flash-head zoomed to maximum.)

So let’s make it an even 200′ just for ease of explanation.

GN  =  distance  *  f-stop

So as an example:
200 = 20 ft * f10

So in fact, there we have it for the 1/250 sync speed (and the accompanying f/10 aperture). The GN of the Canon 600EX-RT says we have to be 20 ft from our subject when we shoot at f/10 @ 100 ISO.

To restate that – if we are 20 feet away from our subject, then our aperture is 200/20 = f10

Now let’s see what happens with the 1/200 @ f/11 scenario:

for f/11 we have to be

200 = X * 11
where X is then 18′

So you have to be 18′ away (for f/11) compared to 20′ for f/10

You decide how important that 2 feet change in distance is (compared to the overall distance). The difference between 18′ and 20′ isn’t all that much in my opinion. It’s a shoe-shuffle further.

 

alternately

If your speedlight has a distance scale, then all of this exercise could’ve been skipped. Just by looking at how your speedlight’s distance scale changes as you flick between 1/3rd stop changes on your aperture, you can see just how much the distance changes. This works whether you have your flash set to TTL or manual.

(Keep in mind for some inexplicable reason, the Nikon SB-900 and SB-910 shows a non-linear relationship when we work at maximum sync speed.)

 

video tutorials to help you with flash photography

If you like learning by seeing best, then these video tutorials will help you with understanding flash photography techniques and concepts. While not quite hands-on, this is as close as we can get to personal instruction. Check them these and other video tutorials and online photography workshops.


 

summary

While I am all for bigger, better, faster, more, more … and I would always recommend the more powerful speedlights over the smaller ones - and my favorite camera is the Nikon D4 - I would say that in this case, where someone shoots with a camera that only syncs up to 1/200 for flash, that they aren’t losing much compared to those who shoot at 1/250 th.

 

a little bit of homework

  • How many stops do you have to change your aperture by to double / halve the distance your flash can reach?
  • The specs for the Nikon SB-910 Speedlight (vendor) is given as:
    Guide number of 34/111.5 (at ISO 100, m/ft., 35-mm zoom head position)
    This means that our GN (in feet), is 111.5
    What distance do we need to be at to get f/10 and what distance for f/11 with the flash at full power?

 

related articles

 

{ 19 comments. } Add a Comment

1 olympus June 24, 2013 at 4:44 am

with some olympus cameras we have only max.1/160 in 1/3 stops. (1/180 in half stops).
Just try this out!!!
1/160 :-/
grts

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2 pj sinohin June 24, 2013 at 9:12 am

thanks for the guidelines!

my trial & error activity before a shoot is canceled or is now lessened

homework? um…
-1/3 stops?
-around 11 & 10 feet?

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3 Martin Turrell June 24, 2013 at 9:27 am

is there a reason the article doesn’t mention as a factor in deciding over a camera with a max sync speed of 1/200th sec over one with 1/250th sec the ability of darkening the ambient light more by going to a higher shutter speed as you can 1/250th of a second? (especially trying to battle bright ambient)

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4 Neil vN June 24, 2013 at 9:34 am

1/200 @ f/11 @ 100 ISO, or
1/250 @ f//10 @ 100 ISO

There it is. Then you take a small step forward, and everything is equal again in terms of balancing flash and ambient.

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5 Jon Lloyd June 24, 2013 at 10:35 am

Now I have to admit that I am absolutely flummoxed by all of that! I’ve read the math before on one of your posts (probably more than once) and my little brain struggles… BUT you added an important word in there and that was “shuffle”. I think it is important to know the technical limitations of your gear, but in reality what we ‘all’ do is move back or forward or if the flash is off camera we move it or the subject back and forth…

I’m a reasonably technical person but I reckon on average I would be 2 or 3 feet out on most guesses at distances and would you really carry a tape around?

My measure is a test shot (or three) and some adjustments particularly with off-camera flash. With FEC and the like we are spoilt with finessing the exposure.

Having said all that – I WILL read that again and understand it, but, Sir – the dog just ate my homework….

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6 Matt June 24, 2013 at 11:03 am

Hi Neil,

I just want to clarify that these figures are all based on the speedlite being set to full power correct?

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7 Neil vN June 24, 2013 at 6:47 pm

Yes, for these examples we’re working at full power. This is where we are at the extreme end of what the flash is capable of.

It becomes a more trivial comparison if we’re working at wider apertures and using around an 1/8th of the flash’s power … since we could just open the aperture more, without affecting what the flash is capable of. It is at full power where we hit a kind of ceiling and can really compare the behavior of the flashguns.

Neil vN

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8 Dan Rowe June 24, 2013 at 9:43 pm

Spot on Neil. I’d offer a different thought as to why it CAN be a bigger deal though than what the power difference can mean….While I mostly shoot with Einstiens instead of speedlights, I actually appreciate that extra 3rd of a stop for what I believe is a more important reason, reduction of camera shake (I ain’t using no stinkin’ tripod unless I have to). You see I’m usually shooting pretty balanced to the ambient and often at 200 mm focal length. With my 1DX and the Cybersyncs I can get, reliably, 1/250 which is a more hand-holdable shutter speed for my abilities. I’m seeing much fewer blurred images. While, of course, flash speed can be used to stop the action, I’m usually shooting in situations where the ambient is still used as sculpted fill or backlight. Camera shake can cause issues for me. That extra 3rd gives me more cushion.

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9 Michael June 26, 2013 at 2:38 am

Hi,
In order to get rid of this academic discussion concerning 1/160….1/200….1/250. sync speed, why not using supersync equipment like Pixelking or yongnuo ?

Works fine with my d700 and Metz 50 AF-1 up to 1/1000 without significant loss of power. You can even skip the ND filter which degrades autofocus accuracy.

Greetz
Michael

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10 Neil vN June 26, 2013 at 3:28 am

… because it would be rude of me to reply to a serious question with the dismissive instruction to “just get a Pixelking or yongnuo and a Metz 50 AF-1 for your Nikon D600″.

Neil vN

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11 Matias June 26, 2013 at 8:35 pm

1. In theory you need to double or halve the aperture to double or halve the distance. In practice that is close to changing 2 stops your aperture. So, if you want to double the max distance you have to open 2 stops your aperture, and if you want to halve the distance you have to close 2 stops your aperture

2. 11.15 feet for f/10
10.14 feet for f/11

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12 Suzanne Young June 27, 2013 at 9:43 am

I’m really grateful for people like you who share their gift and do so with such clarity. I’m sure there are literally hundreds of us who have benefited from the time and effort you put into sharing your knowledge on this blog. It’s challenging and enriching, no matter our knowledge and skill level. I’m loving my D600! Thank you Neil!

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13 Rudy June 27, 2013 at 10:25 am

Hi Neil,

I want to add one more bit of info that your readers might not be aware of. There is a difference between how much light a crop sensor and a full frame camera will let in at the exact same settings-at least in my experience. Comparing a 7D and a 5D KM III at the same settings, say 1/200. f/2.8 and ISO 100, the 5D MK III is 0.70 stops brighter. This is significant and would make my 7D my go to camera for situations as you described above. It is letting in 1 full stop less ambient light (2 clicks from being less bright and one click from having 1/250 max sync speed) when shooting with flash. This may be different (I am sure it is) between cameras and brands but one stop might make the difference and it is why I keep the 7D around. Hope this helps those that have crop and FF cameras and it might be worth a test?

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14 mark July 18, 2013 at 9:57 pm

there is a great deal of difference between a straight x-sync and high speed sync (hss or fpsync). Going to hss / fpsync mode eats a lot of flash power as the strobe pulses the light as opposed to just letting it pop one big time. This is fine if we are working well within the limits of the hot shoe flash, but if we are at full already, there is no other option but to get more (McNally, a nikon ambassador is known for using 7 or 8 speedlights in just one group to overcome the limitations of HSS / FPSync). The margins will be much smaller if we use a diffuser eating 1 to 2 stops further. Lastly, this also requires a compatible flash so almost all studio / high power strobes are out of the question. So high speed sync in more of a workaround and is not a substitute to true native sync speed.

This is the reason why many are liking the fuji x100 / 100s with its nearly unlimited sync speed (you are limited only by how fast your flash pops), and one of the reason why I still keep on using my old school nikon d40 (native sync of 1/500s and limited by the flash for other triggering methods).

if somehow nikon releases something truly magical and brings back the 1/500s sync speeds… then I’ll be the first in line for it (and I am sure I am not the only one).

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15 Michel Keppens July 19, 2013 at 4:32 am

Hi Neil,

there is something I don’t understand in the comment Michael gave on using Pixelking or Yongnuo to avoid loss of power in your speedlight.
My understanding (and please correct me if I’m wrong) of things is that your max sync speed is crossed at the moment you use a shutterspeed where your 1st curtain and your 2nd curtain are (partially) in movement at the same time. For that reason when you go in high speed sync, the speedlight sends out multiple pulses of light instead of 1 single pulse, hence the loss of power.
Now how can Pixelking or Yongnuo overcome that physical limitation of your camera?

Cheers,
Michel

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16 Eugene Struthers March 18, 2014 at 8:02 pm

So if I use a flash with a GN of 56 and I set my aperture to F/16.
My flash to subject distance should be 3.5m (about 11 feet)

56 (GN) = 3.5 divided by f/16

Say I want to shoot at an aperture of F/8 rather than f/16. Where do I position the flash unit?
Easy calculated: 56 (GN) = 8 divided 7m (32 feet)

So the lens aperture = guide number (GN) divided by flash to subject distance.

What if I’m in a confined space. And I can only move back a distance of 5m.
I take it the calculation according to your formulae would be: 56(GN) = F divided by (5m) giving us an aperture of f/11. Then what about the inverse square law principal. In cases where you are shooting a couple dancing on a dark lit wedding dance floor.

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17 Naftoli March 18, 2014 at 9:11 pm

thanx for the great post neil! although, i think u may have missed out on 2 important points.
1. having a max sync speed of 1/250 (or 1/320th on newer Nikons) over 1/200 allows a larger aperture to be used resulting in a nice shallow dof. so take a case with a sunny day if u place the subject in the shade, say the exposure is correct at to ISO 100. 1/200th of a sec. f/4.5, now f/4.5 is the max fstop possible without using hss or an nd filter. however if u had the option of a faster X sync speed of 1/250 u can drop down to f/4 and gain a 3rd stop shallower Dof

The second thing not mentioned is the fact that at Max power a speedlights Flash duration is longer than 1/200th of a second, meaning at anything faster than 1/125th the speedlights full burst of light is not being recorded, with the tail end of the flash burst hapening after she shutter has already closed

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18 Philip G March 19, 2014 at 5:13 am

I think you’re overstating the importance of 1/3 stop when it comes to depth of field. You will struggle to tell the difference in depth of field between f/4.5 and f/4.

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19 Neil vN March 19, 2014 at 5:18 am

I would agree. That change in DoF with 1/3rd stop change, is incremental.

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