[LensBeginner]

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*snip*
Ok, so what is the point? Well as you have observed some users complain that Pentax has a slower max sync speed than Canon or Nikon, these folks are also missing the point. The point is that Canon and Nikon's sync speeds are also too slow, but when trying to balance ambient light, every stop counts. Ideally there would be no such thing as max sync speed, you'd be able to sync all the way up to the camera's maximum shutter speed. There are some cameras, like the Nikon D70s, that can do that by using a hybrid electronic/mechanical shutter, but there are some problems getting that trick to work with a CMOS sensor. Leaf shutters in lenses would be a good compromise, but there are far too few of those out there and none for the K-mount. Those who say 1/180th should be good enough are obviously not trying to take the same types of images as those who advocate for higher sync speeds.

An excellent explanation.
I'm probably not trying to get the same type of images of others who ask for higher sync speed, but then again I'm just an amateur.
What I was saying was, just as you pointed out, that even 1/250 is too slow, and people with specific interests should indeed go completely different road in order to achieve what they want.
A half stop is nothing compared to the abyss - I said 4 to 5, you said 4.5 stops - we are trying to bridge here.
Sure, if it comes in the K-FF or the K-3ii or the K-next, I'll be the first to be happy about it.
But it doesn't solve the issue.

[cybertaff]

but then again I'm just an amateur.

makes at least two of us then dude

[Oldbayrunner]

I don't get it...
Let's say you shoot the person from 10ft with a 50mm at f/2, pretty much ok for a portrait. DoF is 0.96ft on a Pentax APS-C
Let's say you take a 200mm tele and walk away, so the subject stays the same size in the frame.
You get 39.8832ft* 200mm at f/2, and FoV is still 0.95ft, so quite comparable... Even by f/2.2 you still get a much deeper DoF...
How is this minimal difference going to help you in dropping ambient light? Am I missing something?

* 27° vertical AoV (50mm lens), vertical size 4.7879ft at 10ft... same vertical size for a 6.87° vertical AoV (200mm lens) entails a 39.8832ft distance from subject

It doesn't but that wasn' what my post responed to, which was this;

When you absolutely need a defocused background in full sunlight only NDs and HSS can help, and it matters not if max flash sync speed is 1/180 or 1/250s...

There is nothing mentioned in this about ambient light which makes this incorrect, ND filters or hss have nothing to do with defocusing a background, the lens and aperture use does.

now in regards to defocusing watch this;

You Tube

You Tube

[BrianR]

Ok, so what is the point? Well as you have observed some users complain that Pentax has a slower max sync speed than Canon or Nikon, these folks are also missing the point....

I agree with the rest of what you said, but this is a pretty un-charitable assumption. Personally, I prefer to keep most of my whining semi-realistic, and imo 1/250 sync speed is a reasonable complaint/wish/goal for a pentax dslr as other manufacturers have demonstrated it's possible. I'd happily take more if it was readily available.

It's not so important to me that I'd be willing to carry an entirely different system to get super high syncs (or switch systems for half or even a full stop), but if one of those old Nikon bodies with the magical shutters were available in a k-mount I'd be tempted to drop a couple hundred and run with the 6mp ccd when the situation warrants it. There are a number of 'advanced' P&S that can sync at high speeds, they're tempting too but I haven't brought myself to it yet

[LensBeginner]

It doesn't but that wasn' what my post responed to, which was this;
There is nothing mentioned in this about ambient light which makes this incorrect, ND filters or hss have nothing to do with defocusing a background, the lens and aperture use does.

1. This is a thread about flash, and I was directly responding to a question which clearly stated "during flash photography"
2. I used the word "HSS" and "synch speed" in the same sentence, giving you a clue that I was implying the use of flash
3. "the lens and aperture use does" Duh! As if I had not said it before... but in order to maintain aperture you must kill light one way or another.

True, different shooting distances have an effect on perspective, but they also change the relationship between objects, which is something you seldom want (and when you want it, you'd like to do it on purpose), and which is something an ND filter or HSS don't do.

[Oldbayrunner]

edit: Oh, almost forgot, because of Pentax's implementation of HSS, you need a HSS flash attached to the hotshoe. This means that unless you have multiple flashes, you won't be able to stand back with a telephoto lens, you need to be close to the subject. Don't get me started on the Pentax flash system]

What about the use of a Pttl compatible sync cord to trigger a compatible hss flash off camea, the use of an Hss flash attached and trigger another Hss slave compatible flash if the lighting isn't too bright or an aokatec Pentax hss compatible radio trigger system? I use all of those sucessfully

[narual]

Fill flash on moving subjects in bright light. Especially at wide aperture and if you forget to bring ND filters. HSS only works well if they're standing still.

Not the biggest deal in the world, but a minor annoyance at times. I'm sure even at 1/320 or whatever it would crop up.

My old D70s official sync speed was 1/500, but could actually sync all the way up to 1/8000 with a non-ttl flash (or some tape on a ttl one). It takes about 1/1000 of a second for a full power flash, though, so it could only be at 1/8 power (give or take), but even 1/1000 is plenty fast. For things like bullets/balloon pops/water drops, using a sound/light/laser trigger on the flash would make more sense. (this guy on eBay has nice kits for lighting, sound, and laser-break triggers, as well as a kit specifically for taking photos of water drops)

[cybertaff]

Fill flash on moving subjects in bright light. Especially at wide aperture and if you forget to bring ND filters. HSS only works well if they're standing still.

Not the biggest deal in the world, but a minor annoyance at times. I'm sure even at 1/320 or whatever it would crop up.

My old D70s official sync speed was 1/500, but could actually sync all the way up to 1/8000 with a non-ttl flash (or some tape on a ttl one). It takes about 1/1000 of a second for a full power flash, though, so it could only be at 1/8 power (give or take), but even 1/1000 is plenty fast. For things like bullets/balloon pops/water drops, using a sound/light/laser trigger on the flash would make more sense. (this guy on eBay has nice kits for lighting, sound, and laser-break triggers, as well as a kit specifically for taking photos of water drops)

Thanks already own a lot of doo dads and gizmos of this ilk,, and i now coustom make drip kits for myself as part of the hobby so to speak

[maxfield_photo]

It's not so important to me that I'd be willing to carry an entirely different system to get super high syncs (or switch systems for half or even a full stop), but if one of those old Nikon bodies with the magical shutters were available in a k-mount I'd be tempted to drop a couple hundred and run with the 6mp ccd when the situation warrants it. There are a number of 'advanced' P&S that can sync at high speeds, they're tempting too but I haven't brought myself to it yet

You could always get a PZ-1(p). That camera has a 1/250th sync speed and supports K-mount. Unfortunately, it doesn't support HSS, so once you are at max sync, that's all you get. Still, it's a fantastic camera in it's own right.

In the quest for higher sync speed, I almost bought a Q7. I figured, "hey, a leaf shutter" that will almost justify the indignity of owning a Q. Ahem, unfortunately, the R&D folks at Pentax missed another golden opportunity and it turns out that you can only take advantage of the 1/2000th sync speed through the pop-up flash. If you use the hotshoe, you are limited to 1/250th Anyone who has ever tried to sync a flash in bright sunlight via optical slaves will understand my frustration. It's unreliable at best, and at worst, impossible, really just depends on the situation.

But realistic you say? Well the original Canon 1D had a kevlar or titanium shutter with a 1/500th sync speed, and a maximum shutter speed of 1/16000th. Obviously it's possible, though I'm sure it's a bit more expensive.

There are actually two benefits to having a faster sync speed, even when dealing with HSS. The obvious one is for every stop of "real" sync speed, one extra stop of ambient light is removed from the equation, making your flashgun effectively one stop more powerful at balancing the ambient light.

The other benefit take a little imagination to visualize. At speeds above the max sync speed, the second shutter curtain begins to close before the first curtain completely opens. This is of course why flash manufacturers resort to HSS which causes the flash to pulse continuously for the duration of the shutter curtains' travel (In the case of Pentax, for 1/180th of a second) . The individual shutter curtains always traverse the distance across the sensor, no matter what shutter speed (30 seconds all the way to 1/8000th of a second), at the same velocity. As the shutter speed increases, the curtains at any one point in time will occupy more and more of the sensor real estate, or one might think of it as an ever-narrowing slit that travels across the sensor. Now, here is the key, with a higher max sync speed, the size of the slit will be wider at any given shutter speed. So the slit on the Canon 1D will be twice the width of the slit on the Nikon D800, and probably 3 times wider than the Pentax K3 (because of the cropped sensor) all at say 1/1000th. What this means is more of the light from the flash actually reaches the sensor, and less bounces off the shutter curtains, reducing the penalty for crossing the sync speed barrier. Also, since the curtains are in motion for less time, in theory the flashgun could put a bit more power into each pulse, further reducing the penalty, but that's assuming that the increase in power wouldn't cause overheating.

Would people pay more for an extra stop of sync speed? Well, I'm asked to pay for video, a feature that I have no intention of ever using, yet video seems to get all the attention these days. Pentax have neglected their flash system for years, and it, along with AF and yes, video, are all thing that need to improve if the brand is to be taken seriously by professionals.

[Oldbayrunner]

1. This is a thread about flash, and I was directly responding to a question which clearly stated "during flash photography"
2. I used the word "HSS" and "synch speed" in the same sentence, giving you a clue that I was implying the use of flash
3. "the lens and aperture use does" Duh! As if I had not said it before... but in order to maintain aperture you must kill light one way or another.

True, different shooting distances have an effect on perspective, but they also change the relationship between objects, which is something you seldom want (and when you want it, you'd like to do it on purpose), and which is something an ND filter or HSS don't do.

I do believe in my posts I have also been mentioning using flash,

2. I never thought otherwise but I still debate the use of ND filter or using HSS as the only way to obtain absolute defocus in bright light, as you stated, primarily because they have very little to do with the background focus. Had you not stated that in the verbage you used we wouldn't be having this debate.

3. True, and using an ND filter or using Hss are only two ways not the only way as stated. One may be forgetting one can manually maintain the aperture and shutter and use EV compensation to drop the ambient light exposure with flash or strobe lighting. There are several ways to control light in strobist photography. All of these work it is strictly dependent on the effect one is trying to create. That is why we have all these gret tools at our disposal.

[LensBeginner]

Now, here is the key, with a higher max sync speed, the size of the slit will be wider at any given shutter speed. So the slit on the Canon 1D will be twice the width of the slit on the Nikon D800, and probably 3 times wider than the Pentax K3 (because of the cropped sensor) all at say 1/1000th. What this means is more of the light from the flash actually reaches the sensor, and less bounces off the shutter curtains, reducing the penalty for crossing the sync speed barrier.

This means shutter curtain speed varies in different cameras, otherwise a 1D would get more light at a given shutter speed than a D800.
Larger slit, faster speed.
Is that the case?

---------- Post added 11-11-14 at 07:56 PM ----------

True, and using an ND filter or using Hss are only two ways not the only way as stated. One may be forgetting one can manually maintain the aperture and shutter and use EV compensation to drop the ambient light exposure with flash or strobe lighting. There are several ways to control light in strobist photography. All of these work it is strictly dependent on the effect one is trying to create. That is why we have all these gret tools at our disposal.

EV compensation changes aperture (don't want it) and shutter speed (only up to shutter speed), then you're left with auto-ISO (up to a point), but it doesn't change the laws of physics.
You simply can't drop ambient light beyond a certain point if a scene meters at, say, 1/4000s, ISO 100, f/4
What are you gonna do? go ISO 80, ok, that's one third of a stop, and then? aperture, ok that's f/5.6, f/8, f/11 (bye bye defocus) and you're still 1/400.

I do believe in my posts I have also been mentioning using flash,

2. I never thought otherwise but I still debate the use of ND filter or using HSS as the only way to obtain absolute defocus in bright light, as you stated, primarily because they have very little to do with the background focus. Had you not stated that in the verbage you used we wouldn't be having this debate.

So, as I have demonstrated above, under certain conditions an ND filter or HSS sync are the only way to lower ambient light in a practical way.
Yes they do have something to do with background focus because otherwise you'd have to shoot at f/22!!!

I'm starting to think that you like trolling, or that your only aim is to obtain reason in a conversation.
And, please, I ask you the favor of not "Huh"-ing me again, that's just plain rude.

[maxfield_photo]

This means shutter curtain speed varies in different cameras, otherwise a 1D would get more light at a given shutter speed than a D800. Larger slit, faster speed. Is that the case?

The word "speed" may be a bit ambiguous here, so let's use "velocity". A camera with a higher max sync speed will have a higher shutter curtain velocity, that's how max sync speed is determined. What ever the camera's max sync speed is, that is the amount of time that it takes for a single shutter curtain to traverse the sensor. So when you think about, let's say the K3 vs. the Nikon D800, not only do the Pentax shutter curtains take longer to close, but they also have 33% less distance to travel. From this we can deduce that Pentax's shutter curtain velocity is significantly slower than other brands.

[LensBeginner]

The word "speed" may be a bit ambiguous here, so let's use "velocity". A camera with a higher max sync speed will have a higher shutter curtain velocity, that's how max sync speed is determined. What ever the camera's max sync speed is, that is the amount of time that it takes for a single shutter curtain to traverse the sensor. So when you think about, let's say the K3 vs. the Nikon D800, not only do the Pentax shutter curtains take longer to close, but they also have 33% less distance to travel. From this we can deduce that Pentax's shutter curtain velocity is significantly slower than other brands.

Thanks, it makes sense.
That's why I was comparing two full frames and left the K3 out of the equation

[BrianR]

But realistic you say? Well the original Canon 1D had a kevlar or titanium shutter with a 1/500th sync speed, and a maximum shutter speed of 1/16000th. Obviously it's possible, though I'm sure it's a bit more expensive.

"Realistic" as in something that could realistically be included in a ~$600-1200 Pentax aps-c camera If money were no object I wouldn't bother wishing, I'd just go buy instead.

[Class A]

... i use up to six of those yougnuo yn560 mk2 set at 1/128 , but recently have upgraded my flashes to hss and am happily shooting as fast as i like ...

Note, however, that if you use HSS, your exposure duration will be 1/180s.

HSS uses many small bursts to emulate continuous light while the shutter slit moves down the sensor (also see maxfield_photo's explanation). So while every pixel will only get an exposure corresponding to the shutter speed (say 1/4000s), the time period between the exposure of the first exposed pixel row and that of the last will be 1/180s.

As a consequence, you get a "rolling shutter" effect, i.e., distortion of anything that moves during 1/180s.

If you want an undistorted image of quick action, you must not exceed the sync speed and use low flash power (in order to achieve short flash pulses).

With respect to getting the right phase (timing) of the event, this can be completely controlled by when you trigger. While a higher sync speed would allow the camera to be ready for exposure more quickly, this is not a big effect and you can completely compensate for a slower sync speed by just triggering a bit earlier. With a laser trigger that has a delay timer, you can trigger on the falling drop and then use the delay to time the exposure as early or late as you like.