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01-01-2017, 07:24 AM - 1 Like   #16
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QuoteOriginally posted by reivax Quote
Thanks for the info! I guess I'm trying to understand the benefit of using x-sync to the other settings. Can't really think of one. Or maybe, I still don't fully understand it.
It keeps you from accidentally turning the shutter to a faster speed where your flashes stop syncing, leaving you wondering what's going on. Especially true if your camera has a mode dial with a lock.

If your camera is set to 1/3 EV steps, 1/180th is not a selectable shutter speed in M mode, so this gives a way to get your highest sync speed without menu diving (same will be true for 1/2 EV steps and 1/200th sec, if that happens to be your cameras sync).


I see it as more of a bookkeeping convenience than anything else. In practice, I don't bother and just use manual mode when working with off-camera flashes.

01-01-2017, 09:07 AM   #17
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Back in the 1970's camera and flash makers came of with "dedication". This added a pin to the flash foot and camera hot shoe. It's purpose is to set the camera shutter speed to whatever the rated flash sync speed was for the camera when the flash was mounted and turned on. Flash sync speeds for manual focus film cameras was typically 1/60 or 1/125 of a second. Otherwise the shooter would have to remember to set the sync speed in manual mode. The pin location and signal protocol varied from manufacturer to manufacturer. That's why a flash dedicated for Olympus will not set the sync speed on a Pentax body.

The X-sync mode does the same thing so you can easily set the sync speed when using non-dedicated flash units with your Pentax. It's a lot easier than having to set the speed using the eDial. Manual focus cameras usually highlighted the flash sync speed in red or some other color on the shutter speed dial.

Flash dedication is still supported. If you mount and power up a flash unit dedicated to Pentax or Pentax TTL on your Pentax DSLR the flash sync speed will be set in all modes except manual (M).

When I use my old Lester Dine (Nissin) ring flash (Pentax TTL) it will set the flash sync speed on my K10D (no TTL). When I use my Minolta 360px or Sunpak 422D for Minolta I have to use X-mode or set the shutter speed manually to 1/180 sec.
01-01-2017, 09:12 AM   #18
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QuoteOriginally posted by derekkite Quote
Have you used the flash in av or tav mode, auto iso auto flash?
Yes. Many times. But the statement never specified auto iso. It was stated that it wasn't possible to use iso lower than 800 except with X-sync mode.
01-01-2017, 09:39 AM   #19
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QuoteOriginally posted by derekkite Quote
On the K3 in other modes the iso wouldn't go lower than 800. So you have flexibility to set things to the optimum value.
QuoteOriginally posted by UncleVanya Quote
???????? I'm really not sure what this is trying to say.
QuoteOriginally posted by Class A Quote
What makes you say that?
QuoteOriginally posted by derekkite Quote
Have you used the flash in av or tav mode, auto iso auto flash?
QuoteOriginally posted by Class A Quote
Have you set your minimum ISO ("ISO AUTO Setting") to be "800"?
QuoteOriginally posted by UncleVanya Quote
Yes. Many times. But the statement never specified auto iso. It was stated that it wasn't possible to use iso lower than 800 except with X-sync mode.
Yikes! What a strange side-thread! I read a comment on another thread just yesterday that quite bluntly said that TAv would not work with flash. I did not inquire further since it had all the appearance of a can of worms and I am not much of a TAv user or fan of canned worms. Turns out it is a bit of a can of worms and another reason why I often mutter that auto-ISO is evil.

FWIW, I have my lower limit for auto-ISO on my K-3 set at 100 and have no trouble doing both P-TTL and manual flash using TAv or Av (auto-ISO) modes. ISO floats freely within my set range for auto-ISO. Auto-ISO is not allowed in X or M modes, so the full range is also available there. When it comes to automation, settings and constraints matter.


Steve


Last edited by stevebrot; 01-01-2017 at 10:16 AM.
01-01-2017, 09:41 AM   #20
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Yes. I'm confused also by the ISO 800 claims.
01-01-2017, 10:17 AM   #21
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QuoteOriginally posted by Class A Quote
Have you set your minimum ISO ("ISO AUTO Setting") to be "800"?
TAV mode, iso settings 100-3200. Install Pentax flash, the new 540. Minimum ISO would be 800. I noticed because of the terrible quality of the shots.

I haven't the faintest clue why. I fiddled any pertinent settings, this was a while ago without any resolution. So I use X mode. It might have to do with the Sigma 500 lens. Not sure. It would auto iso and flash auto meter, but the iso would not go below 800.

X mode auto iso works as expected.

I used it last winter for wildlife shooting to get a couple stops more light. With the K3 sensor noise curves at low light, 800 iso is terrible quality.

Last edited by derekkite; 01-01-2017 at 10:26 AM.
01-01-2017, 10:22 AM   #22
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QuoteOriginally posted by derekkite Quote
TAV mode, iso settings 100-3200. Install Pentax flash, the new 540. Minimum ISO would be 800. I noticed because of the terrible quality of the shots. X mode it works as expected.
What lens, what lighting? What aperture setting?

01-01-2017, 10:43 AM   #23
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QuoteOriginally posted by UncleVanya Quote
What lens, what lighting? What aperture setting?
Sigma 500 f4.5. Pentax 540, the new version. These were at edge conditions, wide open or slightly stopped down. Auto iso, auto flash. For some reason it would lower the flash power and set the iso higher. If I remember correctly it was only evident once the shot was taken.

It likely was the body algorithm seeing the focal length. The distance would require a couple stops more light, or so it thought.

X mode was the solution. A nicely implemented mix of auto and manual settings that works as expected.
01-01-2017, 11:10 AM   #24
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QuoteOriginally posted by derekkite Quote
It likely was the body algorithm seeing the focal length. The distance would require a couple stops more light, or so it thought.
More likely the slow aperture and/or dim light. Drop the shutter speed to about 1/10s in bright room light and see if that makes any difference.


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01-01-2017, 11:17 AM   #25
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QuoteOriginally posted by stevebrot Quote
More likely the slow aperture and/or dim light. Drop the shutter speed to about 1/30s in bright room light and see if that makes any difference.


Steve
No. It was a hard floor. The flash was on less than full power but the iso wouldn't go less than 800. It was an algorithmic decision in TAV mode.

I solved the problem using X mode. That is why I posted it here.
01-01-2017, 11:32 AM   #26
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QuoteOriginally posted by derekkite Quote
No. It was a hard floor. The flash was on less than full power but the iso wouldn't go less than 800. It was an algorithmic decision in TAV mode.

I solved the problem using X mode. That is why I posted it here.
Very strange. I don't have the 540 or the Sigma 500, but have been unable to reproduce a hard floor with my K-3 and any of my kit. My auto-ISO is set to the default response curve. Is yours set to "Fast" by any chance?


Steve
01-08-2017, 08:44 PM   #27
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QuoteOriginally posted by reivax Quote
After a few years, I finally decided to start looking into X-Sync. Only trouble is, every resource I find talks about X-Sync as if you're supposed to already know what it is and how it works. I know it has something to do with the Sync Socket on the camera, but I can't really figure out much more than that. I guess I don't understand why I would want to use it instead of any of the other exposure modes on my camera. Can anyone please explain the purpose and when I would want to use this?

Thank you everyone and Happy New Year!!! (a little soon, but I may not get a chance later).
As others have said, The X-sync mode is used so you don't accidentally change the shutter speed while using flash- typically in a studio. In my studio, I almost always use the X-sync mode. I do this for two reasons:
1) as above so I don't change the shutter speed
2) to minimize the environmental lighting as much as possible. In a studio environment I want all the light in the scene to come from my flash heads only so I have total control of the light. Setting the mode to x-sync insures that, with typical studio flash head light output and a F8 aperture, ISO 100 (or ISO 80) on my K5iis, light from other sources is more than 3 stops less than my strobes. in other words, negligible outside light.
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