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11-17-2013, 12:18 PM   #1
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K-30 and 1/180 sync limit when using flash :/

I have Pentax K-30 and one external flash Metz 52 I would like to take few pictures of my dog running in dark forest.

Max sync speed (without external flash) for Pentax K-30 is 1/180 which is not fast enough to "freeze" running dog on the picture (see attachment).
I don't want to attach my external flash to the camera - that can't provide nice angle of external light.

Any ideas ? I need at least 1/250 sync time and I would like to avoid buying second external flash. No wires. I don't
mind to buy some radio trigger...

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11-17-2013, 01:34 PM   #2
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Stop down the aperture to cut more ambient light and you won't have blur. The flash freezes the motion, not the shutter speed. You could even do this at 1/2 second shutter if you want.
11-17-2013, 02:57 PM   #3
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Im not sure about the Metz 52 but I have a Metz 58 AF-2 and it does high speed sync. The limitiation is that as far as I can tell it will not do that in wireless mode so you will need a P-TTL extension cable to use the HSS mode off camera.

The shutter speed can be taken way up to the maximum and it still works but power falls off very rapidly as you increase shutter speed. For instance At 1/1000sthe GN is reduced from 58 to less than 10.
11-17-2013, 03:39 PM - 1 Like   #4
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QuoteOriginally posted by lister6520 Quote
The shutter speed can be taken way up to the maximum and it still works but power falls off very rapidly as you increase shutter speed. For instance At 1/1000sthe GN is reduced from 58 to less than 10.
It is also strobing the flash, increasing the duration and really does nothing to help freezing motion in dark environments. It is useful for shooting in bright environments where you would need to reduce ambient light as much as possible and you are already stopped down.

The Metz 52 af-1 is a fairly slow flash with a duration of 1/125s at full power, but at 1/4 power it is 1/2000s, which is more than enough for freezing something like a moving dog. This even means at full power you are wasting light by using a shutter speed faster than 1/125s.

Here is what I would do for this shot:
Set the camera on a tripod at f8 and a low ISO, then get the shutter speed for the ambient dialed in without the flash or dog, this will vary depending on how much of the background you want to show. This could be 10 seconds, it really doesn't matter, slower is actually better.

Setup the flash with some form of manual remote trigger, could be optical, could be radio, could be a cable that you touch two wires together to make the flash trigger. Put the flash where you want it on manual and set the power somewhere to start, 1/4 would be a good starting point.

Have your dog stand in place where you will want to take the picture, this is so you can dial in exposure of the flash. Take an exposure and pop the flash by hand at some point during the exposure. Assess the output, if you like the light leave the power where it is, if not adjust it until you like it.

Now you're setup for the actual image. Trigger the exposure of the camera, release the dog and trigger the flash by hand when the dog crosses the point you want.


Last edited by elliott; 11-17-2013 at 03:47 PM.
11-18-2013, 12:08 AM   #5
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re:

Thank you elliot I will try that.

I was thinking about radio triggers e.g. pocketwizards - Pentax with attached pocketwizard won't be limited by 1/180 sync limit and external flash in manual settings could be triggered by radio trigger in correct moment. It will be interesting to see whether is Metz really so slow or I will gather enough light in right moment at e.g. 1/500 ... 1/1000. I will let you know guys.

I agree with idea in this article : Strobist: Control Your World With Ultra-High Sync

"The trick is, you have to fool the camera into thinking there is not a flash attached to it. This way it will not restrict itself to its normal maximum sync speed."

...then it depends on configuration if photographer will manage sync flash with camera in any way (radio trigger, wire...)
11-18-2013, 01:07 AM   #6
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QuoteOriginally posted by martinos Quote
Thank you elliot I will try that.

I was thinking about radio triggers e.g. pocketwizards - Pentax with attached pocketwizard won't be limited by 1/180 sync limit and external flash in manual settings could be triggered by radio trigger in correct moment. It will be interesting to see whether is Metz really so slow or I will gather enough light in right moment at e.g. 1/500 ... 1/1000. I will let you know guys.

I agree with idea in this article : Strobist: Control Your World With Ultra-High Sync

"The trick is, you have to fool the camera into thinking there is not a flash attached to it. This way it will not restrict itself to its normal maximum sync speed."

...then it depends on configuration if photographer will manage sync flash with camera in any way (radio trigger, wire...)
wrong the pocketwizzard will not be triggers above 1/180 either. The contact on the hot shoe will not discharge above 1/180 in any circumstance due to Pentax shutter curtain speed.
11-18-2013, 03:34 AM   #7
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Even if you could use this trick on Pentax (it is a Nikon trick), you would be getting black bars on your images at 1/500 or 1/1000 of a second because of the way the shutter works. The Nikon users get black bars as well.

This video will help you understand why the sync speed is what it is, the sensor of an SLR is never fully uncovered at faster speeds.

Radio triggers will help anyway, a good option are the Cactus V5 triggers, they are much cheaper than PocketWizards and will work just as well. They have a test button on them so you can fire the flash manually from a distance if you try the method I mentioned.
11-18-2013, 04:39 AM   #8
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Ok I got it, maybe theoretical workaround would be to trigger HSS style of flashing (multiple smaller flashes) manually ...but i am not sure if that would sync and I suppose there's no way how to trigger HSS-like-flash manually on Metz 52 AF-1.

For sure I will try method you mentioned.


Last edited by martinos; 11-18-2013 at 04:49 AM.
11-18-2013, 05:33 AM   #9
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The way it is typically done is the way I laid out before. The single burst of the light from the flash freezes the motion, not shutter speed. You want one single quick burst of light to freeze your subject, firing the flash multiple times will cause the effect of multiple exposures, which can be fun, but not what you are looking for. Some flashes have a stroboscopic mode to allow these multiple flashes in manual mode, but I don't believe your Metz does.

You need to think of a flash exposure as two exposures happening at the same time, that is why I broke it down into separate parts. You have what is lit by the flash and you have ambient. In a normal long exposure shot (say 10s or more) in a dark environment you can walk through the frame without appearing in the final image as long as you are not lit by bright light. That is how people do light painting, the light they are holding shows up, but they don't because they are not reflecting enough light.

A flash burst is going to be short, in some cases way beyond the limits of the shutter speed of your camera. My K-5 has a limit of 1/8000s shutter speed in normal shooting, but my YN-560 flash is only lit for 1/23000s at 1/128 power. If the environment is dark enough that the camera won't be capturing much light with the shutter open and I fire the flash during that exposure, only what is lit by the flash will be captured, effectively giving me an exposure of 1/23000s. It doesn't matter if the shutter is open for 1/180s or 180s, if the flash is the main source of light the exposure will be 1/23000s.

The problem with HSS is that it increases the duration of your flash, a flash that might be a 1/1000s burst in normal cases might slow down to 1/100s in HSS mode. HSS is not for freezing motion, it is for using fill flash on a bright sunny day or for turning day into night.

In this example I was syncing at 1/180s because I didn't have to care about ambient light at all. The flash at low power had no problem freezing this motion, which is much faster than a running dog.
11-18-2013, 10:16 AM   #10
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QuoteOriginally posted by elliott Quote
The Nikon users get black bars as well.
Depends on the camera The article clearly mentions the electronic shutter and the Nikon models that support the it.
11-18-2013, 10:44 AM   #11
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QuoteOriginally posted by sterretje Quote
Depends on the camera The article clearly mentions the electronic shutter and the Nikon models that support the it.
I should say modern Nikon users get the black bars, the models that can have a truly fast sync without black bars were discontinued about 7 years ago.
11-18-2013, 12:31 PM   #12
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QuoteOriginally posted by elliott Quote
The way it is typically done is the way I laid out before. The single burst of the light from the flash freezes the motion, not shutter speed. You want one single quick burst of light to freeze your subject, firing the flash multiple times will cause the effect of multiple exposures, which can be fun, but not what you are looking for.........
What you say about the flash freezing the motion rather than the shutter is true but that principle can only be used when there is not already enough ambient light to expose the image.

In the OP's case my undertsanding is that the dog is standing in the bright rays of sunlight breaking in through the foliage.

The dilemma is that a shutter speed of 1/180 or slower will result in blur because the sunlight is there throughout the exposure. If he makes the shutter speed faster than 1/180 without using HSS then only part of the photo will be illuminated by the flash (assuming first of all that the camera triggers the flash) due to the shutter being a travelling slit above 1/180.

HSS can help but the maximum speed is quite limited due to the diminishing power of the flash at higher speeds. I think the only way to make such a photo work would be to use a very powerful studio flash having a duration greater than 1/120s and use a fast shutter speed to freeze the motion.

You would also need to find some way to trigger the studio flash. The only easy way I can think of would be to use an HSS flash (such as the Metz 58) to trigger the main flash using an optical trigger which allows for ignoring the preflsahes (in HSS mode Pentax always fires a preflash as well). There are of course less easy ways that would be more reliable but need some electronics knowledge to build.

The studio flash would need to be quite a beast if you want speeds of 1/2000s or so. I am gusessing at least 2000 to 4000 Joules to be able to compete with the direct sunlight. (to put things in perspective the Metz-58 is equivalent to somewhere in the range of 60 to 100 Joules.)
11-18-2013, 01:25 PM   #13
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QuoteOriginally posted by lister6520 Quote
What you say about the flash freezing the motion rather than the shutter is true but that principle can only be used when there is not already enough ambient light to expose the image.

In the OP's case my undertsanding is that the dog is standing in the bright rays of sunlight breaking in through the foliage.
Check the EXIF, f3.5 @ 800ISO, it was dark enough. Also, the flash is positioned between the dog and the tree.
11-18-2013, 01:26 PM   #14
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Dog is running in full speed and flash was too strong. I did not care much about ratio of ambient light or nearby forest - my intention was to catch running dog in the given moment clearly. I really enjoy all advices from you guys, I have off camera flash just few weeks and it's completely different experience.

Last edited by martinos; 11-18-2013 at 01:28 PM. Reason: typo
11-18-2013, 01:42 PM   #15
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QuoteOriginally posted by martinos Quote
Dog is running in full speed and flash was too strong. I did not care much about ratio of ambient light or nearby forest - my intention was to catch running dog in the given moment clearly. I really enjoy all advices from you guys, I have off camera flash just few weeks and it's completely different experience.
If you don't care about the background just forget the long exposure part. I just assumed you wanted some context to the image, showing it is a forest and not a lone tree.

You'll get it eventually, once you work out the exposure part you can work on the fun part, light placement.
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