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08-19-2014, 05:59 AM   #16
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QuoteOriginally posted by 2351HD Quote
I think it's because people online would rather carry on with complaints rather than positives. It's just the way.

I do not know enough about flash work to offer an opinion but it seems like people with dslrs are doing fine without leaf shutters.
Well, usually they have higher synch speeds now, sometimes much higher, especially in the case of anything that could be deemed "pro" gear.

This is one of the only 2(reasonable...) knocks against the camera, the other being the poor video codec. In the former case, it would have been better to offer the camera with a higher synch speed, but there are still leaf shutter lenses out there, in 645 and 6x7, used, and there's nothing stopping Pentax or someone else offering a new one or several. So this first issue is addressable now and in the coming years. Anyone who is not buying this camera for this reason alone has a screw loose, imo, or really doesn't need/want this camera.

The second issue is unfortunately a missed opportunity, and can't be ameliorated later as I understand it. It's a pity, because it would have made some difference in sales. It's not important to me, per se (although it would have been very nice to have in the back pocket...), but I know some people, one of whom is a friend who shoots both stills and video for his clients and has been for several years now, for whom it would have been extremely important.

08-29-2014, 02:21 AM   #17
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QuoteOriginally posted by Digitalis Quote
Actually studio strobes are at their fastest at full power. As you turn down the power on a studio strobe, every stop you turn it down makes it about 15% slower. By the time you hit the lowest power, you've doubled the duration. Unless you are working with an IGBT Flash ( which basically work the same way compact flash units do). the drawback is that really good IGBT flash units are frigging expensive.

Here are some T.1 durations of common 400-600ws mains powered flash units:

  • 1/966 Bowens Gemini 500 Pro
  • 1/883 Profoto D1
  • 1/683 Elinchrom Style RX 600
  • 1/600 White Lightning X1600
  • 1/533 Paul Buff Einstein 640
  • 1/520 Elinchrom BX 500Ri
  • 1/266 Elinchrom D-Lite it 400

These are all at 1:1 power and the durations are still pretty slow. When I have worked in the studio with subjects that require fast motion to be stopped the first thing I do is turn up the power on my strobes. At really high speeds 1/2000th and above the differences between focal plane and leaf Shutter mechanisms is utterly pointless*. At synch speeds neither of them are anywhere near fast enough to stop motion on their own. If the subject needs to make any type of spin (leap and spin, gymnastic moves, martial arts). For that, you need to be about 1/3,000 sec t.5 to completely freeze motion. And if the action involves swinging anything (sword, baseball bat, golf club, tennis racket) you will need a minimum of 1/6,000 sec - surprisingly "whipping" wind blown hair or clothes can easily get up into that speed.


* Unless you are mixing in ambient light, which will give an advantage to leaf shutters - but even that is rather limiting.
Hi Digi
You have that in reverse actually.
The more you dial your flashes power down (less w/s) the quicker the flash duration becomes.
My Profoto's flash duration is 1/1000s at full power and 1/6800s at minimum power (9w/s or so)
If you want more light, you add more powered units (packs/monoheads).
So let's say I'm happy with the duration at 1/1000s at full power, if I need another stop of light, I'd add another unit at full power again to get twice as much power (one more stop of light) and keep the duration at 1/1000s.
or
If I felt that for some reason 1/6800 wasn't fast enough, I could add another head to that specific channel on the pack. Therefore taking the power of each head down to 4.5w/s but quickening the flash duration further.

That why back in the old speed wars in the 70's and 80's you saw manufacturers like Speedotron adding multiple flash tubes within each head and giving each one their own plug; basically adding more light from one source but dividing the power amongst all the flash tubes and quickening the flash duration further. While Speedotron and Norman took the brawn approach to the problem, European companies like Broncolor and Profoto were working on better ways to "release" the energy from the capacitors and shorten flash duration through new flash tube designs.
So if you want a quicker flash duration, dial your power DOWN. If you need more f stops, add more lights (at the lower power settings).
I hope this helps

Thanks
Rob
09-01-2014, 12:12 PM   #18
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QuoteOriginally posted by Dario79 Quote
I was watching Creativelive tutorial about commercial photography and guess what camera was used?
Pentax 645z)) It was really nice to see Pentax thethered and used by pro.
The really strange thing is which software did he use for tethering with the Pentax 645z?
12-02-2014, 02:23 AM - 1 Like   #19
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Freezing action

QuoteOriginally posted by fuent104 Quote
I disagree. I believe most studio photographers who want to freeze action at short intervals would prefer to use a higher number of strobes, at lower power settings. The duration of a strobe is much shorter than 1/1000 of a second, especially at lower settings. This has been the way to do high-speed photography for a very, very long time.

I think leaf shutter lenses are most frequently used to control ambient light during flash photography. Which is what Grimes has demonstrated can be done using ND filters.
Hi I'm new to this forum because I recently purchased a 645Z for commercial work. I'm primarily a publicity and production photographer for the arts; dance, music and theatre. I highly respect Joel's work and his methods. What prompted me to write is the subject of freezing action. It's really more a function of a strobe's t:1 performance (flash duration) more than anything else. I use Einstein's exclusively because they represent the best value/performance strobes for my work. You can read more about flash duration and t:1 ratios here:
Paul C. Buff, Inc. - Flash Duration

I have not shot anything with the 645 because I just received it today and am awaiting my lens. I had not planned on using it for studio action, but that is certainly something I will consider. My move to medium format is due to the dynamic range.

Anyway the shots attached were both done at 1/250th which is the max sync speed for my camera. That shutter speed is no where near fast enough to freeze Bernard's juggling pins in mid air. As a matter of fact he was tossing them faster than normal goading me to 'freeze' the pins. And the dancers frozen in mid air was accomplished because of the strobe's t:1 performance, not my shutter speed.

I look forward to participating here when time permits.

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12-03-2014, 07:35 AM   #20
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QuoteOriginally posted by 2351HD Quote
I am not and will never be a studio or fashion photographer who needs flash for purposes like that, but I would assume that if you had a fast moving object in the frame, or somebody jumping mid air or waving their arms about, would 1/125 be enough to freeze the action? I would have assumed not. No amount of flash, fast or slow, can freeze movement. Thats what fast shutters are for, no?

Cheers, Scott
You are wrong, a leaf shutter will give you about 1/1600 when an Einstein at low power will give you about 1/12000 and a leaf shutter will not let you use live view, neither work at 10 frames per second like I do with my 1D X. I use regular lenses with fast strobes to make things like this all the time.




Victor Wolansky Photography
12-03-2014, 09:37 AM   #21
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QuoteOriginally posted by Dario79 Quote
I was watching Creativelive tutorial about commercial photography and guess what camera was used?
Pentax 645z)) It was really nice to see Pentax thethered and used by pro.
very nice work by Joel Grimes,
thanks for sharing the link!
12-03-2014, 11:03 AM   #22
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QuoteOriginally posted by xpixel Quote
The really strange thing is which software did he use for tethering with the Pentax 645z?
There is only one. ImageTransfer 2
12-09-2014, 01:58 PM   #23
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QuoteOriginally posted by Digitalis Quote
Actually studio strobes are at their fastest at full power...
Not to harp on the subject but it depends on the design of the flash. For example the Einstein is designed like camera mounted speed lights in that it flash duration gets less as the power level is decreased 1/533 to 1/13500 in action mode and lower power. Paul Buff gives a good explanation of this on his site. My AlienBees, on the other hand, are the old capacitor discharge type that the more juice that's in the capacitor the faster it discharges to time, t.1


Last edited by tuco; 12-09-2014 at 02:03 PM.
12-10-2014, 12:10 PM   #24
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QuoteOriginally posted by 2351HD Quote
I am not and will never be a studio or fashion photographer who needs flash for purposes like that, but I would assume that if you had a fast moving object in the frame, or somebody jumping mid air or waving their arms about, would 1/125 be enough to freeze the action? I would have assumed not. No amount of flash, fast or slow, can freeze movement. Thats what fast shutters are for, no?

Cheers, Scott
Strobe lights are commonly used to freeze motion. Special flash units are used to freeze bullets in flight. The reason for this is that flash effectively becomes the shutter speed and flash durations are measured in thousandths of a second.

---------- Post added 12-10-14 at 01:17 PM ----------

QuoteOriginally posted by 2351HD Quote
So why all the fuss over leaf shutter lenses then?

Leica, Hassy and Phase are using them as a selling point so there must be a benefit in the fast shutter.
A strobe light will not synch with focal plane shutters beyond a certain speed, sometimes as slow as 1/60. When doing this the flash does not fire until the focal plane shutter is wide open and then the exposure is immediate. Sometimes you need a faster shutter speed to control ambient light. This is where the leaf shutter enters because it can synch at all speeds including 1/500 second.

Leaf shutters may be acquired on eBay.
12-16-2014, 12:54 AM   #25
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QuoteOriginally posted by fuent104 Quote
I disagree. I believe most studio photographers who want to freeze action at short intervals would prefer to use a higher number of strobes, at lower power settings. The duration of a strobe is much shorter than 1/1000 of a second, especially at lower settings. This has been the way to do high-speed photography for a very, very long time.

I think leaf shutter lenses are most frequently used to control ambient light during flash photography. Which is what Grimes has demonstrated can be done using ND filters.
Agreed!
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