[Zuar]

I bought a Yongnuo YN460 speedlite for my K-x a while ago and until recently it has worked pretty much flawlessly. The problem I am experiencing now is that when in manual mode, the camera seems to refuse to trigger. I have played around with the camera settings and it seems as though the flash will only trigger on a slow shutter speed (~1") - a problem which hasn't previously occurred. The flash triggers fine in automatic.

That said, it does occasionally decide to work on a faster shutter speed (~1/400), however after a short while, the camera will refuse to trigger the flash again.

If anyone has any ideas as to how I might solve this, I would be very grateful!

Thanks!

[SOldBear]

Are you sure the shutter speed is not 1/180 sec or lower?

Pentax DSLRs don't trigger flash above that speed.

[philbaum]

I bought a Yongnuo YN460 speedlite for my K-x a while ago and until recently it has worked pretty much flawlessly. The problem I am experiencing now is that when in manual mode, the camera seems to refuse to trigger. I have played around with the camera settings and it seems as though the flash will only trigger on a slow shutter speed (~1") - a problem which hasn't previously occurred. The flash triggers fine in automatic.

That said, it does occasionally decide to work on a faster shutter speed (~1/400), however after a short while, the camera will refuse to trigger the flash again.

If anyone has any ideas as to how I might solve this, I would be very grateful!

Thanks!

That's a manual speedlite and you are limited to a shutter speed no higher than 1/180s. I have one of those speedlites and love it, but only at shutter speeds of 1/180 or less.

[Zuar]

That's a manual speedlite and you are limited to a shutter speed no higher than 1/180s. I have one of those speedlites and love it, but only at shutter speeds of 1/180 or less.

Are you sure the shutter speed is not 1/180 sec or lower?

Pentax DSLRs don't trigger flash above that speed.

They don't? That's pretty annoying... I was hoping to do some high speed photography with a few flash guns in the near future... Is there any way around this?

[SOldBear]

Is there any way around this?

Yes. But it's not cheap.

You need a flash that supports high-speed sync. (HSS), e.g. Pentax AF540FGZ, Pentax AF360FGZ. Metz (and probably Sigma) has some models that support HSS but I'm not familiar with them.

Can you elaborate as what kind of "high speed photography" you're after. Maybe you don't need HSS. This photo froze the shutter blades of the Pentax ME Super in action. But the shutter speed of the K10D used to take this photo was 1/4 sec, and the flash was an old Sunpak 36DX (triggered by the Pentax ME Super itself):

[philbaum]

They don't? That's pretty annoying... I was hoping to do some high speed photography with a few flash guns in the near future... Is there any way around this?

If your speedlite is the means of lighting the subject, then you can set fractional power levels of your flash which causes the flash duration to be 1/1000 of a second and faster. There's a website called www.speedlite.com (i think) which shows the flash duration speeds for your flash, they get very fast the smaller the fractional power that is set. The mechanical shutter speed only affects the ambient light.

[Zuar]

Yes. But it's not cheap.

You need a flash that supports high-speed sync. (HSS), e.g. Pentax AF540FGZ, Pentax AF360FGZ. Metz (and probably Sigma) has some models that support HSS but I'm not familiar with them.

Can you elaborate as what kind of "high speed photography" you're after. Maybe you don't need HSS.

In the long term, I'm hoping to do some stuff capturing liquids and other moving objects in mid air using motion sensors to trigger the camera. For the short term, I'd like to be able to get up to 1/400 of a second really...

[joe.penn]

They don't? That's pretty annoying... I was hoping to do some high speed photography with a few flash guns in the near future... Is there any way around this?

Yes, take a deep breath and deal with it - those YN460's have enough power to allow you to freeze action as if you were shooting at 1/3000th of a second...




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[joe.penn]

In the long term, I'm hoping to do some stuff capturing liquids and other moving objects in mid air using motion sensors to trigger the camera. For the short term, I'd like to be able to get up to 1/400 of a second really...

Simplistic and you don't need HSS for that (for the liquid anyways) - for moving objects, depends on the object, distance and power of the flash(es)...




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[Zuar]

Yes, take a deep breath and deal with it - those YN460's have enough power to allow you to freeze action as if you were shooting at 1/3000th of a second...




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It's all well and good them having enough power, but I can't get them to trigger above 1/160th of a second by the looks of it

[joe.penn]

It's all well and good them having enough power, but I can't get them to trigger above 1/160th of a second by the looks of it

You don't, 1/160th is all you need. To better understand, find enough lighting to get a proper exposure at 1/160th with a large aperture WITHOUT A FLASH, bounce a ball and while bouncing snap the pic - the pic will have a little motion blur. Now, same thing but with your flash attached, stop the lens down and shoot the same thing same shutter speed but with the flash and then you will see no motion blur.

To really understand the science behind it, check out the link Phil posted...


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[Zuar]

You don't, 1/160th is all you need. To better understand, find enough lighting to get a proper exposure at 1/160th with a large aperture WITHOUT A FLASH, bounce a ball and while bouncing snap the pic - the pic will have a little motion blur. Now, same thing but with your flash attached, stop the lens down and shoot the same thing same shutter speed but with the flash and then you will see no motion blur.

To really understand the science behind it, check out the link Phil posted...


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Ok, I think I understand. Will have a play around with this in the morning!

Thanks for your help everyone

[philbaum]

Ok, I think I understand. Will have a play around with this in the morning!

Thanks for your help everyone

To make the flash effect more prominent, use Manual exposure mode and set your ambient parameters so the camera is 1 to 3 stops under a perfect exposure. let the flash add the difference. You may need to get your flash as close as possible if you are using really small fractional power settings for faster speeds.

HSS actually produces longer shutter settings than the above approach. And Nikon's 1/250s shutter is still not adequate for the kind of thing you are talking about. The guys that are doing things like freezing a hummingbird's wings are sometimes clustering several flashes, all set at the same fractional setting, to get more light on the subject.

have fun!

[noblepa]

HSS is a neat tool, but its lousy for stopping action. In effect, it turns the flash into a continuous light source, by flashing repeatedly. Its good when you need a high shutter speed to overcome ambient light.

A while back on this or another forum, someone posted comparison pictures. Using a Pentax AF540-FGZ, in normal flash mode, with a shutter speed of 1/180, they were able to freeze the blades of an electric fan. In HSS mode, with a shutter speed of 1/500, the blades showed quite a bit (about two inches) of movement and were blurred almost to invisibility.

A focal plane shutter, as used in all Pentax dslrs, there are two curtains, an opening, or leading cutrain and a closing, or trailing curtain. When you trip the shutter, the leading curtain opens. After the appropriate time, the trailing curtain closes. At speeds of 1/180 and slower, there is a brief period during which the entire sensor is uncovered. At faster shutter speeds, however, the trailing curtain begins closing before the leading curtain is completely open, resulting in a moving slit across the sensor. The faster the speed, the narrower the slit.

This maximum speed, which is 1/180 on all Pentax dslrs, is called the X-synch speed.

If you have, or can borrow a film slr, you can easily demonstrate what happens if you take a flash photo at a shutter speed above the x-synch speed. Get a cheap roll of drugstore film, set the shutter speed to 1/1000, turn your flash on and take a photo. When you have the film developed, you will see that probably less than half the negative has been exposed.

The flash duration on most speedlights in normal mode is usually about 1/1000 second or faster. The lower the power setting (if the flash has a power setting), or the closer the object is, the shorter the flash duration. Many go as fast as 1/30,000 or even 1/50,000 second at the lowest power setting.

In other words, the flash duration, not the camera shutter speed, controls the exposure. So, at 1/180, the flash duration may be 1/5,000 second, which will stop most action. The problem comes in when you are shooting in bright enough ambient light that you can get a recognizable image using 1/180 and whatever aperture you're using.

That's where HSS comes in handy. It allows you to shoot faster than 1/180, while still maintaining the same aperture. It does this by flashing the strobe several times, as that moving slit travels across the sensor. Each flash exposes a different area of the sensor. In this case, the camera shutter controls the action-stopping, not the flash. So, unless you can shoot at the camera's top shutter speed of 1/4,000 second, you probably won't get that frozen water droplet you're looking for.

The good news is that that Yongnuo 460 can be cranked down to, I believe, 1/16 of full power. At that power setting, I believe the flash duration is 1/30,000 second, which will stop even a speeding bullet (the problem there is triggering the flash while the bullet is still in the lens's field of view).

A flash tube is not like an incandescent light bulb; it can't be dimmed. The only way to control its light output, is to control how long it is on. This is done by sophisticated electronics that quench the flash prematurely.

If you want to freeze water drops and such, set things up with the water source only a couple of feet away from the camera. Set the flash to its lowest setting and experiment with triggering the flash. Triggering it by hand, be prepared for a lot of misses.

Many photographers who try this find it easier to focus manually, turn the room lights off, trigger the shutter at a very long speed (1 second, e.g.) and trigger the flash manually, using the test button on the flash. There's no camera made that can autofocus that fast, and you'll be shooting on a tripod, so you don't need SR. The biggest obstacle with ultra-high speed photography, is triggering things at precisely the right moment.

Paul Noble

[SOldBear]

If you want to freeze water drops and such, set things up with the water source only a couple of feet away from the camera. Set the flash to its lowest setting and experiment with triggering the flash. Triggering it by hand, be prepared for a lot of misses.

Many photographers who try this find it easier to focus manually, turn the room lights off, trigger the shutter at a very long speed (1 second, e.g.) and trigger the flash manually, using the test button on the flash. There's no camera made that can autofocus that fast, and you'll be shooting on a tripod, so you don't need SR. The biggest obstacle with ultra-high speed photography, is triggering things at precisely the right moment.

Here's an example, nothing exciting, but illustrating what Paul wrote. My son took this photo a few years back with a K10D, probably the Tamron 18-250mm, and a Metz 45CT4. The shutter speed was 1/30 sec.