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05-04-2013, 09:20 AM   #1
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Flash Radio triggers for dummies? (esp. cheap ones)

Hey all,

I'm, like most, starting out on a budget with no problem of using manual flashes.

These, of course, will require radio triggers & when talking about cheap radio triggers with my mentor, he told me about how they have a delay when firing the flash, relative to shutter
I asked him how fast before this fire-lag is noticeable, he said after 1/60 shutter speed!
that's really low imo, esp. when I read a review of a lighting kit on The Phoblographer & they used the cheap Cowboy Studios triggers and said they perform well

Has anyone tried the CBS or Godox cheap (chinese) flash triggers at high shutter speeds? ~ 1/100-1/180?


=====================

Also, what about High-Speed syncing?
Say I want to over-power ambient sun & use 1/1000 shutter speed!

Does the speedlight/strobe have to have high speed sync?
What about the radio triggers?

(I'm using the K-01 btw, if there's anything settings-wise I should be aware of)

05-04-2013, 09:58 AM   #2
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cactus V5 works right on 1/180 but those arent that cheap...

HSS needs P-TTL, it a very complicated mode where the flash actually strobes depending on the shutterspeed.
05-04-2013, 10:12 AM   #3
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QuoteOriginally posted by Anvh Quote
cactus V5 works right on 1/180 but those arent that cheap...

HSS needs P-TTL, it a very complicated mode where the flash actually strobes depending on the shutterspeed.
Nor available here, AFAIK but worth a look-out

but wait, HSS is not possible without P-TTL???
Don't they do it with studio strobes like the Einstein E640 & the Godox AD180 & AD360 bare bulb speedlights? (these are manual flashes)
05-04-2013, 01:45 PM - 1 Like   #4
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If you're in a studio, you control the light so you won't need faster than 1/180.

For high speed sync you need P-TTL flashes, simple as.

To overpower the sun, you need a neutral density filter on your camera and a manual flash with sufficient oomph to make up for it. Let's say your metered exposure at 1/180 is F11. With a 0.9 ND filter, this becomes F4. With a 1.8 ND filter you can manage F1.4. Then simply adjust flash power upwards to make up for the ND filter. If you haven't got enough flash power, move it closer to your subjects - every 1.4x decrease in distance is an extra stop. Simple.

Cactus 5 transceivers are about fifty quid a pair. If these are too expensive, you need a cheaper hobby! Your main expense is going to be your lights - you need powerful ones. If you're using a 3 stop ND filter, 1/8 flash power needs to be sufficient to illuminate your subject without it so that full power will do the necessary compensation.

05-04-2013, 02:06 PM   #5
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QuoteOriginally posted by top-quark Quote
If you're in a studio, you control the light so you won't need faster than 1/180.

For high speed sync you need P-TTL flashes, simple as.

To overpower the sun, you need a neutral density filter on your camera and a manual flash with sufficient oomph to make up for it. Let's say your metered exposure at 1/180 is F11. With a 0.9 ND filter, this becomes F4. With a 1.8 ND filter you can manage F1.4. Then simply adjust flash power upwards to make up for the ND filter. If you haven't got enough flash power, move it closer to your subjects - every 1.4x decrease in distance is an extra stop. Simple.

Cactus 5 transceivers are about fifty quid a pair. If these are too expensive, you need a cheaper hobby! Your main expense is going to be your lights - you need powerful ones. If you're using a 3 stop ND filter, 1/8 flash power needs to be sufficient to illuminate your subject without it so that full power will do the necessary compensation.
HAHA, pretty helpful
That's it for HSS

About cheaper triggers: They do fire the flash slower than the shutter at >1/100 or so, don't they?
(FYI: the Cactus V5, after it reaches me here from abroad, will be ~$100 :P)
05-04-2013, 02:12 PM   #6
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I have the cheapest kind of radio triggers and while they are not perfect, they work fine at 1/180s.
05-04-2013, 03:10 PM   #7
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QuoteOriginally posted by top-quark Quote
To overpower the sun, you need a neutral density filter on your camera and a manual flash with sufficient oomph to make up for it. Let's say your metered exposure at 1/180 is F11. With a 0.9 ND filter, this becomes F4. With a 1.8 ND filter you can manage F1.4. Then simply adjust flash power upwards to make up for the ND filter. If you haven't got enough flash power, move it closer to your subjects - every 1.4x decrease in distance is an extra stop. Simple.

Cactus 5 transceivers are about fifty quid a pair. If these are too expensive, you need a cheaper hobby! Your main expense is going to be your lights - you need powerful ones. If you're using a 3 stop ND filter, 1/8 flash power needs to be sufficient to illuminate your subject without it so that full power will do the necessary compensation.
Sorry to ask but why are you adding ND filters, it also reduce flash power?
05-04-2013, 03:18 PM   #8
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QuoteOriginally posted by dstructor Quote
HAHA, pretty helpful
That's it for HSS
HSS is a complicated system, it actual fires the flash multiple time during the photo, the reason is the shutter.
It kinda works like a window, at 1/180 the window is fully open across the frame so the whole sensor is lid by the flash light. With 1/360 the gap between the shutter is half the space so only half of the sensor is exposed at a time.
So when you flash then only half of the sensor is lid and you get a bar across the photo.

With HSS the number of flashes is calulated so that the flash actually fires the whole time during the exposure.

05-04-2013, 03:24 PM   #9
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QuoteOriginally posted by Anvh Quote
Sorry to ask but why are you adding ND filters, it also reduce flash power?
The ND filter reduces ambient light and flash light equally. But you can adjust the flash power to compensate. That's why you need a powerful flash: so that you can increase the output by n stops from the power that would be sufficient without an n-stop filter.
05-04-2013, 06:40 PM   #10
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QuoteOriginally posted by dstructor Quote
HAHA, pretty helpful
That's it for HSS

About cheaper triggers: They do fire the flash slower than the shutter at >1/100 or so, don't they?
(FYI: the Cactus V5, after it reaches me here from abroad, will be ~$100 :P)
Check out the inexpensive PT-04 NE on ebay . they do fine < 1/180".
05-04-2013, 08:55 PM   #11
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I don't think it gets any cheaper than these Cheaplights NPT-04 units. They also trigger using my flashmeter by attaching the Tx to the meter via cable. Cooool.

Amazon.com: Cheaplights NPT-04 4 Channel Wireless Hot Shoe Flash Trigger and 2 Receivers Set for Canon Nikon Pentax,OTT-04GY: Camera & Photo

An old Sunpak 433D and a Yongnuo YN560II firing at 1/180 shutter speed:
Attached Images
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PENTAX K-30  Photo 

Last edited by MD Optofonik; 05-04-2013 at 09:06 PM.
05-04-2013, 09:51 PM   #12
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QuoteOriginally posted by MD Optofonik Quote
I don't think it gets any cheaper than these Cheaplights NPT-04 units. They also trigger using my flashmeter by attaching the Tx to the meter via cable. Cooool.

Amazon.com: Cheaplights NPT-04 4 Channel Wireless Hot Shoe Flash Trigger and 2 Receivers Set for Canon Nikon Pentax,OTT-04GY: Camera & Photo

An old Sunpak 433D and a Yongnuo YN560II firing at 1/180 shutter speed:
Thanks for the links, dude

My point was the flash delay that cuts from the sync speed, the fraction of a second in delay between the transmitter sending the signal & the receiver firing the flash

that's what my mentor was talking about when I asked him about cheap triggers & said that the cheap ones are good for <1/60 shutter speed
So that's what I was asking y'all about here; not whether or not they actually fire them!
05-04-2013, 10:45 PM - 1 Like   #13
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Both images shot at f9.5, 1/180; one on cabled hotshoe, the other wireless. dstructor quoted me below before I did this edit so ignore the quote. I can't tell a difference between the two that would indicate that the flash was delayed and the shutter was closing before the flash's output reached it's maximum. I think there would be bigger issues if that were the case, actually. See these:

http://neilvn.com/tangents/high-speed-flash-sync/
http://gregfong.blogspot.com/2010/09/hypersync.html

This is a perfect example of exactly what you're taking about:

http://lumenatic.com/2013/01/27/yongnuo-rf603-wireless-flash-trigger-delay/
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PENTAX K-30  Photo 
View Picture EXIF
PENTAX K-30  Photo 

Last edited by MD Optofonik; 05-04-2013 at 11:49 PM. Reason: Re-evaluated images
05-04-2013, 11:09 PM   #14
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QuoteOriginally posted by MD Optofonik Quote
Both images shot at f9.9 1/180, one on cabled hotshoe, the other wireless. I think I see what your talking about. The wireless flash looks slightly darker, measuring it in PS could provide some numbers (I'm not so inclined but if anyone wants to download them I'm curious).

It's by no means scientific although I did try to keep all things equal. The flash and camera were mounted on separate tripods to avoid having to handle either too much when switching between cabled hotshoe and wireless. A small bubble level was used to keep the flash head angle the same between switches. I do wonder if the difference in exposure could be a result of slight movement but I would think tiny differences in position or angle of either the flash or camera wouldn't result in anything noticeable
Quite helpful, dude!
Thanks a ton
05-04-2013, 11:24 PM - 1 Like   #15
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dstructor, I'm afraid I made a mistake so I redid the test. Something didn't look quit right in the original pix, the hotspot in the middle was too perfectly matched between the two. I had accidentally posted two pictures taken with wireless. Sorry. The ones that are up now are as originally intended. I can't see enough of a difference in exposure to indicate that the flash's output is being delayed. I edited the original post to reflect my observation after you quoted me.

I've been testing these triggers before taking them out on a volunteer gig and they work fine. I am, however, going to add the antenna mod to one Tx (I purchased three sets for a total of six Rx, so I have two extra Tx) because I'm only getting about twenty feet out of them at the moment.

One more flash/shutter speed link just for fun:


Last edited by MD Optofonik; 05-05-2013 at 12:00 AM.
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