[yusuf]

Trying to understand, what are the advantages and disadvantages of Radio Slave vs Wireless PTTL; when using single flash and when used with multiple flashes.

AFAIK, no radio slave supports p-ttl so I assumed wireless p-ttl seems like a better solution but as I gathered from another thread that some people seems to prefer radio slaves also.

Which one do you prefer? Can you please explain with your setup.

Thanks
Yusuf

[Emacs]

The first one: with radio you can use the only flash (like that:

You Tube

You Tube

). I've recently used the same technique and like the results.

[philbaum]

wireless pttl refers to optical light pulses used to trigger Pentax compatible dedicated flashes. The problem i've encountered is that the range is usually less than 10 feet and often is better if its line of sight. Any sunlight in the area can cause problems with the trigger.

I currently have 4 radio triggers (Cactus v5's) which have a range of 100 meters. Each unit has a switch and it can be designated as a transmitter or receiver. They run for about $59/pair. I use one as a transmitter on the hotshoe and trigger the other 3 as receivers remotely with a manual flash attached to each one. The manual flashes i use are the Yongnuo brand and cost me from $40 to $70, depending on whether they have a zoom feature or not (models YN560 or YN460II)

I also have a Metz48 which i can use manually or if i want to shoot pttl off the hotshoe. For an enthusiast like myself, the manual flashes are adequate and faster to set up in some ways.

There are other manual radio triggers that are even cheaper than the Cactus ones - Cowboy and Yongnuo (i don't know their capabilities).

Here was a 2 remote manual flash setup:



A single remote manual flash:

[adpo]

from how i see it:
wireless pttl = auto flash exposure
radio slaves = manual flash exposure + no line of sight required for flashes

i use radio slaves since none of my flashes support pttl and i probably wouldn't use p-ttl for off camera flash if they did, due to risking inconsistent exposures. But that's just how i see it.

[pinholecam]

I only see 3 advantages with Pentax wireless :

1. PTTL
2. HSS (with a dedicated flash on the camera)
3. No need to carry additional trigger/receivers

Since PTTL is not very reliable when used for bounced flash, I'd stick to manual, which negates the advantage of Pentax wireless.
The HSS using a dedicated flash is costly (eg. x1 AF540 and x1 AF360 )

The advantages of radio triggers :
1. No LOS (line of sight) needed
2. Ease of placing the flash anywhere to give directional lighting.
3. No need to wait for slow recharge of on-camera flash (if its used as a commander)
4. Can use cheap flashes

[Ash]

Since PTTL is not very reliable when used for bounced flash

I have thus far found P-TTL in wireless flash reasonably reliable (within a stop of good exposure for me). I have used it for weddings and portraits on a K10D, K20D and *ist D and have gotten good results.

[pop4]

Which one do you prefer? Can you please explain with your setup.

I prefer radio flash triggers as opposed to wireless PTTL for a number of reasons, and I always shoot off-camera flash with the flashes in manual mode:

- I don't need line-of-sight to trigger the flashes; meaning I can put flashes in places where I can't when using wireless PTTL
- using the flashes in manual mode means I have full control over the light from the flashes; the exposure is the same from shot-to-shot
- my remote flashes don't have to be Pentax flashes, which means money saved. The cost of one Pentax AF-540FGZ is 5x as much as the Yongnuo YN-560 flashes that I use. And when I'm lighting with two flashes for key, one for fill, and one for separation, that's four flashes already; the savings are pretty substantial
- further to the last point, my remote flashes don't have to be Pentax flashes, which means I can, and do at times, make use of my friends' Nikon SB, Canon EX and other branded/unbranded flashes if needed

[philbaum]

I find the accounts of flash usage by various Pentaxians very interesting.

A week ago, i dropped one of my Cactus Radio Triggers/Yongnuo 460II flashes from a height of 2 feet onto a concrete sidewalk. The $40 Yongnuo flash survived intact, but the radio trigger ejected its battery tray and refused to latch shut after that/won't work even with tray taped in. irritating and cost of new radio trigger for me is $34 plus shipping.

A friend from my camera club has gotten into weddings and portraits. She's now shooting a D700 and uses SB900 flashes. While leaving one shoot recently, she placed a flash onto her car seat rather than putting it away. She had to stop suddenly in traffic and the flash slid off the seat and onto the car's floor. It no longer works. Cost of her misfortune: $450 for one new SB900.

By many reports, Nikon has the best flash system of any mfr. I make no judgement about that. But evidently there are more costs involved than just buying a cls enabled camera. "Shit happens" with any equipment, things get stolen, broken, or just stop working. My friend who is into doing weddings qualifies as a working professional, I don't.

[yusuf]

ok, thanks all. This leads to another question - how do you generally use your flash when used with radio control. Do you use flash meter OR manually calculate flash exposure using guide number/distance OR use flash in Auto mode? During film days, I used to have Sekonic flash meter but later I found it too cumbersome to carry all the time.

[adpo]

guesstimate power based on previous similar lighting setups, take a test shot/set white balance. Repeat until desired results appear =)

[omega leader]

My wife's blink reaction means that she ALWAYS has her eyes partially closed if I use p-ttl. Therefore I have a quartet of radio transevers and use those exclusively. I find her sister the same, as are two members of my extended family. If the processing between prepulse and actual shot was shorter it might be better.

[philbaum]

My wife's blink reaction means that she ALWAYS has her eyes partially closed if I use p-ttl. Therefore I have a quartet of radio transevers and use those exclusively. I find her sister the same, as are two members of my extended family. If the processing between prepulse and actual shot was shorter it might be better.

I've noticed that when i use the redeye option with pttl, i don't have people blinking. Not sure the mechanics of it, but seems to work.

[pop4]

ok, thanks all. This leads to another question - how do you generally use your flash when used with radio control. Do you use flash meter OR manually calculate flash exposure using guide number/distance OR use flash in Auto mode?

guesstimate power based on previous similar lighting setups, take a test shot/set white balance. Repeat until desired results appear =)

Pretty much what adpo does. With enough practice and experience, you very quickly get an idea of the flash power needed

[pinholecam]

I have thus far found P-TTL in wireless flash reasonably reliable (within a stop of good exposure for me). I have used it for weddings and portraits on a K10D, K20D and *ist D and have gotten good results.

No such luck when I switched to a Metz48. If seems to over expose by 0.7 to 1 stop. I did not seem to have this problem when I had the Pentax AF360 on K100D and K7.
Sold the AF360 before I verified anything, so I'm stuck with the Metz.

[steveoliver]

Have just purchased a Seculine Twinlink radio trigger kit (1 Tx and 1 Rx) with the aim of triggering my 540FGZ remotely using the trigger and having my 360FGZ as wireless or even optical slave to the 540.... but there doesn't seem to be a way of getting the 540 to trigger the 360 without being originally wirelessly triggered by my K-7. Anyone know if it's possible? The manuals are so dreadful.