[bobbotron]

I'm not sure whether I should ask this on a flash forum or here, but here it goes. I've been eyeing the af540fgz II for a while, partially so I can play with HSS. I really like setting my flash manually for a lot of work, is it possible to use the HSS feature and manually set the flash power instead of letting P-TTL set the power level? From what I read on this site somewhere, you can only engage HSS with P-TTL, I was wondering if you guys/gals could confirm or deny. While I love having P-TTL for some situations, there's nothing quite like having a flash dialed in just right for multiple shots.

[stevebrot]

From what I read on this site somewhere, you can only engage HSS with P-TTL

This is true. HSS is a flash feature, but it should probably be termed HSS through P-TTL when used with Pentax-dedicated flash. The P-TTL provides the exposure information needed by the HSS. Fortunately, flash EC (within limits) still works for fine tuning.


Steve

[bobbotron]

Interesting - is it possible to manually set the flash power via the camera menu? Ex: 1/32 flash power, but then use a fast shutter speed. There are some situations where it's nice if you don't need to worry about the TTL delay. Wish I could borrow one before committing to it. :P

I guess the alternative is the cactus solution, which seems like it would work quite well, but adds some complexity into your flash/camera setup.

[mcgregni]

As Steve said ..... The shutter time can only be set to shorter values than 180th sec AFTER HS sync has been set on the flash. And HS sync can only be set on the flash in P-TTL mode.

[bobbotron]

Thanks guys. I was just really hoping I could manually set the flash power. Guess I'll just have to get one of these at some point and see how it works in action situations with P-TTL.

[mysterick]

Look at MEMO on p. 84 of the K-3 manual.

[Class A]

I was just really hoping I could manually set the flash power.

Well, you can.

Are you aware of the approach using a V6 to trigger both camera (via a shutter release cable) and the manually controlled flashes at the "same" time, using a delay for the flashes in order to synchronise them with the (slower) camera?

This definitely works with three+ V6 (one remote release trigger, one receiver for the camera and any number of receivers (or RF60) for the number of off-camera flashes you want.

It just occurred to me, however that the release trigger may be hooked up to the camera directly, which should reduce the number of V6 by one. However, my K100D locks up when connected with a shutter release cable to a V6 in transmit mode and while my K-5 II works fine in principle, as soon as the metering becomes inactive (i.e., after the metering time out), it starts producing a pulsating signal on its remote port, which the connected V6 interprets as a trigger signal in Tx mode. So unfortunately, with my two camera models, the setup requires two V6 (one transmitter & one receiver) just to release the camera.

There is also the alternative of using the regular shutter release button of the camera, but then you need one HSS-PTTL-capable flash, otherwise you won't be able to convince the camera to provide you with a flash trigger signal (once you take the shutter speed past the sync speed).

P.S.: I initially forgot to mention that the above works with RF60s which you can manually set to HSS mode. For other flashes, you still get to use high shutter speeds but not by using HSS bursts (which are approaching continuous light), but by using the HyperSync approach. The latter only works with speedlights set to near maximum power and you'll get some gradation of the flash output across the frame (bright to darker from bottom to top).

---

Last edited by Class A; 11-03-2015 at 08:00 PM.

[clackers]

Interesting - is it possible to manually set the flash power via the camera menu? Ex: 1/32 flash power, but then use a fast shutter speed.

Yep, and if there's no ambient light you'll be faster than 1/180s by going low power.

[osv]

is it possible to use the HSS feature and manually set the flash power instead of letting P-TTL set the power level?

i could never do it with my af540fgz flashes, on the old k10d, and i doubt that has changed with the newer pentax gear... it was very irritating.

you could see if the pentax flash system will separate the ev comp function, body vs. flash... in other words, you can increase ev comp for one, but not the other.

i think that nikon locks 'em together, while canon and sony separate the functionality? for example, in the sony menu i can select ev comp to only apply to ambient, or only apply to the flash.

[mcgregni]

The camera exposure compensation (for ambient brightness) and the flash compensation (for automatic flash exposure brightness adjustments) are separate things, and are controlled independently.

Assuming that we're talking about a dedicated system flash using an automatic flash exposure mode, then flash compensation can be set from the camera flash modes panel, or directly on a flashgun. The two settings are cumulative and will add together mathematically, so you can force more or less power by using both.

For example, I was outdoors in sunshine at the weekend taking backlit shots of the family ... Manual exposure mode, set the ambient light to around 0.7stop under the centre, then take a quick test shot in HS mode. A bit dark, so dial in plus 1.5 stop flash compensation on the AF-540FGZII. Because I was moving around the sun was changing position behind ... When it was very bright I needed plus 2.0 FC on the flash AND plus 1.0 on the camera ...so plus 3.0 FC in total.

I could see no advantage to having manual flash power control in the situation .... Automatic gets you started and just adjust as things change ... There's a logic to the concept of 'compensation' as it relates to the cameras base exposure decision.

[clackers]

I could see no advantage to having manual flash power control in the situation .... .

Horses for courses, McGregni. You can vary manual flash by seven stops, compared to EC.

And the output is predictable/constant, compared to P-TTL metering. Look out if there's a reflective surface in shot, even very small!

A handheld light meter is more consistent and is surprisingly quick. Portraits and sports are better because of the lack of pre-flash - a distraction in the former, a delay in the latter.

You just can't use manual flash well when doing anything spontaneous like event photography.

[bobbotron]

Well, you can.

Are you aware of the approach using a V6 to trigger both camera (via a shutter release cable) and the manually controlled flashes at the "same" time, using a delay for the flashes in order to synchronise them with the (slower) camera?

This definitely works with three+ V6 (one remote release trigger, one receiver for the camera and any number of receivers (or RF60) for the number of off-camera flashes you want.

It just occurred to me, however that the release trigger may be hooked up to the camera directly, which should reduce the number of V6 by one. However, my K100D locks up when connected with a shutter release cable to a V6 in transmit mode and while my K-5 II works fine in principle, as soon as the metering becomes inactive (i.e., after the metering time out), it starts producing a pulsating signal on its remote port, which the connected V6 interprets as a trigger signal in Tx mode. So unfortunately, with my two camera models, the setup requires two V6 (one transmitter & one receiver) just to release the camera.

There is also the alternative of using the regular shutter release button of the camera, but then you need one HSS-PTTL-capable flash, otherwise you won't be able to convince the camera to provide you with a flash trigger signal (once you take the shutter speed past the sync speed).

P.S.: I initially forgot to mention that the above works with RF60s which you can manually set to HSS mode. For other flashes, you still get to use high shutter speeds but not by using HSS bursts (which are approaching continuous light), but by using the HyperSync approach. The latter only works with speedlights set to near maximum power and you'll get some gradation of the flash output across the frame (bright to darker from bottom to top).

I'm super aware of the cactus system, and extremely tempted by it! I'm really on the fence on which to invest in - I don't really want to invest in both at this point in time. Both have great features, the pentax one being a little easier to work with, but the cactus would really let you dial in everything, but then you've gotta work and carry around extra electronics.... Spoiled for choice.

---------- Post added 11-05-15 at 10:14 AM ----------

Horses for courses, McGregni. You can vary manual flash by seven stops, compared to EC.

And the output is predictable/constant, compared to P-TTL metering. Look out if there's a reflective surface in shot, even very small!

A handheld light meter is more consistent and is surprisingly quick. Portraits and sports are better because of the lack of pre-flash - a distraction in the former, a delay in the latter.

You just can't use manual flash well when doing anything spontaneous like event photography.

Agreed!

That is great info though McGregni. I agree, I have a P-TTL flash now (the cheap sigma) - it does very well in most situations, but as clackers says, sometimes when you're dialing things in, it's nice to avoid the preflash delay and the P-TTL getting confused.

[osv]

The camera exposure compensation (for ambient brightness) and the flash compensation (for automatic flash exposure brightness adjustments) are separate things, and are controlled independently.

that's the ideal situation, but not all camera systems can do it easily... kudos to pentax if it works like that:

"With current Canon cameras, EC only affects ambient exposure, whereas with most Nikon cameras, EC simultaneously affects flash intensity and ambient exposure. Some of the newer Nikon cameras, such as the D4 and D800, can work either way via a custom function"
Camera Flash: Exposure

great link for anyone wanting more info.

I could see no advantage to having manual flash power control in the situation.

it's a huge advantage, because for one thing it entirely eliminates the blinding preflash metering shot that causes many people to blink their eyes in the photo.

there is no shutter delay with preflash on the a7r, probably because it already has a horrible .163 second shutter delay to begin with.

p-ttl is not always accurate, i've had to abandon it entirely in some situations, and manual flash power control gives you that capability, regardless of the shutter speed.

the sony evf attempts to compensate for whatever manual power setting you put on the flash; pentax probably does that with liveview in the lcd.

that's not to say that sony has a better flash system, even with manual flash power control capability; i can't, for instance, have hss at all when the flash is pointed upwards, but i can do that with pentax.

[jake14mw]

The camera exposure compensation (for ambient brightness) and the flash compensation (for automatic flash exposure brightness adjustments) are separate things, and are controlled independently.

Assuming that we're talking about a dedicated system flash using an automatic flash exposure mode, then flash compensation can be set from the camera flash modes panel, or directly on a flashgun. The two settings are cumulative and will add together mathematically, so you can force more or less power by using both.

For example, I was outdoors in sunshine at the weekend taking backlit shots of the family ... Manual exposure mode, set the ambient light to around 0.7stop under the centre, then take a quick test shot in HS mode. A bit dark, so dial in plus 1.5 stop flash compensation on the AF-540FGZII. Because I was moving around the sun was changing position behind ... When it was very bright I needed plus 2.0 FC on the flash AND plus 1.0 on the camera ...so plus 3.0 FC in total.

I could see no advantage to having manual flash power control in the situation .... Automatic gets you started and just adjust as things change ... There's a logic to the concept of 'compensation' as it relates to the cameras base exposure decision.

Are the flash exposure compensation systems on the camera and flash really cumulative? I thought I remembered reading that they were not? Logically, you would think they would be.

[bobbotron]

Are the flash exposure compensation systems on the camera and flash really cumulative? I thought I remembered reading that they were not? Logically, you would think they would be.

I thought they were not, but to be honest whenever I'm working with P-TTL, I just adjust EV and flash EV numbers until I start getting things that look about right. I generally treat them as non-cumulative, that the camera is exposing for "correct exposure" and so is the flash. I would love a definitive answer if my assumptions are incorrect!

I will say, bounce flash + P-TTL is an amazing combo for poor light situations indoors.