[jab2980]

Is it common for an external flash to automatically switch from manual mode to P-TTL when shooting in AV mode? I was shooting an outdoor session and attempting to use my flash as a fill in AV mode, however as soon as I focused the shot (and the camera exposed), the flash automatically switches to PTTL mode. Is this a feature/bug of the flash or is this a user error in that manual flash always requires manual mode on the camera. My mindframe is that I'd like the camera to expose on my subject, and I'd like the flash only to flash at enough power to lighten the shadows on a face or to have the catch light show up in their eyes. Forgive me if I'm doing something stupid - I'm not new to my camera or photography but I am new to flash photography.

Equipment used:
K5II with latest firmware
FA 77
Sigma 610 Super

Extra information that may or may not be relevant:
Outdoor portrait shoot
Using flash both direct as a fill flash with the sun behind the subject (and using a 3 stop ND filter) and also with the flash set to 90 degrees, using the flash as a catch light.

[enoeske]

You had the flash in Manual mode and it changed to P-TTL on its own? That normally requires the pressing of a mode button repeatedly until you get into the mode you want.

[jab2980]

You had the flash in Manual mode and it changed to P-TTL on its own? That normally requires the pressing of a mode button repeatedly until you get into the mode you want.

Yup. As soon as i focused/camera exposed the flash changed from manual mode to P-TTL. It would go back to manual a few seconds after letting go of the AF button. This doesn't occur in manual mode on the camera. Perhaps the flash is anticipating that one would never want to use manual flash while in AV mode?

[enoeske]

Yup. As soon as i focused/camera exposed the flash changed from manual mode to P-TTL. It would go back to manual a few seconds after letting go of the AF button. This doesn't occur in manual mode on the camera. Perhaps the flash is anticipating that one would never want to use manual flash while in AV mode?

I don't have that flash, but it doesn't sound normal for any flash to do that. Can you return it?

[MikePerham]

Which flash?

[jab2980]

Which flash?

Equipment used:
K5II with latest firmware
FA 77
Sigma 610 Super

[Bob from Aus]

I know your frustration all to well. I have used my camera in manual mode to reduce, but not eliminate the problem. I hate it when I've set everything up and then the flash goes into auto. Along with my sigma flashes (around 4 models) I have the same problem with my pentax flash as well.

So I gave up and purchased couple of Godox flash guns which are totally manual. I wish they sold them 10 years ago. Auto over ride no longer an issue and the flash re charges within 1.5 seconds or zero if on a low power. I only have basic controls so it's dead easy. they are also around a quarter of the price. My other flash guns are collecting dust.

[RAART]

I don't think is a bug but while you mention that you tried to have fill in flash I am just wondering if you went over x-speed sync limit of 1/180 or stayed bellow. If you was above I guess that your flash had to switch to P-TTL as it HSS and this works with P-TTL only and your flash went back to selected mode after the shot. I have Metz flash and there I must select HSS P-TTL mode if I like to have fill flash unless I am bellow 1/160 speed sync. With manual flash is the same thing as long as you do not go above the max speed sync of the Pentax otherwise will not fire.

Just my 2c.

P.S. I do not have Sigma flash therefore cannot reproduce your problem.

[enoeske]

I don't think is a bug but while you mention that you tried to have fill in flash I am just wondering if you went over x-speed sync limit of 1/180 or stayed bellow. If you was above I guess that your flash had to switch to P-TTL as it HSS and this works with P-TTL only and your flash went back to selected mode after the shot. I have Metz flash and there I must select HSS P-TTL mode if I like to have fill flash unless I am bellow 1/160 speed sync. With manual flash is the same thing as long as you do not go above the max speed sync of the Pentax otherwise will not fire.

Just my 2c.

P.S. I do not have Sigma flash therefore cannot reproduce your problem.

That's an interesting idea: HSS. Still, I wouldn't think the flash would fire if it was set to manual mode and the camera body went above 1/180th. It shouldn't fire, at least.

[jab2980]

That's an interesting idea: HSS. Still, I wouldn't think the flash would fire if it was set to manual mode and the camera body went above 1/180th. It shouldn't fire, at least.

With the flash turned on and connected, the camera wont go past 1/180th without HSS enabled... even in manual exposure mode. Good idea though.

[enoeske]

With the flash turned on and connected, the camera wont go past 1/180th without HSS enabled... even in manual exposure mode. Good idea though.

I think that is only if the flash is in P-TTL mode and communicates with the camera. If the flash is in manual mode, the camera should be able to be set to anything. If over 1/180th, the flash just won't activate.

[jab2980]

I don't think is a bug but while you mention that you tried to have fill in flash I am just wondering if you went over x-speed sync limit of 1/180 or stayed bellow. If you was above I guess that your flash had to switch to P-TTL as it HSS and this works with P-TTL only and your flash went back to selected mode after the shot. I have Metz flash and there I must select HSS P-TTL mode if I like to have fill flash unless I am bellow 1/160 speed sync. With manual flash is the same thing as long as you do not go above the max speed sync of the Pentax otherwise will not fire.

Just my 2c.

P.S. I do not have Sigma flash therefore cannot reproduce your problem.

I don't think it's a bug either... kinda bizarre though. Am I a wacko for expecting to be able to use AV mode to link my exposure to a auto focus point and lock it... and then be able to control my flash power separately?

[RAART]

if you use center focus point only you will be able to lock the exposure however to use flash manually on the hot-shoe I think that you have to set camera to manual flash and than control it from there, but to able to control flash from camera the flash has to use P-TTL mode. Maybe this is what it is happen to you. The solution what I would recommend is to use flash of camera with wireless triggers (like cowboy studio) and it will work how you wanted but remember you cannot exceed max sync speed of 1/180s. You can use your Sigma flash in full manual mode when attach to those receiver and then experiment from there how much power you will need for fill in or use the light meter (like Sekonic) to get it right... it will work for sure.

Here is an example when I was hiking with an older friend and I had only flash and remote triggers in my bag and had to improvise to light him up as he was in complete shadow... I locked the exposure to the background and with guessing the amount of flash power was able to get it right at the beginning with second try and later when I knew the flash power and distance right away... not the fill flash exactly but this was done with only one flash off camera and wireless triggers...


on Flickr


on Flickr

on this example you can see according to hard shadows from where the flash was firing... I wish that I had second flash with me to soften the hard shadows on the opposite side but I did not plan to make any photos of this kind and it just happens that he wanted the photos and as a good friend I did it for him...


on Flickr

[MadMathMind]

I just got my flash and used it outside in bright light for fill in. Here are some results:


Exposure: 1/800


Exposure: 1/400


Exposure: 1/500


Exposure: 1/2000

There's a bunch more of Harley (last girl) photos there if you click the photo and go to my Flickr. Notice the shadows on her face? Yeah, the shutter speed is too high. It's not enough time for the flash to do anything. The 1/400 or 1/500 are much better. Even 1/800 worked out well in that scenario, although it didn't fare as well in others. 1/250 may be ideal, although perhaps a bit slow.

Is it common for an external flash to automatically switch from manual mode to P-TTL when shooting in AV mode?

I made this mistake in my first session out. Av mode is not a good choice because the shutter speed will go too high and then you lose all the fill-in. If you set it to HSS, it will stay that way, but PTTL + Av mode is not a supported combination, technically. Or at least, it doesn't work well. The Pentax flash manual says to put it in P, TAv, or M mode.

If you want to do fill-in in bright light, you need to use TAv mode and ND filters. Probably 3 or 4 stops. I need to get a set for my FA31 myself for this purpose. Keep in mind that you can always raise the ISO to 200 to get the exposure up, but you can't lower it below 80 or 100. It's better to see ISO100 at 1/125, which you can turn into ISO200 at 1/250 or ISO250 at 1/320, than to see ISO80 and 1/800. You can't do anything about that if you're maxed out on filters.

[geru2000]

I just got my flash and used it outside in bright light for fill in. Here are some results:


Exposure: 1/800


Exposure: 1/400


Exposure: 1/500


Exposure: 1/2000

There's a bunch more of Harley (last girl) photos there if you click the photo and go to my Flickr. Notice the shadows on her face? Yeah, the shutter speed is too high. It's not enough time for the flash to do anything. The 1/400 or 1/500 are much better. Even 1/800 worked out well in that scenario, although it didn't fare as well in others. 1/250 may be ideal, although perhaps a bit slow.



I made this mistake in my first session out. Av mode is not a good choice because the shutter speed will go too high and then you lose all the fill-in. If you set it to HSS, it will stay that way, but PTTL + Av mode is not a supported combination, technically. Or at least, it doesn't work well. The Pentax flash manual says to put it in P, TAv, or M mode.

If you want to do fill-in in bright light, you need to use TAv mode and ND filters. Probably 3 or 4 stops. I need to get a set for my FA31 myself for this purpose. Keep in mind that you can always raise the ISO to 200 to get the exposure up, but you can't lower it below 80 or 100. It's better to see ISO100 at 1/125, which you can turn into ISO200 at 1/250 or ISO250 at 1/320, than to see ISO80 and 1/800. You can't do anything about that if you're maxed out on filters.

I'm a little confused, is your flash set to HSS, if so then 1/2000 shouldn't be a problem for the flash.
The shadows on Haley's face aren't caused by the flash performance nor would the flash be able to remove them properly. Using a scrim or even turning her 180 would probably have removed them. The shadows are not unlike dappling found sometimes when under trees.

Anyway some nice and colorful shots.