[Tickolas]

Hey guys!

Just got back from the Stockholm Photo Marathon using my LX. Was a blast!

However, when taking a portrait of my girlfriend with the sunset behind her I wanted to use my flash unit, a AF540FGZ, as a fill flash. However, the flash didn't fire. Is this some kind of safeguard to prevent overexposure or is there something wrong here? Had the LX set to Automatic and the flash set to P-TTL and 35mm.

Thanks!

[UncleVanya]

LX doesn't do P-TTL it does TTL right? Maybe auto mode flash would be a better bet? I only ever used the LX with flashes of the same vintage. I don't have one now so I can't test it.

[wombat2go]

As far as I know, it is not possible to fire high speed sync on the Pentax AF540, AF360 etc unless a camera supporting P-TTL is used.

It seems that fill flash was not a big item for Pentax at the time of those cameras.
For example the Pentax LX ( manual page 16) and MX (Page 19) had a maximum "X" ( and hotshoe) flash sync speed of 1/60th.
To use higher shutter speeds it was necessary to use an "FP" focal plane flash bulb with a long burn time.

The manual for the Pentax AF16 ( approx 1979 vintage) Page 4 shows a very garish image with a 28mm lens
"thus giving rich and well illuminated flash pictures..."
And that was typical of my flash photos !

None of the Pentax manuals I have here from that time, including Herbert Keppler, mention use of fill flash.

[gylfimag]

The LX will not trigger the flash if the TTL exposure system senses that a faster shutter speed than 1/75s (the maximum sync speed for a flash) is needed. That is probably what happened here. If you can expose at 1/75s or slower you should be able to use the AF540 for fill flash on the LX but it will be hard to get it right. You might want to try using the flash in manual mode. I have an LX and this flash and they work quite well together usually but getting fill flash right is much easier with a digital camera as you can experiment and see right away what the outcome is.

[gofour3]

The LX supports TTL flash and not P-TTL.

Set your AF540FGZ flash mode to "TTL Auto Flash", see page 27 in your instructions:

http://c2b6d376b97bcc466063-5420c200a1f030d1394a9548df6eadbd.r5.cf2.rackcdn....391_manual.pdf

Phil.

[filmamigo]

Daylight fill on a camera with sync speed of 1/50 or 1/60 is very tough.

You need slow film, small apertures, and bright flash.

I have found the flash automation on my LXs not very useful. Probably easiest to set the camera to X, set the lens aperture, and then use Auto mode on your flash with the flash controls set to the same aperture as the lens. Another advantage of Automatic (or TTL) over P-TTL, there is no pre-flash to delay your exposure or make people blink.

[pentaxpete]

Yes -- I have two LX bodies -- both now faulty so don't use them often but was very disappointed for a 'Top-of-the- Range- Professional- Pentax' to have such a SLOW Flash Synch speed -- why could they not get it up to at least 1/250th second ? Even my ME Supers have 1/125th synch speed ( and they are still going and don't suffer the Sticky Mirror Syndrome' as do the LX's. )

[Tickolas]

Thanks for all your tips, guys. Sounds to me like I should use a very small aperture next time I want to take a pic like that. I figure that if I get the automatic time down below the X speed the flash should go off, right?

Also, does anyone know for sure if the AF540FGZ's P-TTL works with the LX if you set it to 35mm mode? I'm lacking a manual for it.

Edit: The 540 does indeed support the LX for TTL. See the PDF manual here, page 61.

[LesDMess]

Yes -- I have two LX bodies -- both now faulty so don't use them often but was very disappointed for a 'Top-of-the- Range- Professional- Pentax' to have such a SLOW Flash Synch speed -- why could they not get it up to at least 1/250th second ? Even my ME Supers have 1/125th synch speed ( and they are still going and don't suffer the Sticky Mirror Syndrome' as do the LX's. )

Dubbed the "three kings" by Herb Keppler as they were the top pro cameras at the time of their near simultaneous release.



What they all have in common is horizontal travel shutters that limited their sync speeds to less than the vertical travel shutters becoming more widespread at that time.
At that time, horizontal titanium shutters were considered more reliable than the vertical shutters which was a more important consideration.

BTW, I have two LX's that are completely functional with no issues. Of course when buying used, there is no accounting for previous use and not indicative of build.

[UncleVanya]

Yes -- I have two LX bodies -- both now faulty so don't use them often but was very disappointed for a 'Top-of-the- Range- Professional- Pentax' to have such a SLOW Flash Synch speed -- why could they not get it up to at least 1/250th second ? Even my ME Supers have 1/125th synch speed ( and they are still going and don't suffer the Sticky Mirror Syndrome' as do the LX's. )

Time. Introduced in 1980/81; 1/250th shutters were introduced about 10 years later. The contemporary F3 did 1/80th vs. 1/75th for the LX.

[LesDMess]

Thanks for all your tips, guys. Sounds to me like I should use a very small aperture next time I want to take a pic like that. I figure that if I get the automatic time down below the X speed the flash should go off, right?

Also, does anyone know for sure if the AF540FGZ's P-TTL works with the LX if you set it to 35mm mode? I'm lacking a manual for it.

Edit: The 540 does indeed support the LX for TTL. See the PDF manual here, page 61.

I believe I confirmed this previously that when using the AF280T in manual mode and the LX in aperture priority mode that the flash will fire using the settings on the flash. Of course determining the amount of fill will have to be manually calculated - or metered with a flash meter. Is that how it works with your AF540FGZ+LX combination?

[gofour3]

The K2's had a 1/125 flash sync back in 1975/1976, but that was a different vertical shutter. So the limitation was as Les said, the newer horizontal type shutter.

Don't complain about how slow the LX sync is, the Pentax 6x7 flash sync is only 1/30 of a second and that's a "Professional" system!

Phil.

[UncleVanya]

The K2's had a 1/125 flash sync back in 1975/1976, but that was a different vertical shutter. So the limitation was as Les said, the newer horizontal type shutter.

Don't complain about how slow the LX sync is, the Pentax 6x7 flash sync is only 1/30 of a second and that's a "Professional" system!

Phil.

Phil that's true. But not in a pro level 35mm body. The Nikkormat FT3 I had made in 1977 sync'd at 1/125th and had a vertical metal shutter. It was loud and probably that shutter would not have worked for long with an MD4 motor drive attached. The reliability of the shutter as well as noise levels all impacted what was put into what body. In the 1990's 1/250th finally arrived...

[LesDMess]

The reliability of the shutter as well as noise levels all impacted what was put into what body. In the 1990's 1/250th finally arrived...

I have some models that achieved 1/250 long before 1990. The Nikon FM2 achieved a sync speed of 1/200 in 1982. In 1983 this went up to 1/250 for the FM2N, FA & FE2. The 1986 Olympus OM4T + the F280 flash can synchronize at all speeds up to 1/2000.

BTW, I believe the fastest sync speed achieved by a horizontal shutter system was that installed in the 1972 Minolta XK and it was 1/100. The Canon F-1 New sync speed is 1/90.

[UncleVanya]

I have some models that achieved 1/250 long before 1990. The Nikon FM2 achieved a sync speed of 1/200 in 1982. In 1983 this went up to 1/250 for the FM2N, FA & FE2. The 1986 Olympus OM4T + the F280 flash can synchronize at all speeds up to 1/2000.

BTW, I believe the fastest sync speed achieved by a horizontal shutter system was that installed in the 1972 Minolta XK and it was 1/100. The Canon F-1 New sync speed is 1/90.

Phil that's true. But not in a pro level 35mm body. The Nikkormat FT3 I had made in 1977 sync'd at 1/125th and had a vertical metal shutter. It was loud and probably that shutter would not have worked for long with an MD4 motor drive attached. The reliability of the shutter as well as noise levels all impacted what was put into what body. In the 1990's 1/250th finally arrived...

Sorry I wasn't as clear as I meant to be The comment about a Pro-level 35mm body was meant to be for the entire reply but the last sentence could be misread as any shutter not just a pro body one. Sorry if that was unclear. I meant that 1/250th didn't arrive in a top of the line body (unless I am mistaken) until the 1990's.