[sinus007]

Hi,
I wonder if something's not right with me, K-1, flash or any combination of the above.
I tried AF540 on K-1. In P-TTL mode it severely overexposes the subject.
In A mode the exposure is great.
Both pictures are taken from the same distance, show the same parameters.
BTW, on K-3 it worked OK.
Any ideas, suggestions?
Thanks in advance.

[Phenix]

on my K-5 I always got severe underexposed via pttl. But mine could be a defect flash as I bought it used. What lens are you using?

[sinus007]

Hi,
I tried with 2 lenses: DA40Ltd and DFA 24-70. Same result.

AK

[UncleVanya]

Hi,
I wonder if something's not right with me, K-1, flash or any combination of the above.
I tried AF540 on K-1. In P-TTL mode it severely overexposes the subject.
In A mode the exposure is great.
Both pictures are taken from the same distance, show the same parameters.
BTW, on K-3 it worked OK.
Any ideas, suggestions?
Thanks in advance.

What f/stop? What distance?
Less than about f/8 and less than 8-10' you can expect some overexposure.
When you compare the A vs. P-TTL - look at the basic exposure parameters. I will bet the A shots were at a higher f/stop.

[clackers]

Hi,
I wonder if something's not right with me, K-1, flash or any combination of the above.
I tried AF540 on K-1. In P-TTL mode it severely overexposes the subject.
.

Look at the scale on the flash to make sure your subject lies between the minimum and maximum distance, Sinus.

Take charge and manually set the ISO if you discover it keeps choosing too high values.

[beholder3]

Hi,
I wonder if something's not right with me, K-1, flash or any combination of the above.
I tried AF540 on K-1. In P-TTL mode it severely overexposes the subject.
In A mode the exposure is great.
Both pictures are taken from the same distance, show the same parameters.
BTW, on K-3 it worked OK.
Any ideas, suggestions?
Thanks in advance.

Using flash there are millions of ways for user errors, but there is one way to check if there is a hardware issue:

• Shoot M.
• Use F8.
• Shutter time 1/160.
• ISO 100.
• Use Matrix metering.
• Shoot a subject that contains no bright, highly reflective (e.g. white, silver, glass...) parts.
• Subject Distance minimum 3-4 m.
• Show us the results as raw (!) file. Getting a JPG to appear as overexposed when the raw is properly exposed is just too easy. And keep in mind that subjective "too bright" is not "overexposed".

If there was any hardware issue, it must be there in the raw. If it is not in this scenario, then there is a user error, as obviously you can avoid any issues.

[mcgregni]

Agree on all above points. .... Use the flash range scale, with the head pointed straight ahead, to assess that your settings are realistic. It also often helps to set a small flash compensation amount, so try with -1 stop for example. And no Auto -ISO ... Use realistic ISOs for the distances involved. So ISO 100 for closer, direct flash, and 400-800 for indoor work with bounce, maybe up to 3200 if its a big room and you're using an extreme bounce angle or a high ceiling.

Also I recommend manually fixing your ambient exposure in M mode first to be sure that is nicely set ... Usually backgrounds are nice when a little underexposed when using flash on the closet subject.

[Flasher]

Wow lots of advise above. Forgive me if I am wrong but isn't the idea of P-TTL to be able to take photos with minimal effort required in getting a good exposure? Pointless having it as an option if you have to use all the manual settings as mentioned above, even if manual is the best method to use.

From what sinus says I am assuming he takes the same shot one with P=TTL and the other with A. Same aperture, same ISO, same distance (he says that) and the flash is mounted on the camera. Maybe he can confirm.

So if A can take a correctly exposed image then the flash is within the range of the Aperture selected and the Max/Min Distance for the flash to measure the reflected light and control the flash duration. Surely if the flash can do that then the camera can do the same in P-TTL. It sounds like a problem in the camera, either an incorrect setting (compensation or shutter or a changing iso???) or there is a bug in the camera. Hopefully it isn't another repeat of the disastrous K5 bounce flash problem!

Or possibly he has an old AF540 that needs its firmware updated to work on the K-1 but he does say it works on the K-3 so that shouldn't be the problem.

[clackers]

Wow lots of advise above. Forgive me if I am wrong but isn't the idea of P-TTL to be able to take photos with minimal effort required in getting a good exposure? ... or there is a bug in the camera. Hopefully it isn't another repeat of the disastrous K5 bounce flash problem!

The advice is to help the OP diagnose.

P-TTL is very easy unless you've screwed up other settings.

I have exactly that setup - 540 on a K-1 - and it's fine.

[Flasher]

So telling him to use it in full manual is helping...how? If it works on your setup then it should work on his without the need to use manual I would have thought.

Your advice of setting a manual iso in the camera is sound (assuming he hasn't already) as that could be his problem but it is within the flashes distance range otherwise A would not expose correctly.

It could be his spot meter settings, aiming at a dark window for example so suggesting he change that would be a start in diagnosis.

---------- Post added 06-30-16 at 10:47 PM ----------

More information about his settings from him is necessary to narrow it down.

---------- Post added 06-30-16 at 10:48 PM ----------

Also another possibility is that the flash is not pushed fully into the hotshoe. and not making P-TTL contact.

[mcgregni]

With flash you have to isolate the various components to get a good grip on controlling it. The other thread now about the AF-540FGZ on full power seems to be having similar confusions getting in the way. Manual mode on the camera allows you to isolate just the flash exposure component and assess what factors are influencing it. If any other things are changing on the camera automatically then its very difficult. TBH most of these sorts of issues are to do with inappropriate flash to subject distances for apertures and ISOs that are being used.

[sinus007]

Hi,
To answer some of the questions:
shooting in Av
ISO100
F2.8
1/60s
distance = 3-4m (the flash shows effective distance 1.5-20m)
no reflective, white, etc surfaces on the subject
direct flash (no bounce, reflectors or diffusers)
As I mentioned before, all settings are the same for P-TTL and A modes.

The difference between P-TTL and A is about 2 stops.
As Flasher suggested isn't P-TTL supposed to pre-flash to measure and provide more or less correct lighting? BTW, is AF540 flash f/w upgradable?
I mean, I can use A mode or I can find the right settings in M mode and get a more or less good lighting. But why to have P-TTL flash and not use the feature.
Thanks again for all responses.

[clackers]

Your advice of setting a manual iso in the camera is sound (assuming he hasn't already) as that could be his problem but it is within the flashes distance range otherwise A would not expose correctly..

You can't assume that.

In 'A' mode the ISO is set by the photographer.

[mcgregni]

You're very very near the extreme limits there, with direct flash and F2.8 !! That's a hell of a powerful flash you're using. I think you're just too close ....

Try the same settings and distances but bounce the light this time ... Over your shoulder or at right angles onto a wall .... That should stand a better chance. Also, zoom in on your subject .... If you are shooting wide then the meter sees more of the scene and tries to light more of it, so things that are close get overexposed.

[clackers]

.
As Flasher suggested isn't P-TTL supposed to pre-flash to measure and provide more or less correct lighting? .

Does for me, Sinus, so you have a problem with your hardware or technique.

If you choose -2 as the FEC, do the shots then resemble A mode ones?