[cbope]

I had 3 EV overexposure with the first flash I bought (Bower SFD926P Power Zoom Flash.) Just got the Pentax 360 but haven't tried it yet. The old one needed the diffuser, ceiling bounce and -1 EV comp, when on auto. I was kinda hoping the Pentax would work better.

From what I've read, all 3rd party flashes have reverse engineered P-TTL, because Pentax does not publish the details. I would assume Pentax flases could be a bit better in that respect, but it really depends on how well the reverse engineering has been done. I'm not really sure how complex or simple the P-TTL communication is, so it's a bit hard to know for sure. If it's not too complex a good reverse engineering could be just as good as Pentax' own. Of course this is all speculation on my part, no facts to back any of this up so take it with a huge grain of salt

I also have the AF360FGZ, and I've had some of the overexposure issues that are mentioned in this forum. I don't believe this is an issue with P-TTL itself but a less-than-mature flash firmware in the K-5 that can be fooled in specific situations. After reading the suggestions here, I have set up a user mode with D-range highlight correction enabled and -1 flash exposure compensation, which many have reported to fix the problems. I haven't really tested it yet, so time will tell.

[newmikey]

...speculation on my part, no facts to back any of this up so take it with a huge grain of salt

As far as I know the Sigma and Metz have this down to a fine art so shouldn't be an issue.

I don't believe this is an issue with P-TTL itself but a less-than-mature flash firmware in the K-5 that can be fooled in specific situations.

I think there is slightly more wrong than that, some talk of a subject to flash distance reversal issue.

After reading the suggestions here, I have set up a user mode with D-range highlight correction enabled and -1 flash exposure compensation, which many have reported to fix the problems. I haven't really tested it yet, so time will tell.

That should indeed kill the issue stone-dead. After these adjustments my K-5 exposes beautifully with the Metz 58 AF-1.

[Lowell Goudge]

When I look at the answers I have some questions. First P mode will try to make the exposure without flash which includes bumping ISO. Any flash at 1 meter will over expose if the ISO is bumped. Start in manual mode with a low ISO and 1/150 shutter

[Ron Kruger]

Lowell, I'm not sure about the K5, because I haven't tried flash in P mode with it yet, but with my K10D and K20D, putting them on P mode with either the camera or hot-shoe flash always chose a default 100 ISO.

[Lowell Goudge]

Lowell, I'm not sure about the K5, because I haven't tried flash in P mode with it yet, but with my K10D and K20D, putting them on P mode with either the camera or hot-shoe flash always chose a default 100 ISO.

I don't know either as I don't use P mode. But the other issue is that the Pentax approach to flash is to make the exposure without flash first and this leads to a real problem at short distance

[Rupert]

I've read about this problem for some time...but have never experienced it with my K5 and in fact it is better than on my K20D at getting it right most of the time. Overall, it is my belief that the Pentax flash is deficient in comparison to Nikon's very dependable system. This is just based on my slight experience with friends that shoot Nikon, where I see their flash to be near perfect almost every time.
For my limited flash use, the K5 has not been a real problem at all, and I don't suffer overexposure at any flash position with the 540 or 360 except for the very occasional mishap, which could easily be my fault.
Regards

[aleonx3]

Actually, I've never liked P mode and auto flash settings with any camera. Flash, even fill, is kind of tricky, and over the years, I've gravitated toward using it in AV mode, most of the time with the flash in manual mode. I've developed an instinct for ambiant light/apature/distance/flash output settings (mostly full power). It's not as hard as it sounds. Stopping down gives me a more pleasing effect for DOF, sharper shots and I like the light fall off it creates for low light situations. The only time P and P-TTL works well for me, is in bright sunlight, and even then, I can usually get a richer shot in AV with calculated overrides. It's not just Pentax, because I shot Nikons for decades. Auto modes are inconsistent with flashes, and I almost always use a diffuser to avoid hot spots, glare and harsh shadows, especially with slaves. I use flash a great deal outdoors, because I love the rich, smooth look it gives colors and the Nat Geo kind of 3D look and pop it produces.
Experiment with it.

I don't have much experience in flash photography, but I will chime in as Ron has pretty much summed up what I have learned over the past years since I wanted to use flash effectively and getting results that I want. Keeping in mind that using flash is more of an art than science, as there are infinite possibilities.... just think about bounce flash alone (how high is the ceiling? what is the reflective index of the surface that you bounce the flash and so on).

The important concept is the flash-and-ambient-light mix, the camera can not decide for you, you have to set the camera to do what you want. Another concept is that PTTL on the flash takes care only of the proper exposure on the subject (in focus) with input setting from the camera. Using flash in auto-mode both on flash and camera is a hit-and-miss chance since it depends very much on the environment. People claiming that certain brands are better only means that there are finer degrees of control in a given brand, not that they have a solution that works right every time. I have shot side-by-side with people having "pro" grade camera with me, they were mostly worse but no better; my conclusion: it is all in your skill, not the camera.

I find that these rules generally apply:
-for indoor, use M mode with Slow-sync bounce flash
-for outdoor, use Av with HSS for fill flash

So, back to OP's question: k-5 flash over-exposure? my answer is: does not apply to me... besides, I use +/-EC in many situations.

I just remember something about the flash battery - if you happen to use the alkaline AA batteries for the external flash - don't do that.. those batteries will always release full power no matter what.. I suggest you use the Eneloop (slow release battery), your flash will be happier and last longer with that.

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Last edited by aleonx3; 12-10-2011 at 01:33 PM. Reason: missing key word..

[glanglois]

The flash-to-ambient-light ratio is key and, as aleonx3 notes, must be under the control of the photographer. The flash/camera cannot read our minds.

After a bit of fooling around with P-TTL, I gave up and now use auto mode on the flash (Metz 54AF and 58 AF-1) and manual on the camera. The aperture gives me the DOF I want, shutter speed helps the ambient/flash ratio, and ISO also affects the impact of the ambient light as well as the recycle time of the flash and, of course, noise. I started out that way with my first decent flash (Nikon SB-26 on K-10D) and found it's easy enough to manage.

Never had much of a problem with overexposure on any flash unless the flash was a bit loose on the K-7 hot shoe. Then it simply blasted at full power. I have not had that problem with K-5 and K-X so I assume my K-7 hot shoe (of all things!) was just a bit off in some way.

[Ron Boggs]

On my K5 the 540 overexposed nearly every shot so I started using the 360 with normal exposure results. Tested my 540 on two other bodies with similar overexposure probs. Planned to send it in for service more than a year ago but it has now "healed" by shooting in the rear sych setting. Did some pretty tricky indoor situations recently with fine results. I always shoot in aperture priority and now the 540 that had been on a dusty shelf is back in my kit set to rear curtain synch.

The fact that the 360 worked on all three bodies and the 540 overexposed on all three bodies lead me to blame the flash not the K5.

Just for fun I shot a few with the 540 in standard synch and they now work correctly too...

Perhaps the post discussing cleaning the contacts factors in here. A "coated" contact on the 540 would have made it not function correctly on all the bodies. Rub the contact clean and suddenly it works fine. Just happened to occur after setting it to rear synch so I thought the setting was the difference. Perhaps cleaning the contacts is part of this equation?

Regardless, try setting Pentax flash to rear synch to see how it works with your overexposure probs. And of course, clean the contacts.

[blockamon]

For those of you using the Highlight Correction and -1 FEC, how do you get around the underexposure with RAW. I always shoot RAW (DNG) and process in Lightroom, and it doesn't recognize Highlight Correction, so all of the photos are underexposed by about 1 stop. Is there a way to get around that without using the Pentax RAW software?

[newmikey]

For those of you using the Highlight Correction and -1 FEC, how do you get around the underexposure with RAW. I always shoot RAW (DNG) and process in Lightroom, and it doesn't recognize Highlight Correction, so all of the photos are underexposed by about 1 stop. Is there a way to get around that without using the Pentax RAW software?

I use UFRaw and I found that manually setting exposure to +1.5 solves this for me. When I process batches, I actually have it automated through a step in my script that accounts for this:

Code:

    Drange=$( exiv2 print -pt "$i" | grep "Dynamic" | awk '{print $4}' )
    echo "D-Range="$Drange"!!!"
    if [  $Drange == "On"  ]
    then
      expose=" --exposure=1.5000 " # max value
    else
      expose=" --exposure=0.5000 " # max value      
    fi

[Markbrumbaugh]

I tried the 360 on some indoor shots last night in P mode P-TTL and results were fine.

[EsBee]

I recently got a K-5 also and noticed over-exposure when using flash, regardless of on-board, hot-shoe or wireless.

Using the same flash unit (AF 540 FGZ), same lens (Tamron AF28-75mm f2.8) and same settings (f2.8, 1/180 and ISO 100), I took the following test shots in wireless mode with the flash bouncing off low White ceiling from the same spot. I tried to keep most of the settings the same yet some could be slightly off, but not enough in my opinion to justify the significant over-exposure by K-5.

All shots were taken with the flash in p-TTL mode, in RAW (PEF) format and then re-sized while converting to JPEG using Pentax Digital Camera Utility v4.33. No other PP.

K200d, f2.8, ISO 100, 1/180

---------------------------------------------------------

K20d, f2.8, ISO 100, 1/180

---------------------------------------------------------

K-5, f2.8, ISO 100, 1/180

[amoringello]

I would say the last is an optimal exposure (no overblown highlights, and no overly dark shadows.)

It is arguably better to slightly overexpose just to the point where your whites are close, but not quite clipping. Then post process to drop exposure. You will have a greater range of detail and color to work with... Also better to drop exposure, than to pull is up from darkness... the latter causing more grain where the former should remain clean.

Although the first two may be more closely matching the environment, the last would have greater latitude for editing and post processing.

If this were to happen with JPEG in P mode, I might be disappointed with the result. But if I needed P mode, I'd probably not have a $1500 DSLR, either. :-)

[simico]

For those of you using the Highlight Correction and -1 FEC, how do you get around the underexposure with RAW. I always shoot RAW (DNG) and process in Lightroom, and it doesn't recognize Highlight Correction, so all of the photos are underexposed by about 1 stop. Is there a way to get around that without using the Pentax RAW software?

Turn highlight correction off and use -2 FEC.