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09-19-2010, 02:53 AM   #16
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p-TTL means Pathetic in the P for me. If Pentax has the courage to drop their PTTL and have their new cameras takes on TTL or some other non-pathetic TTL, that will be a new milestone to celebrate in Pentaxian land and it will actually suit its customers better. A new flash won't hurt.

09-19-2010, 03:01 AM - 1 Like   #17
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QuoteOriginally posted by Steelski Quote
here have been a few theories as to why Pentax does not sync faster than 1/180th.
Perhaps just a bit off topic, but I was always interested what would be the real world applications of fast native flash sync speeds where "High Speed" (HS) flash setting would not suffice?

I remember reading only one somewhat justified reason from a wedding photographer, and that is, to shoot in broad daylight with wide aperture for shallow depth of field while using fill flash. OK, fair enough. In that case shutter speed may easily go to 1/500 or 1/1000. With Pentax that would not be possible due to 1/180 limit.

However, for this particular application, HS mode solves the problem: HS extends flash duration to avoid moving curtain problem, but at the expense of flash power. Luckily, flash exposure is controlled by aperture ONLY, so going from full flash power at, say, f/8 with 1/180s to reduced power but in HS mode at f/2.8 with 1/1000s would actually fairly well compensate for lost power and yield comparable and useful result. I've tested this with AF-360 and FA 35/2 (down to f/2) and HS works extremely well. Note that while in HS mode flash does not reduce power at 1/180s or slower. Just over. But again, generally faster shutter speed requires wider aperture which compensates for reduced flash power in HS mode.

Maybe lack of real necessity leaves flash sync speed at 1/180s? Especially 1/180s to 1/250s is only 1/2 stops, I see no real benefit.

P.S. Just YouTubed to find episode I remember from a year or two ago about flashes in Digital Photography 1 on 1 series with good explanations on the subject, but instead I found another good one:


And here is the one I was looking for, adds a bit more in the second half of the video:


Advanced tutorial and what to do on location WITHOUT high speed sync:


You CAN try this at home: set camera to M mode, flash to M mode and you can do EXACTLY the same (no need for a powerpack, flash heads, and soft box). If you wish to do this with off-camera AF360/540 see my older post:

https://www.pentaxforums.com/forums/519219-post1.html
09-19-2010, 03:02 AM   #18
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QuoteOriginally posted by hinman Quote
p-TTL means Pathetic in the P for me. If Pentax has the courage to drop their PTTL and have their new cameras takes on TTL or some other non-pathetic TTL, that will be a new milestone to celebrate in Pentaxian land and it will actually suit its customers better. A new flash won't hurt.
Actually P-ttl isn't all that bad once you learn how to use it, I got fairly consistent results with it.

I remember reading that you should link metering to AF points in the custom menu on the K-7.

The issue with the Pentax system is the quality of the flash guns themselves, P is Pathetic in that case!
09-19-2010, 03:17 AM   #19
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QuoteOriginally posted by thibs Quote
The situation you describe is with your K110D? If so, I can say the K-7 is whole lot better. It may not be perfect, sure, but a lot better.

The problem isn't really PTTL, that just a flash protocol. The metering is done by the same meter as the non-flash exposure (TTL had its own meter which was Center weighted btw, no multizone). And it worked so-so with their old metering. The 77 zones metering of K7 manage a lot better.

Now PTTL would be improved/tweaked for: higher X-sync and allow Nikon-like features (ratio between flashes etc.) but it would probably make present flashes incompatible or at least incapable of newest features.
Well Thibs, you have really given me something to think about here. Of course I know that P-TTL isn't really any different in concept from E-TTL or i-TTL or whatever the other manufacturers call their systems. I fully trust you that the K-7 (and K-5 no doubt) perform better in this area. What I don't get is if I am doing something very basic like spot metering on a subject and using the center focus point, why always the blown highlights? I never had such a problem with Minolta's TTL system. I'm sure that part of the problem is in the sharp cutoff in highlights with these sensors. Perhaps Pentax is just helping me "expose to the right" LOL. Seriously though, it's a headache. I am just a novice when it comes to digital photography really, so I am sure that with a little more practice and a better tool in my hands, I can get the hang of P-TTL too.

What I'm sure would help greatly is tweaking the default tone curve to roll off more gently in the highlights. It seems Pentax is a little afraid to do this at the risk of introducing shadow noise - but really the precipice at the right side of the tone curve is a bit scary, especially on outdated equipment like mine.

09-19-2010, 04:25 AM   #20
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We really need someone able to crack pentax firmwares to remove this absurd 1/180 sync speed limit. With Nikon the black curtain trail is well manageable up to 1/400, you just have to crop it away..
09-19-2010, 05:32 AM   #21
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QuoteOriginally posted by Ivan Glisin Quote
Perhaps just a bit off topic, but I was always interested what would be the real world applications of fast native flash sync speeds where "High Speed" (HS) flash setting would not suffice?
Let's say you want to underexpose the background a bit, have a main flash at full power at your subject and then a fill flash from the side to reduce hard shadows - you really want to control this manually! You would really want to have as fast shutter speed as possible to reduce ambient. If you go for the HS solution you're basicly telling the camera to please do something you would want it to do and then hope and pray that a quite unsophisticated metering system will do it right. Put on a snoot or grid etc and you'll really have to fight the controls to get whatever you're after.

HS flash is great if you're a point and shoot guy that just want to fill some face with a bright background. However it sux when you want to do any advanced lighting because you have no _real control_ over the exposure. The camera does all the calculations for you.

And of course, if you really need a lot of light, a hotshoe flash running at (very) reduced power through HS is not sufficient in the first place.

I do realize that the majority of users will never see this as a problem. The majority of users "never" use flash, they never use more than one flash, they never use the flash in manual mode and never use high power studio strobes either. But for a small segment of portrait/product/commercial photographers the manual flash sync speed is important. There might not be a big difference in 1/180 vs 1/250 but at least 1/250 would put Pentax up among it's competition where they have been for years.
09-19-2010, 10:10 AM   #22
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Shouldn't sync times have gotten better since there's less distance for the shutter to cover (18.3mm versus 24?)
09-19-2010, 10:24 AM   #23
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QuoteOriginally posted by junyo Quote
So what you're saying is, Pentax is putting a slower/less capable shutter in the K-7, of 2010, than they were putting in the PZ-1P, of 1999?
The explanation Andreas (and) gave is correct.
The sync speed of a shutter is depending upon the minimum amount of time the shutter is completely open, before the trailing curtain comes down.
If the shutter is not completely open when the flash fires, you will see a dark area on the upper part of the image.

Have a look at this:


The timing is not the same as of your Pentax camera and it is in German, but I think it is more or less self explaining.

- Cheers, Bert

NB. Yes, it can be possible that Pentax was making shutters in 1999 that moved faster than the shutters today.
Perhaps todays shutters use less power, last longer and create less vibration?

09-19-2010, 12:58 PM   #24
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QuoteOriginally posted by bymy141 Quote
NB. Yes, it can be possible that Pentax was making shutters in 1999 that moved faster than the shutters today.
Perhaps todays shutters use less power, last longer and create less vibration?
Mmm Minolta once had a shutter going up to 1/12.000 in the high end camera (9 something as usual with Minolta). Nobody did it again, neither Canon nor Nikon. Guess why? AFAIK, Power ...
09-19-2010, 04:28 PM   #25
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On an another OT point regarding HSS : you are better off using ND filters to get back under the X-sync speed, you lose less flash power this way.
And frankly, there is simply no reason Pentax would limit their cameras to 1/180 if it was not for hardware limits (namely, shutters speed), so I'd not wait for a magic FW update...

On another aside note, the current P-TTL implementation is nearly capable of multi-channel control, a la Nikon (but without the mode control), as it can already handle 4 different channels... It could be made available by a simple firmware update on all DSLR cameras, and would be compatible with all existing flashes...
But I guess Pentax is not so interested in multi-channels control...

EDIT : from memory, someone took a high-speed video of a K7 shutter action, so actual speeds can be measured... I think it was more or less in line with the 1/180 X sync speed, with some extra time allowed for shutter stabilization...
09-19-2010, 04:36 PM   #26
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QuoteOriginally posted by dlacouture Quote
On an another OT point regarding HSS : you are better off using ND filters to get back under the X-sync speed, you lose less flash power this way.
And frankly, there is simply no reason Pentax would limit their cameras to 1/180 if it was not for hardware limits (namely, shutters speed), so I'd not wait for a magic FW update...

On another aside note, the current P-TTL implementation is nearly capable of multi-channel control, a la Nikon (but without the mode control), as it can already handle 4 different channels... It could be made available by a simple firmware update on all DSLR cameras, and would be compatible with all existing flashes...
But I guess Pentax is not so interested in multi-channels control...

EDIT : from memory, someone took a high-speed video of a K7 shutter action, so actual speeds can be measured... I think it was more or less in line with the 1/180 X sync speed, with some extra time allowed for shutter stabilization...
I am not hoping for a firmware update. I think they could be limited by the P-TTL protocol. If that is the case and they make a new PTTL2 protocol, like Ettl II and (I know Ettl did not get faster all of a sudden).
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