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10-16-2010, 04:10 PM   #16
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Does it stand to reason that if Pentax is going to come up with a shuttter than can handle a faster sync, they would do it with one that could handle ff? That's a philosophical question.

10-16-2010, 04:32 PM   #17
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QuoteOriginally posted by Blue Quote
Does it stand to reason that if Pentax is going to come up with a shuttter than can handle a faster sync, they would do it with one that could handle ff? That's a philosophical question.
I don't grasp the philosophical part.

Pentax introduced 1/250X 1/8000s vertical run metal blade shutters 20 years ago with the Z-1. FF indeed... It's still laying around in their lab, I am pretty sure
10-16-2010, 04:45 PM   #18
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QuoteOriginally posted by falconeye Quote
I don't grasp the philosophical part.

Pentax introduced 1/250X 1/8000s vertical run metal blade shutters 20 years ago with the Z-1. FF indeed... It's still laying around in their lab, I am pretty sure
The philosophical part is that we may not see the 1/250 sync until we see a ff body.

Edit: They had switched to a different shutter for the MZ-S and MZ-3.
10-17-2010, 01:54 AM   #19
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Falk, I'd like to know your thinking about that Sony x-sync being different with or without SR.
What could cause this ?
Thank you.

10-17-2010, 02:10 AM   #20
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why does every 1/180th Vs 1/250th flash synch speed always end up mentioning FF?

cool video falk, how did you actually get that?

QuoteOriginally posted by Blue Quote
At this rate we'll have 1/60 sec sync in the K1, and then won't all the other kids be jealous.
the Leica M6 had a synch speed of 1/50th of a second...fancy spending $6000 on a camera that has a synch speed barely faster than a pentax 67.
10-17-2010, 05:19 AM   #21
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QuoteOriginally posted by Digitalis Quote
why does every 1/180th Vs 1/250th flash synch speed always end up mentioning FF?

cool video falk, how did you actually get that?
Every topic ends up mentioning FF, doesn't it?

We wanted to do a high speed lab video in Rüdiger's mechatronics lab. But there was a waiting list, so I rather made a bid for an Exilim EX-FC100 on ebay and that way turned out to be the faster one (that camera is amazing for its two-digit price!) I scaled the video a bit because the original video size at that speed is very small. You need good light and a faster electronic shutter would help because 1/1000s leaves a lot of motion blur ... Originally, we only wanted to know if the shutter runs top-down or bottom-up

About X-sync with SR: I've read nothing about. But it sounds logical. With SR on, the sensor can be anywhere +/- 2mm of its original location and you have to keep the shutter open longer to make sure the sensor area is not obscured. At least, if the engineers didn't make their homework and synchronized the exact flash trigger with the exact sensor location which both should be known to the firmware :ugh:
10-17-2010, 05:35 AM   #22
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The reality is even if going over 1/180 causes a small black band we should still be able to exceed if we choose to, surely the engineers don't think we are all idiots!
10-17-2010, 05:44 AM   #23
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QuoteOriginally posted by Christopher M.W.T Quote
surely the engineers don't think we are all idiots!
with jewellery photographers running around with Nikon D3X cameras with their lenses stopped down to f/40 I think the answer to that question is obvious.

no matter how many well educated, bright people there are in the world there is always a healthy population of idiots, and we all know who is in the majority.

IDIOT, n.
A member of a large and powerful tribe whose influence in human affairs has always been dominant and controlling. The Idiot's activity is not confined to any special field of thought or action, but "pervades and regulates the whole." He has the last word in everything; his decision is unappealable. He sets the fashions and opinion of taste, dictates the limitations of speech and circumscribes conduct with a dead-line.

-Excerpt from the Devils dictionary.



Last edited by Digitalis; 10-17-2010 at 05:50 AM.
10-17-2010, 08:24 AM   #24
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QuoteOriginally posted by Digitalis Quote
-Excerpt from the Devils dictionary.
PHOTOGRAPH, n.
A picture painted by the sun without instruction in art. It is a little better than the work of an Apache, but not quite so good as that of a Cheyenne.


PENTAX, n.
Missing entry, redirecting to

PENITENT, adj.
Undergoing or awaiting punishment.

-Excerpts from the Devils dictionary.
10-17-2010, 07:23 PM   #25
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It is the weakest link of all the parts that determent the limit on a system and not all the parts are visible. Improving the limit of a given part when other parts still limit the system only increases the cost of the system with no system improvement. With the exception of that part is limiting something else like top end shutter speed. A good engineer will design a system so that all the parts just exceed the limit (with a margin) needed, to save money, unless that part is more expensive to design (or purchase) then a part with additional limits. To me it looks like there are multiple parts that need to be changed with the shutter being only one of them. With the newer shutter on the K7/K5 the next limit maybe the flash or some other part still. To an engineer a glass is not half full or have empty but over built and that means badly engineered.

Yes, engineers think everyone is an idiot. Ever time they think otherwise some technician named Murphy points out that they are not as smart as he. It is always the engineer not Murphy that has to go find a new job.

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10-17-2010, 08:58 PM   #26
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QuoteOriginally posted by DAZ Quote
Yes, engineers think everyone is an idiot. Ever time they think otherwise some technician named Murphy points out that they are not as smart as he. It is always the engineer not Murphy that has to go find a new job.

DAZ
Are you blaming the flash sync problem on the engineers?
10-18-2010, 04:24 AM   #27
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Is it possible that Pentax just ordered a boatload of 1/180th sync shutters.
Or that their sized shutter is actually nonstandard. being 20mm makes it larger than a Nikon/Canon APSC shutter, therefore noone makes one at that size and speed combination.
10-18-2010, 05:45 AM   #28
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QuoteOriginally posted by HawaiianOnline Quote
Are you blaming the flash sync problem on the engineers?
It is not a problem but it is what is the design limit. It maybe to limiting for some but it works, as it was intended so it is not a fault. Why this was picked as the limit is a whole new discussion. What I am saying is it is probably not just one part like the shutter that limits the camera to a flash sync of 1/180s. The fact that no one has managed to trick the system to go faster (even if there is a black bar at the bottom) is not going to keep an engineer up at night. Engineers are responsible that the camera works as intended at the cost projected.

Just about ever item we buy has limits determined by cost not what technology can make. Can the engineers make a camera with a flash sync of 1/250s? Absolutely they can. They can probably even make one go to 1/500s. They may have to also design a new flash but it can be accomplished. The question is cost and profit. When it is shone to be profitable then engineers will build it.

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10-18-2010, 06:01 AM   #29
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Pentax K-5 shutter dimension details

QuoteOriginally posted by Steelski Quote
Is it possible that Pentax just ordered a boatload of 1/180th sync shutters.
Or that their sized shutter is actually nonstandard. being 20mm makes it larger than a Nikon/Canon APSC shutter, therefore noone makes one at that size and speed combination.
I computed the exact shutter opening height from my image now. It is 20.9mm.

The exact sensor height is 15.7mm, which is ~19.7mm with SR margins. Probably, the shutter opening height is another 1mm larger to avoid any vignetting and allow for some mounting tolerance.

This makes 17mm for a "standard" APSC shutter, 20.7mm for a Pentax APSC shutter, 25mm for a FF shutter and 27mm for an SR FF shutter.

However, I don't see why Pentax couldn't have used the Sony A700 shutter (1/200X 1/8000s) if from a 3rd party. BTW, the 250/200 diff. is exactly the 16.7/20.7 diff. (25%).

I also looked at the 2nd curtain stack of 3 blades sitting in the top of the shutter in the cut model image. It is 6pixels thick (in the "O" size image) which translates to 0.08mm or 1/12mm thickness per blade. Could be thinner if the cut made an imprecise cut.

Each blade is 9.5mm high, totalling to 28.5mm for a 20.9mm opening. That's 1.3mm for each of the 6 overlaps making the blades cover 23.4mm. Assuming the same horizontally makes the blades 31.4mm wide.

3 blades of 9.5mm x 31.4mm x 0.08mm is 23.9mm^3. At 7.9 mg/mm^3 (high quality steel) this is 189 mg. Or because not all blades move with equal speed, an effective weight of (1/3+2/3+3/3)/3=2/3 of this which is 126mg or 1/8 g. Note that the Sony A700 shutter blades are made of carbon fiber though. In the video, you can see the curtain blades flatter. So, carbon fiber can be a better material (lighter) but this isn't necessarily so (less stiff).

Of course, the whole shutter has more moving parts than just the blades and therefore, its total effective weight is larger than this.

I mention this because we looked at this number in our shutter blur study.

Last edited by falconeye; 10-18-2010 at 06:09 AM.
10-18-2010, 06:35 AM   #30
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QuoteOriginally posted by Digitalis Quote
why does every 1/180th Vs 1/250th flash synch speed always end up mentioning FF?

cool video falk, how did you actually get that?



the Leica M6 had a synch speed of 1/50th of a second...fancy spending $6000 on a camera that has a synch speed barely faster than a pentax 67.

I never made the 1/60th K-1 comment. Regarding ff, the last 1/250th sync shutter in a Pentax body was on a ff body.
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