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10-20-2015, 01:12 AM - 2 Likes   #1156
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QuoteOriginally posted by Class A Quote
I think you used unfortunate wording here.

Surely you were convinced that Pentax is the best way forward for you based on the merit of the products. Getting the latter free is a nice bonus, rather than the price they had to buy your opinion, isn't it?
Hehe i am always honest..So i got to admit, i hadn't changed system, if i didn't get such good offer. Its a hard world for photographers and freelancers now, so you do what you have to do..BUT, i wouldn't change if i didn't feel it could deliver what i needed! I was sure the FF would come sooner then it does, but i still manage to deliver quality! I have had talks with both Nikon (who wants me back), Leica and Sony. But i prefer to stay loyal, since the teamwork between me and Ricoh is so good in many areas

10-20-2015, 02:37 AM - 1 Like   #1157
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QuoteOriginally posted by kenspo Quote
Im more then that now. Im ambassador for everything Pentax I get everything i need..cameras, lenses, extras etc. It had to be done that way, since they had to convince me to change system

But software developer, I'm not
I hope that do not include beta-testing of Pentax endoscopes.
10-20-2015, 02:39 AM   #1158
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It doesn't..hahaha!
10-20-2015, 02:41 AM - 1 Like   #1159
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Fortunately, that part stayed with Hoya. Otherwise, kenspo would be much less willing to be a Pentax ambassador and product tester

10-20-2015, 06:17 AM   #1160
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QuoteOriginally posted by Fogel70 Quote
To be able to regulate horizontal/vertical shift (X and Y shift) you need to know the magnification of the shot.
The closer the focus is, the more you need to move the sensor.

So for the forth and fifth axis you need to know the focus distance together with focal length to be able to calculate magnification.
Which is also the reason why you only get 3-axis stabilization on Sony A7-series with lenses that do not report focus distance to the camera.
I have trouble understanding this. If I understand you correctly, a shift is corrected to the portion of the image where the lens is focused, and the amount of correction will be different if the lens is focused on something near rather than something far in the image (given the same shift-mode shake input). Which implies that only parts of the image near the focus plane will be well corrected for a shift-mode shake, right? What if your shot is at hyper-focal - only one distance plane within the image has effective SR?

I guess the saving grace is that shift mode corrections are most important at close distance and the effect of shift rapidly decreases with distance.
10-20-2015, 11:23 AM   #1161
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QuoteOriginally posted by cfraz Quote
I guess the saving grace is that shift mode corrections are most important at close distance and the effect of shift rapidly decreases with distance.
Yes, this is correct.

If you use very deep DOF in your image you might see that closest parts within DOF have camera shake blur if using handheld camera if the camera shake is purely x and y shift, while further away parts of the image is perfectly sharp. But in practice this is not often seen as camera shake usually consists of shifts and angular movements, and angular camera shake affect the image as much on all distances in the image.
10-20-2015, 01:53 PM   #1162
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QuoteOriginally posted by Fogel70 Quote
Yes, this is correct.

If you use very deep DOF in your image you might see that closest parts within DOF have camera shake blur if using handheld camera if the camera shake is purely x and y shift, while further away parts of the image is perfectly sharp. But in practice this is not often seen as camera shake usually consists of shifts and angular movements, and angular camera shake affect the image as much on all distances in the image.
Yes, I understand why there will be more shift-induced blur on closer parts of an image than further parts.

I don't understand why a shift correction equal in magnitude and opposite direction doesn't result in a blur-free image regardless of object distance from the camera. don't the magnification terms for the shift and the SR shift correction cancel out?

You are saying a left shift of 1 mm by the camera operator is corrected by a right shift of the sensor by the SR system of not 1 mm, but 0.5 or 0.8 or 1.2 mm or some other number, depending on if you want near objects or far objects in the image to be corrected. Have I got that right?

And it follows that objects at only one focal distance in an image can be corrected for shift-mode shake. Objects at all other distances will still show shake induced blur even after correction. Right?

Hmm. The shake moves both sensor and lens. SR correction moves only the sensor. Maybe that's where my thought process derailed. Anyway I'd appreciate your comments.
10-20-2015, 02:14 PM   #1163
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QuoteOriginally posted by Class A Quote
While I don't have any inside information, I strongly suspect that the camera initiates all communication with the lens.

A lens could thus respond with the crude information whenever it receices a respective message from the old protocol, but return precise data in response to a camera request that conforms to a newly added message type.
This is certainly the case with Canon EF lenses, they have a SPI bus to/from the lens. The camera sends commands/questions and the lens answers. The ability to understand a new command can be indicated by setting some bit in the response to some lens ID command, just as for SDM focus and any other already existing optional features.

Specific example for EF lenses: Camera B0 -> lens answers 4 bytes of min/max aperture. Camera 071308 -> lens closes aperture to "8" (one stop below open, not necessarily aperture 8) answers 11. And so on.

10-20-2015, 03:13 PM   #1164
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QuoteOriginally posted by cfraz Quote
Yes, I understand why there will be more shift-induced blur on closer parts of an image than further parts.

I don't understand why a shift correction equal in magnitude and opposite direction doesn't result in a blur-free image regardless of object distance from the camera. don't the magnification terms for the shift and the SR shift correction cancel out?

You are saying a left shift of 1 mm by the camera operator is corrected by a right shift of the sensor by the SR system of not 1 mm, but 0.5 or 0.8 or 1.2 mm or some other number, depending on if you want near objects or far objects in the image to be corrected. Have I got that right?

And it follows that objects at only one focal distance in an image can be corrected for shift-mode shake. Objects at all other distances will still show shake induced blur even after correction. Right?

Hmm. The shake moves both sensor and lens. SR correction moves only the sensor. Maybe that's where my thought process derailed. Anyway I'd appreciate your comments.
I believe the issue is not "X-Y" (across - updown) movement, but twisting ( I could say, "like a washing machine", if that means anything to you, or maybe we need to bring in Chubby Checkers "Come on baby, let's do the twist" if you're old enough).
10-20-2015, 03:28 PM   #1165
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QuoteOriginally posted by reh321 Quote
I believe the issue is not "X-Y" (across - updown) movement, but twisting ( I could say, "like a washing machine", if that means anything to you, or maybe we need to bring in Chubby Checkers "Come on baby, let's do the twist" if you're old enough).
Yea, the twist (sometimes called "yaw" when talking about shake reduction) is one axis, tilt (point up or down) is a second axis, rotate about the lens centerline is a third axis. Pentax uses SR which corrects for these three axes.

The discussion was about axes four and five, x and y shift, which Pentax does not have. Someone a lot smarter than me pointed out that shift correction is more difficult because it requires input of both focal length and focus distance. I'm just trying to understand why.
10-20-2015, 06:24 PM   #1166
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i would rather love to see a real fit fullHD video-mode with 60fps and a 4K video mode with 30fps...
And for recording non-professional neat private videos, real good AF while video recording with several options how and on what to focus.. predefined focus points(follow focus programming like ) individually adjustable,
and dedicated directional focusing backward or forward.
Maybe one lens with real silent powerzoom for doing video... and we are done... yummy.
10-20-2015, 06:33 PM   #1167
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QuoteOriginally posted by patarok Quote
i would rather love to see a real fit fullHD video-mode with 60fps and a 4K video mode with 30fps...
And for recording non-professional neat private videos, real good AF while video recording with several options how and on what to focus.. predefined focus points(follow focus programming like ) individually adjustable,
and dedicated directional focusing backward or forward.
Maybe one lens with real silent powerzoom for doing video... and we are done... yummy.
You were dreaming of Olympus or Sony surely..

Pentax is NOT a video oriented product line. Nor will be. That is, until the money drops off still shooting because everyone is plucking single frames off their video feeds. But that is years and years away..
10-20-2015, 09:17 PM   #1168
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QuoteOriginally posted by cfraz Quote
Yea, the twist (sometimes called "yaw" when talking about shake reduction) is one axis, tilt (point up or down) is a second axis, rotate about the lens centerline is a third axis. Pentax uses SR which corrects for these three axes.

The discussion was about axes four and five, x and y shift, which Pentax does not have. Someone a lot smarter than me pointed out that shift correction is more difficult because it requires input of both focal length and focus distance. I'm just trying to understand why.
It is movement up/down, left/right at the end of the lens. The sensor would have to move down if the end of the lens tilts down. The amount would depend on the distance to the first lens element, and the characteristics of the lens bending the light as it goes off center and travels a diagonal path through the lens elements. That would change based on the position of the elements as it adjusts focus distance. I would imagine the aperture would have an effect as well. Focal length would change in a zoom.
10-20-2015, 09:43 PM   #1169
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QuoteOriginally posted by cfraz Quote
Yes, I understand why there will be more shift-induced blur on closer parts of an image than further parts.

I don't understand why a shift correction equal in magnitude and opposite direction doesn't result in a blur-free image regardless of object distance from the camera. don't the magnification terms for the shift and the SR shift correction cancel out?
Magnification will vary depending on the distance to the subject. Try moving you hand in front of you eyes. The same movement with the hand very close to your eyes will seem to move more and faster than if holding the hand further away.

QuoteQuote:
You are saying a left shift of 1 mm by the camera operator is corrected by a right shift of the sensor by the SR system of not 1 mm, but 0.5 or 0.8 or 1.2 mm or some other number, depending on if you want near objects or far objects in the image to be corrected. Have I got that right?
On a shot at 1:1 magnification each camera shift will affect the image at 1:1, at 1:1000 magnification the shift will affect the image at 1:1000.

The camera shift will shift the whole scene captured with the same amount. A 1mm shift of the captured scene on a macro shot that are a couple of cm wide will affect the image very much, but a 1mm shift of the captured scene of a landscape shot that are hundreds of meters wide will probably not affect the image at all.

Most images are captured at low magnification which make the camera shifts a insignificant problem, and I guess most 5-axis stabilization simply turn off shift compensation when magnification get too low.

QuoteQuote:
And it follows that objects at only one focal distance in an image can be corrected for shift-mode shake. Objects at all other distances will still show shake induced blur even after correction. Right?
This is more of a theoretical issue than a real one, as on most shots (low magnification shots) the angular camera shake contributes to most blur, and on high magnification shots where this could be an issue the DOF is usually too limited.

QuoteQuote:
Hmm. The shake moves both sensor and lens. SR correction moves only the sensor. Maybe that's where my thought process derailed. Anyway I'd appreciate your comments.
10-20-2015, 10:00 PM   #1170
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QuoteOriginally posted by derekkite Quote
It is movement up/down, left/right at the end of the lens. The sensor would have to move down if the end of the lens tilts down. The amount would depend on the distance to the first lens element, and the characteristics of the lens bending the light as it goes off center and travels a diagonal path through the lens elements. That would change based on the position of the elements as it adjusts focus distance. I would imagine the aperture would have an effect as well. Focal length would change in a zoom.
Then the solution is simple -- Ricoh must develop a system that moves all objects in space in accordance with the camera moving in one's hands.
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