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11-05-2013, 01:07 PM   #346
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QuoteOriginally posted by lister6520 Quote
AFAIK it has to do with keeping an integer (or at least half integer) scaling factor between the sensor and the recorded video.

Full HD is 1920 pixels wide whereas the K3 sensor is 6016. With a 1:3 ratio, that is 3 horizontal pixels per one horizontal pixel in video makes 5760 pixels, which is about 95% of the width.

With the K-30 you have 4928 hoirizontal pixels so the closest is 1:2.5, giving 4800 pixels, being about 97%.

To get the full frame you would need to scale some odd ratio. For the K-3 that would be 3.13333. Although it can be done it takes far more processing to do and especially if you want to avoid alisasing artifacts.

All digital cameras I've ever had crop the video to a greater or lesser extent, even the ones without image stabilisation, most likely for this very reason.
Still, it's the only DSLR in the market that crops the video. And I think it crops way more than 5% of the width, something close to 10%.

And, why doesn't the K5 crop the video?

11-05-2013, 01:28 PM   #347
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QuoteOriginally posted by JohnnyXD Quote
Still, it's the only DSLR in the market that crops the video
sony Alpha's as well... also digital SR
But you are right, the others do not "crop"
11-05-2013, 01:48 PM   #348
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QuoteOriginally posted by JohnnyXD Quote
Still, it's the only DSLR in the market that crops the video. And I think it crops way more than 5% of the width, something close to 10%.

And, why doesn't the K5 crop the video?
That surprises me somewhat. Could it be that other DSLRs sensors match the HD video resolution?

By any chance do you know what is the horizontal resolution and the resolution of the recorded video for the K-5 and some other DSLR that does not crop video? I am somewhat intrigued that they would be doing non integer scaling as it is very processing intensive compared to ratios of small integral numbers (like 1:3, 5:2, 6:7 and so on)
11-05-2013, 02:17 PM   #349
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QuoteOriginally posted by JohnnyXD Quote
And, why doesn't the K5 crop the video?
The K-5 uses mechanical SR, so doesn't need the extra pixels around the crop to invoke digital SR.

Thus it's able to interpolate down to 1920x1080 by using the whole sensor.

Whatever is left over (if indeed there is anything left over) in the scaling calculation, doesn't show up possibly because it equates to

only a pixel or two of the overall sensor's dimensions.

AB

11-05-2013, 05:00 PM   #350
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1. First picture is the video image (-> crop) of Pentax K-30 over photo image, a little bit zoomed for right perspective -> see point #2:

2. In the 2nd picture you can see the real perspective distortion causes by crop (video image over photo image). The real SR area will be a little bit greater as video size fits in pictures.

Notice the blur in front and back parts of both pictures (video and photo). I think, K-3 solution will be the same with better specs .?.

Shot with smc Pentax-A 50mm f/2.
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11-05-2013, 05:52 PM   #351
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QuoteOriginally posted by hopsing Quote
2. In the 2nd picture you can see the real perspective distortion causes by crop (video image over photo image).
Cropping does not cause a perspective distortion. If distance is the same there should be no difference in perspective.
11-05-2013, 06:56 PM   #352
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So in video mode we essentially have a 4/3rds, APS-C camera with terrible image quality with stabilization enabled. But it's great because it has a headphone jack! Brilliant design by Pentax engineers.


QuoteOriginally posted by hopsing Quote
1. First picture is the video image (-> crop) of Pentax K-30 over photo image, a little bit zoomed for right perspective -> see point #2:

2. In the 2nd picture you can see the real perspective distortion causes by crop (video image over photo image). The real SR area will be a little bit greater as video size fits in pictures.

Notice the blur in front and back parts of both pictures (video and photo). I think, K-3 solution will be the same with better specs .?.

Shot with smc Pentax-A 50mm f/2.
11-05-2013, 10:00 PM   #353
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QuoteOriginally posted by Ayoh Quote
So in video mode we essentially have a 4/3rds, APS-C camera with terrible image quality with stabilization enabled. But it's great because it has a headphone jack! Brilliant design by Pentax engineers.
Remember, they also say it has proffessional video.

It's good that we're all getting annoyed by this - maybe they'll get the message.

"We're as mad as hell, and we're not going to take it any more!!"

AB

11-06-2013, 01:05 AM   #354
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QuoteOriginally posted by jaad75 Quote
Cropping does not cause a perspective distortion. If distance is the same there should be no difference in perspective.
Yes, indeed. I mean the 2nd crop effect, it's not a perspective distortion .
11-06-2013, 05:07 AM   #355
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Here's what Jordan from The Camera Store has to say about the K-3 video capabilities:

"2- I'd put the K-3 above the Sony NEX and Nikon D7100, but the 70D has a great high bitrate with wonderful continuous autofocus, and the GH3 is still the best small camera option out there. I love the image from the Blackmagic Pocket Camera, but it can't shoot stills, and the audio control is abysmal."

Read more at: https://www.pentaxforums.com/forums/172-pentax-k-3/241653-tcstv-k-3-field-tes...#ixzz2jrmWqe8y
11-06-2013, 05:10 AM   #356
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QuoteOriginally posted by johnmflores Quote
Here's what Jordan from The Camera Store has to say about the K-3 video capabilities:

"2- I'd put the K-3 above the Sony NEX and Nikon D7100, but the 70D has a great high bitrate with wonderful continuous autofocus, and the GH3 is still the best small camera option out there. I love the image from the Blackmagic Pocket Camera, but it can't shoot stills, and the audio control is abysmal."

Read more at: https://www.pentaxforums.com/forums/172-pentax-k-3/241653-tcstv-k-3-field-tes...#ixzz2jrmWqe8y
That gives us something to hang our hats on, for sure.

For me it's been a toss up between the Black Magic Pocket Cinema Camera and the K-3.

The BMPCC does have some early "got-yas", as pointed out, plus once you start shooting, there's no idea of how much storage you have left, and there's a lack of wide angle options.

AB
11-08-2013, 06:09 AM   #357
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Hi, later a k7 , I take a k5 , and disaproved , in video mode, again was no MANUAL setting , like , SHUTTER, ISO and many more... automatic exp. (so automatic iso/shutter) and LOCK with ae-l button.
So bad in many situations of light... NOW again another pentax...but my question is , what really change new in VIDEO OPTIONS ? more resolutions but....any one can say to me , IF have manual setting durng recorder of ISO, SHUTTER, IRIS... separatly ? or meaby cou can set them only in stanby , or lile k7 and 5...no one of this setting are manual ?
THANKS !!!
11-08-2013, 06:49 AM   #358
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QuoteOriginally posted by gambadilegno Quote
what really change new in VIDEO OPTIONS ?
Iso/shutter/iris is fully manual!

and I understand: also during recording. Can someone confirm the latter?
11-08-2013, 09:11 AM   #359
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I wonder if anyone with an actual K-3 could actually check and actually see if the actual image "crops / zooms in and out" when actually switching between still and video shooting with image stabilization actually turned off. (using a tripod and not messing with the zoom would probably be good) A test with the image stabilization actually turned on (for those run and gun non cinematic shoots) would be cute to.
11-08-2013, 09:26 AM   #360
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QuoteOriginally posted by MrStupid Quote
I wonder if anyone with an actual K-3 could actually check and actually see if the actual image "crops / zooms in and out" when actually switching between still and video shooting with image stabilization actually turned off. (using a tripod and not messing with the zoom would probably be good) A test with the image stabilization actually turned on (for those run and gun non cinematic shoots) would be cute to.
Switching from Live View stills to Video crops the image a couple degrees to either side and top and bottom (3:2 to 19:9 proportions). SR has no effect on amount of crop.

Turning SR on and off while in video mode has no effect on crop.
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