Confused about formats

[Mike Trewhella]

I have an NX5E (PAL). The menu boasts many formats. I know I can shoot in 1920x1080i but can I shoot in 1080p? If I can what do I choose to obtain this?
regards
Mike

[Stelios Christofides]

Mike

The first thing you must do is READ the manual and if you get confused you must always know that there is "Google" then if you still have a problem do a search here and finally if you are still confused post your question here.
Did you see this?
MediaSpace | Oregon State University



stelios

[Mike Trewhella]

Thanks for you reply Stelios.
regards
Mike

[David Heath]

Originally Posted by Mike Trewhella

I know I can shoot in 1920x1080i but can I shoot in 1080p?

If you're in the UK, there are fundamentally three formats for HD that you may choose: 1080i/25, 1080p/25, and 720p/50. (The first may also be called 1080/50i - old terminology, but still often used.)

It's worth reading up on the differences, but in basic terms the main difference between 1080i/25 and 1080p/25 is that the first gives "smooth" motion (as normal for sport etc), the second gives "jerky" or "film-look" motion (as more often used for drama).

720p/50 gives "smooth motion", and keeps all the advantages of progressive - but at the expense of resolution. It is worth considering that the NX5 chips are about 1 megapixel, so the difference between recording in 720p and 1080p modes won't be anywhere near as great as with a camera with 1920x1080 (2 megapixel) sensors such as the EX.

[Mike Trewhella]

Thanks for the reply David. The NX5 shoots 1920x1080i ? That is one of the formats available.
Were you meaning 1920x1080p when referring to the 2 megapixel chip?
regards
Mike

[David Heath]

Originally Posted by Mike Trewhella

Were you meaning 1920x1080p when referring to the 2 megapixel chip?

I think you're getting confused between two things - resolution and "p" for progressive.

Progressive really means "a complete frame at a time" - the alternative is interlace, where a frame is split into two. (Look at some references like Interlaced video - Wikipedia, the free encyclopedia and Progressive scan - Wikipedia, the free encyclopedia )

In the case of "2 megapixel cameras" there are indeed 1920x1080 photosites, but that's rare in 1/3" chip cameras, and tends to give noise and sensitivity problems when it is the case. Consequently, it's common for 1/3" cameras to have less - half the pixel count in the NX5, hence about "1 megapixel".

The arrangement in the NX5 is complicated, but take it as read that the resolution corresponds to about 1440x810. It may get recorded as 1920x1080, but the signal isn't capable in resolution terms of doing the recording format full justice.

[Mike Trewhella]

Thanks David. Looks like the specifications of the NX5 claiming (1920x1080) may be a bit misleading then.
regards
Mike

[Ron Evans]

The sensors in the Sony are constructed on a diagonal array of 1080 horizontal lines each with 960 sensor sites offset from each other on alternating lines. Do a search and there is a lot of information on this approach. The measured TV resolution is thus the effectiveness of the interpolation algorithm used in the Bionz DSP processor in the camera. Consequently this may not be the same under all lighting conditions. The DSP will of course always create the number of pixels needed for the recording chosen. 1920x1080 or 1280x720, 720x480.

Ron Evans

[David Heath]

Originally Posted by Mike Trewhella

Thanks David. Looks like the specifications of the NX5 claiming (1920x1080) may be a bit misleading then.

I think you'll find they refer to the *RECORDING* format, and it's perfectly accurate to say that is 1920x1080 - the spec is also quite open about the fact that the sensors are 1 megapixel each.

What it really shows is that all 1920x1080 recordings are not equal ! Talking about "1920x1080 recording" or "full HD recording" is quite common in spec sheets, and in many occasions the actual performance isn't even as good as the NX5.

It's best to think of the sites on the sensor as two diamond patterns interleaved, each 960x540 measured corner to corner. (Think a tiled bathroom floor with 960x540 white tiles and the same number black!)

[Steve Game]

Originally Posted by David Heath

In the case of "2 megapixel cameras" there are indeed 1920x1080 photosites, but that's rare in 1/3" chip cameras, and tends to give noise and sensitivity problems when it is the case. Consequently, it's common for 1/3" cameras to have less - half the pixel count in the NX5, hence about "1 megapixel".

The arrangement in the NX5 is complicated, but take it as read that the resolution corresponds to about 1440x810. It may get recorded as 1920x1080, but the signal isn't capable in resolution terms of doing the recording format full justice.

The native resolution of the NX5, (and the Z5 from which the NX5's front end design is derived), is indeed only1440 x 810. However, the 'green pixel shift' technique increases the horizontal luminance resolution for most images to about 1.5 times the native pixel count, i.e. 1920. This is at the expense of the colour registration which is tidied up in processing to match the codec's 4:2:0 limitations. A similar technique is performed on the vertical resolution but the gain increase in effective resolution is not so great owing to the slanting nature of the 'Clear View' sensor array pattern.
The pixel shift technique is not new, and was used at least 7 years ago on the Z1 where the 960x1080 array gave an effective increase in luminance resolution to 1440x1080, which exactly matched the HDV codec.

Steve

[Stelios Christofides]

Originally Posted by David Heath

....What it really shows is that all 1920x1080 recordings are not equal ! Talking about "1920x1080 recording" or "full HD recording" is quite common in spec sheets, and in many occasions the actual performance isn't even as good as the NX5....

How true David. Not all 1920x1080 are equal.

stelios

[James Kuhn]

Mr. G...thank you for your technical insight. I'm merely a user, but I love to know how things work.

Best regards,

J.

[Ron Evans]

These are some references to the Sony technology on the single chips sensors Sony Global - Technology - ClearVid CMOS Sensor. It is my understanding that the 3 chip products are single colour versions and should yield full colour signals to the DSP for processing and thus higher quality to HD/ SDi and HDMI than are recorded to AVCHD for instance. I know I read some other articles from Sony about the 3 chip sensors but cannot find them now.

Ron Evans

[David Heath]

Ron - I think you know, but it's worth emphasising that what you link to is (with greater than 50% green photosites) a single sensor design - not 3 chip as the NX5 uses. I believe the >50% green arrangement is most found on relatively low cost camers with small sensors - compared to Bayer, it trades colour fidelity for sensitivity.

[Ray Turcotte]

Yes the way Sony details the HD recording setting for its cameras is confusing. It took me a while to figure them out, after cross referencing many on-line documents, with the provided manuals, for each of my 3 cameras.

What i learned is the following.

When choosing a recording setting there are 3 parameters that can be set: bit rate, frame rate and interlaced (i) or progressive (p).

[As you only asked about the HD settings I'll skip listing the SD settings].

The bit rates (and pixel size) are set with the following Sony cross platform convention:

PS ~24-28MBps, 1920x1080 (square pixels) (recent cameras)
FX ~20-24mBps, 1920x1080 (Square pixels)
FH ~16-17MBps, 1920x1080 (square pixels)
HQ ~11-16MBps, 1440x1080 (rectangular pixels)
LP ~5-16MBps, 1440x1080 (rectangular pixels)



On my AX2000 and a65 and cx550v cameras there are only certain combos of Bit rate and frame rates that can be selected:

Ax2000:

PS
FX 24p,30p,60i
FH 24p,30p,60i
HQ 60i
LP 60i

And on my A65:

PS 60p
FX 24p,60i
FH 24p,60i
HQ 30p
LP

my cx550v only has 4 combos

FX 60i
FH 60i
HQ 60i
LP 60i


and thus, is not the best match for my other 2 cameras.