rrrconserve
New member
The ability to record HDV to tape like the Sony Z7U.
AF-100 Wishlist/Suggestion Discussion Thread
- Thread starter Luis Caffesse
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Ben_B
Veteran
Joke?
Mike Harvey
Veteran
One hopes.
Barry_Green
Moderator
Not sure exactly why one would want it, but you could always cable through component, HDMI, or HD-SDI out to an external HDV recorder if necessary.
mikkowilson
Steadi-Guru
I'm not sure if I'd oppose Tape or HDV compression more.
- Mikko
- Mikko
Chris Light
Veteran
clarify...i forget which is which <, >, +, =....
strangways
Well-known member
AVCHD is better than HDV.
Otis Grapsas
Carbonite Member
So, it's UNCOMPRESSED>HDCAMSR>DNXHD>>HDCAM~=DVCPROHD100>AVCCAM~=XDCAMEX>AVCHD>HDV>DV ?
Ignoring Mpeg IMX and DVCPRO50, the problem is placing Digital Betacam and uncompressed SD, many put those above the GOP HD formats.
Ignoring Mpeg IMX and DVCPRO50, the problem is placing Digital Betacam and uncompressed SD, many put those above the GOP HD formats.
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i think
Intraframes:
AVCINTRA>DVCPROHD100
Long GOP
CANONMPEG2 4:2:2>XDCAMEX=AVCHD>HDV
anyway
It would be great to have a scientific test on Dynamic range(gradability) & pixelation between these codecs
Otis Grapsas
Carbonite Member
It is possible but it will not be very meaningful. Codecs come as packages with cameras, their noise is different, the denoising is different, the sensor resolution is different, even the compression implementation is different.
The compression techniques are stardard really, there is DCT (low compression intraframe, natural looking artifacts), mpeg2 (high compression gop, compares to DCT at static images, motion introduces blocking) and mpeg4 (a little more efficient than mpeg2, softened artifacts due to filtering, better in PSNR metrics but not so much in actual pixel quality). If you calculate bits/pixel for luma/chroma on each format you will have a good measure of pixel quality.
A good example in the Canon 4:2:2. It has higher rate, but inferior quantisation compared to generic mpeg2 and a lot more luma/chroma pixels to compress. It ends up at similar pixel quality because it's not 2x the bits per pixel despite the 2x rate.
The sad thing is that the top quality intraframe formats only provide DV pixel quality after all those years of progress (with the exception of DNXHD) and the GOP formats cannot even approach DV pixel quality when there is motion in the frame.
I don't know if this is the right thread to post this question but here it goes...
If part of the DOF that the AF100's micro 4/3 can achieve is due to the lens to sensor distance, wouldn't we be minimizing shallow DOF with adaptor mounts for other manufacturer lenses such as Nikon, Canon and Olympus?
If part of the DOF that the AF100's micro 4/3 can achieve is due to the lens to sensor distance, wouldn't we be minimizing shallow DOF with adaptor mounts for other manufacturer lenses such as Nikon, Canon and Olympus?
Barry_Green
Moderator
No, your premise isn't correct. Lens to sensor distance has nothing to do with it. DOF is determined by the aperture, the focal length of the lens, and the distance to the subject, not the distance to the sensor.
A larger sensor uses longer focal length lenses, therefore, for any given field of view, the larger sensor camera will have the shallower DOF than the smaller sensor. And a 4/3 sensor is huge, it's 4x bigger than a 2/3" sensor.
Thanks for you answer. Nonetheless, it isn't my premise, hence my post. Please take a look at the camera presentation at NAB by the Panasonic guys. Pay attention from the 1:25 minute on...
http://www.youtube.com/watch?v=_KtcBNQwIe4
That guy is clearly stating that lens to sensor size has an impact on Field Of View. Focal lenght - contrary to what many people say - don't have an impact on DOF. We say it has because we have the perception that the narrower FOV that it catches tranlates to a shallow DOF, which makes your statement true to an extent ("DOF is determined by... the focal length of the lens..."), and making me think if this guy is actually right on his argument, which I (as you), find odd at least!
On that respect, if focal distance had an impact on DOF it would be counter-productive to put the lens closer to the focal plane, since that would contribute to a deeper DOF for any given lens, not a shallower one.
Anyway, one thing is for sure though. Even if - for instance - a 50mm lens were a "normal" in the 4/3 imager (which is not but lets assume it is just to make things easier), it won't be any more when you put an adapter between the lens and the camera. The focal distance will be obviously higher, and if that is good for people who want to use long focal lenses, it presents a problem on the other end.
My wider prime is a 20mm Nikon which will make about a +40mm lens on the AF100 16:9 aspect plus adapter
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Ben_B
Veteran
The alligator wants to eat the bigger one.
d1rockwild
Well-known member
and the bird goes for the lesser one.
Starshine Video
Well-known member
Anyway, one thing is for sure though. Even if - for instance - a 50mm lens were a "normal" in the 4/3 imager (which is not but lets assume it is just to make things easier), it won't be any more when you put an adapter between the lens and the camera. The focal distance will be obviously higher, and if that is good for people who want to use long focal lenses, it presents a problem on the other end.
My wider prime is a 20mm Nikon which will make about a +40mm lens on the AF100 16:9 aspect plus adapter
Yes the 20mm nikon will, on a micro 4/3, be the equivalent FOV of the 40mm lens on a Full frame camera, it will not actually change the focal length. The Flange Focal Distance has nothing to do the FOV or DOF, nothing. The reason that micro 4/3 is so cool is that the flange focal distance is so short that it allows the lenses from almost all 35mm cameras ever made to be mounted on them. The adapter not only adapts the mount, it also gives the lenses the proper Flange focal distance.
Micro 4/3 FFD is 20mm
Nikon is 46.5mm
Canon EF is 44mm
Canon FD is 42mm
When a nikon adapter is placed on the m4/3 mount it, not only adapts for the bayonet of the nikon but also spaces the mount at the correct 46.5mm Flange focal distance. That is why Nikon lenses can be mounted on canon cameras but Canon Lenses can't be mounted on Nikon cameras.
I hope that all makes sense.
additional info here: http://en.wikipedia.org/wiki/Flange_focal_distance
Otis Grapsas
Carbonite Member
There are equations for DOF, we don't have to argue about it.
But the problem is that many people do not mean DOF when the say DOF, they mean how much blur their background will get. You can calculate that from the DOF equations if you know the background distance. If you are on 1080p, use a COC = sensorwidth/1920 for single pixel sharpness (DOF) and a COC of 32x that COC if you want to know your 32pixel blur level. Using the normal focus distance for everything. You will get new minimum and maximum distance values out of the DOF equations. Out of that range the blur is greater than 32pixels.
But the problem is that many people do not mean DOF when the say DOF, they mean how much blur their background will get. You can calculate that from the DOF equations if you know the background distance. If you are on 1080p, use a COC = sensorwidth/1920 for single pixel sharpness (DOF) and a COC of 32x that COC if you want to know your 32pixel blur level. Using the normal focus distance for everything. You will get new minimum and maximum distance values out of the DOF equations. Out of that range the blur is greater than 32pixels.
Starshine Video
Well-known member
I guess I kinda glossed over my main point, which is; a 50mm lens is a 50mm lens is a 50mm lens, they don't actually change focal lengths based on what camera or mount it is on. The reason is is a Telephoto on a super8 camera, a portrait lens on a Micro 4/3, a "normal" on FF35 and Wide on a Medium Fomat, has everything to to with the size of the Imager/sensor/film gate. And nothing at all with the flange focal distance.
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