DV Info Net - Surprising Lens Options!!

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- - Surprising Lens Options!! (https://www.dvinfo.net/forum/jvc-gy-hd-series-camera-systems/43262-surprising-lens-options.html)

Hi Micheal,
I posted these three/four days back, I think you have seen them, below nis the link

http://www.dvinfo.net/conf/showthread.php?t=52880

Quote:

Originally Posted by Yusuf Thakur

Can one post pictures on this forum, I can post some comparitive grabs. We shot the same scene with exactly the same lighting and setup just changed the lens, from standard to nikon with the adapter. The results I guess would be helpfull to those looking at doing this. (Mounting Nikon Lenses)

I'm sure Chris could post them for you - I have seen many posts where he offers to do this. I think you can PM him.

I have already done that, with links pls check this in the forum
http://www.dvinfo.net/conf/showthread.php?t=52880

These are not the frame grabs but the setup, will post these on Saturday.

Quote:

Originally Posted by Barry Green

I didn't get the hard copy, but I had read them online, and that's where I got the 80-to-100 lp/mm figures for regular (2/3") lenses...

And we should all keep in mind -- this gives us something to do until the camera comes out, but it's all theoretical. The proof will be when we actually test the darn thing. If it looks great, I won't care whether the MTF or lp/mm hold up! ;)

Quote:

Originally Posted by Barry Green

Doing some calculations with Graeme, it looks like the lens will need to resolve at least 133 line pairs per millimeter in order to deliver the full resolution possible from the JVC's 1280x720 chip.

I know this is an old thread, but I got to it while researching about the HD100 lens and saw this comment. I find it hard to believe normal 2/3" lenses resolve 80-100 lp/mm when Zeiss Digiprimes resolve only 56 lp/mm. I’m sure the Digiprimes will be sharper and better than any 2/3” lenses out there.
Based on this fact, I also find the found 133 lp/mm for the HD100 a weird number. If the 2/3” 1920x1080 Cinealta get the best results with a 56 lp/mm lens, I don’t think the 1280x720 HD100, even if 1/3”, needs almost 3 times more resolution at 133 lp/mm.
Just speculating, but something tells me the numbers in this thread are somewhat off.

BUMP. Just figured I'd revive this. Does anyone have any new reports on using alternate lenses on the HD100? (Not so much the 13x option, but 1/2" lenses or others?)

I've been trying to dig up info on other options myself. There is one I was wondering about, a lens for the GY-X3 and Panasonic AJ-D215 cameras: T14X5.5BRM. It's one of the few native 1/3" lenses I could find. Certainly an older model, but someone out there might have one they could try. The big questions are: does the quality hold up for HD, and is the 1/3" mount the same as the HD100?

MTF (modulation transfer function)

Quote:

Originally Posted by Michael Maier

I find it hard to believe normal 2/3" lenses resolve 80-100 lp/mm when Zeiss Digiprimes resolve only 56 lp/mm. I’m sure the Digiprimes will be sharper and better than any 2/3” lenses out there.
Based on this fact, I also find the found 133 lp/mm for the HD100 a weird number. If the 2/3” 1920x1080 Cinealta get the best results with a 56 lp/mm lens, I don’t think the 1280x720 HD100, even if 1/3”, needs almost 3 times more resolution at 133 lp/mm.
Just speculating, but something tells me the numbers in this thread are somewhat off.

The numbers are not off but its the way you use them.
Testing a lens for MTF performance usually involves projecting an image through the lens from a graticle, onto a screen and the MTF is then measured by a sensor.
A figure of 80%-99% (the measured difference between the black and white portion of a line pair)
would be thought of as reasonable measured at the centre.
When people say that the Zeiss resolves only 56 lp/mm this is not strictly true. In actual fact the Zeiss can probably resolve around 200 lp/mm.
The figure of 56 lp/mm only refers to the standard by which HD lenses are measured and , hence the graticle that is used during MTF testing.

Incidentally, the standard for 35mm motion picture lens testing is only 20 lp/mm, However when I was at Optex we used a 40 lp/mm standard.

I hope this makes things a bit clearer.