Tagged with pixel - Personal View Talks

Which CCTV lens for wide angle fisheye use ?

TruHype — Fri, 26 Jul 2013 05:31:26 +0000

Hello everyone,

I've recently started to get interested in C mount (CCTV) lens, for they are fast, wide, and cheap. So I wondered, is there any CCTV lens that I could use as a Fisheye (and get the same effect as the Panasonic 8mm f3.5, but faster) ? Here's a few lens I've found looking on the internet :

Rainbow 3.5mm 1.6
Tamron 4-12mm 1.2
Pentax 6mm 1.2 (+ wide conversion lens x0.45)

Wanted effect :

The GH2 exact m4/3 sensor crop is x1.86.

So I would like to get the same widness as the Panasonic 8mm or any 8mm Fisheye (Samyang, Peleng, Rokinon...) :

Panasonic 8mm : 8 x 1.86 = 14.88mm equivalent (no need for ETC mode)

Rainbow 3.5mm : 3.5 x 1.86 = 6.51 -> 6.51 x 2 = 13mm equivalent

Pentax 6mm : 6 x 1.86 = 11.16 -> 11.6 x 2 = 23.2mm equivalent -> 23.2 x 0.45 = 10.44mm equivalent

x 1.86 : GH2 Sensor Crop

x 2 : ETC tele conversion mode crop (to cover vignetting)

x 0.45 : Wide convversion lens

Does that mean we could use any CCTV c mount lens instead of the Panasonic lens to get the wide fisheye effect ?

A few videos :

Lenses :

C mount lens (1/2") work well on the GH2, but I heard that the CS mount lens (1/3") would still have really heavy vignetting because even with the ETC mode it would not cover entirely the GH2 sensor. Is that true ?

Interesting CS mount lens, but 1/3 inch : http://www.ebay.fr/itm/TAMRON-Manual-Iris-CCTV-Lens-3-0-8mm-1-1-0-ASPHERICAL-C-Mount-3-Mega-Pixel-/261248954560?pt=UK_CCTV&hash=item3cd3a6b0c0

I would use the fisheye to film Skateboarding.

Thank you.

Resample GH4 8 bit 4:2:0 to 10 bit 4:4:4 on PC

schprox — Thu, 24 Jul 2014 23:46:02 +0000

Has anyone one been able to do this on a PC?

i;ve tried it in every way to do it but no luck

I tried this guy apps on a mac and it works perfectly

How can we do this on a pc? anyone knows how to do pixel summing? Thanks

Canon 75 mega pixel camera coming soon?

driftwood — Mon, 22 Jul 2013 10:12:14 +0000

Rumour has it that a new Canon 75MP Pro DSLR is in testing with a possible launch next year.

http://www.cameraegg.org/rumors-canon-75-mp-pro-dslr-is-in-testing/

Smoothest hack, intra, macroblocking... Noob questions !

TruHype — Wed, 03 Jul 2013 18:17:07 +0000

Hello,

Attention, noob questions ahead !

I would like to know a few things : - Which is the smoothest hack on the GH2 ? (All the detail, no macro-blocking) - What does "Intra" or "AVC-Intraa" mean ? - What is Auto Quantitizer ? I'm not sure if a higher number means a better image (lower compression) or it's the inverse. What is better, AQ0 (all to motion), or AQ4 (all to details) ? - What does GOP stand for, and there is "Low-GOP", but then does that mean there's "high GOP" ? What are 12/15 GOP, 3 GOP and 6 GOP ? - What are P-frames, B-frames... ? - What is "Matrix" and "444 Matrix" ? - On some settings there's written "14-16 QP", or "QP16". What does QP mean ?

I've not seen much smooth looking GH2 videos on Youtube (unlike the canon videos), lots of them have a lot of macroblocking or whatever and causes the video not to be smooth, and sometimes there are some sort artifacts (I think it's because of the compression or something...). I'm a bit of a pixel-peeper :P Could someone explain me the causes of the un-smoothness, and why are some videos really clean compared to others ?

Example of smooth videos I've found :

(his videos are all smooth and clean)

PS : Can someone give me the link to download the 244mb/s hack ?

And here on EOSHD there's an article about Intra :

http://www.eoshd.com/content/4452/gh2-gets-avchd-intra-at-176mbit

But I still don't understand the difference between the 176mbit so-called "Intra" hack and any other one ! I'm confused...

Please answer !

Thank You.

Hot/Stuck/Dead Green Pixel in Video Footage

matt_gh2 — Fri, 21 Dec 2012 22:28:46 +0000

I'm hoping someone has some knowledge on this problem and hopefully a solution. I've got a "green dot" appearing in all my video footage. It's in the same location and doesn't move. It's not always visible, but when panning, I'll see it if it goes over certain types of colors, focus, etc. There's also another gray/translucent dot. I've eliminated the following possible causes (different SD Cards, with or without Hack, different Lens, & different Monitor footage is viewed on.)

So I guess this is what is called a "Hot Pixel"?

How do I fix this? Thanks.

Strange dots, diagnosing help needed

Ruub — Mon, 10 Sep 2012 09:38:43 +0000

Hello guys,

I have a problem with my GH2.

Made several photos, Tried different lenses, different subjects and even different SD cards (just to cancel out all the variables). In every photo though, these strange purple dots pop up in the right corner of the image. My conclusion: the problem must be with the sensor. Visually checked the sensor, could not see anything on the surface. Tried sensor cleaning out of the menu: did not help. After that I tried very carefully with a dust blower to blow any possible dust particles of the sensor: did not help either. Forgot to mention that I also cancelled out the possibility of dead pixels. On a photo with the lens cap on, nothing is seen...

So I guess, (sticky) dust? Or can anyone with more experience in this field give me an idea of what is causing this problem.

Thanks a lot in forward,

Ruben

Pixel pitch size & Sensor Refresh rate

stoney — Wed, 29 Aug 2012 09:18:27 +0000

Here is pixel pitch size information.

iPhone4S 1.4µm
LX7 1.85µm
X10 2.2 µm
RX100 2.5µm
GH2 3.6µm
NX200 4.25µm
650D 4.3µm
5N 4.75µm
X-Pro1 4.8µm
D800 4.88µm
X100 5.5µm
5DmkIII 6.25µm
BMCC 6.5µm

Would a bigger pixel pitch take longer to refresh a sensor? Or technically more difficult to implement faster refresh rate?