Tagged with etc - 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.

Extended Tele Converter (TEC) Mode wont activate on GH3. Any advices?

pedrinho — Thu, 06 Mar 2014 14:40:16 +0000

Hi there!

I went to film racing event last weekend with my GH3. I've remembered playing with this option on my GH2 but then never require it really. I wanted to give it a go on this event.. and it dosen't activate. I mean it's available and goes to "ON" mode in menu but does not affect picture at all (it's still same focal distance being displayed.)

I have being played it with different manual recording modes and while in preveiw and actuall recording mode. Tried different codecs and resolutions. I've swaped and tried 3 different lenses (20mm lumix, 35-100 lumix and 45olympus). I went to menu and used "Reset" option to bring camera to factory settings. No result

Is there something I'm missing any advices before getting myself introduce to Panasonic customer service :) ?

Thanks

FS: BMCC (EF) + 2x 128GB SSD + RESOLVE

sicovdplas — Tue, 28 May 2013 07:20:31 +0000

He guys

i'm selling my bmcc, ef mount, i've used it on 1 project, run hours are 10 +- No damage no problems what so ever, i preffer selling it face to face in Holland, altho all options are open.

Package: Original boxing, manuals etc. BMCC EF Mount 2x Kingston v200 128GB SSD's V-Mount D-Tap to BMCC power unit (Cable)

Optional with Or without davici resolve, up to the buyer.

with resolve 2800€ without resolve 2600€

Direct contact => srvdplas@gmail.com open to offers

Lumix gh3 blurry display problem ?

Max_Kislinsky — Tue, 04 Jun 2013 13:10:43 +0000

I have a problem with my Limix GH3 camera. The picture which I see through the viewfinder or internal display is blurry. Like it have been downscaled somehow. Especially it's obvious then I use non-kit lens and Ex. Tele Conv mode. Therefore it's impossible to catch focus right. The picture becoming perfectly sharp when I start video recording so this in not a problem with viewfinder or display. Do you known something about this issue? Maybe there is some workaround to cope with it?

ETC Mode Discussion

AlbertZ — Sun, 29 Apr 2012 15:04:20 +0000

I own only a GH1 (no etc mode) but I'm planning to buy a GF2, which has only x3.2 ETC mode (while GH2 has more options on ETC). I like very much old fast lenses like c-mount tamron 4-12 zooms, pentax 6-41, it would be great to use them (they're very cheap, you know) on GF2, however most of the demos I've found on the net are GH2-specific,and I don't know what are ETC drawbacks. A x3.2 could be too "extreme" in terms of video quality? It would be a good idea to use a c-mount 4-12 tamron f 1.0 on a GF2 x3.2 ETc (24-72mm!!) or video quality would be worse than a common kit lens panasonic 14-42 f3.5?

GH2 ETC-mode noise penalty

balazer — Thu, 03 Nov 2011 21:06:56 +0000

I have a 50-mm lens, which gives almost the same field of view as the Lumix 20-mm lens with ETC turned on, so I did a little experiment to see how much noise ETC adds. This was just eyeballing it, i.e., not scientifically rigorous. Tests were performed with 100-Mbps intra recording and NR at -2.

The ETC noise penalty is: 2 and 2/3 stops. Specifically, the picture with ETC off at 3200 ISO looks about as noisy as the picture with ETC on at 500 ISO.

What I find interesting about this result is that increasing the sensitivity by a factor of 6.4 increases noise about as much as using 6.76 times as much sensor area (2.6^2) reduces noise. In other words, the GH2 is making very good use of those 16 million pixels when it downsamples to 1080p, giving nearly all the reduction in noise that you would hope to have from using a larger sensor area and correspondingly larger lens aperture.

Though there definitely is aliasing in the downsampled picture. The aliasing is not as bad as in the GH1's 1080p, or in the Canon 5dmkii, but it's there, and it makes you see things that you shouldn't be seeing. I can put together a little demonstration video if anyone is interested, but that's a separate topic.

GH2: ExTele check disable to get ETC and HDMI out?

DirkVoorhoeve — Sun, 18 Nov 2012 13:53:02 +0000

Disclaimer: Tried finding an old topic about this but couldn't find it. If it's there, please excuse me for starting a new one and link to the topic.

I like using my camera with a B4 lens and exTele mode set to on. Now I want to use this with my HDMI viewfinder and I remember this used to be possible with the first firmware version. I couldn't find it anywhere in the new one, so I loaded the firmware v1.0 into Ptool 3.65d and checked the 'ExTele check disable' box in the patches for testers. Now, when I connect my GH2 to the HDMI monitor the ITC gets disabled, but when I hit record, it will go back to ETC mode. Unfortunately the camera locks up and the only way to solve this is to remove the battery.

My questions:

What can I do to prevent the from locking up. I thought this patch was pretty reliable? I also tried it with Ptool 3.63d and no other patches but the Extele check disable patch, but still the same problem. I want to record in 1080i50 FSH mode.
I remember it would stay in ETC mode also with live view, but can't remember how I did it. Any tips?

Does ETC Mode Affect Rolling Shutter Jello?

mpgxsvcd — Wed, 02 May 2012 02:32:09 +0000

This video shows the Jello Effect when ETC mode is used. I used the 14-140mm @ 35mm plus the 3.9x 720p ETC and the 14-140mm @ 140mm to give the same equivalent field of view.

I filmed passing trucks at the same speed with 1/250th shutter speed. I could not tell any difference in the angle of distortion between the two clips. A lot people think that rolling shutters only affect the video if the camera is moving. It will actually slant vertical lines if the subject is moving fast enough horizontally even if the camera is still.

I do not believe that using ETC mode over just the lens has any affect on the rolling shutter jello effect. Theoretically sensor readout speed is the only thing that could affect it. Using ETC mode should reduce the number of pixels that the camera reads. However, that does not appear to help at all. Instead it appears to read the entire sensor in the same time that it takes to read it without using ETC. Maybe it is just throwing out the data the ETC mode doesn't need?

Proposition about variable ETC mode

stuckvoxel — Wed, 14 Dec 2011 00:55:56 +0000

I'm here to make the case again to Vitaliy to figure out how to control the GH2's cropping and downscaling features, and allow us to change them through ptool. (If it's not obvious, this post concerns video, not stills.)

There's a universe of old C-mount lenses out there, in 1/3, 1/2, 2/3, 1 inch, and 16mm, each of which makes a different sized image circle. To use each of these lenses to their fullest, you want your camera's sensor to be slightly smaller than that image circle. With the GH2 we have a camera with the capability to have any sensor size you want, up to 4/3. The "universal-format camera" is in our hands, we just need some awesome hardware hacker to unlock it!

The "proof" that the GH2 is capable of this is found in the facts that 1) the GH2 is currently able (has the processing power) to take the entire 4/3-inch, 4976x2800, 16:9 portion of the sensor, and downscale that to 1920x1080 or 1280x720 (did I see that some of you had got the GH2 to use other sizes?); and 2) the GH2 is also capable of using only part of the frame, with no downsampling (as demonstrated in ETC mode). So it's not much of a stretch to believe that the GH2 is capable of taking any 16:9 subset of the sensor's pixels AND downscaling that to any 16:9 pixel size! (Indeed, by de-centering the crop region, you could correct for the inevitable misalignment between lens and sensor.)

So the challenge to you, Vitaliy, is to figure out how to choose that subset of pixels and add that item to ptool. Then, for example, I can take the 4160x2340 subset of the GH2 sensor's 4976x2800 pixels* that my cheap, fast, good 1-inch format C-mount lens can cover, and get great video. Right now, the only way to use this lens is to crop the video in post, which kills resolution (up-sampling, yecch) and wastes bandwidth encoding parts of the frame that are going to be cropped away.

(*yes I know it's more complicated than that, since it's a Bayer sensor, and the full sensor is more like 4976x3456, but you know what I mean.)

Further, as balazer pointed out in the posting "GH2 ETC-mode noise penalty" ( www.personal-view.com/talks/discussion/comment/27293 ) the GH2's downsampling achieves 95% of theoretical efficiency at noise reduction by binning. So in my example above, where I'd be using about 70% of the area of the whole 16:9 portion of the sensor, my lens would have only a half-stop noise penalty compared to some way overpriced lens that could light the whole 4/3 frame--if such a lens even exists in this focal length. And spatial resolution (as in lines per picture height) would still be excellent, since the downscaling to 1920x1080 would still be a reduction to around 45% of the raw image. So the result would look far better than the existing ETC mode.

Suddenly, all that old C-mount glass, as ridiculously overpriced as some of it has become, will finally be worth using. No more dark corners. No more frustration with not knowing what image format a given C-mount lens that you find on eBay was designed for. If it's a C-mount lens, your GH2 would be able to use it to full advantage. As a side effect, this would encourage more reasonable pricing of Noktons, Noktors, and the rare cine lens that happens to fully cover 4/3.

Here's hoping that with Panasonic's release of the v1.1 firmware, this level of control will finally be possible! Perhaps this feature can be implemented as a modification to ETC mode, which would provide a handy way of turning this feature on and off through the camera's menu in the field.

Thanks again, Vitaliy, for all you've done.

GH2 and Wildlife filmmaking

Faudel — Tue, 25 Oct 2011 22:29:43 +0000

@driftwood or any user of the nice driftwood hack !
I dont own a GH2 yet so...
Could you post videos using the "intrhack" ,ETC mode and a long focal lens or even extreme telephoto lens(the longest you have :p) ?
It seems the hack could open mindblowing possibilities in wildlife filmmaking,for example; capture some amazing animal behavior without being intrusive where cameras like Ex1 are still kings due to their 1/2" sensor.
Thank you.

ETC mode hack possibilities

sphipps — Tue, 26 Jul 2011 19:35:49 +0000

whats the possibility of changing the aspect ratio of the ETC mode with the hack? could that allow higher resolutions?

ive asked this question a few times a few diff places without a response. feel free to delete the topic if the answers already out there.