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-   -   Companion to HD200 (https://www.dvinfo.net/forum/jvc-gy-hd-series-camera-systems/91675-companion-hd200.html)

Tim Le April 17th, 2007 11:22 AM

According to the pics that Chris posted here, the focal length is 5.8-81mm (14X). And according to Fujinon, the conversion factor for 1/2" to 35mm photo is .178. So that makes 5.8 equal to about 32.6mm, which isn't that wide but it matches the Z1U, HVX200 and XH-A1.

The reason they were able to fit such a small 1/2" lens on there is probably because it's 14X and not 18X and the max aperture is slightly smaller than Fujinon's ENG XDCAM-HD lens (f/1.9 vs f/1.4).

Guy Barwood April 17th, 2007 03:38 PM

I didn't think it would be 6.8. That would be a 11.94x zoom. At 5.8 it is a 14.00x zoom, as said before.

I was basing my 1.3" & 35mm conversions from Stephans 6.8 results. Clearly if they were wrong too, so were mine for 5.8.

My lens on my GY-DV500 (1/2") is about 7mm so 5.8 would be welcoming wider for me.

Stephan Ahonen April 17th, 2007 10:25 PM

Mmkay, 5.8mm it is. That actually is pretty decently wide, I take back what I said about that. On a side note, I think it's hilarious that they stamped the cinealta logo on that thing.

I use diagonal angle of view for my focal length conversions, Fuji may be using horizontal or vertical in theirs. Here's the math I use:

35mm is 36x24mm, Pythagoras tells us the image circle diameter is sqrt(36^2+24^2) = about 43mm, which is 1.7 inches.

1/3", 1/2" and 2/3" are named after their diagonal lengths, so simply divide them into each other or 1.7 to get the multiplier. 1.7/(1/3) = 5.11, 1/2" is 3.4, and 2/3" is 2.56.

For angle of view I use this angle of view calculator and use pythagoras + some algebra to get actual width and height for image sensors.

Tim Le April 18th, 2007 12:10 AM

Quote:

Originally Posted by Stephan Ahonen (Post 662357)
1/3", 1/2" and 2/3" are named after their diagonal lengths, so simply divide them into each other or 1.7 to get the multiplier. 1.7/(1/3) = 5.11, 1/2" is 3.4, and 2/3" is 2.56.

I think this might be causing the error in your calculations. The type designation (1/3", 1/2", etc.) isn't the diameter of the image circle of the sensor but rather the outer diameter of the long glass envelope of the old camera tubes, which his about 1/3 bigger than the sensor size. So unfortunately you can't just ratio it from the 35mm still photo image diameter. It's all very confusing. Here's an article that explains it pretty well: article.

Either way, it's good to see that this camera comes with a decently wide standard lens.

Stephan Ahonen April 18th, 2007 12:43 AM

Hmm, I did not know that. Learn something new every day I guess.

Guy Barwood April 18th, 2007 01:30 AM

Isn't the 1/3" etc a measure of the diagonal dimension of the sensor? Hence why we are told it has a 1/3" sensor?

Joshua Frye April 18th, 2007 07:36 AM

Looks like a decent camera with a lot of features.

The JVC PRO HD series still offers a LOT more for me though. Interchnageable lenses really do it for me ( I bought an XL-1 when if first came out and own(ed) most of the XL lenses), and having to work with a fixed lens is unacceptable. If Sony had taken a DSR-250ish body and VF, added these HD features, AND offered interchangeable lenses, then we'd have a camera.

Guy Barwood April 18th, 2007 07:48 AM

lol, I'd guess that would kill a lot the sales of their 330/350/355 though.

Joshua Frye April 18th, 2007 08:15 AM

Got me there. The big-boy XDcams are excellent, but the old 250s didn't cost in the neighborhood of 20k either.

Tim Le April 18th, 2007 08:50 AM

Quote:

Originally Posted by Guy Barwood (Post 662394)
Isn't the 1/3" etc a measure of the diagonal dimension of the sensor? Hence why we are told it has a 1/3" sensor?

Unfortunately Guy, it's not. The inch type designation goes way back to the days of the vacuum tubes. It's a measure of the glass tube envelope, but the usuable imaging area is less that that tube diameter. When CCDs came around, they sized them to this same usuable image area so that they could use the same lenses. Of course, we don't use vacuum tubes anymore but they're still using this crazy inch type designation. Another thing to make it more confusing is that a native 16:9 sensor isn't the same size as a native 4:3 sensor whose dimensions are show in that DPReview article.

Anyhow, I thought Sony might have come up with a 1/3" compact shoulder mount interchangeable lens camera to compete against JVC but it looks like their strategy is to go straight to 1/2". The good news is JVC is going to have to do something to respond to this camera and maybe with the new owner's backing they will.

Guy Barwood April 18th, 2007 09:41 AM

As it stands JVC win on form factor and lens (outside the body), Sony win the imaging and electronics (inside the body, in theory at least), but that's not until this beast is on the street some 6-9 months away. Having said that I can happily wait that long, if not another 6-9 months again without a problem. I might want HD, but I certainly don't need it.

Stephan Ahonen April 18th, 2007 07:42 PM

Quote:

Originally Posted by Tim Le (Post 662524)
Another thing to make it more confusing is that a native 16:9 sensor isn't the same size as a native 4:3 sensor whose dimensions are show in that DPReview article.

16:9 chips are designed to have the same diagonal width as the 4:3 chips. If you take the diagonal length of a 4:3 chip and throw the pythagorean theorem at it you can get the dimensions of a 16:9 chip. It ends up being a little wider and not as tall. Like the move from tubes to chips, this was done so you could use the same lenses for 4:3 and 16:9 (since the imaging circle size can stay the same), though for HD you need new lenses anyway because the old SD lenses aren't designed for HD tolerances.

Joshua Frye April 19th, 2007 08:41 AM

Well in anycase, and getting back to the thread topic, competition at this level seems to be picking up. With all the variety of players on the scene, and the rapid pace of development, the future for low-cost video aquisition seems to be bright. JVC and Panasonic seem to be heading in the right direction for those who like Pro shouldermount form factors. Canon and Sony (Sony in the low end) seem to be going for ultra feature rich palmcorders.

At least thats what it looks like to me.


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