Can it use existing XL-1/2 Lenses?

Chris Hurd · November 5th, 2005, 06:23 PM

Quote:

Originally Posted by Mike Tesh

I can't understand how for years Canon can build film quality optics, which are being used nowadays on 12+megapixel DSLRs and suddenly when it comes to the XL series lenses they can't resolve a 2 megapixel resolution.

Resolving for 35mm film and resolving for standard definition DV are two very different things. The older Canon XL series lenses were made for 720x480 DV, which is much less than a megapixel image frame. If those old XL lenses could resolve for two megapixels, it would have meant that their cost would have been much higher, and that you'd have paid for something you couldn't use. Those old XL lenses resolved for 720x480 because that's all they needed to be... and that's all we ever paid for (remember, all of the older XL lenses were well below $2000, practically a give-away price compared to other broadcast video lenses).

Canon certainly can build high-res video lenses... they've been in the HD video lens business for years now. You could buy five XL2 camera kits for the price of one of those HD lenses.

XL series lenses were dirt cheap, the most expensive one was never more than $1800 (the 20x IS II), and they needed to resolve only 720x480, which they did quite well.

Also, for the record, at the PhotoPlus Expo in NYC last month, I had an opportunity to put an XL 3x on the XL H1 and the results were just as I expected... too soft to be of any use at all. As the H1 starts to ship to owners who have other XL lenses, they'll confirm what I'm reporting here as they're able. Hope this helps,

Steve House · November 6th, 2005, 09:20 AM

I recall reading somewhere that a 35mm still frame has the resolution equivalent to a digital image sensor with something like 35000x50000 pixels. Plus larger image circles are harder to get uniformly sharp and aberration free than are smaller ones. So why does a zoom that needs to be sharp over an area about 1/3 the size and resolving a mere 720x480 start at more than 4 times as expensive at the entry level and go up exponentially from there? If we even things out image size-wise so we're looking at lines per inch resolution instead of raw pixel count, the lens shooting on a 35mm still frame is required to have more than 10 times better resolution than a lens for a 1/3" native HD 1920x1080 sensor would. Yet they're doing that at small a fraction of the video lens cost. Think it has more to do with a perceived "deep pockets" in the entertainment industry than actual manufacturing and R&D costs, sort of like the Pentagon's $500 hammers?

While $1800 is "dirt cheap" compared to other professional video lenses, a lens with a similar zoom range, better low-light abilities, and 10 times the native resolution can be had for 35mm still cameras for $100-$500.

Chris Hurd · November 6th, 2005, 01:20 PM

Quote:

Originally Posted by Steve House

While $1800 is "dirt cheap" compared to other professional video lenses, a lens with a similar zoom range, better low-light abilities, and 10 times the native resolution can be had for 35mm still cameras for $100-$500.

Well, the question in general then is really, why do video lenses cost so much more than photo lenses. Somewhere I saw a great explanation for this from Graeme Nattress. I'll have to get him to come back in and explain it.

Certainly one significant part of the answer is the zoom motor... there's no motorized zoom on any removeable 35mm still photo lens, but of course there's a lot more to it than just this.

See also this thread, the input from Chas Papert and Graeme:

http://www.dvinfo.net/conf/showthread.php?t=50525

By the way I always defer to these guys, if it looks like something I'm saying conflicts with them, you should take their word over mine every time.

Graham Hickling · November 6th, 2005, 09:34 PM

Interesting discussion. Part of the explanation will be that while SD requires only 720x480 resolution, that resolution is required within a MUCH smaller area that the 24mm by 36mm area that a standard 35mm still camera lens has to work with.

So in that sense, the video lens still has to provide a high resolution, just over a rather narrow angle angle.

If I had a bit more time I'd do the math, but hopefully you'll understand what I'm on about.

Barry Green · November 7th, 2005, 05:29 AM

A 35mm movie film frame is about 22mm wide; a 16:9 1/3" CCD is about 5.24mm wide.

Assuming a movie frame is scanned at 4k resolution, that puts 4,000 pixels (or thereabouts) in 22mm, or about 182 pixels per mm.

On a standard-def 1/3" CCD you're talking about 720 pixels in 5.24 mm, or about 137 pixels per mm.

But in high def, you're potentially fitting 1440 pixels across, or nearly 275 pixels per millimeter! On the vertical, it's even worse -- 1080 lines in 2.95mm, or 366 pixels per millimeter. TWICE as dense as 35mm cine film!

A high-def 1/3" chip then needs lenses that are substantially sharper than even cine lenses need to be. Using a standard-def lens runs the risk of not resolving nearly enough for the incredibly tight demands of 1/3" high-def.

And, totally off-topic but tangentially related, it also makes me wonder if we'll ever see that rumored high-def GL3. The GL1 and GL2 were 1/4" CCDs. Would it even be possible to make a 1/4" high-def CCD? Maybe 1/3" is as small as high-def can go; at 366 pixels per millimeter, we're already being limited by optics as to the ability to resolve the image. Making the chip smaller and still able to resolve the full resolution may actually be impossible.

Jean-Philippe Archibald · November 7th, 2005, 08:39 AM

Interesting... So, since the lenses seems to be the most expensive part of HD cameras, in order to cut the price to enable everyone to buy an HD cam, manufacturers will have to put "bigger" CCDs? It could be a really interseting side effect of the HD revolution.

Mike Teutsch · November 7th, 2005, 09:47 AM

Quote:

Originally Posted by Jean-Philippe Archibald

Interesting... So, since the lenses seems to be the most expensive part of HD cameras, in order to cut the price to enable everyone to buy an HD cam, manufacturers will have to put "bigger" CCDs? It could be a really interseting side effect of the HD revolution.

Very interesting point indeed! I assume that larger CCD's are prohibitively expensive to produce at this time. But, we know that most all things come down in price and go up in quality and durability over time, and that development time is decreasing exponentially.

Larger CCD’s and faster data transport systems could really change the way we shoot video soon!?!? It does seem that making larger CCD’s will be preferable to much more expensive lenses. And, lens making is what you might call a “hard industry,” and is not going to undergo rapid updating of procedures and methods. Dang things will still have to be ground and polished out of the finest materials.

The future looks interesting indeed!

Mike

Thomas Smet · November 7th, 2005, 10:17 AM

Barry,

With pixel shift on SD cameras isn't there extra small points 1/2 the size on the CCD's that end up giving much higher detail than 720x480? If a SD lens cannot handle more detail than 720x480 then wouldn't pixel shift be kind of useless since shifting the CCD's wouldn't gain any extra detail anyways because the lens would be limited to 720x480?

I do think certain SD lenses can resolve more than SD resolution. It may not be as much as a HD lens but it might still look good. Even current 1/3" HD lenses don't seem to resolve the full 1440x1080 anyways.

I will be very interested to see resolution tests of a SD lens on a HD camera to see how bad it actually is. Maybe it would only be a little bit softer kind of like a diffusion filter.

What I do know is that the lens on the DVX100 is a SD camera with a SD lens but by using the pixel shift the reel stream product does gain a lot more detail to create a HD image. Here the SD lens does seem to resolve a lot more detail than just SD.

Steve House · November 7th, 2005, 10:49 AM

Quote:

Originally Posted by Jean-Philippe Archibald

Interesting... So, since the lenses seems to be the most expensive part of HD cameras, in order to cut the price to enable everyone to buy an HD cam, manufacturers will have to put "bigger" CCDs? It could be a really interseting side effect of the HD revolution.

Well, several 35mm still digital cameras have hit the market recently with 24mmx36mm image sensors. Gotta be just a matter of time before they make it over to video.

Mathieu Ghekiere · November 7th, 2005, 12:50 PM

Quote:

Originally Posted by Steve House

Well, several 35mm still digital cameras have hit the market recently with 24mmx36mm image sensors. Gotta be just a matter of time before they make it over to video.

Isn't that a fact already?
I think ARRI and another company (Sony? Panasonic? Neither? don't know for sure) already has a camera with a 35mm sensor. I believe I read it once, not sure.
Still, I don't want to know the price of the thing at this moment ;-)

Hse Kha · November 7th, 2005, 04:59 PM

The Panavision Genesis has a 35mm size sensor.

See:-

http://www.hollywoodreporter.com/thr..._id=1000527854

Graham Hickling · November 7th, 2005, 08:17 PM

I gather the obstacle to putting a large chip into a video camera on the cheap is that you can't achieve an adequate frame rate. Large-sensor 50fps requires a MUCH more expensive chip than the typical digital still camera uses.

But meanwhile, people that dont require real-time framerates (e.g. stop-motion animators) do indeed use digital still cameras to generate super-high resolution footage.

Christopher Glaeser · November 7th, 2005, 11:42 PM

"I gather the obstacle to putting a large chip into a video camera on the cheap is that you can't achieve an adequate frame rate. Large-sensor 50fps requires a MUCH more expensive chip than the typical digital still camera uses."

It is possible to keep the data rate the same by building large sensors with large pixels and same pixel count (versus leaving the pixels the same size and increasing the pixel count). Benefits of such an approach would include improved noise characteristics and allow narrow DOF.

Steve House · November 8th, 2005, 11:25 AM

Quote:

Originally Posted by Mathieu Ghekiere

Isn't that a fact already?
I think ARRI and another company (Sony? Panasonic? Neither? don't know for sure) already has a camera with a 35mm sensor. I believe I read it once, not sure.
Still, I don't want to know the price of the thing at this moment ;-)

Yep - the Canon EOS-1Ds Mark II has a 35mm full-frame, 16.7 megapixel sensor. B&H price about $7500 USD for the body only.

Graeme Nattress · November 10th, 2005, 12:51 PM

Basically, as Barry puts it, it comes down to pixel size on the sensor. As you try to fit more pixels (ie HD) into a smaller chip, ie 1.3", the resolution, in line pairs per mm, that the lens has to be able to pass, is necessarily greater and greater.

Although lens cost is usually proportional to the square of the radius, hence bigger lenses for bigger chips being exponentially more expensive (and lenses for smaller chips very much cheaper), this is not really mitagated by the extreme sharpness demands of HD video on 1/3" sensors.

That's why you get affordable "HD" lenses that are only sharp in the middle, not at the edges, have severe chromatic aberations, and breathe heavily on pulling focus.

Canon make great lenses for 35mm stills cameras, but even so, you need to get the expensive L series lenses to fully do justice to the smaller pixels on the 20D compared to, say the 5D or 1dsMK2. Although the sensor is smaller on the 20D, so if the lens is a bit soft at the edge, you don't see it anywhere near as much.

Hope that helps,

Graeme

November 6th, 2005, 09:20 AM	#17
Steve House Inner Circle Join Date: Mar 2005 Location: Hamilton, Ontario, Canada Posts: 5,742	I recall reading somewhere that a 35mm still frame has the resolution equivalent to a digital image sensor with something like 35000x50000 pixels. Plus larger image circles are harder to get uniformly sharp and aberration free than are smaller ones. So why does a zoom that needs to be sharp over an area about 1/3 the size and resolving a mere 720x480 start at more than 4 times as expensive at the entry level and go up exponentially from there? If we even things out image size-wise so we're looking at lines per inch resolution instead of raw pixel count, the lens shooting on a 35mm still frame is required to have more than 10 times better resolution than a lens for a 1/3" native HD 1920x1080 sensor would. Yet they're doing that at small a fraction of the video lens cost. Think it has more to do with a perceived "deep pockets" in the entertainment industry than actual manufacturing and R&D costs, sort of like the Pentagon's $500 hammers? While $1800 is "dirt cheap" compared to other professional video lenses, a lens with a similar zoom range, better low-light abilities, and 10 times the native resolution can be had for 35mm still cameras for $100-$500. __________________ Good news, Cousins! This week's chocolate ration is 15 grams!

November 7th, 2005, 08:39 AM	#21
Jean-Philippe Archibald Trustee Join Date: Sep 2003 Location: Saguenay, Québec, Canada Posts: 1,051	Interesting... So, since the lenses seems to be the most expensive part of HD cameras, in order to cut the price to enable everyone to buy an HD cam, manufacturers will have to put "bigger" CCDs? It could be a really interseting side effect of the HD revolution. __________________ Jean-Philippe Archibald http://www.jparchibald.com - http://www.vimeo.com/jparchib

November 7th, 2005, 11:42 PM	#28
Christopher Glaeser Major Player Join Date: Sep 2005 Location: Pleasanton, CA Posts: 258	A large sensor could use large pixels "I gather the obstacle to putting a large chip into a video camera on the cheap is that you can't achieve an adequate frame rate. Large-sensor 50fps requires a MUCH more expensive chip than the typical digital still camera uses." It is possible to keep the data rate the same by building large sensors with large pixels and same pixel count (versus leaving the pixels the same size and increasing the pixel count). Benefits of such an approach would include improved noise characteristics and allow narrow DOF.

November 10th, 2005, 12:51 PM	#30
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	Basically, as Barry puts it, it comes down to pixel size on the sensor. As you try to fit more pixels (ie HD) into a smaller chip, ie 1.3", the resolution, in line pairs per mm, that the lens has to be able to pass, is necessarily greater and greater. Although lens cost is usually proportional to the square of the radius, hence bigger lenses for bigger chips being exponentially more expensive (and lenses for smaller chips very much cheaper), this is not really mitagated by the extreme sharpness demands of HD video on 1/3" sensors. That's why you get affordable "HD" lenses that are only sharp in the middle, not at the edges, have severe chromatic aberations, and breathe heavily on pulling focus. Canon make great lenses for 35mm stills cameras, but even so, you need to get the expensive L series lenses to fully do justice to the smaller pixels on the 20D compared to, say the 5D or 1dsMK2. Although the sensor is smaller on the 20D, so if the lens is a bit soft at the edge, you don't see it anywhere near as much. Hope that helps, Graeme __________________ www.nattress.com - filters for FCP

November 6th, 2005, 09:34 PM	#19
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	Interesting discussion. Part of the explanation will be that while SD requires only 720x480 resolution, that resolution is required within a MUCH smaller area that the 24mm by 36mm area that a standard 35mm still camera lens has to work with. So in that sense, the video lens still has to provide a high resolution, just over a rather narrow angle angle. If I had a bit more time I'd do the math, but hopefully you'll understand what I'm on about.

November 7th, 2005, 05:29 AM	#20
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	A 35mm movie film frame is about 22mm wide; a 16:9 1/3" CCD is about 5.24mm wide. Assuming a movie frame is scanned at 4k resolution, that puts 4,000 pixels (or thereabouts) in 22mm, or about 182 pixels per mm. On a standard-def 1/3" CCD you're talking about 720 pixels in 5.24 mm, or about 137 pixels per mm. But in high def, you're potentially fitting 1440 pixels across, or nearly 275 pixels per millimeter! On the vertical, it's even worse -- 1080 lines in 2.95mm, or 366 pixels per millimeter. TWICE as dense as 35mm cine film! A high-def 1/3" chip then needs lenses that are substantially sharper than even cine lenses need to be. Using a standard-def lens runs the risk of not resolving nearly enough for the incredibly tight demands of 1/3" high-def. And, totally off-topic but tangentially related, it also makes me wonder if we'll ever see that rumored high-def GL3. The GL1 and GL2 were 1/4" CCDs. Would it even be possible to make a 1/4" high-def CCD? Maybe 1/3" is as small as high-def can go; at 366 pixels per millimeter, we're already being limited by optics as to the ability to resolve the image. Making the chip smaller and still able to resolve the full resolution may actually be impossible.

November 7th, 2005, 10:17 AM	#23
Thomas Smet Trustee Join Date: Mar 2004 Location: Milwaukee, WI Posts: 1,719	Barry, With pixel shift on SD cameras isn't there extra small points 1/2 the size on the CCD's that end up giving much higher detail than 720x480? If a SD lens cannot handle more detail than 720x480 then wouldn't pixel shift be kind of useless since shifting the CCD's wouldn't gain any extra detail anyways because the lens would be limited to 720x480? I do think certain SD lenses can resolve more than SD resolution. It may not be as much as a HD lens but it might still look good. Even current 1/3" HD lenses don't seem to resolve the full 1440x1080 anyways. I will be very interested to see resolution tests of a SD lens on a HD camera to see how bad it actually is. Maybe it would only be a little bit softer kind of like a diffusion filter. What I do know is that the lens on the DVX100 is a SD camera with a SD lens but by using the pixel shift the reel stream product does gain a lot more detail to create a HD image. Here the SD lens does seem to resolve a lot more detail than just SD.

November 7th, 2005, 04:59 PM	#26
Hse Kha Regular Crew Join Date: Nov 2003 Location: New England Posts: 195	The Panavision Genesis has a 35mm size sensor. See:- http://www.hollywoodreporter.com/thr..._id=1000527854

November 7th, 2005, 08:17 PM	#27
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	I gather the obstacle to putting a large chip into a video camera on the cheap is that you can't achieve an adequate frame rate. Large-sensor 50fps requires a MUCH more expensive chip than the typical digital still camera uses. But meanwhile, people that dont require real-time framerates (e.g. stop-motion animators) do indeed use digital still cameras to generate super-high resolution footage.