Lenses for 4K?

moldcad

moldcad

Veteran
I've been wondering (forgive me if naively) whether the FS700 (or any entry-level large sensor camera for that matter) makes s good candidate for 4k. The strength of the S35 sensor is in shallow DOF; for the 4K "wow" factor we need as much as possible in pin-point focus - otherwise what's the point of all this resolution?


Of course the top-level film cameras must (and do) offer both, but with the FS700 (and lenses at a comparable quality/price level) is both possible? To make DOF large we need to close the aperture - will the 4k resolution not be ruined by excessive CA, diffraction softness and alike?


What kind of lenses one needs to build a good 4k system around the FS700+Odyssey7Q?


I'm tending to think that with all the above in mind, smaller sensors cameras (like the new Sony Z100) make more sense for the prosumer market... Or am I wrong?


Piotr
 
i think, if you study the footage that has been posted on the internet, for 4k recordings from the FS700, you won't see any resolving power limitations in the footage. It might also be worthwhile to look at the published optics used for acquisition for this footage.

I might also suggest you review some of the product reviews for these so-called Sony 4k Handicams. They're not true 4k. And the sensor is a 1/2 inch exmor, with three channels each for RGB.
 
The lenses that a lot of us are using are also used on 24 and 36 megapixel photo cameras and they look great, so I'm assuming they are more than capable to do 4k, which is about 11 (if my math is right) megapixels.
 
The FS700 makes a great candidate for 4K. In the Cinegear presentation, Art Adams and Adam Wilt seem quite impressed with the FS700's 4K sharpness: http://vimeo.com/69884277

Most good DSLR still glass is built to resolve for 20-30+ megapixel images. 4K resolution is just 8-12 megapixels, so if your'e happy with the sharpness of your current glass for still photos, they should do fine in 4K.

If you wanted even sharper images, then the next step up would be dedicated cine lenses like the Zeiss CP.2/Superspeeds or the Canon Cine Lenses, though some of cine lenses, by Zeiss and Canon for example, are just rehoused versions of their stills glass. I'm really excited about testing out the new Schneider Xenon FF-Prime on the FS700 when the come out, as Schneider built the lenses with a top down approach (vs Canon/Zeiss), modeling it after their higher end Cine-Xenars cinema lenses.
 
I've heard the "stills cameras have resolutions in the region of 20mpx so if they can resolve that, they're bound to be Kay for 4k" argument before. The problem is that it really doesn't hold muster in the real world when you actually look at the images close up.

They tend to be really poor at resolving - especially the long zooms (the Canon 100-400 is pretty awful) when focused towards the distance. At wide wrangles They tend to drop off and go soft towards the edges. In general there is a lot of chromatic aberration and colour fringing and often they're quite soft, especially when wide open.

Put them side by side (ie on the same camera) with a set of decent film lenses (Angeniuex or Arri zooms, Zeiss or Cooke Primes) and you will very clear, see the difference when viewing pixel to pixel.

The issues is that these 20mpx camera images rarely (ie never) get blown up to the size of a cinema screen for viewing, s they can get away with being poorer of quality. That and it costs a lot of money to make lenses that are sharp and clean across the whole circle - which is one reason why they are so expensive (small production runs is another).

Having said all that, however.... 95% of the time your target audience is unlikely to notice the difference (apart from the softness - maybe). In fact, most cinema audiences seem unable to notice when the projector isn't focused properly, so a little obit of fringing will slip by them entirely.

Plus, if your shooting on the FS700, odds are it's a tight budget and most of the time, the extra money spent on better lenses can be better spent elsewhere on the production - e.g. More lighting, bigger art department budget.

If you're on a big feature, TV show, or commercial, however, then everything has to look the very best it can - at that point it is definitely worth using the better glass - and you will definitely see the difference...

colin Elves

DoP, London
www.colinelves.com
 
Thanks guys; you convinced me.

cuervo said:
i
I might also suggest you review some of the product reviews for these so-called Sony 4k Handicams. They're not true 4k. And the sensor is a 1/2 inch exmor, with three channels each for RGB.
Click to expand...

If you mean the AX1/Z100, their sensors are even smaller than that...
 
Colinelves said:
I've heard the "stills cameras have resolutions in the region of 20mpx so if they can resolve that, they're bound to be Kay for 4k" argument before. The problem is that it really doesn't hold muster in the real world when you actually look at the images close up.

They tend to be really poor at resolving - especially the long zooms (the Canon 100-400 is pretty awful) when focused towards the distance. At wide wrangles They tend to drop off and go soft towards the edges. In general there is a lot of chromatic aberration and colour fringing and often they're quite soft, especially when wide open.

Put them side by side (ie on the same camera) with a set of decent film lenses (Angeniuex or Arri zooms, Zeiss or Cooke Primes) and you will very clear, see the difference when viewing pixel to pixel.

The issues is that these 20mpx camera images rarely (ie never) get blown up to the size of a cinema screen for viewing, s they can get away with being poorer of quality. That and it costs a lot of money to make lenses that are sharp and clean across the whole circle - which is one reason why they are so expensive (small production runs is another).

Having said all that, however.... 95% of the time your target audience is unlikely to notice the difference (apart from the softness - maybe). In fact, most cinema audiences seem unable to notice when the projector isn't focused properly, so a little obit of fringing will slip by them entirely.

Plus, if your shooting on the FS700, odds are it's a tight budget and most of the time, the extra money spent on better lenses can be better spent elsewhere on the production - e.g. More lighting, bigger art department budget.

If you're on a big feature, TV show, or commercial, however, then everything has to look the very best it can - at that point it is definitely worth using the better glass - and you will definitely see the difference...

colin Elves

DoP, London
www.colinelves.com
Click to expand...
I beg to differ.
first of all it's the stills that are blown up to poster sizes all the time ans scrutinized.
MP lenses are designed to hold good resolution in center but don't need sharp corners because the short spanned viewer attention for motion picture is controlled by the creatives and usually in the center of the frame.
Sharp corners can be destracting.
BTW have you ever seen Angenieux lenses projected. The 10:1 zoom (HR) is very soft in the corners and that was the most popular lens in its time.
Still lenses need sharpness all over because the frame (postcard for example) is looked at and scrutinized all over- center and corners.
and I've projected enough lenses in the 26+ years career to confirm that.
Modern still lenses are as sharp as they can be- they are amazing. Add to that the other features like the IS, light weight and low cost and there is no doubt where the industry is heading...
My 2c
 
Ya gotta love technology when a cinematographer has to intentionally add blur to a clip in order to make it look less video...
 
All I can say is my experience is very different. Side by side, modern cine lenses out perform modern stills lenses by quite some measure. To me this is most obvious when you compare the wide angle lenses (the Canon 24mm is seriously soft in the corner, while a Master Prime is pin sharp).


Also your logic is somewhat off: Most of the pro photographers I know that shoot for poster campaigns would never think of using a 35mm camera and the equivalent lenses - they'd shoot medium format and those lenses are not far off the cost of cine lenses. 35mm is reserved for photojournalists and sports photographers.

You only have to hold a film lens in your hand to realise the difference: they're considerably heavier - and that's because they contain a lot more glass per element (it's not just the metal housings) - which makes them faster and means (I believe) the centre of the element is used what covers the chip. The glass is also of a better quality and more care is taken to grind it. On top of this, the elements in the zoom lenses are individually selected so that the abberations from one element cancel out the abberations in another.


At the end of the day, this is what you would expect from hand-crafted, small run lenses that cost 10x as much as a mass produced 35mm stills lenses. Don't get me wrong, stills lenses are great for the price - but they really aren't as good as film lenses. Nor, do I believe they really do most have the chops to properly resolve a 4K+ chip (with no fringing or aberrations) which, generally being a single layer of sensors is a much more critical task than resolving 3 layers of 35mm film stacked one on top of another.


From what you're saying, it seems like you think lens manufacturers like Zeiss and Cooke are screwing their customers just for the name (although Zeiss probably are a little bit with the compact primes - but even then, the CPs tend to be the best from a run of ZF lenses rehoused), whereas I really don't think they are.


But, to be honest, I don't really think our positions are too far apart. As I said, I think stills lenses are great for the price and more than adequate for most projects - for no other reason alone than most audiences are much less critical of image quality than film makers are. Sure they don't perform too well when you look too closely at them in 4K, but when do you ever do that anyway?
 
I'm seeing contradictory information about the 4K fps capability using Odyssey -- is it up to 30 fps (as per Adam)or 60p (as per CD own webpage)?
 
I've been involved in lens design for the MP industry for many years on a very intimate level.
I can assure you that your assumptions about the "whys?" are completely incorrect.
Still lenses are cheaper because of the economies of scale. They are also optically excellent for the very same reason. Why would manufacturers settle for an inferior design and a risk related to it with the failed sales if they are planning to sell 10000, 20000 copies of a lens? The expense in this case is not in few millions difference in R&D but in the tooling, and technology used for the manufacturing.
Yes the Cine lenses get the benefit of "cherry picking " the glass but that's about it in csae of the CN/E lenses for example. Maybe also different iris.
The cine lenses are designed for a smaller format so yes they will be faster and may perform better. But IMO the economies of scale offset that.
I can assure you that the amounts of money invested by Nikon and canon in their designs are unheard of in the MP industry.
 
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Fair enough. I'll bow to your superior experience and knowledge then. It's entirely possible that I'm being blinded by their association with 'high end' work and the higher price. Or it might simply be the fact I find them more difficult to work with.
 
moldcad said:
I'm seeing contradictory information about the 4K fps capability using Odyssey -- is it up to 30 fps (as per Adam)or 60p (as per CD own webpage)?
Click to expand...


Dear Piotr,

Here is the wording from our latest document covering FS700:

Sony FS700 RAW: 2K RAW 12-bit up to 240fps,
Compressed 1080p 10-bit YCC up to 60fps (super-sampled from 4K Raw),
Compressed 4K YCC 10-bit up to 30fps

Thus, we are promising Compressed 4K, up to 30 fps, from the FS700 with the Odyssey7Q and the FS700 Option.

But, if we can support Compressed 4K, up to 60 fps, then we will. We just do not want to over-promise and under-deliver.

Respectfully,


Dan Keaton
Convergent Design
 
Dan, does that mean you took 12 bit 444 RGB 1080 sub sampled from raw off the table? That would be a major blow.
 
moldcad said:
I've been wondering (forgive me if naively) whether the FS700 (or any entry-level large sensor camera for that matter) makes s good candidate for 4k. The strength of the S35 sensor is in shallow DOF; for the 4K "wow" factor we need as much as possible in pin-point focus - otherwise what's the point of all this resolution?
Click to expand...
The exact same question was asked about HD, since film-style shooting usually results in a lot being out of focus, what was the big appeal for going with HD in filmmaking? There was much arguing back and forth on that, and the net result is this: wide shots, vistas, landscapes, all look decidedly better in HD. But most folks at home, even on a large screen, wouldn't notice the difference whether they were watching a standard-def DVD or a high-def Blu-ray.

Regardless, more is better, for today's purposes and tomorrow's.


but with the FS700 (and lenses at a comparable quality/price level) is both possible? To make DOF large we need to close the aperture - will the 4k resolution not be ruined by excessive CA, diffraction softness and alike?
Click to expand...
In short -- no. Stills lenses are far from ideal for cine-style work, but they can resolve quite well. Users of Red cameras have been using stills-camera lenses for five years now. Good-quality lenses can resolve plenty for a 4K image. As to whether you get CA or not, that depends on the lens -- junk lenses will have lots more CA than good lenses will.

As for diffraction softness, that's not really a worry on a camera with a sensor as large as S35. Diffraction would be a tremendous worry on a 4K camera with a 1/3" chip (such as the forthcoming Z100 or whatever it's called) but on a large sensor, it's not much of an issue at all. The issue with diffraction is all related to pixel size on the sensor -- the smaller the individual pixel size, the more likely the camera will be affected by diffraction. A 1/4" 1080p camera is affected by diffraction as early as f/2.8. I haven't done the math yet but an off-the-wall guess is that a 1/3" 4K camera will probably run into diffraction softening as early as f/2.0. But with a Super35 sensor size, you've got a chip that's literally 20x bigger than that 1/3" camera, and -- using the same pixel count, that means the individual pixels are 20x larger on the S35 camera than they are on the 1/3" camera. So no, diffraction shouldn't be an issue at all on the FS700 or other comparably-large-sensor cameras.


What kind of lenses one needs to build a good 4k system around the FS700+Odyssey7Q?Depends on what you want to shoot. And what you want to spend. If you want to shoot cinema-style, you really should have cinema-style lenses, and those cost around $10k to $100k or more for a set of primes. Or you can get a couple of zooms, ranging from the Red zooms on up to the Fuji 4K zoom lens. Or, you can do what no-budget guys do and use stills-camera lenses; I put together a complete set of 8 Duclos-cinevized Zeiss ZFs for under $12k.


I'm tending to think that with all the above in mind, smaller sensors cameras (like the new Sony Z100) make more sense for the prosumer market... Or am I wrong?
Click to expand...
That Z100 would make more sense for handycam uses, such as events or sports coverage, which are the kinds of things that large-sensor cameras are worst at. But no, I can't see how a Z100 would be a better filmmaking tool than an FS700.
 
Colinelves said:
(the Canon 100-400 is pretty awful)
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Colin,
from 6 years professional use of this lens in still photography I was more than happy with this lens. I shot billboards, posters, city light posters, double pages - and it is razor sharp at f=5.6 . Image stabilizer is awesome, I realized hand-held shots at 1/250"

For filmimg I mostly use on my FS700 the 70-200 / f=4 and this is pretty sharp and brilliant too! In summer on landscape shoots I see at 400mm heat haze quite often, that's one reason why I prefer the 70-200.
 
On a recent shoot I was on the DP was shooting 5K on the epic with Duclos Zeiss ZF's. After the shoot we chatted about lens choice, and I asked why not use s4's, or Ultra primes, and he said he actually preferred the ZF's when he is operating. Client had nothing but great things to say about the image, and not sure if a 10K hunk of glass would have made it better. Now if you are using a 1st for focus pulling then cinema glass is a must.
 
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