Can a 2/3" lens shoot 2k???

[TimothyD]

Hello everyone,

I had been operating under the false assumption that 2k was supported with 2/3" lenses for some time now. I happened to read the formats section on the Red site again yesterday (it had been a long time) and realized that only the 16mm lenses support 2k.

I am now wondering if I need to go with a S16 lens to be able to utilize 2k? I am assuming that a 2/3" lens would vignette at something a bit less than the 2k frame? If this is the case, I would just shoot 2k with a 2/3" lens and have a little room for pan and scan, zooming, and image stabilization in post.

Can anyone tell me if that is a reasonable plan?

Tim

[TimothyD]

By the way, another (maybe not so obvious) reason I want to shoot 2k over 1080 is that there is no Redcode Raw in 1080...

[Martin Drew]

Tim

I don't know absolutely for certain, but I think the information about coverage on the Red site is old. Originally the B4 adapter was only going to cover 1080p but that was before it was actually designed. I believe that the Red B4 mount is now based on the Abacus 132 converter. Assuming that is the case the B4 lens will cover 2k because there are optics in the mount that multiply by 1.32. Have a look at this thread:

http://www.reduser.net/forum/showthread.php?t=392&page=2

Of course I could be wrong and everything is subject to change, but that is certainly what we have been lead to believe.

M

[Steve Gibby]

You'll need a B4 adaptor to use 2/3" HD lenses on RED One. With either a RED B4 adapter or an Abakus B4 adapter you will be able to shoot 2k, 1080p, or 720p with B4 2/3" HD lenses. That has been discussed at length in some previous threads.

You can shoot 2k REDCODE RAW with RED One using a B4 adapter + 2/3" HD lenses. 2K in the RED camera is 2048 x 1152, 1080p is 1920 x 1080, thus a 6% increase in frame size. The B4 adapters will magnify the 2/3" lens to cover the 2048 x 1152 frame. A 2/3" HD lens with good optics, when used with a B4 adapter, should do fine at 2k with RED One.

[JD Holloway]

Hi Gibby,

http://www.red.com/formatoptions.shtml still does not reflect this. I have asked on a couple of occasions but have not heard a response (i'm looking in the wrong place?). Considering how close 2K is to 1080 in terms of chip real-estate, I would think its a no-brainer. Might lose 1/8-1/3 of a stop, but be way less demanding on harddrives and SSDs in terms of storage.

Hope your right Gibs!

J.

[Steve Gibby]

On this thread, after TJ’s inquiry (Post #22), Abakas verified that their B4 adapter magnifies the image by a factor of 1.32. Link: http://www.reduser.net/forum/showthread.php?t=828&page=3

I am assuming that since the RED B4 adaptor will be a modified Abakas B4 adapter, that it will use the same magnification factor of 1.32.

A 1920 x 1080 image multiplied by a factor of 1.32 = a 2534 x 1425 image size.

A 2k image in RED One is 2048 x 1152, thus the adapted image from using a B4 adapter, of 2534 x 1425 is significantly larger than the RED 2k image, plus there is periphery room in the frame to deal with any potential vignetting issues.

Of note in the thread link above, is the mention that the quality of the 2/3 HD lens is important. A good B4 adapter will not compensate for a bad 2/3” HD lens.

On this thread, after testing an Abakus B4 adapter on a RED One prototype with a Fujinon 13 x 4.5 HD ENG zoom, Jarred reported good results. What he didn’t state is if he was able to test at 2k or just at 1080p and 720p. Since 1080p RGB and 720p RGB won’t be enabled in the first batch of cameras to ship, and RED’s footage examples have all been shot in RC RAW to date, I’d say Jarred’s B4 tests were probably in 2k.

Links: http://www.reduser.net/forum/showthread.php?t=828
http://www.reduser.net/forum/showthread.php?t=392&highlight=abakus

[TimothyD]

Thanks everyone,

I'm glad that 2/3" lenses will be able to provide 2k.

On another note, Gibby, do you think it would be better/cheaper to use an S16 lens and the Red Motor and Supergrip over a 2/3" lens? I'm guessing that is one of the configurations you may be testing when you get #8, providing that the Red Motor and Supergrip are available to test with. I will have quite a long wait by the time I order my camera, so I have no fear that they will be available by then. On the other hand, as to if prices are available by the time I have to place my order (July 1st) is another question. If there are no prices announced by then, I will obviously not be able to order them...

Also, I'm not sure if you ran across my other thread, but I am trying to get word from Red on whether it would be possible for them to release a version of the B4 adapter with a Canon or Nikon mount instead of the PL mount. I don't know if that is even possible, but if so I am assuming it would allow me to switch from 2/3" to still glass without collimation? This would be huge for me, as it would allow me use both still and 2/3 glass in the field. I doubt I will be able to handle, or more importantly, have the time to collimate a mount when I need to shoot 4k scenics.

Thanks so much,

Tim

[JD Holloway]

Thanks Gibby many thanks. Makes sense.

Jarred? Confirm?

[TimothyD]

As an aside, would it be possible to have the camera record 4k and use the extra coverage of a B4 lens for stabilization and pan/scan/zoom in post as I mentioned wanting to do with 2k? The more pixels I have beyond 1080 the more I can tweak things...

[JD Holloway]

I think that might look like the beginning of a James Bond film...all barrel. Still useful.

[TimothyD]

I think that might look like the beginning of a James Bond film...all barrel. Still useful.

Not sure I follow? I know the 2534 x 1425 image from a B4 lens will have vignetting on the outside, and that everything beyond the 2534 x 1425 will be black. I just think that in some cases (for fake steadycam, etc.) it might be worth the extra file size to have an image that large to work with for stabilization, pan/scan/zoom, etc... 6% will only get me so far, I have to imagine that even just walking slowly and carefully will produce more than 6% shake in the image. Who knows though...

Tim

[JD Holloway]

I fully understand. I just was remarking at how much vingnetting you will have on your original image, like looking down the barrel of a gun.

[tj williams]

Hi Gibby, just reading your post and have a question?



I am assuming that since the RED B4 adaptor will be a modified Abakas B4 adapter, that it will use the same magnification factor of 1.32.

A 1920 x 1080 image multiplied by a factor of 1.32 = a 2534 x 1425 image size.
A 2k image in RED One is 2048 x 1152, thus the adapted image from using a B4 adapter, of 2534 x 1425 is significantly larger than the RED 2k image, plus there is periphery room in the frame to deal with any potential vignetting issues.

This assumes that the pixel size on a sony chip block is the same as the pixel size on the red since it is figured in pixels. I can't find any information that this is true. My understanding is that the size in mm or inches of the Red windowed area was the same as the S16 frame. The adapter resizes the image 2/3video image, to the size of a S16 frame. Therefore before reading your post above I believed that the 2K red windowed sensor was almost exactly filled by the expanded B4 lens with the adapter?

[Stephen Williams]

Hi TJ,

A 4X3 2/3 sensor is 6.6mm x 8.8mm if that helps.

Stephen

[TimothyD]

I fully understand. I just was remarking at how much vingnetting you will have on your original image, like looking down the barrel of a gun.

Gotcha,

Would it also be a round image? I have to imagine it would. If so, that probably puts some limitations on the usefulness of having the larger 2534 x 1425 image if its corners are rounded off.

Interesting...

[Steve Gibby]

Hi Gibby, just reading your post and have a question?This assumes that the pixel size on a sony chip block is the same as the pixel size on the red since it is figured in pixels. I can't find any information that this is true. My understanding is that the size in mm or inches of the Red windowed area was the same as the S16 frame. The adapter resizes the image to the size of a S16 frame. Therefore before reading your post above I believed that the 2K red windowed sensor was almost exactly filled by the expanded B4 lens with the adapter?

That's a good question TJ. I don't have the data for the comparative pixel sizes - I'm sure Jarred would. Someone else will have to answer that. It's safe to assume that at least a S16mm frame will be covered when using a B4 adapter and 2/3" HD lens on RED One, thus enabling 2k RC RAW shooting.

[Steve Gibby]

The Format Options page of the RED web site lists:

S16mm = 11.1 x 6.3
2/3" B4 = 10.4 x 5.9

Link: http://www.red.com/formatoptions.shtml

[JD Holloway]

Gotcha,

If so, that probably puts some limitations on the usefulness of having the larger 2534 x 1425 image if its corners are rounded off.

Interesting...

To a certain degree. There may be a vignetting removal tool in some raw application software like photoshop has, but thats speculation. That being said, its probably why the magnification factor is so high; to push vignetting further away from the recorded area and make the image "safe" at the cost of the wide end of the lens. Unfortunately that means using more expensive HD wide glass (+4000$)

[Martin Drew]

...What he didn’t state is if he was able to test at 2k or just at 1080p and 720p. Since 1080p RGB and 720p RGB won’t be enabled in the first batch of cameras to ship, and RED’s footage examples have all been shot in RC RAW to date, I’d say Jarred’s B4 tests were probably in 2k.

I think the tests were done will the full sensor area, Jarred posted a frame from the test showing the image vignetting and a superimposed panel to indicate 2k area. http://www.reduser.net/forum/showpost.php?p=7326&postcount=11 Coverage looks great here but Jarred didn't let on what the focal length was, so all we can assume is that it will cover 2K.

M

[Steve Gibby]

I think the tests were done will the full sensor area, Jarred posted a frame from the test showing the image vignetting and a superimposed panel to indicate 2k area. http://www.reduser.net/forum/showpost.php?p=7326&postcount=11 Coverage looks great here but Jarred didn't let on what the focal length was, so all we can assume is that it will cover 2K.

M

Good catch Martin. Yes, I think we can assume that 2k will be covered.

[TimothyD]

Ah, ok, so I hadn't noticed that was round before. I had assumed that was shot with a 35mm at 4k and the white area was to show the difference in size between 2k and 4k. Very interesting...

[TimothyD]

It looks like there is a LOT of room to do stabilization, pan/scan/zoom and other fun post production tricks. Hmm...

[Stuart English]

With a B4 lens on the RED B4 to P/L mount adaptor, you should be able to get 2K, plus 10% surround view area. We suggested 1080p as the limit as we had not tested 2K for image quality. That's still the case.

[Brook Willard]

I assume that the acceptable optical coverage of a given lens is the potential limiting factor?

[Stephen Williams]

I assume that the acceptable optical coverage of a given lens is the potential limiting factor?

Hi,

One thing to remember as you zoom & pull focus the size of the circle will change. Also most zoom lenses 'porthole' to some extent when wide open, looks like vignetting, but goes away when you stop down a stop or two.

Stephen

[TimothyD]

Thanks guys,

I would be just be happy to be able to stabilize otherwise unusable footage. I won't have a steadycam, but would like to be able to fake it occasionally. That and zoom into interviews slightly, etc.

Sounds very feasible, though it would be even better with a 35mm lens. I'm just not sure that will work for me (Budget, etc.)

Tim

[Brook Willard]

Hi,

One thing to remember as you zoom & pull focus the size of the circle will change. Also most zoom lenses 'porthole' to some extent when wide open, looks like vignetting, but goes away when you stop down a stop or two.

Stephen

Given, I was just trying to determine if the slim potential for limitation is coming from the lens or the adapter.

[TimothyD]

Has anyone had a chance to read my thread about the possibility of versions of the B4 adapter with Canon or Nikon mounts instead of PL? That would be EXTREMELY useful to myself, and I would guess a whole lot of other ENG/EFP shooters. Assuming that is, that no collimation would be required to switch from 2/3" to still glass.

Beuller???

[Stephen Williams]

Given, I was just trying to determine if the slim potential for limitation is coming from the lens or the adapter.

Hi Brook,

Almost certainly the lens, however the adapter magnifies the image so errors will be more obvious IMHO.

Stephen

[Brook Willard]

Has anyone had a chance to read my thread about the possibility of versions of the B4 adapter with Canon or Nikon mounts instead of PL? That would be EXTREMELY useful to myself, and I would guess a whole lot of other ENG/EFP shooters. Assuming that is, that no collimation would be required to switch from 2/3" to still glass.

Beuller???

The PL mount has a flange focal distance of 52mm, but the Nikon F mount has a FFD of 46.5mm [I believe] and the Canon FD mount has a FFD of 42mm [I believe]. I could be wrong on those latter figures.

Either way, it means that the lenses need to be closer to the sensor than the PL mount will allow, so the entire lens mount needs to be removed. No adapters will work... at least not without some creative [and expensive] optics.

[edit: whoops, misread your post, Timothy. Answered a question that wasn't asked.]

[Stephen Williams]

Has anyone had a chance to read my thread about the possibility of versions of the B4 adapter with Canon or Nikon mounts instead of PL? That would be EXTREMELY useful to myself, and I would guess a whole lot of other ENG/EFP shooters. Assuming that is, that no collimation would be required to switch from 2/3" to still glass.

Beuller???

Hi Timothy,

Problem is you would need a B4 mount without an adapter, then Video lenses wont work! Nikon to B4 exist but you would only use the 2K area. I am also fairly sure that Canon & Nikon mounts are wider than a B4 so I don't think it's going to work.

Stephen

[TimothyD]

Hi Stephen,

I think you must be misunderstanding my question.

What I am hoping is that the B4 adapter that Red is offering could be offered in a Canon or Nikon mount instead of PL. That way I could have a Canon or Nikon mount on the camera and a matching mount on the B4 adapter.

I'm ok with the 2k when using 2/3" glass, I'm just hoping to be able to shoot with 35mm still glass as well, without changing the lens mount, only taking off the B4 adapter and 2/3" lens attached to it, and putting on a 35mm still lens.

[Edit: In addition to PL mount, not instead of.]

[Brook Willard]

Timothy, because those mounts have different flange focal depths than PL, the optics would need to be completely redesigned to work with the shorter FFD of still mounts.

In other words, I bet it'd be a big pain in the ass.

[Stephen Williams]

Timothy, because those mounts have different flange focal depths than PL, the optics would need to be completely redesigned to work with the shorter FFD of still mounts.

In other words, I bet it'd be a big pain in the ass.

Hi,

It's basically impossible!

Stephen

[Brook Willard]

Well, I wouldn't go that far. The mount could just move the optics another 5.5mm or 10mm [depending on the mount] farther away from the sensor to match the 52mm FFD of the optics in the PL/B4 converter. That route would require no optical redesign.

Still a PITA, though.

[TimothyD]

Hi,

It's basically impossible!

Stephen

Hey Jim,

Did you hear that someone said this is IMPOSSIBLE!!!

I'll be anxiously awaiting the announcement:)

Seriously though, if this can be done I'm sure that it would sell very well. I know as an ENG/EFP guy, that I would LOVE to have the option of using still glass and 2/3" without changing mounts...

Thanks,

Tim

[Stephen Williams]

OK you could add a boroscope if you did not mind quality & light losses, but fairly impractical IMHO.

Stephen

[TimothyD]

Well, I wouldn't go that far. The mount could just move the optics another 5.5mm or 10mm [depending on the mount] farther away from the sensor to match the 52mm FFD of the optics in the PL/B4 converter. That route would require no optical redesign.

Still a PITA, though.

Would making the mount 5.5 or 10mm deeper really be that big a pain in the ass?

Tim

[Brook Willard]

Good question. This is where my knowledge ends.

[TimothyD]

Well, just tell Jim that someone said it is impossible. I imagine that will be all it takes:)