Hans von Sonntag
Well-known member
Hi all,
some thoughts on a subject I've posted about several times here and there and that now deserves an own thread: S16mm doc shooting with RED.
S16mm zooms are the best option for documentarian work: They are light weight and don’t deliver the shallow DOF of 35mm lenses, good for single operated handheld work. The DOF shot wide open is still nice but not as challenging. The possible B4 route is not a good option.
No B4 route.
If you evaluate a B4 HD-ENG lens setup on one RED side by side with a fairly modern S16mm zoom on a second RED you instantly see what I am talking about:
1. RED turnes virtually into a dog slow 160 ASA camera because the necessary B4 adaptor adds 1 stop light-loss. For comparison, a F900R has approx. 500 ASA. Pushing 2K footage in REDCine creates much more visible noise than with 4K footage and must be avoided for satisfactory results.
2. Additionally the FVO is cropped due to the nature of the adaptor, meaning a lens that has a wide FOV on a F900 for instance has a considerably more narrow FOV on the RED.
3. The adaptor contains glas and therefore reduces the performance of the B4 lens to a certain extend which has been developed for an entirely different optical system (3CCD prism 2/3”). Also HD ENG lenses tend to have more CA than S16mm zooms.
2K vs 3K concerning S16 lenses.
S16mm zooms cover 2K windowed, but vignette considerably in 3K windowed. The FOV in 2K mode is reduced about 25% because 2K windowed has a smaller projection area than S16mm. To make a S16mm lens fit with the RED and to get the most possible FOV one needs a windowed format between 2K and 3K, lets say 2.5K windowed.
Now, S16mm lenses vignette differently. A Zeiss 9.5 SuperSpeed MKII vignettes more than a Canon 8-64. Thus, a customisable windowing would be great; making sure that a given lens gets the optimal window of the sensor.
Workflow.
Lets assume that we want a 1080p master. Today there are two ways to achieve this with a S16mm lens:
1. Either one shoots 2K, does a center crop for 1080p and loses FOV,
2. or one shoots 3k, gaines FOV, scales the picture until the lens does not vignettes (approx. 2.5k) and down converts to 1080p.
- Shootig 2K windowed has the advantage that no scaling to the debayered pixel is added.
- Shooting 3K windowed has the advantage that the maximum FOV of the lens is used and considerable “flesh” for oversampling is generated for true 1080p resolution which is with a 2K resolution bayer pattern sensor generated picture not possible since 20-30% of the pre-debayer resolution will be lost after debayering.
- Shooting 3K windowed has the downside of displaying a heavily vignetting picture in the EVF, which is fairly distracting for the operator.
Pictures.
To illustrate how much FOV is lost with 2K windowed I have two pictures attached. One shows 2K windowed, and one shows 3K windowed. Both were shot with a Canon 8-64, the classic wide angle zoom in S16mm photography. Please note that the 3K example shows how 3K windowed mode looks in the EVF, distracting I find. Customised windowing would be a huge step towards versitality.
Summary.
2.5K windowed, or even better customisable windowed modes are necessary for convenient, true 1080p, documentarian filmmaking utilising S16mm zooms.
Hans
some thoughts on a subject I've posted about several times here and there and that now deserves an own thread: S16mm doc shooting with RED.
S16mm zooms are the best option for documentarian work: They are light weight and don’t deliver the shallow DOF of 35mm lenses, good for single operated handheld work. The DOF shot wide open is still nice but not as challenging. The possible B4 route is not a good option.
No B4 route.
If you evaluate a B4 HD-ENG lens setup on one RED side by side with a fairly modern S16mm zoom on a second RED you instantly see what I am talking about:
1. RED turnes virtually into a dog slow 160 ASA camera because the necessary B4 adaptor adds 1 stop light-loss. For comparison, a F900R has approx. 500 ASA. Pushing 2K footage in REDCine creates much more visible noise than with 4K footage and must be avoided for satisfactory results.
2. Additionally the FVO is cropped due to the nature of the adaptor, meaning a lens that has a wide FOV on a F900 for instance has a considerably more narrow FOV on the RED.
3. The adaptor contains glas and therefore reduces the performance of the B4 lens to a certain extend which has been developed for an entirely different optical system (3CCD prism 2/3”). Also HD ENG lenses tend to have more CA than S16mm zooms.
2K vs 3K concerning S16 lenses.
S16mm zooms cover 2K windowed, but vignette considerably in 3K windowed. The FOV in 2K mode is reduced about 25% because 2K windowed has a smaller projection area than S16mm. To make a S16mm lens fit with the RED and to get the most possible FOV one needs a windowed format between 2K and 3K, lets say 2.5K windowed.
Now, S16mm lenses vignette differently. A Zeiss 9.5 SuperSpeed MKII vignettes more than a Canon 8-64. Thus, a customisable windowing would be great; making sure that a given lens gets the optimal window of the sensor.
Workflow.
Lets assume that we want a 1080p master. Today there are two ways to achieve this with a S16mm lens:
1. Either one shoots 2K, does a center crop for 1080p and loses FOV,
2. or one shoots 3k, gaines FOV, scales the picture until the lens does not vignettes (approx. 2.5k) and down converts to 1080p.
- Shootig 2K windowed has the advantage that no scaling to the debayered pixel is added.
- Shooting 3K windowed has the advantage that the maximum FOV of the lens is used and considerable “flesh” for oversampling is generated for true 1080p resolution which is with a 2K resolution bayer pattern sensor generated picture not possible since 20-30% of the pre-debayer resolution will be lost after debayering.
- Shooting 3K windowed has the downside of displaying a heavily vignetting picture in the EVF, which is fairly distracting for the operator.
Pictures.
To illustrate how much FOV is lost with 2K windowed I have two pictures attached. One shows 2K windowed, and one shows 3K windowed. Both were shot with a Canon 8-64, the classic wide angle zoom in S16mm photography. Please note that the 3K example shows how 3K windowed mode looks in the EVF, distracting I find. Customised windowing would be a huge step towards versitality.
Summary.
2.5K windowed, or even better customisable windowed modes are necessary for convenient, true 1080p, documentarian filmmaking utilising S16mm zooms.
Hans
