It just occurred to me: will lenses made for super16 or 2/3 video cover 1280x720 of the sensor? If so, could you use a fast 2/3 zoom lens and do some run & gun doc shooting with the AF100, then crop - if you had a project that only required 720p? If so, it seems to me that this camera becomes a much more flexible documentary camera...
Crazy idea: shooting 720p with super16 or 2/3 lenses?
- Thread starter rda
- Start date
Joseph Hudson
Member
When I had a 2/3" lens with B4 adapter on an AF 100 at a demo a couple of weeks ago, the vignetting took up quite a bit of the image (it was fine at 2x) . You had to zoom in a lot to get past the vignetting. Wish it were easier with the 2/3" broadcast lenses. Let us know if you figure anything out.
Barry_Green
Moderator
Super16 has a frame width of 12.4mm.
Regular 16mm has a frame width of 10mm.
2/3" 16x9 chips are 9.6mm wide.
The AF100 chip is 17.8mm. A 720p extraction would use 2/3 of the width, or about 12mm. So yes any Super16 lens should cover a cropped 720p, but only some 16mm lenses will, and some 2/3" lenses might.
EDIT: I just re-ran this through an image circle calculator, to make sure I had it right.
2/3" video needs a lens that projects an image circle of 11mm.
16mm film needs an image circle of 12.5mm.
Super16mm film needs an image circle of 14.5mm.
By my calculations, the AF100's sensor, when cropped to 720p mode, would cover an image circle of 13.62mm.
So, the conclusion stands, only Super16 glass would be guaranteed to cover the whole 720p-extraction area of the frame. However, keep in mind that some 16mm glass will cover Super16 anyway, even though it's not advertised as such; usually the longer focal lengths will cover. Heck, some Super16 glass will cover the entire AF100's 1080p frame! (especially lenses of 35mm or longer focal length). So you might find that 16mm glass will cover from maybe, oh, 15mm focal length on up? And if you want wider-angle than that, you'd probably need to look at Super16 glass for the wide angles.
I doubt you're going to find much in the way of 2/3" video lenses that will cover; asking a lens that covers 11mm to cover an image circle of 13.62mm seems quite a stretch. With an optical doubler in place, yes, pretty much all 2/3" glass should cover. Without a doubler, I don't know -- maybe some will, but I wouldn't count on it.
Regular 16mm has a frame width of 10mm.
2/3" 16x9 chips are 9.6mm wide.
The AF100 chip is 17.8mm. A 720p extraction would use 2/3 of the width, or about 12mm. So yes any Super16 lens should cover a cropped 720p, but only some 16mm lenses will, and some 2/3" lenses might.
EDIT: I just re-ran this through an image circle calculator, to make sure I had it right.
2/3" video needs a lens that projects an image circle of 11mm.
16mm film needs an image circle of 12.5mm.
Super16mm film needs an image circle of 14.5mm.
By my calculations, the AF100's sensor, when cropped to 720p mode, would cover an image circle of 13.62mm.
So, the conclusion stands, only Super16 glass would be guaranteed to cover the whole 720p-extraction area of the frame. However, keep in mind that some 16mm glass will cover Super16 anyway, even though it's not advertised as such; usually the longer focal lengths will cover. Heck, some Super16 glass will cover the entire AF100's 1080p frame! (especially lenses of 35mm or longer focal length). So you might find that 16mm glass will cover from maybe, oh, 15mm focal length on up? And if you want wider-angle than that, you'd probably need to look at Super16 glass for the wide angles.
I doubt you're going to find much in the way of 2/3" video lenses that will cover; asking a lens that covers 11mm to cover an image circle of 13.62mm seems quite a stretch. With an optical doubler in place, yes, pretty much all 2/3" glass should cover. Without a doubler, I don't know -- maybe some will, but I wouldn't count on it.
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TheReverend
Well-known member
Is 720p mode on the AF100 cropping the sensor size? Or does it scale it down?
I plan on using the AF100 at 720p/60 often and I'm wondering what that'll look like. If it crops from the sensor, wont DoF change compared to full sensor? Is it more telephoto similar to the GH2? I thought that AF100 didn't have a crop mode like the GH2...
I plan on using the AF100 at 720p/60 often and I'm wondering what that'll look like. If it crops from the sensor, wont DoF change compared to full sensor? Is it more telephoto similar to the GH2? I thought that AF100 didn't have a crop mode like the GH2...
pannyfreak
Active member
It scales the regular 1080 sensor area down. Otherwise, there would be an additional crop factor change when using 720p mode, which there is not.
People have stated perhaps Panasonic should add a cropped 720p mode so 16mm lenses would be usable, but currently there is no cropped 720p mode on this camera.
From the photographic experience with c-mount lenses (16mm film, 1 inch TV tube), on m43 one thing is sure--up to ca 25mm f-length they will vignette. Around 25mm ( the 43 "normal") some will have an image circle covering the m43 frame . But it does not mean the whole illuminated area will have acceptable quality. A lot of threads on that at getdpi.com , eg this search:
http://forum.getdpi.com/forum/search.php?searchid=1542652
http://forum.getdpi.com/forum/search.php?searchid=1542652
Barry_Green
Moderator
Right, the AF100 has no sensor-crop mode, it's always using the full sensor. We were discussing the idea of cropping down in post (extracting the central 1280x720 out of the 1920x1080 frame). So for purposes of this discussion you wouldn't shoot in 720p mode, you'd shoot in 1080p, and then slice off the vignetting in post.
Again, if you want to be sure of coverage for this extracted-720p proposed post-created mode, Super16 lenses are the only way to know for sure -- but it's possible some regular-16 lenses will cover anyway.
Well, yes and no. It depends on what format the lenses are made to cover. You probably understand this because you included "16mm film, 1 inch TV tube" in your statement, but for the purposes of informing folks who don't know, c-mount lenses can also be made for smaller formats, such as 2/3", 1/2", or 1/3" CCTV cameras. The very nature of the lens being c-mount, doesn't describe what kind of circle of illumination the lens provides. So, yes, if the lens is made to cover 16mm film or a 1" sensor size, then it should start covering the full frame some point after 25mm (so, 30mm or longer should be good). I've got some c-mount 25mm lenses and they don't cover the AF100's frame.
Again, if you want to be sure of coverage for this extracted-720p proposed post-created mode, Super16 lenses are the only way to know for sure -- but it's possible some regular-16 lenses will cover anyway.
starcentral
Veteran
starcentral
Veteran
Was it a guy using a J14 xB4 with 2x doubler or something? I remember footage of a family or something outdoors, and a lot of manual zooming that looked cool as anything. I thought he was using a GF1 or GH1 but honestly it might have been a totally different SLR. I don't know if we're looking for the same video but man I can't find it anywhere. Someone commented that it had a nice vintage look and feel and I searched this forum and DVinfo.net using the word "vintage" but can not find it.. crap man that drives me nuts 
