Filip Aladdin Posted January 21, 2020 Share Posted January 21, 2020 Hi! I have a problem with a Cooke 25-250 T3.9. I tried it on the Panasonic Varicam 35 (shot with 4k and 2k still vignette) and I noticed a small vignette in the corners, even when I Zoomed to different focal length. Do you know what the problem could be? Something about the flange? or the sensor? Its a super35 mm sensor on the varicam. Anyone knows why? I prefer not to crop it digitally after the shoot. Thanks, Filip Link to comment Share on other sites More sharing options...
Premium Member Gregory Irwin Posted January 21, 2020 Premium Member Share Posted January 21, 2020 It’s the rear element of the 35mm lens that wasn’t designed to cover large sensors. The real question is where your frame lines are and is the vignette outside of those? The vignette will change as you zoom due to the zoom curve. G 1 Link to comment Share on other sites More sharing options...
Premium Member David Mullen ASC Posted January 21, 2020 Premium Member Share Posted January 21, 2020 A lot of those old zooms don’t cover Super-35. We shot HBOs “Big Love” for the first few seasons on a Cooke 20-100mm in Super-35 and there was definitely fall-off in the corners. 1 Link to comment Share on other sites More sharing options...
Premium Member Dom Jaeger Posted January 21, 2020 Premium Member Share Posted January 21, 2020 The Cooke 25-250 Cinetal zooms have an image circle of about 28mm, which is usually enough to just cover most standard S35 aspect ratios. As Greg said, where are your frame lines on that monitor image? Is your final image going to be all the way to the edges of that monitor? The image circle is smallest at the wide end and should definitely not vignette at longer focal lengths, so check that the matte box for example is not shading the corners. 1 Link to comment Share on other sites More sharing options...
Filip Aladdin Posted January 22, 2020 Author Share Posted January 22, 2020 Ok! thank you for getting back to me so fast. Im planning on using the whole frame. 16:9 but I guess that's it with those vintage lenses. It'll work out fine! thank you! Link to comment Share on other sites More sharing options...
Neal Norton Posted January 23, 2020 Share Posted January 23, 2020 The vignette will be dependent on both the aperture, the focal length and the focal distance. Each zoom (even the same make and model) might have a slightly different "ramp" in the zoom and focus that could have an effect. You will need to test with the lens at a range of stops and frame sizes and distances. Often a wide open lens at a midpoint on the zoom will looks good with a mild maybe even pleasing fall-off and a deeper stop like maybe an 8 or 11 will make for a pretty hard vignette. Best of luck, Neal Norton DP Link to comment Share on other sites More sharing options...
Aldo Garcia Posted November 11, 2023 Share Posted November 11, 2023 On 1/21/2020 at 11:34 AM, David Mullen ASC said: A lot of those old zooms don’t cover Super-35. We shot HBOs “Big Love” for the first few seasons on a Cooke 20-100mm in Super-35 and there was definitely fall-off in the corners. Hi David! I would like to know if the Cooke 20-100mm is parfocal? I saw a lot of zoom in Kubrik scenes and mine seems not to keep the focus while zooming. Thank you for your reply in advance. Cheers, Aldo. Link to comment Share on other sites More sharing options...
Premium Member Dom Jaeger Posted November 11, 2023 Premium Member Share Posted November 11, 2023 19 hours ago, Aldo Garcia said: I would like to know if the Cooke 20-100mm is parfocal? I saw a lot of zoom in Kubrik scenes and mine seems not to keep the focus while zooming. Thank you for your reply in advance. Cheers, Aldo. All cine zooms are designed to be parfocal. If yours is not holding focus, chances are the back-focus needs adjustment. Take it to a lens tech for assessment. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now