Lee Young Posted June 10, 2007 Share Posted June 10, 2007 I was just wondering how to use retrofocus lenses. I have a 10mm angenieux lens that goes under this title. Is the depth of field table for this lens the same as what I would see on another 10mm lens? Is it always set on infinite focus? If I had a depth of field of 10 feet where would it start and end? Thanks for any help you can give me. I wasn't able to find it anywhere else. Link to comment Share on other sites More sharing options...
Premium Member Laurent Andrieux Posted June 10, 2007 Premium Member Share Posted June 10, 2007 On my point of view, the fact it's a retrofocus doesn't matter. Use the DOF tables or calculators just the same as a normal lens. Link to comment Share on other sites More sharing options...
Premium Member Stephen Williams Posted June 10, 2007 Premium Member Share Posted June 10, 2007 On my point of view, the fact it's a retrofocus doesn't matter. Use the DOF tables or calculators just the same as a normal lens. Hi Laurent, As most wide angle lenses are retrofocus & long lenses are of telephoto design, standard DOF tables will work fine. Stephen Link to comment Share on other sites More sharing options...
Premium Member Charles MacDonald Posted June 10, 2007 Premium Member Share Posted June 10, 2007 Hi Laurent, As most wide angle lenses are retrofocus & long lenses are of telephoto design, standard DOF tables will work fine. Stephen Retro focus really means that the lens has a backfocus distance longer than the focal length. for example many cameras have a flange to film distance on the order of 40-50mm, which allows for things like viewers and the shutter. so to have a lens of say 10mm it must actually be of the retro-focus design to allow for the needed space. (They often will look like the front eleiment is a negative lens). As far as the film is concerned it is as if the lens was phyicaly closer than is posible. In the case of telephotos, they do the oposite so that a 6 inch (150mm) does not have to be phyicaly 6 inches from the film. ( I have an old c mount 6 inch lens, and it looks impresive with a long alluminum barrel) Link to comment Share on other sites More sharing options...
Daniel Madsen Posted June 10, 2007 Share Posted June 10, 2007 Retro focus really means that the lens has a backfocus distance longer than the focal length I would call this an inverse telephoto design. Link to comment Share on other sites More sharing options...
Premium Member Stephen Williams Posted June 10, 2007 Premium Member Share Posted June 10, 2007 I would call this an inverse telephoto design. Hi, It's the same thing. Stephen Link to comment Share on other sites More sharing options...
Lee Young Posted June 11, 2007 Author Share Posted June 11, 2007 my question is sense there is no selective focus, where does my depth of field start from. This may be a very naive question, but I am not use to a lens that does not have focus selection. I am assuming that I treat it like infinity focus? Link to comment Share on other sites More sharing options...
Premium Member Charles MacDonald Posted June 11, 2007 Premium Member Share Posted June 11, 2007 my question is sense there is no selective focus, where does my depth of field start from. This may be a very naive question, but I am not use to a lens that does not have focus selection. I am assuming that I treat it like infinity focus? You have a lens without a distance scale? these are sometimes found on "consumer" cameras. Some of the old Keystones come with a fixed focus lens at about f 3.5 or so. the idea is that the Depth of Field will cover you for most shot sin the "snapshot" range, 8-10 ft, and still not make the background too Blurry. On a wide angle, that range can be from a few feet out. Link to comment Share on other sites More sharing options...
chuck colburn Posted June 11, 2007 Share Posted June 11, 2007 Hello Charles, The Angenieux 10mm made for 16mm use was a fixed focus lens. So was the 5.9mm. Chuck Link to comment Share on other sites More sharing options...
Premium Member Charles MacDonald Posted June 11, 2007 Premium Member Share Posted June 11, 2007 The Angenieux 10mm made for 16mm use was a fixed focus lens. So was the 5.9mm. that makes sense, in that the depth of field would be from very close to infinity at most settings. Link to comment Share on other sites More sharing options...
Patrick Neary Posted June 11, 2007 Share Posted June 11, 2007 my question is sense there is no selective focus, where does my depth of field start from. This may be a very naive question, but I am not use to a lens that does not have focus selection. I am assuming that I treat it like infinity focus? I was always under the assumption that a lens like the 10mm retrofocus was set somewhere near its wide-open hyperfocal distance (about 8 or 10 feet?)... Link to comment Share on other sites More sharing options...
chuck colburn Posted June 11, 2007 Share Posted June 11, 2007 I was always under the assumption that a lens like the 10mm retrofocus was set somewhere near its wide-open hyperfocal distance (about 8 or 10 feet?)... I use to fudge the infinity collimation on those lenses. That is I adjusted it just shy of infinity to the point that I knew it would reach it even wide open. Link to comment Share on other sites More sharing options...
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