sps Posted January 23, 2007 Share #1 Posted January 23, 2007 Advertisement (gone after registration) Someone asked me how I can tell if the Noct is in focus at a certain point given that lenses have a depth-of-field. Attached is a picture taken at min focusing distance. The only razor thin plane is exactly what I focused on. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Quote Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/14207-noctilux-on-m8-dof-close-focus/?do=findComment&comment=149848'>More sharing options...
Advertisement Posted January 23, 2007 Posted January 23, 2007 Hi sps, Take a look here Noctilux on M8 DOF @ Close Focus. I'm sure you'll find what you were looking for!
Iron Flatline Posted January 23, 2007 Share #2 Posted January 23, 2007 Eww... what is it? But thank you, as expected that extremely shallow dof must be used with caution. I guess it is a good thing that the 50mm on the M8 has the cropped effect of shooting a 75mm when filling the image, which is a good lenght for portrait work. At those kinds of distances, you could conceivably use the f/1 stop and still get both eyes in focus. Quote Link to post Share on other sites More sharing options...
blakley Posted January 23, 2007 Share #3 Posted January 23, 2007 ...that extremely shallow dof must be used with caution. I guess it is a good thing that the 50mm on the M8 has the cropped effect of shooting a 75mm when filling the image, which is a good lenght for portrait work. At those kinds of distances, you could conceivably use the f/1 stop and still get both eyes in focus. No; with the Noct at minimum focus distance you can't get both eyes in focus unless they're in exactly the same plane parallel to the sensor. Here's the older f/1.2 Noct at 1.2 and minimum distance - you can see that the point of focus is the far arc of the iris of the subject's right eye (to the left in the picture). The iris of the near eye is noticeably out of focus already. Quote Link to post Share on other sites More sharing options...
sps Posted January 23, 2007 Author Share #4 Posted January 23, 2007 It is a little disturbing. It is the corner of an antique painting frame, shot looking from the side. Not a pretty picture, but illustrates the point. Quote Link to post Share on other sites More sharing options...
robertwright Posted January 23, 2007 Share #5 Posted January 23, 2007 you can do the test yourself, shoot a tape measure at the required distance and you can see what is in and what is out: I did a job on the canon 85 1.2L and even at 6 to 8 feet, there is only about 1.5" of dof, enough that if I move and the subject moves just a little after focusing, it is out. You get a lot of soft frames shooting at 1.2 or 1.0, it takes a lot of work. Kind of surpised me at that distance, to be so shallow. Even at f2 on the 85, at about 6 feet, or headshot distance, the dof is only about 2 to 3 inches, not much more, the eyes will be in and the ears will be out. Quote Link to post Share on other sites More sharing options...
Tony C. Posted January 23, 2007 Share #6 Posted January 23, 2007 No question that the depth of field is extremely narrow when using a Noctilux. This makes using the lens quite a challenge, but also extremely satisfying when an image works well. In my admittedly brief experience with the M8 thus far, the unique capabilities and potential of the Noctilux easily outweigh the challenges which it presents. Regards, Tony C. Quote Link to post Share on other sites More sharing options...
Eoin Posted January 23, 2007 Share #7 Posted January 23, 2007 Advertisement (gone after registration) To get both eyes in focus on a typical tight head & shoulder slight profile (head turned towards camera but not facing directly) you need a minimum of f/2.2 - f/2.8 to get both eyes in sharp focus reliably with this focal length. Quote Link to post Share on other sites More sharing options...
eronald Posted January 23, 2007 Share #8 Posted January 23, 2007 To get both eyes in focus on a typical tight head & shoulder slight profile (head turned towards camera but not facing directly) you need a minimum of f/2.2 - f/2.8 to get both eyes in sharp focus reliably with this focal length. I usually have the Canon 85/1.2 set at F4 when not playing games. Any place under F4 you can start to check the screen to see where the focus falls and what the result looks like. At F1.2 the DOF is around 2-3 mm !!! when at closes distance - a problem because if you focus on the eyelashes of ONE eye the iris won't be sharp et etc. Edmund Quote Link to post Share on other sites More sharing options...
jaapv Posted January 23, 2007 Share #9 Posted January 23, 2007 Don't forget the Noctilux has considerable focus shift. I.e. it moves the plane of focus as the lens is stopped down. Towards the camera, if I recall correctly. Quote Link to post Share on other sites More sharing options...
Arielv13 Posted January 23, 2007 Share #10 Posted January 23, 2007 Does this mean that I would have to manually figure out the focus shift via distance scale on the lens. I don't see how a rangefinder could handle the shift. I have a line on a used Noctilux. This may dissuade me. Thanks Arielv13 Quote Link to post Share on other sites More sharing options...
sps Posted January 23, 2007 Author Share #11 Posted January 23, 2007 About focus shift.... Maybe I got lucky (I shot hand-held), but this is exactly where I focused, and used nothing but the rangefinder to determine that focus. Mine is the most recent N-lux. Quote Link to post Share on other sites More sharing options...
jaapv Posted January 23, 2007 Share #12 Posted January 23, 2007 Does this mean that I would have to manually figure out the focus shift via distance scale on the lens. I don't see how a rangefinder could handle the shift. I have a line on a used Noctilux. This may dissuade me. Thanks Arielv13 I wouldn't worry too much about it. Noctilux users have lived with this without complaint since the lens came to the market.There are many other lenses that do this to some extent. Sometimes it disappears into DOF, sometimes users compensate nearly without noticing they do so. It is part of the fairly steep learning curve with this type of lens. The lens is normally used at wide apertures too, which is where it is most accurate. If you have the M8 instant feedback will soon help you cope. Quote Link to post Share on other sites More sharing options...
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