tag:blogger.com,1999:blog-1320126156594375642.post643578109602819055..comments2024-03-27T11:02:08.037-05:00Comments on LEICA Barnack Berek Blog: INFRARED PHOTOGRAPHY WITH THE LEICA M8LEICA Barnack Berek Bloghttp://www.blogger.com/profile/09055435560407011075noreply@blogger.comBlogger21125tag:blogger.com,1999:blog-1320126156594375642.post-78862025100112335422018-08-13T11:41:22.243-05:002018-08-13T11:41:22.243-05:00Think back a bit to physics class in high school. ...Think back a bit to physics class in high school. When light transmits through a prism, it is split up into the spectral colors with red on one side and blue on the other. The same thing happens when light transmits through a single lens element, like a magnifying glass. With other words, regardless how you focus that lens, some of the "rainbow" colors will focus in front and some in back of the focal point, which is always your sensor or your film. Lens designers have learned to eliminate that problem by using more than one glass element in our lenses. This allows the lenses to focus all the visible light such that there are no out of focus parts. This is relatively difficult to do for light of the visible spectrum, and therefore infrared (and ultra violet) usually are being ignored. Films generally are not sensitive to infrared light and digital sensors are made such that they don't record infrared either. Since the Leica M8 has a certain infrared sensitivity, we can take advantage of that and take photographs with infrared light. However, since most lenses are not corrected for infrared light, we are faced with the problem that infrared light comes into focus in back of the plane of focus of the visible spectrum and thus would render out of focus images and since the rangefinder of the Leica cameras is designed for the visible light of the spectrum, it would render infrared images to be out of focus. Therefore we need to compensate for that with the above described methods.LEICA Barnack Berek Bloghttps://www.blogger.com/profile/09055435560407011075noreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-29226908246106073602018-08-13T11:39:20.744-05:002018-08-13T11:39:20.744-05:00I am confused. Why can't you use the rangefind...I am confused. Why can't you use the rangefinder?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-66286699042787095282018-08-13T11:38:47.679-05:002018-08-13T11:38:47.679-05:00Got it! Thanks.Got it! Thanks.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-39269733995087822882018-08-13T11:38:13.796-05:002018-08-13T11:38:13.796-05:00No. Please keep in mind that with the above exampl...No. Please keep in mind that with the above example, you are actually shooting at f/8. You only apply the f/5.6 or f/4 depth of field scales.LEICA Barnack Berek Bloghttps://www.blogger.com/profile/09055435560407011075noreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-46975772965895018922018-08-13T11:37:43.297-05:002018-08-13T11:37:43.297-05:00But f/5.6 or f/4 have less depth of field than f/8...But f/5.6 or f/4 have less depth of field than f/8. Wouldn't that increase any potential focus errors?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-21918501313030713812018-08-13T11:36:59.631-05:002018-08-13T11:36:59.631-05:00Yes, it is. Of course the most accurate means woul...Yes, it is. Of course the most accurate means would be to find out the focus shift of your lenses. Another means to increase focusing accuracy is to use the depth of field scale with the next larger aperture. For instance, if you are shooting at f/8, apply the focus settings on the depth of field scale for f/5.6 or even f/4. That should make up for any focusing errors that otherwise might occur.LEICA Barnack Berek Bloghttps://www.blogger.com/profile/09055435560407011075noreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-22264414373276593872018-08-13T11:36:23.834-05:002018-08-13T11:36:23.834-05:00Isn't the 300 times the focal length just a ba...Isn't the 300 times the focal length just a ballpark figure and is there a more accurate way to focus my lenses with infrared?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-77216966897632596982018-08-13T11:35:35.288-05:002018-08-13T11:35:35.288-05:00No, it's about 50 feet.No, it's about 50 feet.LEICA Barnack Berek Bloghttps://www.blogger.com/profile/09055435560407011075noreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-37815816656433659742018-08-13T11:35:00.629-05:002018-08-13T11:35:00.629-05:00Is 15 meters the same as 45 feet?Is 15 meters the same as 45 feet?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-30957672214347891382018-08-13T11:34:24.084-05:002018-08-13T11:34:24.084-05:00YesYesLEICA Barnack Berek Bloghttps://www.blogger.com/profile/09055435560407011075noreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-66829658562423066012018-08-13T11:33:47.955-05:002018-08-13T11:33:47.955-05:00Would that be the case with a dark red filter?Would that be the case with a dark red filter?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-67491692723350594512018-08-13T11:33:24.471-05:002018-08-13T11:33:24.471-05:00You would get less of the infrared effect because ...You would get less of the infrared effect because part of your exposure would be from the visible spectrum.LEICA Barnack Berek Bloghttps://www.blogger.com/profile/09055435560407011075noreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-21989946998335443702018-08-13T11:32:59.303-05:002018-08-13T11:32:59.303-05:00What would happen if I use a filter with not as hi...What would happen if I use a filter with not as high a cut off as the B+W filter that you describe in the article?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-64294516654489688792018-08-13T11:32:28.831-05:002018-08-13T11:32:28.831-05:00Yes, as long as you compensate for the focus shift...Yes, as long as you compensate for the focus shift. With a 50mm lens, for instance, you would set the 15 meter mark opposite the aperture you are using on the depth of field scale instead of the infinity mark. The same aperture on the other end of the depth of field scale will then indicate your minimum focus distance.LEICA Barnack Berek Bloghttps://www.blogger.com/profile/09055435560407011075noreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-56713405121751478562018-08-13T11:31:50.353-05:002018-08-13T11:31:50.353-05:00Can I use the depth of field scale for correct foc...Can I use the depth of field scale for correct focus?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-62594795934697279412018-08-13T11:31:03.930-05:002018-08-13T11:31:03.930-05:00Yes, with an adapter that converts the Leica R mou...Yes, with an adapter that converts the Leica R mount to the M mount. However, since the M8 has no live view provision, the lens would have to be focused manually. since there is no focus shift, it is relatively easy to focus the lens manually by utilizing the depth of field scale. However, since infrared photography usually results in relatively long exposure times because of the IR filter, it might be advisable to shoot the 180mm Apo Telyt R wide open to gain as short an exposure time as possible. That is no problem with this lens because by design, it reaches optimum performance already at maximum aperture.LEICA Barnack Berek Bloghttps://www.blogger.com/profile/09055435560407011075noreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-49166780015334642332018-08-13T11:30:21.228-05:002018-08-13T11:30:21.228-05:00Could that lens be used on an M8?Could that lens be used on an M8?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-80635289584431431912018-08-13T11:29:48.495-05:002018-08-13T11:29:48.495-05:00Yes, but very few. The Leica 180mm f/3.4 Apo Telyt...Yes, but very few. The Leica 180mm f/3.4 Apo Telyt-R is such a lens. It is corrected for not just the visible spectrum but for infrared also. It does not need to be refocused when used with infrared.LEICA Barnack Berek Bloghttps://www.blogger.com/profile/09055435560407011075noreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-63741466372301913262018-08-13T11:29:27.144-05:002018-08-13T11:29:27.144-05:00Are there any lenses which don't require refoc...Are there any lenses which don't require refocusing with infrared?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-9367597060879957952018-08-13T11:28:58.916-05:002018-08-13T11:28:58.916-05:00Basically, yes. However, don't forget to make ...Basically, yes. However, don't forget to make a series of MANUAL test exposures since the meter of the camera is calibrated for visible light only. In addition, keep in mind that you need to compensate for the focus shift with infrared light. The infinity focus position, as the article mentions, is 300 times the focal length. This comes out to the 15 meter setting for a 50mm lens.LEICA Barnack Berek Bloghttps://www.blogger.com/profile/09055435560407011075noreply@blogger.comtag:blogger.com,1999:blog-1320126156594375642.post-87457934419051892002018-08-13T11:28:27.782-05:002018-08-13T11:28:27.782-05:00So all I have to do is use an infrared filter like...So all I have to do is use an infrared filter like the B+W on my M8 and I will get results like these?Anonymousnoreply@blogger.com