{"id":850,"date":"2022-01-31T16:11:17","date_gmt":"2022-01-31T14:11:17","guid":{"rendered":""},"modified":"2022-02-25T14:19:48","modified_gmt":"2022-02-25T12:19:48","slug":"the-thermal-camera-lens-that-soltubes-from-it","status":"publish","type":"post","link":"https:\/\/optikwelt.ee\/en\/huvitavat\/termokaamera-objektiiv-mis-sellest-soltub\/","title":{"rendered":"Thermal camera lens - what does it depend on?"},"content":{"rendered":"<p>How do the characteristics of the lens affect the thermal camera image and which lens would be best?<!--more--><\/p>\n<p>In terms of its optical characteristics, a thermal camera is comparable to a photo camera or a long lens. Therefore, if you have not used a thermal camera before, experience with photo cameras or other optical devices will help you to understand the characteristics of the lens.<\/p>\n<p>A video summary of this article can be seen in the video below.<\/p>\n<p><iframe loading=\"lazy\" title=\"Thermal camera lens - what does it depend on?\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/nSlMWNFyIAM?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/p>\n<h2>Field of view of thermal camera<\/h2>\n<p>As with binoculars, the field of view, or field of view of the lens, is crucial, and depends on the focal length, or magnification.<\/p>\n<p>A simple rule applies to all optical devices: the more powerful the magnification, the narrower the field of view. In addition, higher magnification means lower light transmission. Also, lenses with higher magnification are more difficult to focus.<\/p>\n<p>Inexperienced wildlife observers tend to buy the highest magnification equipment first, assuming that it is the best. In practice, this approach fails. The magnification of the lens should be chosen according to the main observation tasks.<\/p>\n<p><a href=\"https:\/\/optikwelt.ee\/wp-content\/uploads\/2021\/04\/helion-objektiivid.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4303\" src=\"https:\/\/optikwelt.ee\/wp-content\/uploads\/2021\/04\/helion-objektiivid.jpg\" alt=\"Pulsar Helion lenses\" width=\"2048\" height=\"1365\" \/><\/a><\/p>\n<p>Pulsar offers thermal cameras with different magnification. For example, the Helion family of interchangeable lens units offers a choice of 28mm, 38mm and 50mm lens models. The table below shows the field of view, angle of view and magnification.<\/p>\n<table width=\"100%\">\n<thead>\n<tr>\n<th>Model<\/th>\n<th>Field of view @100m<\/th>\n<th>Viewing angle H\/V<\/th>\n<th>Enlarge<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Helion XP28<\/td>\n<td>39m<\/td>\n<td>22\u00d716.6\u00b0<\/td>\n<td>1.4x<\/td>\n<\/tr>\n<tr>\n<td><a href=\"https:\/\/optikwelt.ee\/en\/pood\/thermal-imaging-cameras\/soojuskaamera-pulsar-helion-xp38\/\" target=\"_blank\" rel=\"noopener\">Helion XP38<\/a><\/td>\n<td>28.6m<\/td>\n<td>16.3\u00d712.3\u00b0<\/td>\n<td>1.9x<\/td>\n<\/tr>\n<tr>\n<td><a href=\"https:\/\/optikwelt.ee\/en\/pood\/thermal-imaging-cameras\/soojuskaamera-pulsar-helion-xp50\/\">Helion XP50<\/a><\/td>\n<td>21.8m<\/td>\n<td>12.4\u00d79.3\u00b0<\/td>\n<td>2.5x<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Depending on the focal length, the field of view of the device also varies.<\/p>\n<p><a href=\"https:\/\/optikwelt.ee\/wp-content\/uploads\/2022\/01\/objektiivi-omaduste-vordlus-1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-5936\" src=\"https:\/\/optikwelt.ee\/wp-content\/uploads\/2022\/01\/objektiivi-omaduste-vordlus-1.jpg\" alt=\"Comparison of lenses\" width=\"1920\" height=\"1280\" \/><\/a><\/p>\n<h2>Sensor cut-off factor<\/h2>\n<p>In order to be able to compare the focal length of different camera lenses, a crop factor is used. The sensor size of the Helion XP is 640\u00d7480@17\u00b5m, which is approximately 10.9 x 8.2 mm (\u27cb13.64mm) (calculation: 640\u00d717\/1000, 480\u00d717\/1000). The sensor size of the full-frame camera is 36 x 24 mm (\u27cb43.27mm). Sony\/Nikon APS-C sensor size is 23.6 x 15.7 mm (\u27cb28.34mm).  The resolution of the Helion XP sensor compared to the full-frame sensor is 3.17 (43.27 \/ 13.64) . Based on this, we can compare the focal length of Helion XP lenses with other cameras.<\/p>\n<ul>\n<li>28mm = 89mm (60mm APS-C)<\/li>\n<li><span style=\"color: #555555; font-family: Helvetica, Arial, sans-serif;\">38mm = 120mm (80mm APS-C)<\/span><\/li>\n<li>50mm = 158mm (105mm APS-C)<\/li>\n<\/ul>\n<p>The above shows that when comparing Pulsar Helion lenses to full frame camera lenses, the XP28 has a field of view similar to an 89mm lens, the XP38 has a field of view similar to a 120mm lens and the XP50 has a field of view similar to a 158mm lens. Based on this information, it is easy to test with either a full frame or APS-C camera which lens of the Helion series might be better suited for the observation situation.<\/p>\n<p><a href=\"https:\/\/optikwelt.ee\/wp-content\/uploads\/2022\/01\/fookuskauguste-vordlus-helion-xp.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-5945\" src=\"https:\/\/optikwelt.ee\/wp-content\/uploads\/2022\/01\/fookuskauguste-vordlus-helion-xp.jpg\" alt=\"Comparison of focal lengths\" width=\"2048\" height=\"1365\" \/><\/a><\/p>\n<p>Comparison of focal lengths<\/p>\n\n<h2>Thermal camera magnification<\/h2>\n<p>How do the same objects look at different magnifications? This diagram shows a comparison of different magnifications of the same object.<\/p>\n<p><a href=\"https:\/\/optikwelt.ee\/wp-content\/uploads\/2022\/01\/objektiivi-suurenduse-vordlus-2.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-5931\" src=\"https:\/\/optikwelt.ee\/wp-content\/uploads\/2022\/01\/objektiivi-suurenduse-vordlus-2.jpg\" alt=\"Lens magnification\" width=\"1920\" height=\"1280\" \/><\/a><\/p>\n<p>In Estonian landscape conditions, a 38mm lens is suitable for most observation tasks. Thanks to its medium magnification, the 38mm lens is well suited for detecting game as quickly as possible, as well as for following the activity of an already detected animal (e.g. stalking), as the game does not disappear from the camera's field of view as quickly.<\/p>\n<p>Also, don't forget that wider-angle lenses are less tiring on the eyes because the image doesn't shake as much as it does at higher magnifications.<\/p>\n<p>The 50mm lens is better suited to more specific observing tasks where there is a need to track game birds undisturbed from a distance. For longer distance observation, it is recommended to use a tripod with the 50mm lens for convenience, as the narrower field of view makes it more tiring to keep the same point in the frame. With 28mm and 38mm lenses, you can manage without a tripod.<\/p>\n<h2>Summary<\/h2>\n<p>There is no one lens that fits all. More powerful magnification does not necessarily mean a better device. The lens should be chosen according to the observation task.<\/p>\n<p>A camera with a smaller focal length is great for spotting game as quickly as possible. Again, a longer focal length camera is better for those longer exposures where you need to stay as far away from the game as possible.<\/p>","protected":false},"excerpt":{"rendered":"<p>How do the characteristics of the lens affect the thermal camera image and which lens would be best?<\/p>","protected":false},"author":1,"featured_media":876,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[125],"tags":[139,129,133],"class_list":["post-850","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-huvitavat","tag-pulsar-tag-et","tag-termokaamera","tag-termokaamera-objektiiv"],"acf":[],"_links":{"self":[{"href":"https:\/\/optikwelt.ee\/en\/wp-json\/wp\/v2\/posts\/850","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/optikwelt.ee\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/optikwelt.ee\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/optikwelt.ee\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/optikwelt.ee\/en\/wp-json\/wp\/v2\/comments?post=850"}],"version-history":[{"count":0,"href":"https:\/\/optikwelt.ee\/en\/wp-json\/wp\/v2\/posts\/850\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/optikwelt.ee\/en\/wp-json\/wp\/v2\/media\/876"}],"wp:attachment":[{"href":"https:\/\/optikwelt.ee\/en\/wp-json\/wp\/v2\/media?parent=850"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/optikwelt.ee\/en\/wp-json\/wp\/v2\/categories?post=850"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/optikwelt.ee\/en\/wp-json\/wp\/v2\/tags?post=850"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}