{"id":2263,"date":"2012-01-03T17:58:26","date_gmt":"2012-01-03T17:58:26","guid":{"rendered":"http:\/\/www.pmstudios.co.uk\/blog\/?p=2263"},"modified":"2012-01-14T16:35:58","modified_gmt":"2012-01-14T16:35:58","slug":"checking-out-lens-focusing-a-technical-post","status":"publish","type":"post","link":"https:\/\/www.pmstudios.co.uk\/blog\/?p=2263","title":{"rendered":"Checking out lens focusing (A technical post)"},"content":{"rendered":"

Something I have been meaning to do for some time is to check the focusing of my lenses – my camera has a focus ‘micro adjustment’ feature. I had previously done this for a 50mm lens I bought last year, but never go around to checking my other lenses. Below I show the results for one of the lenses, an old (1990’s film era) 100mm macro lens:<\/p>\n

This first image shows the lens set at f2.8 with no adjustment (all these images are at 1:1 pixel size):<\/p>\n

\"f2.8<\/a>You can see the softness of this image. Compare it to the ‘+14’ adjustment:<\/p>\n

\"f2.8<\/a>Quite a distinct difference! But at f8, the same adjustment looks like this:<\/p>\n

\"f8<\/a>Not quite as sharp, but better than no adjustment. For this aperture, I found that an adjustment of +8 was best as can be seen below:<\/p>\n

\"f8<\/a>As this lens will mostly be used stopped-down, I have used +8 at the setting.<\/p>\n

To test, I set the camera up on a sturdy tripod, used mirror lockup and a 2-second delay to minimise camera shake. I took a series of photographs at different adjustments and at 2 aperture settings for each lens. For the other lenses I have, the settings I have used after testing are:<\/p>\n

EF 50mm f1.4 = +14<\/p>\n

EFS 15-85mm f5.6 = +8<\/p>\n

An old film era budget EF 75-300 f4.5-5.6 = +16<\/p>\n","protected":false},"excerpt":{"rendered":"

Something I have been meaning to do for some time is to check the focusing of my lenses – my camera has a focus ‘micro adjustment’ feature. I had previously done this for a 50mm lens I bought last year, but never go around to checking my other lenses. Below I show the results for … Continue reading “Checking out lens focusing (A technical post)”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[65],"tags":[],"class_list":["post-2263","post","type-post","status-publish","format-standard","hentry","category-technical"],"_links":{"self":[{"href":"https:\/\/www.pmstudios.co.uk\/blog\/index.php?rest_route=\/wp\/v2\/posts\/2263","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.pmstudios.co.uk\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.pmstudios.co.uk\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.pmstudios.co.uk\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.pmstudios.co.uk\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2263"}],"version-history":[{"count":11,"href":"https:\/\/www.pmstudios.co.uk\/blog\/index.php?rest_route=\/wp\/v2\/posts\/2263\/revisions"}],"predecessor-version":[{"id":2375,"href":"https:\/\/www.pmstudios.co.uk\/blog\/index.php?rest_route=\/wp\/v2\/posts\/2263\/revisions\/2375"}],"wp:attachment":[{"href":"https:\/\/www.pmstudios.co.uk\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2263"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.pmstudios.co.uk\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2263"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.pmstudios.co.uk\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2263"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}