BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Reply to thread

Message: <blockquote data-quote="Paul Corfield" data-source="post: 1673655" data-attributes="member: 19132">Yeah, that's with all that taken into account. The way I personally work out the magnification is to shoot a stationary object with the scope at 600mm and no barlow. Then I use the barlow with a macro tube to increase the magnification and take another photo. In Photoshop I overlay the 600mm one onto the magnified one and make the 600mm one semi transparent by adjusting the layer transparency. Then using the percentages I increase the 600mm in size until it matches the photo taken with the barlow. The transparency allows you to see when they perfectly match. The percentage needed to get them to match up is your finial figure for the magnification. For example if you had to increase the 600mm photo by 350% to match up with the barlow one then you know it's 3.5X bigger and the barlow in that position is giving 3.5X magnification. It's harder to describe than to actually do. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink    ;)" loading="lazy" data-shortname=";)" />Paul.</blockquote>