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General Photography
Macro
Anyone using a telephoto?
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<blockquote data-quote="Stoshowicz" data-source="post: 359648" data-attributes="member: 31397"><p>Very interesting, so what appeared to me to be sharp and in focus , is actually three times the width of the 'actual' plane of focus.OK.</p><p>But the comparison is still a bit off versus what Id like to know- Ill explain,- the main lens 'claims' its getting a 1:1 ratio which depends on the closest distance it can focus.</p><p>The closer a lens needs to be to get 1:1 magnification the less 'magnifying' the main lens is really doing. </p><p>Depth of field is relative by the amount of 'magnification' that is happening (all else held constant)</p><p></p><p>So the addition of the diopter glass ,(may..) reduces the magnification required to 'fill' the sensor and therefore might potentially expand the DoF relative to the spread of the target on the sensor.</p><p>OR </p><p>is the diopter's effect also a magnification effect. ( so it wouldnt help to preserve field depth.)</p><p></p><p>If I remember correctly ..</p><p>Fiddling with my 70-300mm , I took a photo of a dragonfly at 300mm and the thing took up one third of the sensor length.</p><p> I zoomed all the way back to 70mm, added the diopter, and got close enough to focus again. </p><p>The dragonfly again filled half the sensor width , so I had the same number of pixels per dragonfly... but now... I could zoom in yet father , and get <em>more</em> pixels per dragonfly.</p><p>I dont really have an interest in whether I get a true macro by someone elses arbitrary standards, I just want the greatest number of pixels per bug with enough field depth to cover it wingtip to wingtip.</p><p></p><p>Im trying to figure out if I can get that using diopters added to main lenses <em>sacrificing flexibility in focus distances</em> for greater DOF at whatever aperture I can supply enough light for, at Iso 200.</p><p></p><p><img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /> which is a calculation I dont know how to make. The main lens alone seems to have a sweet spot at 135-200 mm zoom, at an aperture of F11 .</p></blockquote><p></p>
[QUOTE="Stoshowicz, post: 359648, member: 31397"] Very interesting, so what appeared to me to be sharp and in focus , is actually three times the width of the 'actual' plane of focus.OK. But the comparison is still a bit off versus what Id like to know- Ill explain,- the main lens 'claims' its getting a 1:1 ratio which depends on the closest distance it can focus. The closer a lens needs to be to get 1:1 magnification the less 'magnifying' the main lens is really doing. Depth of field is relative by the amount of 'magnification' that is happening (all else held constant) So the addition of the diopter glass ,(may..) reduces the magnification required to 'fill' the sensor and therefore might potentially expand the DoF relative to the spread of the target on the sensor. OR is the diopter's effect also a magnification effect. ( so it wouldnt help to preserve field depth.) If I remember correctly .. Fiddling with my 70-300mm , I took a photo of a dragonfly at 300mm and the thing took up one third of the sensor length. I zoomed all the way back to 70mm, added the diopter, and got close enough to focus again. The dragonfly again filled half the sensor width , so I had the same number of pixels per dragonfly... but now... I could zoom in yet father , and get [I]more[/I] pixels per dragonfly. I dont really have an interest in whether I get a true macro by someone elses arbitrary standards, I just want the greatest number of pixels per bug with enough field depth to cover it wingtip to wingtip. Im trying to figure out if I can get that using diopters added to main lenses [I]sacrificing flexibility in focus distances[/I] for greater DOF at whatever aperture I can supply enough light for, at Iso 200. :) which is a calculation I dont know how to make. The main lens alone seems to have a sweet spot at 135-200 mm zoom, at an aperture of F11 . [/QUOTE]
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Anyone using a telephoto?
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