Lens Breahting on Nikon Micro 105mm

[magicord]

<p>A lot of reviews mentioned that the Nikkor AF-S VR Mirco 105mm f/2.8G IF-ED breathes quite significantly (i.e. image size changes as you focus). I would like to ask those who have used the older AF 105mm f/2.8D and this newer lens, does the older AF-D lens have the same degree of lens breathing? Thanks.</p>

[joseph_wisniewski]

<p>Yes. They have comparable focal length shifts, 105mm at infinity, about 70mm at closest</p>

<p>If you want to get around that, you have to go back to an MF version.</p>

[todd peach seattle, washi]

<p>I have never heard this focal shift described as "breathing". I thought "breathing" on a lens meant that it interchanged some air on zooming or focusing (and thereby maybe sucked dust inside).</p>

<p>Did I miss something? Am I no longer hip nor relevant?</p>

[jwallphoto]

<p>I'm interested to know why you'd want to get around it. Is this a focus-stacking issue?</p>

[joseph_wisniewski]

<blockquote>

<p>I have never heard this focal shift described as "breathing".</p>

</blockquote>

<p>Todd, "breathing" is a term that's been used for decades in the film (movie) industry.You'll see it all the time in lens advertisements and reviews.<br>

Here's a brilliant little writeup <a href="http://broadcastengineering.com/news/broadcasting_cinestyle_lenses_video/">(link)</a> from broadcastengineering.com.</p>

<blockquote>

<p>I thought "breathing" on a lens meant that it interchanged some air on zooming or focusing (and thereby maybe sucked dust inside).</p>

</blockquote>

<p>That's pretty much an urban legend. There are some zooms that "pump", but not many. Even the ones sliding an optic capsule (tube of lenses) back and forth in the rear of the zoom aren't exchanging air with the outside world (the lens itself would get sucked full of dirt and rendered useless in short order). I always enjoyed how people talked about "push-pull" zooms being worse than ring type zooms. The Nikon 80-200mm f2.8 was a perfect example: the push-pull and two ring versions have exactly the same zoom mechanism, the same capsule moves the same way.</p>

<blockquote>

<p>I'm interested to know why you'd want to get around it. Is this a focus-stacking issue?</p>

</blockquote>

<p>John, it's 2010, he might be shooting some video, especially of small, live critters.</p>

<p>But basically, it's not really a focus stacking issue, mostly a composition issue. Good focus stacking software will compensate for changes in image magnification from slice to slice (but woe to those who try to use PhotoShop's stacking feature). Bigger focus stacking issues are perspective shift with focusing. I've used lenses with apocryphal perspective, the center of perspective (the entrance pupil shifts farther from the subject as you focus closer). Breathing is typically caused by "floating element" or "internal focusing" designs. The "breathing" macros often have less entrance pupil shift than good old "extend a whole lot" macros.</p>

<p>For the most part, the composition issues are the same that affect cine use. It's hard enough to focus macro lenses, where you often have to use the focus ring to get roughly in focus, then tweak the camera position (macro rail) or subject position (focusing stage, lab jacks) to refine the focus. If you factor in a change of composition as you focus, you've got three variables to juggle.</p>

[todd peach seattle, washi]

<p>Thanks Joseph. I learned a few things.</p>

[Ed_Ingold]

<p>All lenses change magnification when the focus is changed, because the lens to focal plane distance changes, even in manual focus lenses with a simple helix. This effect is exaggerated when the focal length of the lens changes, typically in order to implement internal focusing of some sort. The 105 AFD Micro shortens the focal length in order to reduce the amount of extension needed to accomplish 1:1 magnification. In its simplest form, a 105 mm lens would require four inches (105 mm) of extension, but the Nikkor lens does this with less than half that amount.</p>

<p>The best technique for focusing at higher magnifications (e.g., 1:4 or greater) is to move the camera and lens fore and aft using a focusing rail, rather than turning the lens. That way the magnification ratio remains fixed, and focusing becomes much more precise.</p>

<p>I've read a lot of lens reviews and have never encountered the term "breathing" in this context. I'm just getting into video, and it's another world (and another language). It makes sense when the flow of time is considered (e.g., to "pull focus"), but doesn't fit well with still photography (there might be three or four operators on one camera in the movie industry).</p>

[joseph_wisniewski]

<blockquote>

<p>All lenses change magnification when the focus is changed, because the lens to focal plane distance changes, even in manual focus lenses with a simple helix.</p>

</blockquote>

<p>And, by pure coincidence, that change tracks the change in composition. Similar triangles, so easy you can do it without math.</p>

<blockquote>

<p>I've read a lot of lens reviews and have never encountered the term "breathing" in this context.</p>

</blockquote>

<p>I'm not sure what timeframe you're discussing. The term "breathing" started appearing in lens reviews about the time floating elements (i.e. Nikon's "close range correction") started appearing in lenses, maybe 1970. The fact that there aren't multiple operators on a camera isn't the issue. Having to move a tripod because your composition changed when you focused is a problem that can annoy even a lone photographer.</p>

<blockquote>

<p>The best technique for focusing at higher magnifications (e.g., 1:4 or greater) is to move the camera and lens fore and aft using a focusing rail,</p>

</blockquote>

<p>The best technique, in these days of focus stacking, is by the use of bellows draw. If that's unavailable, the next best technique is by the use of a lens's focus control on a lens with minimal entrance pupil shift. Focus rails are useful for selecting starting points, but tend to play hob with the stack, adding artifacts commonly known as "echos" or "fringing".</p>

[jwallphoto]

<p>I tend to find echos/fringing in stacks whether I use the focus control or the rail, especially if I stack more than 6-8 images. I'd love to see a "best practices" piece on focus stacking.</p>

[Ed_Ingold]

<p><em>The best technique, in these days of focus stacking...</em></p>

<p>Right! Fix everything in Photoshop. I bet focus stacking works really well on a subject that moves.</p>

<p>The term "breathing" never appears in reviews published by Photodo, DXO or DPReview (to name a few). Perhaps there are wittier reviews elsewhere, for which mere facts don't suffice.</p>

<p>I stand by my recommendations. If you use a focusing rail, you don't have to move the tripod to recompose due to focusing. Point of fact, focusing the lens by racking it does not work at all at or near 1:1 magnification. The effect on magnification is profound any closer than 1:2 (50%) magnification.</p>

[Ed_Ingold]

<p><em>And, by pure coincidence, that change tracks the change in composition. Similar triangles, so easy you can do it without math.</em></p>

<p>I was puzzled by this comment. Obviously if you rack the lens it changes the common vertex, hence the ratio between the lens-to-image and lens-to-subject distances, which changes the magnification hence the composition. You can see this at nearly any distance, but moreso for closeups. The geometry does not consist of similar triangles, because the included angle changes. Furthermore, the reference to similar triangles would allow for a change in the opposite side, hence composition. Perhaps you were thinking of "identical triangles", which doesn't apply either.</p>

<p>I normally charge for math tutoring, but this one's a freebie ;-)</p>

<p> </p>

[joseph_wisniewski]

<blockquote>

<p>I tend to find echos/fringing in stacks whether I use the focus control or the rail, especially if I stack more than 6-8 images.</p>

</blockquote>

<p>Odd. I find echos and fringing are reduced when I use more images. What lens are you using? As I mentioned, some are more prone to fringing than others. Oh, and by "stack more" do you mean more images in a certain stack depth (like doing 3mm as a stack of 7 images in 0.5mm increments vs. 16 images in 0.2mm increments) or more images as in the same increment, but a deeper stack. Some ringing does increase if you stack more images at the same increment, because you've increased the amount of shift against the background. Only way around that is picking a "friendly" lens, using bellows draw, or using the telecentric stop.</p>

<blockquote>

<p>I'd love to see a "best practices" piece on focus stacking.</p>

</blockquote>

<p>I don't know where you'd find one, organized "piece", but if you search the forums on photomacrography.net for "echos" and look for discussions where Rik Littlefield (rjlittlefield) is heavily involved, you'll learn so much, so quickly, that your head will spin. Rik was the one who taught me how easy it is to use a telecentric stop on a bellows to completely eliminate echos, and I extended that technique to coupled lenses.</p>

<blockquote>

<p>The term "breathing" never appears in reviews published by Photodo, DXO or DPReview (to name a few).</p>

</blockquote>

<p>Well, if you redefine "never appears" to mean "appears frequently", sure...<br>

<a href="http://www.dpreview.com/lensreviews/nikon_70-200_2p8_vrii_n15/page6.asp">Nikon AF-S Nikkor 70-200mm F2.8G VR II at dpREview</a></p>

<blockquote>

<p>Conclusion - Cons . Pronounced focus 'breathing', i.e. widening of the angle of view on focusing closer</p>

</blockquote>

<p><a href="http://www.dpreview.com/lensreviews/panasonic_7-14_4_o20/page3.asp">Panasonic Lumix G 7-14mm F4 at dpReview</a></p>

<blockquote>

<p>Change in angle of view on focusing ('focus breathing')<br />The 7-14mm shows practically no perceptible change in its angle of view on focusing.</p>

</blockquote>

<p><a href="http://www.dpreview.com/lensreviews/olympus_m_9-18_4-5p6_o20/page3.asp">Olympus M. Zuiko Digital ED 9-18mm 1:4-5.6 at dpReview</a></p>

<blockquote>

<p>... of view on focusing ('focus breathing'). One immediately obvious feature of the 9-18mm is that the angle of view changes very markedly on focusing, becoming ...</p>

</blockquote>

<p>You notice that although you refer to "reviews published by Photodo, DXO or DPReview (to name a few)" that I only quoted dpReview. This is not "cherry picking" on my part. The term "breathing" never appears in reviews published by DXO because DXO doesn't review lenses, just cameras. Breathing isn't discussed in bicycle reviews or food processor reviews, either. I doubt photodo mentioned breathing, because they did their reviews on a Zeiss optical bench, without focusing at multiple distances. Sort of like how SLRgear does theirs now: frame the VFA test target, and that's it. They don't test multiple focus distances. Chart and analysis based testing is like that.</p>

<blockquote>

<p>Perhaps there are wittier reviews elsewhere, for which mere facts don't suffice.</p>

</blockquote>

<p>Perhaps they're as close as the nearest mirror.</p>

<blockquote>

<p>this one's a freebie ;-)</p>

</blockquote>

<p>Proof that you get exactly what you pay for. ;)</p>

<p>Seriously, Ed, why did you chime into this thread? What motivated you to make multiple, long "I never heard of breathing" posts to a thread about breathing? How did you think it would help anyone?</p>

[Ed_Ingold]

<p><em>Seriously, Ed, why did you chime into this thread? </em></p>

<p>Why do you filibuster on trivial matters? You turned one line into several dozen, using a colorful term to describe one of the effects of internal focusing.</p>

<p>My main point was to introduce (to this thread) the well-accepted practice of using a focusing rail (because racking the lens is ineffective at close range). You dismiss this in favor of "focus stacking". That's Ok if you recognize the pitfalls of any multi-shot technique on dynamic subjects, not to mention artifacts which result from the questionable geometry of this technique. For my part, simpler is usually better.</p>

<p>Another thing which needs correction - zoom lenses "breath" (as in air being moved). A push-pull zoom changes the volume it displaces, which must result in air being moved in and out of its insides (hint, if all the elements move in unison, it wouldn't be a zoom lens). A block of elements moves inside a rotating collar zoom, which results in air being pushed out the front while being sucked in the back (or vice versa). This will inevitably pull dust into the lens, although it doesn't seem to be of much consequence in practice. If necessary, that part of a zoom lens is readily accessible (by a qualified technician) for cleaning.</p>

<p>In the future, try to stick to the practicability of photographic techniques, and not lecture us on your vast knowledge of trivia, nor try to befuddle beginners with your pseudo-mathematics.</p>

[joseph_wisniewski]

<blockquote>

<p>Why do you filibuster on trivial matters?</p>

</blockquote>

<p>You really need to spend more time with a mirror.</p>

<blockquote>

<p>You turned one line into several dozen, using a colorful term to describe one of the effects of internal focusing.</p>

</blockquote>

<p>I used the term that the OP used. It's what this discussion is about. I know that's a hard concept for you to grasp, but you are the one filibustering.</p>

<blockquote>

<p>My main point was to introduce (to this thread) the well-accepted practice of using a focusing rail (because racking the lens is ineffective at close range).</p>

</blockquote>

<p>Yes, that is <em>your </em>main point. It's no one else's. No one cares, but you.</p>

<blockquote>

<p>Another thing which needs correction - zoom lenses "breath" (as in air being moved). A push-pull zoom changes the volume it displaces,</p>

</blockquote>

<p>Thank you for labeling one of your statements as something that "needs correction". Happy to help you out.<br>

Whether or not a zoom lens uses a push-pull mechanism has <strong>no bearing at all on whether or not it pumps air.</strong> I gave the example of the Nikon 80-200mm AF, which in wither its push-pull or two ring version, uses exactly the same sliding optical capsule system, and both versions use an internal channel vent around the optical capsule to prevent the ingress of dust and dirt.</p>

<blockquote>

<p>This will inevitably pull dust into the lens, although it doesn't seem to be of much consequence in practice.</p>

</blockquote>

<p>In other words, you went on for a couple of paragraphs about something that doesn't actually matter. A rather hypocritical act for someone going about other people's attempts to "filibuster" and "befuddle beginners".</p>

<blockquote>

<p>In the future, try to stick to the practicability of photographic techniques, and not lecture us on your vast knowledge of trivia, nor try to befuddle beginners with your pseudo-mathematics.</p>

</blockquote>

<p>Only if you stick to your own "vast knowledge" of absolutely nothing, and try not to "befuddle" anyone by, well, engaging in the sort of bald faced lying that I so easily dismantled.</p>

[magicord]

<p>First of all thank you all of you for your valuable input. I really hope that the discussion can be made in a calm and non-personal attacking way. <br>

The reason why I asked the question is that I am thinking of getting a macro lens for underwater photography. Breathing is something I would think about for the underwater environment where the positioning of the camera can be limited.</p>

[joseph_wisniewski]

<p>OK, OK, we'll try to keep this discussion clam for you.</p>

<blockquote>

<p>Breathing is something I would think about for the underwater environment</p>

</blockquote>

<p>Well, I should hope so!</p>

<p>Sorry, that was impossible to resist. On a more serious note...</p>

<p>I wouldn't be that concerned about breathing. You're going to be working in a range of distances, say 30-45cm if chasing fish, and the angle of view won't change that much as you focus. If you autofocus, and the camera "hunts", you might find it disconcerting as it racks from 1:1 to infinity and back, and you get the largest change of magnification. If you're working pure manual focus, that won't be a problem.</p>

<p>The VR version does have one useful feature: it lets you mix AF and MF freely. I don't know if any ports for the older 105mm macros support the old style A/M collar. As far as the VR, in general, I don't think you'll find it adds anything, with the way a camera moves underwater.</p>