Tutorial: How To Find Your Lens Nodal Point

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Comments

  • nowhereannowherean Beginner grinner Posts: 10Registered Users Beginner grinner
    edited November 26, 2011
    What about rangefinders?
    Hello everyone. Im trying to figure out if its possible to do the same with a rangefinder. If I cant view through the lens is there a way to calibrate? I want to use my M9 for pano landscape work. Wondering whats the best way to calibrate it with RRS pano kit.

    Thanks.
  • pathfinderpathfinder Drive By Digital Shooter Posts: 13,979Super Moderators moderator
    edited November 26, 2011
    While finding and using the nodal point can be quite helpful if you have objects near the focal plane of the camera, I find a lot of times I can shoot drive by panos of 3-10 frames and they stitch up just fine with modern software.

    For example, here is 5 frame pano shot at 28mm with a 7D, hand held, with no concern about the nodal point. Notice the tree limbs in the foreground. I wondered at the time I shot this, if they would stitch up at all shooting handheld. While the photo, of this dishwater overcast sky, is just a snapshot for the memory, the stitch in Photoshop CS4 worked just fine and I cannot find any mis positioning in the near objects, let alone the distant ones.

    You could shoot three frames with your Leica looking straight, right and left of the two vertical lines, and then evaluate the images on your computer to decide whether to move your focal plane fore or aft, but this would really be tedious, and I doubt that important for many photos. I do have my focusing rail labeled with the nodal distances for several of my lenses, so do not think I am poo pooing nodal points, I do use them. I just do not assume that if I don't happen to use them, that nothing will work out, as this pano I posted demonstrates, I think.

    Confluence of the Rivers, Camp du Bois

    Confluence-of-the-Rivers-XL.jpg

    No live view possible with the M9, apparently?

    Does it have an HDMI or a video output to an LCD?

    How about using a WiFi memory card and evaluating the image on a laptop receiving the images via WiFi?
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • MarvinMarvin Beginner grinner Posts: 1Registered Users Beginner grinner
    edited February 11, 2012
    Finding the Nodal Point
    Hi there sorry I don't know your name but I notice other thanks to you mentioned the name Dave so I assume it is Dave. I just recently joined Digital Grin and Smugrug and was browsing the forum and found your entry on finding the nodal point of a lens etc.

    It sure is a good tutorial. I was wondering could you let me have an address where the MPR-CL11 nodal slide can be purchased, I live in Northern Ireland and have been looking for this particular one for some time now.

    I would appreciate the address if you have it.
    Many thanks.
    Kind regards
    Marvin
  • David_S85David_S85 Spotter of Dgrin Spam and Oddities ChicagolandPosts: 11,437Administrators moderator
    edited February 12, 2012
    Marvin wrote: »
    Hi there sorry I don't know your name but I notice other thanks to you mentioned the name Dave so I assume it is Dave. I just recently joined Digital Grin and Smugrug and was browsing the forum and found your entry on finding the nodal point of a lens etc.
    It sure is a good tutorial. I was wondering could you let me have an address where the MPR-CL11 nodal slide can be purchased, I live in Northern Ireland and have been looking for this particular one for some time now.
    I would appreciate the address if you have it.
    Many thanks.
    Kind regards
    Marvin

    Hi Marvin! Really Right Stuff gear is what I use, and is what is seen in my tutorial. You can find them at their site here. Hope this helps.
    My Smugmug
    "You miss 100% of the shots you don't take" - Wayne Gretzky
  • AscherjimAscherjim Beginner grinner Posts: 3Registered Users Beginner grinner
    edited February 19, 2012
    David_S85 wrote: »
    Thanks, David.

    Easy enough to find the middle and mark it with a line, no?

    My camera is mounted on a nodal slide in portrait mode with a generic L-bracket without a lens center line marked on the L-bracket. Aside from positioning the camera on the slide so the vertical center of the lens seems by eyesight to be aligned with the center line of the slide, is there not a more precise way to do this? Or doesn't that level of precision really matter? If the camera were positioned on the slide in landscape mode, without an L-bracket involved, there would likely not be a problem, as in that instance the tripod socket is usually positioned at the vertical center line of the lens. Thanks, Jim
  • David_S85David_S85 Spotter of Dgrin Spam and Oddities ChicagolandPosts: 11,437Administrators moderator
    edited February 20, 2012
    Ascherjim wrote: »
    My camera is mounted on a nodal slide in portrait mode with a generic L-bracket without a lens center line marked on the L-bracket. Aside from positioning the camera on the slide so the vertical center of the lens seems by eyesight to be aligned with the center line of the slide, is there not a more precise way to do this? Or doesn't that level of precision really matter? If the camera were positioned on the slide in landscape mode, without an L-bracket involved, there would likely not be a problem, as in that instance the tripod socket is usually positioned at the vertical center line of the lens. Thanks, Jim

    Initial trial and error is the best way for each lens and focal length. With the advent of live view, you might not even need to take a real shot to set things up. Sure wish I had that option back in my 20D days. But guessing where the center point may be is difficult in many lenses. My Canon 10-22's center pivot points are very odd. One would think that notation marks on a nodal slide would correspond and progress in order up and down the slide. They don't. There are some lenses that the center pivot point might not be physically within the lens' length. I have learned not to guess.

    Exact lens centering matters less when all objects are far away; so in many landscape pano's, you might very well get decent results without calibrating for your camera/lens/focal length combo.

    Stitching programs have more difficulty when objects are nearer. Those are situations where you are best to spend time calibrating first, and somehow marking the slider, or doing whatever is necessary to repeat good results.

    I recently shot an eight image 360 VR pano at 10mm of a small kitchen for a real estate listing. The corner of a doorway was a couple of feet away from the pano head, and with the natural lens distortions at extreme wide angle, I would have had a jumbled mess on my hands with even the best stitching software had I not calibrated the rig those several years ago. Since I had the marks on my slide for my lens, the setup was easy, and I just swung the thing around and shot every 45 degrees. I had no worries that it wouldn't work.

    i-nr9dtjm-XL.jpg
    My Smugmug
    "You miss 100% of the shots you don't take" - Wayne Gretzky
  • zoomerzoomer Major grins Posts: 3,688Registered Users Major grins
    edited February 20, 2012
    Good stuff. Interesting info on how much even small changes affect it.

    I agonized over spending a bunch of money on equipment to do pano's properly.
    Then I decided to try doing them by hand and just using my tripod as a center point to pivot around, handholding the camera, keeping the horizon level.
    It works pretty well even on foreground stuff...I am sure due to the software being really good at stitching things together.

    Certainly there are applications where the right equipment is needed as mentioned...but for me for landscapes....handholding works.
  • AscherjimAscherjim Beginner grinner Posts: 3Registered Users Beginner grinner
    edited February 20, 2012
    David_S85 wrote: »
    Initial trial and error is the best way for each lens and focal length. With the advent of live view, you might not even need to take a real shot to set things up. Sure wish I had that option back in my 20D days. But guessing where the center point may be is difficult in many lenses. My Canon 10-22's center pivot points are very odd. One would think that notation marks on a nodal slide would correspond and progress in order up and down the slide. They don't. There are some lenses that the center pivot point might not be physically within the lens' length. I have learned not to guess.

    Exact lens centering matters less when all objects are far away; so in many landscape pano's, you might very well get decent results without calibrating for your camera/lens/focal length combo.

    Stitching programs have more difficulty when objects are nearer. Those are situations where you are best to spend time calibrating first, and somehow marking the slider, or doing whatever is necessary to repeat good results.

    I recently shot an eight image 360 VR pano at 10mm of a small kitchen for a real estate listing. The corner of a doorway was a couple of feet away from the pano head, and with the natural lens distortions at extreme wide angle, I would have had a jumbled mess on my hands with even the best stitching software had I not calibrated the rig those several years ago. Since I had the marks on my slide for my lens, the setup was easy, and I just swung the thing around and shot every 45 degrees. I had no worries that it wouldn't work.

    i-nr9dtjm-XL.jpg

    David: Many thanks for your quick and informative reply. However, I suspect that my query wasn't worded precisely enough and you possibly misunderstood. I wasn't asking about calculating the nodal (center) point (which I can do through moving the camera forward or backward on the slide) but rather the more simple(!) matter of the initial positioning of my camera and its lens on the slide for LATERAL adjustment on the slide to center the lens on the width of the slide. Sorry for any confusion. Thanks again, and regards, Jim
  • pathfinderpathfinder Drive By Digital Shooter Posts: 13,979Super Moderators moderator
    edited February 22, 2012
    The newer L brackets from Really Right Stuff have lines machined into them that display the exact center of your sensor, so that you CAN center your camera body on the center of the shooting axis of your rotating pano head.

    Some camera bodies have marks showing the center of the sensor plane, and some the central axes of the sensor itself.

    Otherwise, you just have to eyeball getting the lens axis centered on your planned shooting axis...
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • AscherjimAscherjim Beginner grinner Posts: 3Registered Users Beginner grinner
    edited February 22, 2012
    pathfinder wrote: »
    The newer L brackets from Really Right Stuff have lines machined into them that display the exact center of your sensor, so that you CAN center your camera body on the center of the shooting axis of your rotating pano head.

    Some camera bodies have marks showing the center of the sensor plane, and some the central axes of the sensor itself.

    Otherwise, you just have to eyeball getting the lens axis centered on your planned shooting axis...

    My L-bracket is made up of two Arca Swiss-type rails joined at 90-degrees by a 90-degree bracket. Whereas, as I stated earlier, the tripod socket is situated directly under the middle of the lens mounting when the camera is in its horizontal position, when the camera is in a vertical mode on the L-bracket, the precise center alignment of the lens is not subject to so precise a determination. However, I've now figured out a way to measure this for my purposes. Many thanks for your further thoughts.
  • JRSEEJRSEE Jay Posts: 19Registered Users Big grins
    edited May 11, 2012
    pano settings
    i just tried the method explained and came up with very different settings. I was using a 24-70 zoom and most of my settings came almost to the end of the rail, about 3.0. With what little knowledge i have of nodal points it seemed odd to me that the nodal point was almost at the end of the lens. I expected it to be nearer the center of the lens. I did it for several focal lengths and they all came out about the same.

    Jay
  • Pono PhotoPono Photo Major grins Posts: 68Registered Users Beginner grinner
    edited May 11, 2012
    Hmmm.. This is awesome! But I need to figure out how to do it in 3 dimensions as well. I use a Nodal Ninja, the NN5. So it's got a few other things that can slide as well since it rotates vertically also.

    Maybe do this near a wall, where I can have the two Pez dispensers on the table, then two also attached somehow to the wall sticking out horizontally? headscratch.gif Or maybe do one setting, then the second instead of trying to figure both at one time. ne_nau.gif The one setting will never change though once I get it dialed in since it is based off of the distance from the center of my lens to the base of the camera.

    Well, I'm not doing anything today until this evening... no time like the present... :D
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