Nodal point for longer focal lengths?

[rs-eos]

I just got some pano gear (single row for now; nodal slide and leveling base).  I have two lenses: 50mm f/1.2 L and 135mm f/2 L.  And use a 5D IV.

After watching various videos on finding nodal points, I set up two lightstands in my house about 5 feet apart, camera then about 5 feet from the closest one (so 10 feet total distance).  But I found that unless the nodal slide was at the extreme ends (it covers about 120mm movement total), then I couldn't see the effect.

I then thought hmmm... maybe this is because I have a 50mm and the videos I saw typically were using 24mm or wider.

When I then increased the distance of my setup to around 30 feet, and used the 10x magnification in live view, I could then see the paralax effect and start making adjustments.  But I could only narrow down the nodal point to a range (60 to 80mm on the slide).

Today, went outside and increased the distance to around 70 feet and was able to narrow the nodal point down further; between 60 and 65mm.

Put on the 135mm and no luck fine tuning at all.

Thus, is it correct to state that for longer focal lengths, in order to really hone in on the nodal point, you need to be working with objects very far away from each other?  I'm thinking I should find say two or more telephone poles.  Or even some nearby tree and a distant water tower.

Any tips on the ideal distance for the lenses above?  And that attempting to find nodal points is thus easier on wider angle lenses since you don't need much distance?   Thanks.

[Waddizzle]

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@rs-eos wrote:

I just got some pano gear (single row for now; nodal slide and leveling base).  I have two lenses: 50mm f/1.2 L and 135mm f/2 L.  And use a 5D IV.

After watching various videos on finding nodal points, I set up two lightstands in my house about 5 feet apart, camera then about 5 feet from the closest one (so 10 feet total distance).  But I found that unless the nodal slide was at the extreme ends (it covers about 120mm movement total), then I couldn't see the effect.

I then thought hmmm... maybe this is because I have a 50mm and the videos I saw typically were using 24mm or wider.

When I then increased the distance of my setup to around 30 feet, and used the 10x magnification in live view, I could then see the paralax effect and start making adjustments.  But I could only narrow down the nodal point to a range (60 to 80mm on the slide).

Today, went outside and increased the distance to around 70 feet and was able to narrow the nodal point down further; between 60 and 65mm.

Put on the 135mm and no luck fine tuning at all.

Thus, is it correct to state that for longer focal lengths, in order to really hone in on the nodal point, you need to be working with objects very far away from each other?  I'm thinking I should find say two or more telephone poles.  Or even some nearby tree and a distant water tower.

Any tips on the ideal distance for the lenses above?  And that attempting to find nodal points is thus easier on wider angle lenses since you don't need much distance?   Thanks.

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If the videos were using 24-70s, it sounds like you watched this guy, Lester Picker.

https://youtu.be/IFQHoCjFTn8 

I followed his instructions, and got my 70-200 set up no problem.  But, I think my nodal rail is longer than yours.  I am using the Kirk LRP-1, which is 19cm long, or 190mm.  They do not sell the nodal gimbal setup he uses, anymore.

I would have thought that you could find the nodal point with your shorter rail. I currently had my rail setup for macro shots with the 100mm macro.  The lens is at the nodal point, and there is stilll plenty of room for it back up even further.

[rs-eos]

Not sure why I thought the slide was only 120mm of freedom; it has 170mm.

Anyhow, I believe I found my issue.  After seeing other videos, I had noticed that the near object was close to the camera (say within 4 feet) and then the distant object quite far.

So using the front window's pane divisions as the near object, the further away the distant object is, the easier it is to fine-tune the reading.  Already with this setup (with the further object being say 100 yards away), it was very obvious to see the parallex effect with the 50mm.

Earlier, I had the closer lightstand about half-way between the camera and the farther lightstand.  That doesn't work well 🙂

Time for a road trip to so as to increase the distance even further.  Will report back once I have the final solution.

[rs-eos]

Much easier with the futher distance; perhaps 1/4 mile.  Lightstand near the camera, then used a distant radio tower.  50mm was a snap.  135mm though may actually be behind the camera.  At the minimum slide position (0mm), it was very close though.  So I'm not going to invest in any futher gear.

The main reason for the panos are for ultimately doing 3 x 3 shots with very shallow DOF.  Thus the distant objects won't matter.  I want to create wider FOVs with both lenses while at their minimum focusing distance to the subject.   For now, I can only do single-row. But with the calibration done, I can at least start doing some test projects while I wait for the multi-row gear.

[Waddizzle]

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@rs-eos wrote:

Much easier with the futher distance; perhaps 1/4 mile.  Lightstand near the camera, then used a distant radio tower.  50mm was a snap.  135mm though may actually be behind the camera.  At the minimum slide position (0mm), it was very close though.  So I'm not going to invest in any futher gear.

The main reason for the panos are for ultimately doing 3 x 3 shots with very shallow DOF.  Thus the distant objects won't matter.  I want to create wider FOVs with both lenses while at their minimum focusing distance to the subject.   For now, I can only do single-row. But with the calibration done, I can at least start doing some test projects while I wait for the multi-row gear.

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Some software packages may want you to capture the images in certain order for multi-row panos.  The guy in the video, Lester Picker, has videos about multi-row captures.

[Waddizzle]

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@rs-eos wrote:

Not sure why I thought the slide was only 120mm of freedom; it has 170mm.

Anyhow, I believe I found my issue.  After seeing other videos, I had noticed that the near object was close to the camera (say within 4 feet) and then the distant object quite far.

So using the front window's pane divisions as the near object, the further away the distant object is, the easier it is to fine-tune the reading.  Already with this setup (with the further object being say 100 yards away), it was very obvious to see the parallex effect with the 50mm.

Earlier, I had the closer lightstand about half-way between the camera and the farther lightstand.  That doesn't work well 🙂

Time for a road trip to so as to increase the distance even further.  Will report back once I have the final solution.

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I think you have it set well enogh.  You can recheck it in the field, but I would expect it to be aligned. Besides, not unless you have foreground items in the scene, using the nodal point is helpful, but not crucial.