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Raynox DCR-150 tube assembly with flocking
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rjlittlefield
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PostPosted: Wed Nov 13, 2019 8:50 pm    Post subject: Reply with quote

dhmiller wrote:
Thanks Rik, Would self-adhesive flocking "tape" also work?

I assume so, but I've never worked with that material.

Smokedaddy wrote:
Since I haven't dove into this sort of setup yet, will it work fine on a Canon APS-C type sensor instead of a FF?

Yes. I've done Canon also and did not notice that the mount made much difference. Canon's bayonet is larger than Nikon's, which makes the flocking a little easier.

--Rik
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rjlittlefield
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PostPosted: Wed Nov 20, 2019 8:36 pm    Post subject: Reply with quote

This post is to report on my recent experiences with an MJKZZ tube set.

First, I think it's important to say up front that the set of tubes I'm working with is not a random sample. In fact they belong to another fellow, who contacted me because he was not able to make them work well despite lots of assistance from MJKZZ corporate. I was curious to see what the problem was, so I offered to take a look at them for him.

Earlier, mawyatt reported that
Quote:
The tubes in the MJKZZ are the standard extension tubes but of higher quality than you can generally get on eBay unless you know the vendor. I already had a bunch of these and most were very sloppy fit, the Nikon F mount adapter & lens adapter were mostly loose and had to hand pick the better ones and toss the rest. MJKZZ are better tubes & Nikon adapters than I had generally found on eBay.

Sadly, the particular set that I'm working with is quite different. In fact these tubes have turned out to be the worst that I've ever seen. They even have a type of manufacturing defect that I don't recall having seen before.

Skipping forward to the good news, the final product of my labors is a very nice set of tubes.

This is what the final configuration looks like. It's rock solid and focuses perfectly at infinity with the Raynox DCR-150 alone. It's also completely free of internal reflections. Loosening two capscrews on the clamps allows the whole tube assembly to rotate, for switching between landscape and portrait orientations. I'm pretty sure I would enjoy using this set, but I'm going to send it back to the other fellow so he can.



So, the final state is the good news.

The bad news is that the whole process was not a great out-of-the-box experience. In fact it took quite a lot of fiddling to get all the parts to play together well.

The biggest problem, and one that I did not expect, was this:



The above is a GIF animation, and if it's displaying correctly, you're seeing about 1 mm of free play between the female bayonet and the extension tube that it's fastened to.

Here's what the problem turned out to be. In every one of the three sets of tubes, most or all of the screws would not seat fully. The underlying reason is that the screw holes were simply not tapped to full depth, although they were drilled plenty deep enough.



In addition to that problem, there was also an issue that the male bayonets did not snugly fit the female bayonets. In most cases the male flange was not sized to engage the springs at all, leaving the joint to simply flop around. Illustrating this second problem using leftover parts:



Both of these problems could have been addressed with tape, which I understand was MJKZZ's corporate suggestion to the other fellow. I like tape, but I don't consider it to be a good long term solution for parts that are not supposed to move.

So after considering options, I decided to just use my old friend epoxy. I removed the four screws holding the female bayonet loosely in place, cleaned all the parts with a cotton swab soaked in acetone, put a thin layer of slow-set epoxy on all the mating faces, reset the screws to where they had been before, put another thin layer of epoxy on the front of the female bayonet and the back of the bayonet-to-M42 adapter, assembled the set, and clamped it to about 50 pounds overnight to ensure that any spare epoxy got squeezed out before the stuff set.

The resulting sandwich is rock solid and measures flat to within 10 microns from side to side. I'm not anticipating any problems, but in the unlikely event that some of the epoxy eventually debonds, the screws and bayonet flanges will guarantee that nothing actually falls apart.



Now, about that VLE module (variable length extension). It consists of two tubes, one internally threaded, the other externally threaded, both M42, both 20 mm long. You might expect that due to normal manufacturing tolerances these two parts cannot possibly fit together snugly, and you'd be right. To address that problem, the kit I received contained a roll of PTFE pipe thread tape, with the suggestion to wrap the threads with enough of that to make the fit snug but not too tight.



PTFE tape is a pretty clever solution here, but again, I'd rather not go that route if it can be avoided.

What I would do instead, if I needed the VLE to actually be adjustable, is to use this approach:



It's attractive to consider skipping the epoxy and just using two locking rings. The problem with that approach is that the tube is only 20 mm long. By the time you engage two turns at each end (1 mm per turn), plus two locking rings in the middle (6.5 mm per ring), there would be only about 3 mm of adjustment left. Since the fixed tubes come in units of 7 mm, 3 mm of adjustment is not enough to reach all possible lengths. One ring and some epoxy would work better, leaving almost 10 mm of adjustment. Or two rings would work, if you could find suitably thin ones which I'm pretty sure would have to be purpose-made.

But in fact I didn't have to use either the tape or a locking ring, because adjustment turned out to be unnecessary. After determining by experiment exactly how much extension was needed to infinity focus the DCR-150 (stopped down to mimic the rear of an objective), it turned out that I could reach that length by simply choosing proper parts from the kit and screwing them tight together. The VLE in the final configuration is essentially used as just a 20 mm fixed length M42 extension tube.

That left the issue of glare from internal reflections.

According to the mjkzz.com website, "The benefit of using Nikon extension tubes is that it has large enough inner diameter and grooved inside to prevent internal reflection." That sounds good, and I'm sure the grooves make these better than smooth shiny tubes, but test images clearly show that "prevent internal reflection" is way too strong a statement. Without added flocking, there is an easily seen amount of veiling glare.

Here is the demonstration, in the spirit of what I did at the start of this post. The subject is a "black hole" that emits virtually zero light, imaged through a 10X objective (one of MJKZZ's 10X NA 0.25 achromats, in this case). The left column shows the view looking into the tubes with a point-and-shoot camera, the center is the image captured by a Nikon D800E fullframe camera attached to the tubes, and the right column is the histogram of the captured image.



The flocking needed to accomplish this consists of three pieces of Beetle Black cardstock, formed into tubes and inserted into the assembly. The thin one in the camera end is glued in place, the others are just held by cardstock stiffness.



All in all, an interesting exercise. The MJKZZ custom parts are beautifully machined, the ones originating elsewhere were not. Clearly MJKZZ is vulnerable to quality control issues in their supply pipeline too.

--Rik

Edits: to correct typos


Last edited by rjlittlefield on Thu Nov 28, 2019 10:31 am; edited 2 times in total
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mawyatt



Joined: 22 Aug 2013
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Location: Clearwater

PostPosted: Wed Nov 20, 2019 10:04 pm    Post subject: Reply with quote

Rik,

Interesting find, I need to flock these better!!

Another problem with these type adapters is the post that engages and "locks" the adapter in place, and the slot it fits into. These are mostly loose on all the adapters I have except the higher quality ones like the Nikon BR2A. The camera F mount to 42mm adapter that Wemacro supplies with their lens kit is almost as good as the BR2A tho, snug fit with very little play.

I use 3 clamps to help with the lens adapter side of the MJKZZ assembly, one on each side of the lens adapter which secures it in place and prevent its from rotating and tilting, however the camera adapter still has some rotational play. Chris recently posted about his clever device that locks the lens assembly to the camera 1/4-20 mount. I can't use this as Chris has because the bottom will hit the KR20 Rail system I often use, but can use the concept with a 100mm ARCA plate and a spacer. This solves the camera to lens assembly rotation problem and yields a very secure rigid camera/lens mount.

Here you can see the 3 clamps, note the 2 straddling the thin silver F mount Lens Adapter.


The concept from Chris with a 100mm ARCA plate to secure the camera and lens together.


Another View.


Best,
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mawyatt



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PostPosted: Thu Nov 21, 2019 6:50 am    Post subject: Reply with quote

I'm delinquent on posting about the superb Wemacro lens tube set, as I've been tied up with developments with the Piezoelectric Devices.

Here's what the Wemacro tubes look like showing the nice Nikon F mount adapter.





This is on the Nikon Z camera with a Z to 42mm adapter.



Best,
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rjlittlefield
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PostPosted: Thu Nov 21, 2019 11:42 pm    Post subject: Reply with quote

This is to record some more notes about the MJKZZ tubeset.

Despite my having lots of experience assembling various tube sets, I found this one surprisingly fiddly to get right.

Here's the sequence that I finally developed, to assemble the kit of loose parts into a working system:

Step 1. Select for use, the following items:
  • MJKZZ ring with male bayonet to fit camera.
  • 7 mm extension ring, quantity 1
  • 14 mm extension rings, quantity 2
  • 28mm extension rings, quantity 3
  • Extension tube female bayonet with m42 adapter
  • MJKZZ-VLE male and female tubes
  • 42-43mm adapter
  • Raynox DCR-150 lens
  • 49-37mm adapter ring
  • 37mm-RMS adapter ring
  • MJKZZ TLCS clamping rings with locking capscrews, quantity 2
  • MJKZZ Arca rail, with 2 screws installed
Set aside all remaining parts.

Step 2. Assemble the tubes into the order shown:
  • MJKZZ ring with male bayonet to fit camera.
  • 7 mm extension ring
  • 28 mm extension ring
  • 14mm extension ring
  • 28mm extension ring
  • 14mm extension ring
  • 28mm extension ring
  • Extension tube female bayonet with m42 adapter
  • VLE male and female tubes
  • 42-43mm adapter
  • Raynox DCR-150 lens
  • 49-37mm adapter ring
  • 37mm-RMS adapter ring


The total length of all parts from the camera bayonet flange to the front of the 42-43mm adapter, just before the Raynox, measures 164.0 mm.


Step 3. (not illustrated) Mount the tube set with Raynox lens on your camera and check that it focuses at or near infinity. If it's far enough off to bother you, then choose different tubes and/or adjust the VLE as required.

Step 4. Unscrew the tubeset at two points, slip on the MJKZZ TLCS clamps as shown, and screw the tubeset tight together. Press both clamps firmly down onto a flat surface and tighten their locking screws (not shown in photo).



Step 5. Place the MJKZZ Arca rail over the clamping rings and screw in the two retaining screws. Note that you'll need to tighten the screws alternately because the rail tends to tip and get hung up. If you need to reverse this step, then again you'll need to loosen the screws alternately and also lift up on the rail or the screws will jam in the slot of the rail.



Step 6. Cut three pieces of Beetle Black cardstock to fit:
  • snugly inside the male bayonet ring that goes into the camera (10mm x 127.5mm)
  • snugly inside the extension ring set (120.5mm x 168mm)
  • snugly inside the VLE male tube (43mm x 110mm)
(The sizes listed are what I measured after I was done. The actual work was cut oversize and trim-to-fit.)

Blacken the edges of these pieces with a marking pen, just so they look tidy after assembly.

Remove lint and loose fibers from these pieces by rolling with tape or fabric lint remover.

Roll and insert the flocking sheets. Secure the small piece of flocking in the bayonet next to the camera with glue, to prevent possibly dislodging it in handling. The other two sheets are safely held by just the cardstock tension.



Step 8. Finish the assembly:
  • Screw together the two remaining tube sections.
  • Loosen the clamp screws.
  • Attach tube set to camera.
  • Level camera.
  • Tighten clamp screws.



Step 9: Test final assembly to be sure that it still focuses properly at infinity (that is, you did not accidentally omit or add some ring).

Step 10: Label and set aside for possible future use, the numerous parts that you'll have left over:



You will need the extension rings later if you want to slightly increase magnification by adding extension. The additional clamping ring can be helpful if you want to have two-point clamping for the tube lens while having part of the ring set behind it loose to allow for rotating the camera. The set as shown with two clamps is completely rigid when both clamps are fastened, and it can be rotated as a unit when both clamps are loosened. The approach with three clamps and a loose ring offers the advantage of guaranteeing no objective movement when the camera is rotated.

It may be surprising that the list of steps to be performed is so long. But this is what it's like when you receive what is essentially a set of loose parts at a very attractive price. Hopefully the assembly aspect will be improved in some future version of the product.

--Rik

Edit 1: fix typos
Edit 2: add note about total length


Last edited by rjlittlefield on Sun Nov 24, 2019 8:26 pm; edited 2 times in total
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Jittebug



Joined: 14 Nov 2019
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PostPosted: Fri Nov 22, 2019 1:52 am    Post subject: Reply with quote

Many thanks for your detailed description of the MJKZZ set, Rik! I've recently purchased the older (clamp-less) version of the kit, but have not been able to try it yet. I'm definitely looking into flocking now.
On assembly and finding the focus for my Canon EOS 70D body, I also noticed I needed 1x7, 2x14, and 3x28 rings (instead of 3x14 and 3x28 as described by the MJKZZ blog post); perhaps the MJKZZ ring with bayonet is a new addition to the kit, adding length.

Quote:
You will need the extension rings later if you want to slightly increase magnification by adding extension


Is this actually possible (with this setup)? I was under impression that for this kind of 'Raynox tube lens setup' the tube length should be fixed, so that the Raynox will focus at infinity. Adding more length will mess that up, right?
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mawyatt



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PostPosted: Fri Nov 22, 2019 8:07 am    Post subject: Reply with quote

Rik,

Nice discussion on assembling the MJKZZ lens setup. I had struggled with this as well, trying various combinations and such and having to deal with the looseness of the sloppy adapters. Eventually I found a combination and setup that worked, then dotted each element with a paint dot to help identify which items go together for later reference.

Do you find any rotation at the camera mount due to the F mount camera adapter? This is something that still plagues the MJKZZ setup, as I mentioned I had even thought of glueing the F mount adapter to the camera mount Shocked
I found that I had previously super glued the the lens F mount adapter to a F to 52mm adapter, but probably couldn't come to gluing to the camera Confused

So I was always trying to make sure the lens assembly didn't rotate at the camera mount, then I read about the device Chris had created. I've just used hhis concept but with a 100mm ARCA plate and a spacer on the setup using the Sigma LSA for the 200mm tube lens.

Here you can see the 3 clamps, although I'm not sure you need 3 if the lens F mount adapter is glued and stable. Left to right is F mount camera to tube adapter, various tube sections, F to 52mm adapter (glued to F Mount silver adapter), 200mm Sigma LSA tube lens (has 52mm threads), 52mm tube section, then 52 to 26mm adapter for the Mitutoyo lenses. The clamp on the end required adding to the diameter of the 52mm tube section which was required to add the clamp on the end. I've used tape to expand the tube section diameter to fit the clamp, not the most elegant solution but works.

Note the extra ARCA plate (100mm) under the camera on left, this is Chris's concept to secure the camera to the lens assembly in addition to the camera flange to lens support which prevents any camera/lens assembly rotation or tilt due to the sloppy F mount camera adapters.

Does anyone know what the threads are on the these extension tubes, I measure 56.78 outer thread diameter? If we could find a good ring type adapter that could mate these threads to say 52mm, then the quality F mount camera adapter (BR2A) could be employed and the F mount lens adapter could be avoided all together.

Anyway, these MJKZZ lens kits can be made to be stable and useful, but also requires some extra work to get right. The Wemacro lens set is stable and rigid without any additional work, is already flocked, and everything (clamps, tubes, adapters) are beautifully machined.

Best,



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mawyatt



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PostPosted: Fri Nov 22, 2019 8:41 am    Post subject: Reply with quote

The Wemacro lens setup is simpler and requires no fiddling, tape or glue to get right. Since the F mount to camera adapter is snug and doesn't rotate, there is no need for the extra ARCA plate to secure the camera & lens assembly from rotating.

The tubes are smooth without ridges so the clamps can slide along the entire tube set. I haven't found these tubes elsewhere, so suspect these are custom tubes machined for Wemacro, as are the nice wide clamps.

Here's the setup for the Raynox 150 200mm tube lens, it's simple, I like the smooth "Thor Labs" like elegant look.




Maybe William might consider a 52mm tube lens system Very Happy

Just did a very quick test to see if the Wemacro lens set vignettes on Full Frame since it's based upon a 42mm tube set. Here's a image of a handheld white paper (WB is way off, from another custom setting) held in front of the setup with a Raynox 150 and Mitutoyo 5X lens assembly on a Nikon D850 FF camera.




You can some slight vignetting in the upper left corner, but generally not enough to cause issues with most images. This speaks highly of how well the tube set is centered and securely mounted.

Best,
_________________
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Last edited by mawyatt on Fri Nov 22, 2019 3:52 pm; edited 3 times in total
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rjlittlefield
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PostPosted: Fri Nov 22, 2019 9:22 am    Post subject: Reply with quote

Jittebug wrote:
rjlittlefield wrote:
You will need the extension rings later if you want to slightly increase magnification by adding extension

Is this actually possible (with this setup)? I was under impression that for this kind of 'Raynox tube lens setup' the tube length should be fixed, so that the Raynox will focus at infinity. Adding more length will mess that up, right?

Yes, adding more length will mess up infinity focus for the Raynox. It will also alter the front focus distance, from subject to objective. In principle, this will add some spherical aberration to the system.

However, for modest changes in length the added aberration has little or no visible effect, particularly with low magnification objectives such as 10X NA 0.28 and below.

http://www.science-info.net/docs/etc/Tube-Length-na.gif shows the key result from a classic experimental study of this effect with finite objectives, and the combination of infinite objective and tube lens is basically just a finite objective in two parts. The graph shows that at NA 0.25, their experiment found that a nominal 160 mm tube could be extended by another 200 mm before introducing unacceptable aberration. (The full article can be accessed at https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2818.1959.tb04454.x.)

So also yes, it is definitely possible to increase the tube length to get more magnification. This may not yield more resolution on subject, because even at nominal magnification, objectives are typically running with effective F-number around f/18 or f/20.

You can also go the other direction, reducing the extension to get less magnification. In this case the effective F-number gets smaller, so the image on sensor gets sharper, at least in the center. There may be coverage issues, particularly in the corners, and worse with fullframe, but especially on APS-C sensors this can be an effective technique in practice even though simplest theory says that it should be avoided.

--Rik
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Jittebug



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PostPosted: Mon Nov 25, 2019 1:20 am    Post subject: Reply with quote

Very interesting, thank you for the clarification!
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dhmiller



Joined: 11 Nov 2019
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PostPosted: Mon Nov 25, 2019 12:14 pm    Post subject: Reply with quote

Wouldn't;t that extra added 100mm ARCA plate make this hard to mount on a Stackshot?
And coincidentally, I just found a Nikon BR-2A reversing ring that fits a 52mm thread size. Could that be used to mount onto the camera, then adapted to the next MJKZZ adapter in the chain (not sure what the size of that one is..) This would give a better connection at the camera body.. (I assume)

mawyatt wrote:
Rik,

Nice discussion on assembling the MJKZZ lens setup. I had struggled with this as well, trying various combinations and such and having to deal with the looseness of the sloppy adapters. Eventually I found a combination and setup that worked, then dotted each element with a paint dot to help identify which items go together for later reference.

Do you find any rotation at the camera mount due to the F mount camera adapter? This is something that still plagues the MJKZZ setup, as I mentioned I had even thought of glueing the F mount adapter to the camera mount Shocked
I found that I had previously super glued the the lens F mount adapter to a F to 52mm adapter, but probably couldn't come to gluing to the camera Confused

So I was always trying to make sure the lens assembly didn't rotate at the camera mount, then I read about the device Chris had created. I've just used hhis concept but with a 100mm ARCA plate and a spacer on the setup using the Sigma LSA for the 200mm tube lens.

Here you can see the 3 clamps, although I'm not sure you need 3 if the lens F mount adapter is glued and stable. Left to right is F mount camera to tube adapter, various tube sections, F to 52mm adapter (glued to F Mount silver adapter), 200mm Sigma LSA tube lens (has 52mm threads), 52mm tube section, then 52 to 26mm adapter for the Mitutoyo lenses. The clamp on the end required adding to the diameter of the 52mm tube section which was required to add the clamp on the end. I've used tape to expand the tube section diameter to fit the clamp, not the most elegant solution but works.

Note the extra ARCA plate (100mm) under the camera on left, this is Chris's concept to secure the camera to the lens assembly in addition to the camera flange to lens support which prevents any camera/lens assembly rotation or tilt due to the sloppy F mount camera adapters.

Does anyone know what the threads are on the these extension tubes, I measure 56.78 outer thread diameter? If we could find a good ring type adapter that could mate these threads to say 52mm, then the quality F mount camera adapter (BR2A) could be employed and the F mount lens adapter could be avoided all together.

Anyway, these MJKZZ lens kits can be made to be stable and useful, but also requires some extra work to get right. The Wemacro lens set is stable and rigid without any additional work, is already flocked, and everything (clamps, tubes, adapters) are beautifully machined.

Best,


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DimaDD



Joined: 22 Nov 2019
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PostPosted: Mon Nov 25, 2019 4:08 pm    Post subject: Reply with quote

mawyatt wrote:
...
The tubes are smooth without ridges so the clamps can slide along the entire tube set. I haven't found these tubes elsewhere, so suspect these are custom tubes machined for Wemacro, as are the nice wide clamps.

I have found similar smooth tubes (45 mm diameter and length, with T2 = M42x0.75 thread) among other interesting things HERE. SVBONY is more oriented on inexpensive astronomy accessories. Although I have seen negative reviews about their optical elements, their purely mechanical parts seem quite solid. This variable length extension tube with stop-ring may also be very useful.
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rjlittlefield
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PostPosted: Mon Nov 25, 2019 4:33 pm    Post subject: Reply with quote

DimaDD wrote:
This variable length extension tube with stop-ring may also be very useful.

One wrinkle, which you've mentioned but I want to emphasize: those parts are T2: M42 x 0.75mm pitch instead of 1.0 mm pitch like all the other parts discussed in this thread.

--Rik
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mawyatt



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PostPosted: Mon Nov 25, 2019 10:13 pm    Post subject: Reply with quote

Dennis,

I don't use the Stackshot anymore, as I've moved to the THK rail types. This doesn't interfere with the THK rails as I have them setup with medium ARCA clamps. This allows you could mount the long ARCA plate to the THK ARCA clamp or the short ARCA plate to the The ARCA clamp. I prefer the long ARCA plate as this is more directly mounted to the lens with better weight distribution.

With the WeMacro tubes this isn't an issue since the short ARCA plate isn't necessary because the F mount adapter fits properly.

You can't use the Nikon BR2A with the MJKZZ tubes, these tubes have an unknown to me threads (I've asked if anyone knows, but no one answered). They are about 57mm diameter, and seem to be some non-standard thread that only these eBay type tubes use. The tubes are OK, it's the F mount adapters that are the issue.

Agree it would be nice to find a ring adapter for these tubes so we could utilize quality F adapters.

Best,
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dickb



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PostPosted: Tue Nov 26, 2019 2:46 am    Post subject: Reply with quote

mawyatt wrote:

You can't use the Nikon BR2A with the MJKZZ tubes, these tubes have an unknown to me threads (I've asked if anyone knows, but no one answered). They are about 57mm diameter, and seem to be some non-standard thread that only these eBay type tubes use. The tubes are OK, it's the F mount adapters that are the issue.

Agree it would be nice to find a ring adapter for these tubes so we could utilize quality F adapters.


The ebay tubes I own come in 2 diameter s, 60mm for the Canon EF sets and 57mm for Sony E and Minolta MD. The speed seems to be 0.75. So the Nikon ones appear to be the same as the Sony ones. I use cheap M60-M58 and M57-M55 step down rings respectively to connect these tubes to other components. For this purpose maybe an M57-M55 plus M55-M42 step down ring would be a good solution. Or M57-M52 plus Nikon BR2A.
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