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Adding an objective to a Canon T5i
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rjlittlefield
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PostPosted: Tue Jun 03, 2014 5:47 pm    Post subject: Reply with quote

dolmadis wrote:
May I trouble you please to give me an indication of the length of M42 tubes back to the camera that I might need with an assembly for the DCR 250 and DCR150?

Tube sections shown in the photos are 7, 14, and 28 mm.

So for the DCR-250 you're looking at 28+28+7 = 63 mm, and for the DCR-150 it's the same plus 6*14 for a total of 147 mm.

The chain of three adapters to go from M42 (male) to 49mm (male) adds another 12 mm.

As a crosscheck... My DCR-150 and DCR-250 carry labels that specify distance from the shoulder of the outer male threads to the back of the camera mount adapter. Those distances were determined by mounting the lens on a bellows, focusing on something very far away, then measuring the setup. For the DCR-150, the label says "Infinity focus at 175.9 mm from male shoulder of reversed lens to flange of Canon camera". The lens body itself is about 15 mm thick, and the M42 adapter is about 1.5 mm (nominal 1.46), so as shown the DCR-150 setup would be a total of 1.5+147+12+15 = 175.5 mm. The fact that 175.9 and 175.5 are so close together is sheer luck and is quite unnecessary. In my latest tests working with the DCR-150 on D800E using a Mitutoyo M Plan Apo 10X NA 0.25 objective, one thing I did was to shorten the extension by close to 20 mm so as to match magnifications between the 10X + DCR-150 (on shortened extension) and the 10X + Mitutoyo MT-1 tube lens focused at infinity. Aside from making the image smaller, I didn't notice any significant change in image quality from the shortening. (Higher power objectives with larger NA would be more picky, however!)

Quote:
On the DCR150 is there another tube or tubes behind the cone?

As shown, yes, but I suspect it doesn't really matter. In my D800E tests, I has to use shorter separation between the objective and the DCR-150, to avoid vignetting caused by some baffling in my tubes. (Increased separation means that rays in the corner of the field strike the tube lens farther from the axis. From there they get bent to refocus on the sensor. So the greater the separation, the wider the clear space has to be, up close to the tube lens.)

--Rik
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dolmadis



Joined: 07 Dec 2011
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Location: UK

PostPosted: Tue Jun 03, 2014 10:39 pm    Post subject: Reply with quote

Thanks Rik. As well as the simple answer thank you so much for the explanation.

John
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mawyatt



Joined: 22 Aug 2013
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Location: Clearwater

PostPosted: Sat Jul 26, 2014 6:29 am    Post subject: Reply with quote

rjlittlefield wrote:
dolmadis wrote:
May I trouble you please to give me an indication of the length of M42 tubes back to the camera that I might need with an assembly for the DCR 250 and DCR150?

Tube sections shown in the photos are 7, 14, and 28 mm.

So for the DCR-250 you're looking at 28+28+7 = 63 mm, and for the DCR-150 it's the same plus 6*14 for a total of 147 mm.

The chain of three adapters to go from M42 (male) to 49mm (male) adds another 12 mm.

As a crosscheck... My DCR-150 and DCR-250 carry labels that specify distance from the shoulder of the outer male threads to the back of the camera mount adapter. Those distances were determined by mounting the lens on a bellows, focusing on something very far away, then measuring the setup. For the DCR-150, the label says "Infinity focus at 175.9 mm from male shoulder of reversed lens to flange of Canon camera". The lens body itself is about 15 mm thick, and the M42 adapter is about 1.5 mm (nominal 1.46), so as shown the DCR-150 setup would be a total of 1.5+147+12+15 = 175.5 mm. The fact that 175.9 and 175.5 are so close together is sheer luck and is quite unnecessary. In my latest tests working with the DCR-150 on D800E using a Mitutoyo M Plan Apo 10X NA 0.25 objective, one thing I did was to shorten the extension by close to 20 mm so as to match magnifications between the 10X + DCR-150 (on shortened extension) and the 10X + Mitutoyo MT-1 tube lens focused at infinity. Aside from making the image smaller, I didn't notice any significant change in image quality from the shortening. (Higher power objectives with larger NA would be more picky, however!)

Quote:
On the DCR150 is there another tube or tubes behind the cone?

As shown, yes, but I suspect it doesn't really matter. In my D800E tests, I has to use shorter separation between the objective and the DCR-150, to avoid vignetting caused by some baffling in my tubes. (Increased separation means that rays in the corner of the field strike the tube lens farther from the axis. From there they get bent to refocus on the sensor. So the greater the separation, the wider the clear space has to be, up close to the tube lens.)

--Rik


Hi Rik,

Sorry to hijack this thread but have a question. I am using the D800E with a Nikon 70-200 f2.8 as a tube lens for the Mitutoyo M Plan Apo 10 0.28 f200 inf objective. I think this is similar to your setup mentioned above. Do you think I would be better off with the DCR-150 than the 70-200 f2.8? I do see some small vignetting with the 70-200. Is there a better option than the 70-200 f2.8 that has better IQ and won't vignette as much?

Cheers,

Mike
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rjlittlefield
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PostPosted: Sat Jul 26, 2014 7:44 am    Post subject: Reply with quote

mawyatt wrote:
I am using the D800E with a Nikon 70-200 f2.8 as a tube lens for the Mitutoyo M Plan Apo 10 0.28 f200 inf objective. I think this is similar to your setup mentioned above. Do you think I would be better off with the DCR-150 than the 70-200 f2.8? I do see some small vignetting with the 70-200. Is there a better option than the 70-200 f2.8 that has better IQ and won't vignette as much?

The short version is that I don't know. The long version is that I've heard good reports about the fixed-length 200's, most recently at http://www.photomacrography.net/forum/viewtopic.php?p=150212#150212 and the links therein. The DCR-150 definitely will solve the vignetting problem, but it's unclear how much of a sharpness hit the corners might be taking. My gut feeling is that an expensive telephoto would surely have better corners than the DCR-150, but given that the objectives themselves get soft out there, I don't know what the overall impact is. It would be nice to see a solid head-to-head comparison of that, but I don't have the lenses to do that test.

--Rik
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mawyatt



Joined: 22 Aug 2013
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PostPosted: Sat Jul 26, 2014 9:35 am    Post subject: Reply with quote

rjlittlefield wrote:
mawyatt wrote:
I am using the D800E with a Nikon 70-200 f2.8 as a tube lens for the Mitutoyo M Plan Apo 10 0.28 f200 inf objective. I think this is similar to your setup mentioned above. Do you think I would be better off with the DCR-150 than the 70-200 f2.8? I do see some small vignetting with the 70-200. Is there a better option than the 70-200 f2.8 that has better IQ and won't vignette as much?

The short version is that I don't know. The long version is that I've heard good reports about the fixed-length 200's, most recently at http://www.photomacrography.net/forum/viewtopic.php?p=150212#150212 and the links therein. The DCR-150 definitely will solve the vignetting problem, but it's unclear how much of a sharpness hit the corners might be taking. My gut feeling is that an expensive telephoto would surely have better corners than the DCR-150, but given that the objectives themselves get soft out there, I don't know what the overall impact is. It would be nice to see a solid head-to-head comparison of that, but I don't have the lenses to do that test.

--Rik


Since the DCR-150 isn't too expensive, I may give it a try. Looks like I would need the Nikon F mount to M42 adapter, M42 tubes and the host of rings you mentioned above. I use a 26 to 52mm for the Mit and then a 52 to 77mm to mount on the front of the Nikon 70-200. This is flat up against the 70-200, not a cone type. Could this be a problem with my present setup needing more distance from the Mit to the 70-200 front? Might be with the DCR-150 too?

Thanks,

Mike
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rjlittlefield
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PostPosted: Sat Jul 26, 2014 9:15 pm    Post subject: Reply with quote

mawyatt wrote:
This is flat up against the 70-200, not a cone type. Could this be a problem with my present setup needing more distance from the Mit to the 70-200 front?

No -- vignetting is always caused by too much separation, not too little. The problem with some telephotos is that even zero separation is too much, because the telephoto is designed to take its corner rays only from the edge of its front element, not from the center. See discussion at http://www.photomacrography.net/forum/viewtopic.php?p=142089#142089 and surrounding.

--Rik
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mawyatt



Joined: 22 Aug 2013
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PostPosted: Sun Jul 27, 2014 6:00 am    Post subject: Reply with quote

rjlittlefield wrote:
mawyatt wrote:
This is flat up against the 70-200, not a cone type. Could this be a problem with my present setup needing more distance from the Mit to the 70-200 front?

No -- vignetting is always caused by too much separation, not too little. The problem with some telephotos is that even zero separation is too much, because the telephoto is designed to take its corner rays only from the edge of its front element, not from the center. See discussion at http://www.photomacrography.net/forum/viewtopic.php?p=142089#142089 and surrounding.

--Rik


Is there any advantage to moving the objective away from the front of the tube lens, sharpness, contrast?
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rjlittlefield
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PostPosted: Sun Jul 27, 2014 6:31 am    Post subject: Reply with quote

mawyatt wrote:
Is there any advantage to moving the objective away from the front of the tube lens, sharpness, contrast?

Sometimes. It depends on the tube lens. With the Nikon and Thorlabs units that are designed to be tube lenses, and with the Raynox DCR-150, there are some improvements in sharpness and CA. With telephotos, no. The difference is because telephoto lenses are designed to accept rays from the edge of the field through the same side of the lens that the edge is on. But the objective will be directing them through the other side of the lens, and the other lenses are designed with this in mind. The longer the separation, the farther from center those edge rays hit.

--Rik
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Koorosh



Joined: 20 Jun 2014
Posts: 215
Location: London

PostPosted: Sun Feb 01, 2015 8:12 am    Post subject: Reply with quote

A question on this set-up. I have lomo bellows instead of the extension behind the Raynox, but just wondered what the extension is or should be in front of it between the Raynox and Nikon BE objective?

I've ordered these extension tubes and am hoping they will suffice, plus this fitting for the objective to m42.

http://www.ebay.co.uk/itm/151553626866?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.co.uk/itm/111197263932?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
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rjlittlefield
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PostPosted: Sun Feb 01, 2015 10:59 am    Post subject: Reply with quote

Koorosh wrote:
... just wondered what the extension is or should be in front of it between the Raynox and Nikon BE objective?

That distance is not critical. With my lens and my eyes, anything in the range of 1" to 3" looks about the same, except that full-frame sensors have to be on the short end of that to avoid vignetting.

--Rik
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Koorosh



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PostPosted: Sun Feb 01, 2015 12:18 pm    Post subject: Reply with quote

Thanks Rik Smile
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bendecamp



Joined: 22 Jun 2015
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PostPosted: Sun Sep 06, 2015 9:00 pm    Post subject: Reply with quote

Been having a difficult time getting all of this put together. The RMS cone adaptor doesn't fit my Nikon 10x infinite objective achromat Rolling Eyes
Also trying to use an old Vivitar bellows with T-mount that is equally mystifying.
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rjlittlefield
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PostPosted: Sun Sep 06, 2015 9:23 pm    Post subject: Reply with quote

bendecamp wrote:
Been having a difficult time getting all of this put together. The RMS cone adaptor doesn't fit my Nikon 10x infinite objective achromat Rolling Eyes

Which Nikon 10X infinite did you get? The black CFI BE (MRN70100) has RMS threads, but both the black and the gold CFI's (MRP70100 and MRL00102) have 25mm threads.

Quote:
Also trying to use an old Vivitar bellows with T-mount that is equally mystifying.

That's probably 42mm x 0.75mm, versus the 42mm x 1.0mm pitch that most of the adapters are made to fit. But with an infinite objective, you'll be needing to use a tube lens anyway, not just a bellows. If you're planning to use a Raynox, then that should be straightforward by getting an ordinary 42mm step ring (also 0.75 mm pitch) to fit between the bellows and the Raynox, instead of the less common 42x1 adapter.

--Rik
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bendecamp



Joined: 22 Jun 2015
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PostPosted: Mon Sep 07, 2015 9:42 am    Post subject: Reply with quote

Yes, it's the gold one. I bought the adaptor from RAF camera to fit the objective on the end of a 100mm macro. So I already own the flat adaptor, and might not need the RMS, if I can figure out how to step down from 67mm to the extension tubes...

Yes, I thought it was off by a fraction of a mm, it was lining up exactly with the threads but they wouldn't screw in. .25mm difference. My plan was to use both the bellows WITH the extension tubes, to have control over magnification, more so projecting the image to the perfect size on the sensor... maybe that's overkill though.
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bendecamp



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PostPosted: Mon Sep 07, 2015 9:45 am    Post subject: Reply with quote

http://www.amazon.com/M25x0-75-RMS-thread-adapter-bronze/dp/B00OF9WI2A/ref=sr_1_2?ie=UTF8&qid=1441644266&sr=8-2&keywords=rms+to+25mm+adapter

That looks reasonable?
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