Thanks David!dmillard wrote: ↑Sun Feb 28, 2021 4:41 pmHello Robert,RobertOToole wrote: ↑Sat Feb 27, 2021 8:34 pmThe tube lens used for the sample is a Rodenstock APO-Gerogon and it according to Rodenstock it is symmetrical. They were designed to be used in reduction or mag without having to remove the lens to reverse it. Range was given from 1:3 to 3:1.RobertOToole wrote: ↑Sat Feb 27, 2021 8:14 pm......I thought it was a symmetrical lens so I didn't bother!
That said, since I don't trust camera manufacturers, I should still double check the performance in reverse.
Very impressive image!
You may already have it, but I just sent you a pdf of some Rodenstock literature about the Graphigon/Gerogon process lenses.
Best regards,
David
8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
The Zeiss Superachromats looks interesting! I read that the lens does not use multicoating, at least not the normal T* M/C, since the corrected range of the lens is so wide. I have the data sheets for the Superachromats if anyone is curious.Lou Jost wrote: ↑Sun Feb 28, 2021 7:30 amRobert, the results with the Mamiya 250mm lens do depend on the objective used. With some objectives it shows a slight, mostly correctable red fringe.
An even better choice would be the famous Zeiss/Hasselblad 250mm Superachromat. This can't add a red fringe, because it is a lens designed for space applications that explicitly required perfect correction across the IR and visible spectrum. But this is expensive and I have not tried it yet. I have one sitting in the US waiting for me, and I'll pick it up when it is once again safe to travel. The 350mm version is apparently corrected also into the UV! But that one, made with very exotic materials, costs a fortune, far beyond my means.
I really wish someone would look into one of these: https://williamoptics.com/redcat-51
MTFs look good at least.
The manufacturer claims its the sharpest and best corrected 250mm lens every made!?!
Best,
Robert
Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
Robert, I spent a lot of time looking at that scope last year, and almost bought it. But many users report bad quality control, and many people had to return theirs for adjustment.
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
Thanks for the report Lou!
I emailed them a few times a couple of years ago but was not too impressed with their response/data.
Best,
Robert
Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
Robert, in any case I strongly agree with you that telescopes shouild be the best tube lenses out there. Actually, we should be more specific. Telescopes designed for astrophotography (especially fluorite ones) should be outstanding tube lenses. These would have high-quality field flatteners and possibly focal reducers. Telescopes designed for viewing don't need to have such a flat image plane.
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
The Mag8x test is finally completed and the results are online: https://www.closeuphotography.com/qiopt ... -objective the lens is back at Qioptiq. The final cost was around $300 USD with shipping, paperwork and insurance and I don't regret it but this one was on the most time consuming tests I've ever done by far.
Tests were done with A7RIV in full frame and crop mode ( 26 MP! ). Normal and Pixel-Shift Multi Shoot 4 image mode. And some A6300 results also.
Tests:
MITUTOYO M PLAN 7.5X 0.21 VS MAG.X LD PLAN 8X 0.32 (mag.x pushed down)
MITUTOYO M PLAN 7.5X VS MAG.X LD PLAN 8X PUSHED DOWN (6.7x)
MITUTOYO M PLAN 10X VS. MITUTOYO HR 10X VS. MAG.X 8X PUSHED DOWN
MAG.X 8X FULL FRAME COVERAGE ON THE SONY A7R4
and a tube lens test at the end.
Be sure to check out the Pixel Shift mode 2500 pixel samples, they look fantastic.
Questions or comments welcome.
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
An impressive lens, and an impressive review -- nice work!
One tiny niggle: the objective by itself is telecentric only on the object side. To get double telecentric, the objective must be precisely paired with a matching tube lens. In that configuration, the combo will also have fixed magnification, meaning that it gives the same magnification even if extension behind the tube lens is changed. This is very handy for industrial applications, because it gives more options for adjusting focus without changing magnification. But using a different tube lens, or even changing the separation between objective and matched tube lens, will make the combo non-telecentric on the image side.
--Rik
One tiny niggle: the objective by itself is telecentric only on the object side. To get double telecentric, the objective must be precisely paired with a matching tube lens. In that configuration, the combo will also have fixed magnification, meaning that it gives the same magnification even if extension behind the tube lens is changed. This is very handy for industrial applications, because it gives more options for adjusting focus without changing magnification. But using a different tube lens, or even changing the separation between objective and matched tube lens, will make the combo non-telecentric on the image side.
--Rik
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
Yes, correct Rik, good point, thanks for the notes. I didn't think about including that. The $6000+USD. mag.x tube lens they sell is supposedly matched to be telecentric.rjlittlefield wrote: ↑Fri Mar 19, 2021 6:14 pmAn impressive lens, and an impressive review -- nice work!
One tiny niggle: the objective by itself is telecentric only on the object side. To get double telecentric, the objective must be precisely paired with a matching tube lens. In that configuration, the combo will also have fixed magnification, meaning that it gives the same magnification even if extension behind the tube lens is changed. This is very handy for industrial applications, because it gives more options for adjusting focus without changing magnification. But using a different tube lens, or even changing the separation between objective and matched tube lens, will make the combo non-telecentric on the image side.
--Rik
During testing I found myself getting side-tracked reading about telecentricity! fascination stuff and here on this forum we have lots of interesting posts that someone can search for if they want to learn more of course.
I did see one interesting thing when testing the mag.x lens against the Mitutoyos. Getting the wafer perfectly flat normally takes a couple of attempts and some tweaking. With the mag.x it seemed like the first attempt was always good, at first I attributed that to luck, but then it happened a few more times. My first thought was that was an effect of telecentricity. Can that show up as more DOF in this case?
Best,
Robert
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
No, something else must be going on. DOF is determined by the angular width of the entrance cone, for each point on the subject. That angle is what's measured by NA, so any two lenses that are working at the same NA will have the same DOF, regardless of telecentricity.RobertOToole wrote: ↑Fri Mar 19, 2021 7:28 pmeffect of telecentricity. Can that show up as more DOF in this case?
The only thing very special about telecentric lenses is that all the entrance cones have their chief ray (central axis) pointed straight along the optical axis. With non-telecentric lenses, chief rays in the periphery of the field will splay in or out, producing an image that has either normal or inverted perspective.
--Rik
Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
Hello Robert,RobertOToole wrote: ↑Fri Mar 19, 2021 5:24 pmThe Mag8x test is finally completed and the results are online:
Excellent test and documentation , the only thing I`m missing is the "Thank you Robert" PayPal button.
Have you ever combined pixelshift and Zerene and if so could you automate getting all the pixelshift images done?
best regards
Lothar
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
Hi Lothar,lothman wrote: ↑Sat Mar 20, 2021 4:27 amHello Robert,RobertOToole wrote: ↑Fri Mar 19, 2021 5:24 pmThe Mag8x test is finally completed and the results are online:
Excellent test and documentation , the only thing I`m missing is the "Thank you Robert" PayPal button.
Have you ever combined pixelshift and Zerene and if so could you automate getting all the pixelshift images done?
best regards
Lothar
Thanks for the comments, yes, that would be helpful for me, maybe someday, I an add a "buy me a coffee" button
The cost of shipping + insurance to send the mag.x back was quite a bit even though the loan was free! Fedex wanted over $400 to take the lens back to Bavaria! DHL, which is excellent also, saved me some cash by charging me only $190 for express service. Just yesterday I read that Fedex profit during the Covid Pandemic is up 2x or 3x over the year before! They don't need my business, that explains the high prices. BTW, I tried the send the mag.x back USPS Int. Express but the DE post office has a strict limit of $500 value for priority and express mail for inbound packages. DHL express was just a few dollars more than USPS express anyway.
No, I have not, good idea to look into though. I'm doing it the slow method. Shoot, download, combine, make TIFF, Stack, sharpen, re-size. It would be nice to combine a few of these steps!
Best,
Robert
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
My problem? I was reading too much about optics and telecentricity information from line scan manufacturers which I think would naturally tend to oversell or exaggerate the advantages of a telecentric lens. Some would actually say that a telecentric optics have more DOF (and are sharper) so naturally I would investigate by reading more technical papers online and it seems that this is not the case. The transition from focus to OOF is different with telecentric optic, I think the change is more abrupt, but an increase in DOF is not due to telecentricity at least.rjlittlefield wrote: ↑Fri Mar 19, 2021 8:16 pmNo, something else must be going on. DOF is determined by the angular width of the entrance cone, for each point on the subject. That angle is what's measured by NA, so any two lenses that are working at the same NA will have the same DOF, regardless of telecentricity.RobertOToole wrote: ↑Fri Mar 19, 2021 7:28 pmeffect of telecentricity. Can that show up as more DOF in this case?
The only thing very special about telecentric lenses is that all the entrance cones have their chief ray (central axis) pointed straight along the optical axis. With non-telecentric lenses, chief rays in the periphery of the field will splay in or out, producing an image that has either normal or inverted perspective.
--Rik
Thanks again for adding the info. I think I will add your telecentricity notes to my mag.x page!
BTW Rik, hope this isn't covered already someplace on the forum....what is your take on lp/mm and l/mm? Line pair is one dark and one light, so l/mm is 50% of that figure? I'm reading some optical specs and if they quote l/mm but that is not the same as lp/mm I know that right. Or is it? I'm getting lots of conflicting info online. Supposedly ANSI PH3.50 (1970s) says, "Line pairs per millimeter" may also be expressed as "Lines per millimeter."
Best,
Robert
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
Nope, not that either. If that's what you're seeing, then I expect it's a matter of other fixed aberrations in the non-telecentric lens that obscure the onset of the particular variable aberration we call "out of focus".RobertOToole wrote: ↑Sat Mar 20, 2021 10:24 amThe transition from focus to OOF is different with telecentric optic, I think the change is more abrupt
I think you're seeing conflicting information because different people use "lines per millimeter" in different ways. No matter what ANSI says, some people will count a white/black pair as "two lines", either from ignorance of the standard or because it makes the quoted number be twice as large. The result is that I never put much trust in "lines per millimeter", particularly if the number seems too big to mean line pairs per millimeter.what is your take on lp/mm and l/mm? Line pair is one dark and one light, so l/mm is 50% of that figure? I'm reading some optical specs and if they quote l/mm but that is not the same as lp/mm I know that right. Or is it? I'm getting lots of conflicting info online. Supposedly ANSI PH3.50 (1970s) says, "Line pairs per millimeter" may also be expressed as "Lines per millimeter."
--Rik
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
Sorry Rik, I'm not saying that the personal perspective, but from what I read online. The info didn't seem to be correct, like other internet myths. Maybe in this case its more of a subjective thing where the user sees the head of a bolt or something seems to be sharper since the telecentric optic does not see the OOF edges around the corner. I'm just wondering where they got the extended DOF in the first place.rjlittlefield wrote: ↑Sat Mar 20, 2021 10:56 amNope, not that either. If that's what you're seeing, then I expect it's a matter of other fixed aberrations in the non-telecentric lens that obscure the onset of the particular variable aberration we call "out of focus".RobertOToole wrote: ↑Sat Mar 20, 2021 10:24 amThe transition from focus to OOF is different with telecentric optic, I think the change is more abrupt
--Rik
Thanks for the lp/mm note also!
Best,
Robert
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Re: 8x HR NA 0.32 + α7R IV 4 Image Pixel Shift Mode
When making measurements, a telecentric lens gives more leeway for positioning errors without messing up the measurement.I'm just wondering where they got the extended DOF in the first place.
So, if we equate "depth of field" with "allowable range of subject positions", then telecentrics give more.
I'm not sure that's the real source of the myth, but it's at least a plausible story.
--Rik