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Four at 5X: A pixel peep show!
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ChrisLilley



Joined: 01 May 2010
Posts: 680
Location: Nice, France (I'm British)

PostPosted: Wed Jan 26, 2011 4:30 pm    Post subject: Reply with quote

dmillard wrote:

Unfortunately, I don't currently have any lenses between 90mm and 300mm to mount on my D300, so the answer is no. A comparison would be very interesting.


Oskar O wrote:

It's OK, I have more lenses than my better half approves anyway Smile
The Fujinon 180/9 just looked like a neat lens when I googled it. Your test is indicating that a better corrected lens would be a better choice than a simple achromat as a tube lens.

It may be that the dedicated 200 mm lenses for 35mm do not perform any better in this role, the effective aperture being so small.


Chris S. wrote:
I briefly checked my copy of the 20x/0.42 on my Nikkor 105mm f/2.8 AF-D micro lens, and on casual glance, it looked good and didn't vignette.


I don't have a Mitutoyo, but in the last couple of weeks I have joined the Nikon 10/0.25 infinity club and over the last few days the jinfinance M25-M52 adapter arrived, also a 52-62 and 52-72.

So I am close to being able to add to the pool of tested tube lens replacements, having a number of lenses in the 200-ish range and more outside that range.

Don't hold your breath though as my health has been a bit dodgy of late. But I thought the following might make an interesting comparison. These are all manual focus prime lenses, and they might throw some light on whether 'better than achromatic' helps.


    * Voigtländer Apo-Lanthar 180mm f/4. Probably my best lens in that range, gives very good results wide open, apochromatic. On the downside, its optimised for closer focus, at least in terms of the spacing of the focus ring. A generous 300 degrees or so of throw, but the infinity to 5m area is all bunched up so precisely getting infinity can be problematic. 49mm thread, I have a 49-52 step-up for it.

    * Nikkor AIS 180mm f/2.8 ED. A well regarded and well corrected lens, gives good results, but not apochromatic and does suffer from axial CA (lateral CA is very well controlled). 72mm thread, I have the 72-52 step-down.

    * Arsenal Telear-N 200mm f/3.5. Probably my worst lens in that focal range, in terms of build quality at least. Arsenal was a manufacturer in the Ukraine, they made some lenses for a film camera which used a copy of the Nikon F mount, so their lenses work on modern Nikons. This lens needs a custom white balance as the rear element has a yellow-green colour. 62mm thread; I have the 62-52 step-down.


As I said, it might take me a while, but I think it would be interesting.
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Oskar O



Joined: 13 Dec 2010
Posts: 243
Location: Finland

PostPosted: Thu Jan 27, 2011 12:10 am    Post subject: Reply with quote

Chris S. wrote:

I was seriously considering it, but one not only needs the over-$600 tube lens—there are also the mounts, connectors, tubes, etc. needed to make this tube lens a useful functioning device. I put together a shopping cart at Edmund optics with most of the necessary items, and it came to over $1100 (including the tube lens). Ouch! I did not hit the “buy” button, and will stick to Nikon camera lenses for now. If anyone would like a pdf file of the shopping cart, PM me.


Yes, and I think there's a non-zero risk that the end results will not be any better or only marginally better than the results with some good lens that is much cheaper (such as an older 200/4 prime lens). But at some point, someone might be able to try the lenses through work or similar borrowing scheme...if we're lucky.
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Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 3352
Location: Ohio, USA

PostPosted: Thu Jan 27, 2011 12:32 am    Post subject: Reply with quote

Oskar O wrote:
Yes, and I think there's a non-zero risk that the end results will not be any better or only marginally better than the results with some good lens that is much cheaper (such as an older 200/4 prime lens).

I think so, too. And there is the fact that these objectives work well with prime lenses shorter and longer than 200mm--a flexibility that is reduced with the Mitutoyo tube lens approach. Edmund does, of course, offer a 400mm tube lens, but there goes quite a bit more money, and taking apart the mounting rig I was thinking about in order to change tube lenses would be a bit of hassle. And they don't offer a shorter tube lens.

On the other hand, even with a selection of older primes, I won't be happy until I come up with a really solid support that is easy to exchange with the bellows in my rig. While not rocket science, neither is this a trivial exercise. The $1100 approach did appear to offer very solid support, and would be easy for me to exchange, in my rig, with the bellows for finite optics.
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Blame



Joined: 14 May 2010
Posts: 342

PostPosted: Thu Jan 27, 2011 3:52 am    Post subject: Reply with quote

ChrisLilley wrote:

* Voigtländer Apo-Lanthar 180mm f/4. Probably my best lens in that range, gives very good results wide open, apochromatic. On the downside, its optimised for closer focus, at least in terms of the spacing of the focus ring. A generous 300 degrees or so of throw, but the infinity to 5m area is all bunched up so precisely getting infinity can be problematic. 49mm thread, I have a 49-52 step-up for it.


No problem. You don't need to get it precisely. If it is a bit out your objective will just focus at a slightly different length. Within reason there will be no noticable effect on image quality.
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Oskar O



Joined: 13 Dec 2010
Posts: 243
Location: Finland

PostPosted: Thu Jan 27, 2011 10:54 am    Post subject: Reply with quote

Chris S. wrote:

On the other hand, even with a selection of older primes, I won't be happy until I come up with a really solid support that is easy to exchange with the bellows in my rig. While not rocket science, neither is this a trivial exercise.


Yeah, I've been thinking about that too; attaching the camera and lens at one point of support doesn't sound too good. I've come up with two basic ideas;

1. Get a lens without focusing helicoid and put it at the end of a bellows or extension tube with tripod mount, attach from several spots to support the length.

2. Come up with some sort of universal lens support that attaches under the end of the lens and holds it firmly. I've seen some, but not yet a perfect model...

This would actually be more in line with material for a new thread...
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dmillard



Joined: 24 Oct 2006
Posts: 571
Location: Austin, Texas

PostPosted: Thu Jan 27, 2011 4:13 pm    Post subject: Reply with quote

Oskar O wrote:
Chris S. wrote:

I was seriously considering it, but one not only needs the over-$600 tube lens—there are also the mounts, connectors, tubes, etc. needed to make this tube lens a useful functioning device. I put together a shopping cart at Edmund optics with most of the necessary items, and it came to over $1100 (including the tube lens). Ouch! I did not hit the “buy” button, and will stick to Nikon camera lenses for now. If anyone would like a pdf file of the shopping cart, PM me.


Yes, and I think there's a non-zero risk that the end results will not be any better or only marginally better than the results with some good lens that is much cheaper (such as an older 200/4 prime lens). But at some point, someone might be able to try the lenses through work or similar borrowing scheme...if we're lucky.


Hello Oskar,

It would be really nice if somebody had access to one of Mitutoyo's tube lenses, if only briefly for comparison tests. I find it hard to believe that their dedicated tube lens would be the weak link in such an expensive system, although the relative optical benefits of using one may be very slight.

I'm also curious about why Mitutoyo's and Nikon's tube lenses show up so rarely on eBay or LabX; since their infinity objectives are offered on a routine and regular basis, I would expect at least an occasional appearance of a tube lens, unless they are almost always sold with whatever microscope contains them. Confused

David
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Bob S



Joined: 07 Aug 2010
Posts: 16

PostPosted: Tue Feb 01, 2011 11:04 am    Post subject: Reply with quote

If you are testing a simple achromat with non-symmetric external shape for use as a tube lens, try to test it at both orientations. Aberration performance will depend on the orientation. (Whether the effect will be large enough to be visible is not obvious.)

For a simple lens used at infinity for "normal" purposes, the best shape is slightly more meniscus than plano-convex, and the convex side should be toward infinity.

However, use as a tube lens is rather different than "normal" infinity use, and I have a hunch that the best orientation may be reversed.
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Horstl



Joined: 02 Feb 2011
Posts: 32
Location: Austria

PostPosted: Mon Feb 07, 2011 6:23 am    Post subject: Reply with quote

Chris S. wrote:
...
I was seriously considering it, but one not only needs the over-$600 tube lens—there are also the mounts, connectors, tubes, etc. needed to make this tube lens a useful functioning device. ....


Hello,
there is a tube lens available called "MT-40", which can be screwed directly to the objective. This makes attachment to the camera very simple and gives a rugged system with minimal risk for any disalignment or unwanted movement of parts. The image circle is specified to 24 mm, but I think it is possible to use it a bit wider.
I have tried it with the M Plan Apo 2x on fourthirds - cameras and the results are great.

There is not much inside this tiny lens and it seems to be a little expensive - however it is well made, the optical surfaces are multicoated. It is also a nice solution if you want as few as possible optical parts in the way from the object to the sensor.

Horst
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shrek



Joined: 01 Nov 2009
Posts: 99
Location: Toulouse (France)

PostPosted: Mon Feb 07, 2011 7:05 am    Post subject: Reply with quote

We are poor boy ,because we must used lens the are made for "argentique photo" and not numérique !
When the pro lens numérique come on the market ,somes problèms was solved

jp
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enricosavazzi



Joined: 21 Nov 2009
Posts: 1212
Location: Borgholm, Sweden

PostPosted: Mon Feb 07, 2011 7:13 am    Post subject: Reply with quote

Horstl wrote:
...
there is a tube lens available called "MT-40", which can be screwed directly to the objective. This makes attachment to the camera very simple and gives a rugged system with minimal risk for any disalignment or unwanted movement of parts. The image circle is specified to 24 mm, but I think it is possible to use it a bit wider.
I have tried it with the M Plan Apo 2x on fourthirds - cameras and the results are great.
...
Horst

The MT-40 is designed to produce an image circle of 24 mm, which is a bit small for a DSLR (even an APS-C). I believe the MT-40 is designed primarily for use with videocameras. The MT-4, on the other hand, does provide a 30 mm image circle and directly mounts an M26 objective. Even if feasible to use with a DSLR, the problem remains how to connect the MT-40/MT-4 to the rest of the equipment.

The MT-1 is much cheaper than the MT-40 and gives a 30 mm image circle. The rear of a flat jinfinance adapter might be wide enough for attaching the flange of the MT-1 via its three screw holes and an ordinary M49 or M52 extension tube might be wide enough to contain the MT-1 (I am unable to confirm either assumption, though), so this could be an easy and cheap way.
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Horstl



Joined: 02 Feb 2011
Posts: 32
Location: Austria

PostPosted: Mon Feb 07, 2011 7:42 am    Post subject: Reply with quote

enricosavazzi wrote:
...
Even if feasible to use with a DSLR, the problem remains how to connect the MT-40/MT-4 to the rest of the equipment....


FT-cameras have an image circle of 22mm - this is a good match.
If there is interest, I can test the MT40 also on a 24x36mm camera - this will not work together, but it would be possible to determine the usable field. I think APS should be acceptable.
For the connecting parts - access to a lathe helps a lot Wink



Horst
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Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 3352
Location: Ohio, USA

PostPosted: Mon Feb 07, 2011 12:38 pm    Post subject: Reply with quote

Horst, welcome to the forum! And thanks for your useful information and photos.

As Oskar suggested the other day, this line of discussion probably warrants a separate thread--especially as David's excellent analysis at 5x is so important on its own.

So my reply is posted in a new thread. I'd invite anyone who wishes to talk about integrating a Mitutoyo tube lens into a macro rig to join me there.

Cheers,

--Chris
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dmillard



Joined: 24 Oct 2006
Posts: 571
Location: Austin, Texas

PostPosted: Mon Feb 07, 2011 5:34 pm    Post subject: Reply with quote

Hello Horst,

That looks like a very elegant rig that you have assembled!


Chris S. wrote:


As Oskar suggested the other day, this line of discussion probably warrants a separate thread--especially as David's excellent analysis at 5x is so important on its own.

So my reply is posted in a new thread. I'd invite anyone who wishes to talk about integrating a Mitutoyo tube lens into a macro rig to join me there.

Cheers,

--Chris


I think thats's an excellent idea - I'm looking forward to seeing some ideas in action! Smile

Regards,
David
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SONYNUT



Joined: 22 Jan 2011
Posts: 635
Location: Minnesota USA

PostPosted: Mon Feb 07, 2011 6:21 pm    Post subject: Reply with quote

comparing center and corner on a item that is not flat isn't a fair test...
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