Mitutoyo plan apo 7,5/21

A forum to ask questions, post setups, and generally discuss anything having to do with photomacrography and photomicroscopy.

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jotafoto
Posts: 134
Joined: Fri Feb 26, 2010 8:20 am
Location: Sevilla-España

Mitutoyo plan apo 7,5/21

Post by jotafoto »

Does anyone know this lens? Does this have coverage for FF?
Thanks
best

Chris S.
Site Admin
Posts: 4042
Joined: Sun Apr 05, 2009 9:55 pm
Location: Ohio, USA

Post by Chris S. »

Jotafoto,

So far as I know, five or six of us in this forum use this lens. (This figure may grow by two, as a pair of these lenses were sold on eBay, today, almost immediately upon listing.)

I regard this optic as something a bit special, as both my specimen and another that I tested for a forum friend seem to have slightly better resolution than one would expect for an optic halfway between the Mitutoyo 5x and 10x. However, this is just a subjective sense, not something I've bothered to measure.

I don't recall having shot a full-frame body with this lens, but would expect it to cover full frame. However, at least a couple of other forum members surely have done so, and can weigh in.

--Chris

jotafoto
Posts: 134
Joined: Fri Feb 26, 2010 8:20 am
Location: Sevilla-España

Post by jotafoto »

Hahaha. I am sorry. I knew that if we waited they would take them away. Those two are coming to Spain. One for seta666 and one for me. That's why I asked, in case it was a good buy for $ 700.
I can not find photos made with this lens anywhere. Thanks

best
Javier

Chris S.
Site Admin
Posts: 4042
Joined: Sun Apr 05, 2009 9:55 pm
Location: Ohio, USA

Post by Chris S. »

Javier,

You and seta666 were wise to jump on these immediately. They were a very good buy at $700. Also, this lens almost never appears on the second-hand market. EBay has been notifying me for at least six years--probably more--of offerings for this lens. During this time, only three specimens, including your two, have appeared. (I bought the other one.)

Having tested quite a few microscope objectives for forum members, I'd strongly advise that you test these within the return window. About one in ten microscope objectives, in my experience, are bad--probably because they have been bumped or dropped. Other respected forum members report considerably higher failure rates. Your having two specimens arrive together is very helpful, as you can compare them. If they render a test subject similarly, and in a way that seems appropriate in comparison with Mitutoyo 5x and 10x objectives, you have a pair of winners.

I hope that both lenses pass any quality tests you perform. And am happy that members of our community have acquired specimens of this fine lens.

Cheers,

--Chris S.

Beatsy
Posts: 2105
Joined: Fri Jul 05, 2013 3:10 am
Location: Malvern, UK

Post by Beatsy »

I understand that putting a 5x on a longer tube lens will compromise resolution, but deliver consistent quality across a full frame. Putting a 10x on a shorter tube lens will compromise corner and edge quality (a bit), but with improved resolution (due to larger NA and shrinking the image scale).

So what is it that makes the 7.5x mitty apparently so desirable? I have 5x, 10x, 20x and 50x. It's a toss up between the 10x and 20x, but I think the 20x has the edge for contrast and colour (ignoring resolution and FoV differences). Of course, these may just be per-sample variations - a different 10x mitty might be better than my 20x.

So is the 7.5x considered better in a similar sense? Or is it just a desire to have the exact magnification "fit"?

abpho
Posts: 1524
Joined: Wed Aug 17, 2011 7:11 pm
Location: Earth

Post by abpho »

:( Congrats jotafoto. I hope to see some images with this lens really soon. :twisted:
I'm in Canada! Isn't that weird?

Medwar
Posts: 72
Joined: Mon Apr 16, 2012 1:46 am

Post by Medwar »

Hi all,
I will join with the question to Chris:
what makes this lens so desirable to you?

Does it perform better and in what parameter, then 5x, 10x & 20x Mitutoyos?

seta666
Posts: 1071
Joined: Fri Mar 19, 2010 8:50 am
Location: Castellon, Spain

Post by seta666 »

For anyone interested, I published a test of this lens:

http://www.photomacrography.net/forum/v ... hp?t=33379

It is a great performer that can go down to 4.5X on APS-C with good corner performance, way better than nikon 4/0.20

It covers well the gap between 5X and 10X, the magnification range I work more with

Regards
Javier

nathanm
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Joined: Thu Jun 02, 2016 8:13 pm
Location: Bellevue, WA
Contact:

Post by nathanm »

I have the 7.5X and it works very well for full frame, which is how I used to use it. These days I actually use it on PhaseOne which is much bigger than FF, and it works well there too.
nathanm

nathanm
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Contact:

Post by nathanm »

I will add that the reason I like it is simple - sometimes I want a magnification intermediate between 5X and 10X. Photographic composition is about what you can put in the field of view, and 2X increments are pretty coarse.

In normal scale photography you have lenses with intermediate focal lengths besides 2X increments, and you have zoom lenses, and you have the ability (usually) to move physically closer or farther away to change magnification and thus the field of view and composition.

With Mitutoyo objectives, you can't change distance or magnification easily. A different tube lens will do that but then you need to refocus it at infinity. It much easier to use a different objective.

Quality wise you are always going to be better off using a 7.5X objective than cropping a 5X.
nathanm

TheLostVertex
Posts: 317
Joined: Thu Sep 22, 2011 9:55 am
Location: Florida

Post by TheLostVertex »

nathanm wrote: With Mitutoyo objectives, you can't change distance or magnification easily. A different tube lens will do that but then you need to refocus it at infinity. It much easier to use a different objective..
I use infinity lenses with a tube lens on bellows. With,

Objective-adaptor-raynoxAsTubeLens-bellows-camera

I have found there is not much change in quality for me when changing the raynox distance away from it being at infinity focus.

On my nikon 10x and the dcr150 for instance, the bellows can make it range from ~6x to 11.8x magnification, with little change in center sharpness. Of course increase in effective aperture at higher magnifications, and corners at low magnifications are worth thinking about. In the 10x nikon for example, the corners turn to garbage at 6x, which is to be expected.

But all of this is to say, if you set up your tube lens so you can move it, you should be able to change magnification pretty easily. With the possible quality caveats depending on the objective used.

nathanm
Posts: 222
Joined: Thu Jun 02, 2016 8:13 pm
Location: Bellevue, WA
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Post by nathanm »

This thread has some tests that I did on the 7.5X Mitutoyo

http://www.photomacrography.net/forum/v ... 6&start=30

It is really great..
nathanm

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