New M42 to M42 Iris available on ebay (test added)

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seta666
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New M42 to M42 Iris available on ebay (test added)

Post by seta666 »

Hello,
few weeks ago I asked ebay seller jinfinance if he could build a M42 Iris; with the rigth adapters it could be used on bellows with any microscope lens
The Iris is ready 140547138653 ; I asked him to make several adapters for mitutoyo BD 40mm, nikon bd infinity 27mm, Mitutoyo/nikon BD, and RMS, also a M25 adapter would be nice for those Nikon lenses that use that thread. I askd him to make them ring type so the lens will stay close to the iris
Regards
Javier
Last edited by seta666 on Wed Jun 29, 2011 12:49 pm, edited 2 times in total.

RogelioMoreno
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Post by RogelioMoreno »

Thank you.

Rogelio

ChrisLilley
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Post by ChrisLilley »

Adding an iris is an interesting idea.

I'm puzzled why this is M42-M42. The jinfinance adapters for Nikon CFI etc are to 52mm filter thread. So either this needs 52mm-M42 and M42-52mm adapters, or it needs new objective-M42 adapters ...

Since an infinite objective is used with a tube lens and tube lenses typically don't have M42 mounts on the front, I assume then that this is aimed at finite objectives used on (M42?) bellows.

I see the iris is available separately, which may be a better idea for use with infinite objectives.

seta666
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Post by seta666 »

ChrisLilley wrote: Since an infinite objective is used with a tube lens and tube lenses typically don't have M42 mounts on the front, I assume then that this is aimed at finite objectives used on (M42?) bellows.

I see the iris is available separately, which may be a better idea for use with infinite objectives.
Hello,
I asked an M42 Iris because as you say I use my lenses on Bellows; but I think that the iris makes more sense with infinity lenses, as the use of an iris with these lenses producers no vigneting
I use the bellows with adapted tube lenses (morfanon and somco 240mm) which are fitted inside M42 tubes, so adding the Iris in between is very easy
I already use Iris from stripped down enlarging lenses but is a pain to find the right thread, with this M42 iris and the right adapters I will be able use any microscope lens
I have ordered adapters for 40mm (mitutoyo bd), 27mm (nikon BD infinity) 26mm (mitutoyo BD) and RMS (nikon infinity EPI); custom made for this iris so the lenses will stay as close as possible to the iris
Regards
Javier

dmillard
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Post by dmillard »

Thanks Javier - this looks very useful.

Regards,
David

Craig Gerard
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Post by Craig Gerard »

Thanks Javier,

Yep, I'll be adding some of those pieces to my box'o'things in the near future.

The additional adapters that couple with the M42 iris assembly are now available :)

Some of the listing images show the iris assembly in the photos; but the iris assembly is a separate piece.

Here is the M42 iris assembly:
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0547138653

and here are the additional adapters

http://cgi.ebay.com/thin-M42-Nikon-CFI- ... 0563723217

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0619040662



Craig
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

seta666
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Post by seta666 »

Thank you Craig,
I was going to update the post today, you did first ;-)
Mine is on the way with some of the adapters, I requested to build adapters for mitutoyo BD plans M40, Nikon BD infinity M27, mitutoyo m plans and nikon BD finite M26; nikon infinity CFI M25 and RMS

Also a M42 to BD flat adapter is now available rathar than just the cone shaped

I hope it works as expected

Regards

BugEZ
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Got my new Iris last week

Post by BugEZ »

I purchased the iris mentioned above and installed it in my rig. I am very pleased. I use M42 extension tubes to support my microscope lenses and it installed with no difficulties.

Thanks for bringing the iris to my attention!

Keith

seta666
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Post by seta666 »

Yesterday I recieved the iris and adapters for mitutoyo BD, nikon BD infinity, mitutoyo M plan / nikon BD and RMS
The Iris is beautifully round, closes to 1mm and has 14 blades; only con would be the blades being a bit more reflective than desired but yesterday I did a quick test and did not notice any contrast lost
The thin adapters allow the rear element of the objective to be 5mm to the Iris, the Mitutoyo BD M40 adapter is thicker in desing and stays 11mm awy from the Iris
From right to Left the iris with mitutoyo BD plan 20/0.42, nikon BD 20/0.46 oo, Mitutoyo M plan 10/0.28 and nikon Epi 50/0.55 ELWD 00 with their adapters
Image
Here the Mitutoyo BD 20/0.42, Iris and Morfanon lens tube inside cheap chinese M42 tubes
Image

As soon as I can run some test I will let you know

Craig Gerard
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Post by Craig Gerard »

Javier,

Thanks for the update.

Looking forward to your report.


Craig
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

Harold Gough
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Post by Harold Gough »

It was jinfinance who supplied (ready made) my X-Pan to micro 4/3 adapter. Nice kit.

Harold
My images are a medium for sharing some of my experiences: they are not me.

ChrisLilley
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Post by ChrisLilley »

I can see that the thin objective adapters, screwing into the body of the iris housing, give a shorter distance between the objective and the iris than would be provided with the existing objective to m52 adapters.

For use with infinity objectives and (non-M42-mounted) tube lenses, M42 macro reversing adapters can be used such as this item

http://cgi.ebay.com/Macro-Coupler-Rever ... 0324995025

ChrisLilley
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Post by ChrisLilley »

seta666 wrote: The Iris is beautifully round, closes to 1mm and has 14 blades;
Here are some back of the envelope calculations, I would be interested to see if I have got them right.

A 10x/0.25 objective has an effective aperture at 10x of m/2NA = 10/0.5 = f/20

with a 20μm CoC c, and 550nm wavelength λ, in air (n=1),
DOF = (λ/NA^2) + c(1/mNA))
= 16.8 μm

A 10x infinity lens designed for use with a 200mm tube lens has a focal length of 200/10 = 20mm.

An iris of 1mm diameter on a 20mm lens is f/20 nominal aperture. (20/20=1).

Treating the objective as a 20mm objective, and pretending it is on 220mm of extension to give 10x, stopped down to nominal f/20 would give an effective aperture of
F * (1+m) = f/220
and a DOF = 2Fc((m+1)/(m^2)
= 88 μm

However, the objective is actually a 20mm lens stopped down to f/20 then mounted on a 200mm lens and I don't know how to work out the effective aperture or DOF of the combination.

Maybe I should instead be converting the nominal f/20 back to NA? So NA =1/2F = 1/40 = 0.025

A 10x/0.025 objective at 10x is effective f/200 and the DOF is 960 μm.

Really? almost a millimeter of DOF?

lauriek
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Post by lauriek »

Close to 1mm of DO'something' - not much focus at f200...

seta666
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Post by seta666 »

I do not intend to use the 10x at f200, but the iris can be usefull to close a few stops for last shots
closing down to 1mm will allow the iris to be used with my 50x lens, with very smallrear element
one more use for the iris is making objectives work with smaller apertures than they were designed for
I can turn my 10/0.28 into a 10/0.20 or my 20/ 0.46 into a 20/0.35 for subjects that may require that kind of lens (hairy subjects or deep stacks)

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