Canon MPE 65 + Raynox MSN 202 or MPE plus Extension tubes

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anvancy
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Canon MPE 65 + Raynox MSN 202 or MPE plus Extension tubes

Post by anvancy »

Hello,
Hope this is the correct sub forum for my question. If my question is answered before, please do provide me a link and i can go ahead and read it.

For the purpose of this question, I do not have access to microscope objectives. I was suggested the Nikon ones but due to budget constraints I did not move ahead on that aspect.
First my gear.
Canon 80D
Canon MPE 65mm
Raynox 150, 250 and MSN 202.
Wemacro Rail
3x Ikea Janso Lights
2 Yongnuo Flash
1 Venus KX800 onfield flash

For stacking purposes I am using the MPE till the 5x range. Beyond 5x I have recently started experimenting usage of MSN 202 over and above the MPE.

As I understand raynox having its own optics, things look visibly hazy/blurry as when we see the MSN attached to a regular lens/macro lens. I have to considerably stop down the aperture (F6.3 or so ) to register some depth in the image for stacking. But I think I know I am going heavily wrong here.

Given the circumstances, will usage of extension tubes instead of Raynox yield comparatively better result in my workflow? The instant drawback I think of is prestopping my aperture before I attach the extension tubes. But that is part and parcel of the setup. Auto extension tubes do cost a bit.

Any leads will be helpful.

Thanks

Anvay
www.anvancy.com

Raynox 150|Raynox 250|Raynox MSN 202|Canon MPE 65mm|Canon 100mm.|Wemacro Rail

billjanes1
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Re: Canon MPE 65 + Raynox MSN 202 or MPE plus Extension tube

Post by billjanes1 »

anvancy wrote:Hello,

For stacking purposes I am using the MPE till the 5x range. Beyond 5x I have recently started experimenting usage of MSN 202 over and above the MPE.

As I understand raynox having its own optics, things look visibly hazy/blurry as when we see the MSN attached to a regular lens/macro lens. I have to considerably stop down the aperture (F6.3 or so ) to register some depth in the image for stacking. But I think I know I am going heavily wrong here.

Anvay
The laws of physics are going against you. An approximation of the effective f/number is nominal f/number * (m+1), where m is the magnification. At m = 1 with a nominal f/number of 6.3, the effective f/number is 37.8 and there will be a severe loss of resolution from diffraction.

Look at Rik's Table 2-A (http://zerenesystems.com/cms/stacker/do ... romicrodof). For a magnification of 5, he recommends an aperture no smaller than f/2.8.

Regards,

Bill

Edited 8 Jan 2019 GMT 12:24 to specify the case where m = 1
Last edited by billjanes1 on Tue Jan 08, 2019 5:26 am, edited 1 time in total.

ChrisR
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Post by ChrisR »

Yes - if you already have unacceptable blur and unacceptable depth of field, no optics can help, because one or the other will get worse.
Chris R

anvancy
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Post by anvancy »

Thanks Bill and Chris.

Then it boils down to me buying a microscope objective as they are the best gear to use given my requirement. Hmm...

Maybe ill share a base image to show my problem. When I use 2.8 its kind of extremely blurry but can understand i am working close to 9-10x. Wonder how do we actually focus when using the objective.

Anvay
www.anvancy.com

Raynox 150|Raynox 250|Raynox MSN 202|Canon MPE 65mm|Canon 100mm.|Wemacro Rail

Lou Jost
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Post by Lou Jost »

I wonder if you are mixing up two very different kinds of blur. One is general blurriness due to too-small physical aperture, and the other is very blurry due to the depth of field being very shallow. In the latter case, there is still a thin (perhaps almost un-noticeable) sliver of the image that is sharp.

If the latter case, the solution is not to get a microscope objective but to use stacking.

anvancy
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Post by anvancy »

Maybe I am confusing two things Lou.

Image

Here is an example about my question. The photo is taken with the MSN and the MPE at 5x with F3.5.

That blurriness is DOF being extremely shallow with the combo or its because of the additional optics of the MSN?

So in this case my step size being small, i have to take hundreds to cover the depth range?
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Raynox 150|Raynox 250|Raynox MSN 202|Canon MPE 65mm|Canon 100mm.|Wemacro Rail

Lou Jost
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Post by Lou Jost »

I think you have both problems. You'll definitely have to stack at that magnification, but no part of that image is sharp. What aperture did you use?

anvancy
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Post by anvancy »

Lou Jost wrote:I think you have both problems. You'll definitely have to stack at that magnification, but no part of that image is sharp. What aperture did you use?
This I shot at F3.5.

And as you pointed out, my assumption is if I use the extension tubes instead of the MSN I can eliminate some of the extra blurriness that the MSN is causing to happen.

I have the wemacro setup but when I ran my tests, the sample images showed that during the stacking no depth as such will be registered as per me. This is where I dialed down at F6.3 and the extra blur kind of vanished. Ofcourse diffraction territory, but I could make out the image.

Will this situation be there even when I use a microscope objective?
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Raynox 150|Raynox 250|Raynox MSN 202|Canon MPE 65mm|Canon 100mm.|Wemacro Rail

Lou Jost
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Post by Lou Jost »

The blur outside the plane of focus will get worse, and the plane of focus will be even thinner, when you use a microscope objective. But that is what you want. Stacking will handle it fine, and the part in focus will be really sharp even though just in a very narrow zone.

I think also maybe the optics of the close-up lens are causing part of your problems.

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Post by ChrisR »

Photographing at 10x, f/3.5 is near eff/40 so you wouldn't get a very sharp image, but it is good enough for web use.
The DOF is only about the diameter of a human hair for a pic 1024 wide.
A 3D subject means almost nothing is in focus, so try something flat, like laser printed paper (Bank statements have useful odd little patches of code squares, etc.).

I haven't tried extending an MP-E, though others have; I remember member jsp doing it with her ferns, and LordV with a springtail and piece of ruler - see the link.
jsp pic, 4th one down, MPE on tubes, stacked.
On other lenses, I have found that using a Raynox 250 gave me better results than extending the lens on tubes, at the same magnification.

You will find that wide apertures give you more of the OOF image intruding over the sharp part because the cone of light is wider. (Lighting has a big effect on that too.)

The main point though, is that at even the best balance point between DOF and diffraction blur and the other effects, 3D subjects don't look very good at 10x, unless you stack images!
Chris R

anvancy
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Post by anvancy »

Thanks Chris for this insight.

Maybe Ill check extending the MPE via the tubes to see how it goes and get back here what I find.

I tried the Raynox 250 on the MPE but think I am achieving only 7x by my calculation? Or I am wrong here?
www.anvancy.com

Raynox 150|Raynox 250|Raynox MSN 202|Canon MPE 65mm|Canon 100mm.|Wemacro Rail

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