Good first experience with (used) Mitutoyo 20x

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santiago
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Good first experience with (used) Mitutoyo 20x

Post by santiago »

My lens adapter arrived yesterday, so I was finally able to test my recently purchased used Mitutoyo 20x/0.42 (#378-804-2) for the first time. As suggested here, I did a direct comparison with the Nikon CFI 10x/0.25 (#MRL00102) which I purchased new some months ago. The results were as expected (the Mitu outresolving the Nikon), but given the risk factor when buying used objectives it was still nice to see this confirmed so I wanted to share the results here.

For this test I used the wing of a moth (Noctua sp.). Here are some side by side comparisons:

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Animated GIFs:

https://c1.staticflickr.com/5/4897/4508 ... f7c4_o.gif
https://c1.staticflickr.com/5/4911/3194 ... 5e82_o.gif
https://c1.staticflickr.com/5/4892/4576 ... 888f_o.gif

Full-size stack with the Mitutoyo:
https://c1.staticflickr.com/5/4835/4489 ... eece_o.jpg

Full-size stack with the Nikon:
https://c1.staticflickr.com/5/4854/3087 ... 79fa_o.jpg

The Nikon stack was enlarged to match the Mitutoyo stack (I didn't want to lose any information by down-sampling the 20x image). I used the same tube assembly as shown here (when using the Mitutoyo the only difference is the M52 - M26 lens adapter). The images were stacked with Zerene (DMap to preserve information which was needed for this test), 40% unsharp mask 1px radius. Canon EOS 5D Mark II, ISO 100, diffused flash. The step size was 3um (should have been 2um).

My final conclusion is that I'm happy with the Mitu (thanks Javier :wink:) and that this is a good place to buy used equipment :)!

Any feedback is welcome.
Santiago
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RobertOToole
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Post by RobertOToole »

Santiago

Nice results with the 20x.

At first glance the The 10x results look very soft but the image was upscaled to match the 20x right? Otherwise the 10x sharpness looks like something you find out of a defective 10x objective.

Robert

santiago
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Joined: Tue Sep 25, 2018 5:56 am
Location: Nijmegen, The Netherlands

Post by santiago »

RobertOToole wrote:At first glance the The 10x results look very soft but the image was upscaled to match the 20x right? Otherwise the 10x sharpness looks like something you find out of a defective 10x objective.
Thank you Robert. Yes, the Nikon stack has been upscaled from 5616 px to 11178 px (width), that's 1.99x.

Here are 3 100% crops from a Nikon stack (raw DMaps with artifacts)... are these looking better?

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Thanks for your comment. I'm always impressed by your tests btw :).
Santiago
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Macro_Cosmos
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Post by Macro_Cosmos »

Still looks a bit too soft to be honest from my experience.

~MC

santiago
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Post by santiago »

Macro_Cosmos wrote:Still looks a bit too soft to be honest from my experience.
Thanks Macro_Cosmos. What could be the reason? The reversed Raynox DCR-150? The objective was purchased new some months ago from SEO Enterprises.

(Edit) To me these last 3 Nikon crops look crisper than the Mitutoyo crops (as expected). What do you think of the Mitutoyo crops, do those also look too soft to you?

Thanks in advance
Santiago
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RobertOToole
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Post by RobertOToole »

santiago wrote:
RobertOToole wrote:At first glance the The 10x results look very soft but the image was upscaled to match the 20x right? Otherwise the 10x sharpness looks like something you find out of a defective 10x objective.
Thank you Robert. Yes, the Nikon stack has been upscaled from 5616 px to 11178 px (width), that's 1.99x.

Here are 3 100% crops from a Nikon stack (raw DMaps with artifacts)... are these looking better?

Image
Image
Image


Thanks for your comment. I'm always impressed by your tests btw :).
Hi Santiago,

This looks about right for that objective at 100%. I'm pretty familiar with CFI Plan 10x since I was just shooting with one last month for a 10x test.

The 10x/0.25 CFI Plan is not as sharp as the Mitutoyo 10s or other higher NA Nikon 10x objectives. I think this objective's strength is coverage not sharpness anyway.

Best,

Robert

santiago
Posts: 109
Joined: Tue Sep 25, 2018 5:56 am
Location: Nijmegen, The Netherlands

Post by santiago »

RobertOToole wrote:This looks about right for that objective at 100%. I'm pretty familiar with CFI Plan 10x since I was just shooting with one last month for a 10x test.
It's good to hear that!

I have a beginner's question: to calculate the step size for stacks I use the formula 0.5/(NA^2). For NA 0.42 this gives 2.834um. But does magnification play any role at all? If I were to push down the magnification of the Mitu from 20x to 18x (using bellows), will the DOF increase at all? I wouldn't mind (ocasionally) trading some magnification for more DOF, so that I can use a step size of 3 instead of 2.

Thanks in advance!
Santiago
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JohnyM
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Post by JohnyM »

Not really, you're oversampling anyway, so changing mag would result only in different FOV.
That being said, you certainly can use 3um step or even bigger, without obvious banding, just decreased resolution.
If you want to experiment, check your most recent 2um stack with software stacking every 2nd or 3rd frame and compare output.

Im pretty sure you'll be hard pressed to point any difference between 2um or 3um step.

santiago
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Location: Nijmegen, The Netherlands

Post by santiago »

JohnyM wrote:Not really, you're oversampling anyway, so changing mag would result only in different FOV.
Ok, good to know.
If you want to experiment, check your most recent 2um stack with software stacking every 2nd or 3rd frame and compare output.
That is a great way to simulate different step sizes, will definitely try that!

Thank you JohnyM :)
Santiago
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Macro_Cosmos
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Post by Macro_Cosmos »

Oh my bad, I didn't read carefully. I thought it was a mitutoyo 10x. Sorry about that.

For step size, I use 3um for 10x and would use 1-2 um for 20x and 50x magnifications. Another contributor to softness is lighting, which is the hardest aspect IMO. I've seen some photos with old finite objectives that are just amazing because of extremely well done lighting. It's an area everyone would always be able to improve in.

MC

santiago
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Location: Nijmegen, The Netherlands

Post by santiago »

Macro_Cosmos wrote:Oh my bad, I didn't read carefully. I thought it was a mitutoyo 10x. Sorry about that.
No problem :).

I agree with lighting being one of the most challenging areas!
Santiago
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rjlittlefield
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Post by rjlittlefield »

Another thing to remember is that images like these can and should be aggressively sharpened to get the most out of them. Just from diffraction, MTF drops to only around 40% at half the cutoff frequency. But you can recover that to near 100% with simple sharpening. See http://www.photomacrography.net/forum/v ... hp?t=33724 and http://www.photomacrography.net/forum/v ... 198#203198 for some illustrations and discussion.

--Rik

santiago
Posts: 109
Joined: Tue Sep 25, 2018 5:56 am
Location: Nijmegen, The Netherlands

Post by santiago »

rjlittlefield wrote:Another thing to remember is that images like these can and should be aggressively sharpened to get the most out of them. Just from diffraction, MTF drops to only around 40% at half the cutoff frequency. But you can recover that to near 100% with simple sharpening. See http://www.photomacrography.net/forum/v ... hp?t=33724 and http://www.photomacrography.net/forum/v ... 198#203198 for some illustrations and discussion.
That was very interesting material on sharpening and deconvolution, thank you. I tend to use little sharpening for fear of ruining the images but these posts have made me reconsider that a bit!
I'm also curious to try RawTherapee's (blind) deconvolution sharpening...
Santiago
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