50:1 and 100:1

Images taken in a controlled environment or with a posed subject. All subject types.

Moderators: Pau, rjlittlefield, ChrisR, Chris S.

Cornel
Posts: 26
Joined: Tue Feb 07, 2017 11:33 pm

50:1 and 100:1

Post by Cornel »

Greetings,

This is my first attempt with my new 100x objective Nikon LU Plan BD 100x NA 0.80.
Nikon D610 + Raynox DCR-150 + MJKZZ rail + 3xflash
Stack 64 frames, 0,9 um step size

Working distance is 3,5mm so it's pretty hard to bring light to subjects like eyes, but I'll do some more testing. Also the step size should be smaller but there are some mechanical limitations...

Vanessa atalanta white spot on the wing.

100:1

Image

Crop 100:1

Image

I'm happy that there is an obvious improvement in detail over 50:1 and NA 0.55. Also I like the 3d look of the ridges.

This is the same kind of wing with the same setup and Nikon LU Plan 50x NA0.55. Both pictures have some crop and processing, nothing too fancy.

50:1
Image

Crop 50:1

Image

The 50x can be better, it's kinda flat here because of the front-ish lighting.

Saul
Posts: 1716
Joined: Mon Jan 31, 2011 11:59 am
Location: Naperville, IL USA
Contact:

Post by Saul »

Very nice patterns.
0.9um step worked pretty good, I'm using 0.5um for 50x. Maybe overkill ?

Pau
Site Admin
Posts: 5317
Joined: Wed Jan 20, 2010 8:57 am
Location: Valencia, Spain

Post by Pau »

This is quite an improvement!
With some levels adjustment and sharpening it looks really good.
Saul wrote:0.9um step worked pretty good, I'm using 0.5um for 50x. Maybe overkill ?
It depends of the subject, exigence, illumination and maybe other factors...with a diatoms test stack I did while testing my newly acquired Wemacro coupled to the microscope I found that 0.35um was the best step with a 25/0.65 objective, much smaller than the generally accepted (and well proven) standards
Pau

Lou Jost
Posts: 4772
Joined: Fri Sep 04, 2015 7:03 am
Location: Ecuador
Contact:

Post by Lou Jost »

Very beautiful result!!

Smokedaddy
Posts: 1715
Joined: Sat Oct 07, 2006 10:16 am
Location: Phoenix, Arizona
Contact:

Post by Smokedaddy »

They look excellent to my old eyes.

rjlittlefield
Site Admin
Posts: 21277
Joined: Tue Aug 01, 2006 8:34 am
Location: Richland, Washington State, USA
Contact:

Post by rjlittlefield »

Pau wrote:
Saul wrote:0.9um step worked pretty good, I'm using 0.5um for 50x. Maybe overkill ?
It depends of the subject, exigence, illumination and maybe other factors...with a diatoms test stack I did while testing my newly acquired Wemacro coupled to the microscope I found that 0.35um was the best step with a 25/0.65 objective, much smaller than the generally accepted (and well proven) standards
I am no longer surprised by such reports. At large NA, proper step size seems to vary a lot depending on the subject and illumination. A lot of this is due to utilized aperture effects that make the subject appear to wiggle around laterally, in addition to going into and out of focus. But sometimes I wonder if there is also some important structure in the lightfield reflected/diffracted off a 3D surface that is not captured by the utilized aperture concept either. The standard formula for 1/4-lambda wavefront error (=lambda/(NA^2)) is derived from a planar model and happily ignores all such effects, which means that it's sort of a "necessary but not sufficient" condition.

--Rik

nanometer
Posts: 318
Joined: Sat Apr 30, 2016 10:14 pm
Location: Tucson, AZ

Post by nanometer »

Wow--that's really getting into the detail of the scales. Very nice!

Guppy
Posts: 154
Joined: Mon Dec 20, 2010 10:36 am
Location: Switzerland
Contact:

Post by Guppy »

Hello

Nice pictures and very interesting!

There is a relation between Apertur and depth of field (DOF).
DOF (mm) = Lambda (mm) / (NA x NA)

In reality, i do not know how high the aperture exactly is!

The resolution of a bad objektiv is low, and the depth of field is higher.
There is a relation between Apertur, quality and resolution.
Everything is theoretical.

In practice, I can easily measure the resolution.
So I'm counting from an actually measured resolution to the aperture.

Apertur = (LP/mm x lambda) / 2
(1000LP/mm x 0.00055mm) / 2 = 0.275 NA

and from this aperture to depth of field.
DOF (mm) = lambda (mm) / (NA x NA)
0.00055mm / (0.275 x 0.275) = 0.00727mm DOF

Directly from resolution to depth of field
DOF (mm) = lambda (mm) / (((LP/mm x lambda (mm)) / 2) x ((LP/mm x lambda (mm) / 2))
0.00055 / (((1000 x 0.00055) / 2) x ((1000 x 0.00055) / 2)) = 0.00727mm DOF

The basis of this calculation is the real measured resolution and the result is a depth of field close to the reality

The macro rail is not absolutely exact and sometimes a picture fails.

That's why (for focus stacking) I make 3 pictures within this depth of field.
This manner of calculation works well from 1:1 to 100:1.

Kurt

Post Reply Previous topicNext topic