LOMO 8/0.2 - two poppy seeds

Just bought that first macro lens? Post here to get helpful feedback and answers to any questions you might have.

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jscff
Posts: 2
Joined: Fri Oct 01, 2021 6:26 pm
Location: Southern Germany

LOMO 8/0.2 - two poppy seeds

Post by jscff »

Hi everybody,

I have been wanting to get into macro- und microphotography ever since I took histology, physiology, histopathology and microbiology in university. This summer I bought a Fuji XF 80mm 2.8 OIS to do some in camera stacking with the X-H1 I own. And altough I did not have much sucess with it capturing alive wildlife (they are moving fast), it was a good entry into focus stacking. But since I am most fascinated by the structures one cannot see with the eye, I wanted to have more magnification. With Google, it did not take long to find this forum, and the amount of information provided and your willingness to share, blew me away. Thank you very much for this! And yeah, I bought some stuff.

Today, after a bit of fiddling I captured the first image I want to share. It is an image of two poppy seeds. The first images I took of these seeds suffered from massive sharpness falloff in the corners due to the low quality (and cost) of the Lomo 8x. Then I remembered Roberts posts about the Lomo 3.7x with the Schneider Makro Symmar 120 and decided to try it with the DCR 250. And it worked kind of nice I guess.

Image

Lens: Lomo 8x/NA 0.2 with Raynox DCR 250 reversed with WeMacro adapter and tubing and a generic M42helicoid and M42 to Fuji X adapter. Distance of nearest lens element of Raynox approx 127mm from sensor
Effective Magnification: 6x (measured with a metal ruler)
Stacking Unit: MJKZZ Ultra Rail MINI V2 USB
Stacking Settings: 127 images, 12 µm stepsize, Wait/Hold 2000 ms, Snap 200 ms
Rig: Custom built 45x60 cm long vertical setup with aluminium extrusions sitting on a 45x20 cm granite block, 50x50x50 cube around for the lights
Camera/Settings: Fuji XH1/iso200/1/125
Camera Processing: Velvia, Sharpening +2, Fine JPG
Software: Tethering via Capture One 20, Focus Stacking Studio V2, Helicon Focus B-Mode (8/4)
Postprocessing: < 3 minutes in Photoshop CC (auto remove background, use black layer as background, turning/mirroring of the objects, sharpening)
Lights: 2 x Godox TT350 at 60° approx 20 cm from subject (1/32), Triggered via Godox Trigger
Light modifier: Kitchen paper towel wraped in a cylindrical form losely around the subject, distance to subject about 5 cm
Background: Paper painted with Musou Black


My questions are:
a) please tell me your honest critique - what you like, what you dislike.
b) I want to modify my lights a bit more to get more dramatic effects, but I have trouble to do so, because the flashes are so large. Do you use cone formed strobe midifiers to concentrate the light? Or do you change the light modifier (in this case a papertowel) and use things like non-translucent objects to block unwanted light.
c) the DOF/stepsize calculator of Focus Stacking Studio asks for the sensor size in order to determine the ideal stepsize. I understand the basic concept of this, when I enter the measured magnification and the NA of the microscope objective it makes sense. Because most objectives we use are not constructed for our cameras it is always adviseable to measure the effective magnification before taking the stack? Or how do you determine the stepsize for you different setups
d) I went with Helicon because their UI is dark (which I prefer by a huge marging) and on my PC (Ryzen 2700, 32 gb RAM) it seems much faster than Zerene - than I see a lot of you guys are using Zerene. When does it make sense to switch?



Thank you very much in advance, with kind regards from Germany,
Jon

rjlittlefield
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Re: LOMO 8/0.2 - two poppy seeds

Post by rjlittlefield »

Jon, welcome aboard! :D

It is holiday today in the U.S., so I will be more brief than usual.

Regarding Helicon Focus versus Zerene Stacker, some of the issues that you ask about were recently addressed at viewtopic.php?p=277319#p277319 . Not mentioned there is "slabbing", which is another feature provided by Zerene Stacker for getting best possible results, especially with deep stacks that require retouching. Also not mentioned is that Zerene Stacker does provide a dark UI, which can be manually selected at Options > Preferences > Look & Feel > "Java cross-platform Dark Mode". (Standard discolsure: I'm the fellow who wrote Zerene Stacker and handles all support requests, so I know most of its pros, cons, and quirks.)

Regarding DOF, most macro/micro calculators use a classic formulation based on "circle of confusion". That formulation does not properly account for diffraction, and with classical parameter settings it will produce focus banding when images are examined with "pixel-peeping" at 100%. A more accurate method is described at https://zerenesystems.com/cms/stacker/d ... romicrodof and incorporated into the Tools > Calculators... > "DOF calculator" of Zerene Stacker. Some earlier discussion of the theory can also be read in the long thread that begins at viewtopic.php?t=19756 . I do not know what method the Focus Stacking Studio uses. mjkzz has had access to all this material so perhaps he has already incorporated it. Generally speaking, when using a microscope objective the safest approach is to calculate based on the specified NA. In any case all DOF calculations must be treated with some skepticism because in practice there are other factors that none of the models incorporate. Those issues become more important at higher magnifications. You're still working with low enough magnification that working straight from NA will probably do fine.

I will leave critique and illumination for other people. Illumination will be a long discussion.

--Rik

jscff
Posts: 2
Joined: Fri Oct 01, 2021 6:26 pm
Location: Southern Germany

Re: LOMO 8/0.2 - two poppy seeds

Post by jscff »

rjlittlefield wrote:
Thu Nov 25, 2021 2:09 pm
Jon, welcome aboard! :D

It is holiday today in the U.S., so I will be more brief than usual.

Regarding Helicon Focus versus Zerene Stacker, some of the issues that you ask about were recently addressed at viewtopic.php?p=277319#p277319 . Not mentioned there is "slabbing", which is another feature provided by Zerene Stacker for getting best possible results, especially with deep stacks that require retouching. Also not mentioned is that Zerene Stacker does provide a dark UI, which can be manually selected at Options > Preferences > Look & Feel > "Java cross-platform Dark Mode". (Standard discolsure: I'm the fellow who wrote Zerene Stacker and handles all support requests, so I know most of its pros, cons, and quirks.)

Regarding DOF, most macro/micro calculators use a classic formulation based on "circle of confusion". That formulation does not properly account for diffraction, and with classical parameter settings it will produce focus banding when images are examined with "pixel-peeping" at 100%. A more accurate method is described at https://zerenesystems.com/cms/stacker/d ... romicrodof and incorporated into the Tools > Calculators... > "DOF calculator" of Zerene Stacker. Some earlier discussion of the theory can also be read in the long thread that begins at viewtopic.php?t=19756 . I do not know what method the Focus Stacking Studio uses. mjkzz has had access to all this material so perhaps he has already incorporated it. Generally speaking, when using a microscope objective the safest approach is to calculate based on the specified NA. In any case all DOF calculations must be treated with some skepticism because in practice there are other factors that none of the models incorporate. Those issues become more important at higher magnifications. You're still working with low enough magnification that working straight from NA will probably do fine.

I will leave critique and illumination for other people. Illumination will be a long discussion.

--Rik
Thank you Rik for your thorough reply. I really do enjoy reading the really not so short answers on this forum. Especially your reference to your post "A new way of thinking and calculating about DOF" helped me a lot, since it integrates what I learned in optics/physics.
NA is the subject-side numerical aperture
m is the magnification, from subject to sensor.
C is the diameter of the circle of confusion. We're going to take C as being proportional to the Airy disk diameter implied by the effective f-number, and pick one to match the other.

TDF = lambda/NA^2 [1/4-lambda wavefront error, lambda = 0.00055 mm for green light]

NA = m/(2*f_eff)
f_eff = m/(2*NA)
TDF = lambda*4*f_eff^2/m^2
together with this link https://zerenesystems.com/cms/stacker/d ... romicrodof which includes practical advise, you helped me a great deal.


Thank you again,
Jon


ps: Since I have read many answers by you already, I know that you are the programmer behind Zerene - I felt kind of bad picking Helicon, but your reply makes me feel a bit better. And since I now know there is a dark UI - I may upgrade if I reach the limits of Helicon.

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