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Crystalline Structures

 
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concon



Joined: 01 Jun 2017
Posts: 87

PostPosted: Tue Dec 19, 2017 8:04 am    Post subject: Crystalline Structures Reply with quote

I haven't gotten my hands on any cuts lately so my normal subjects are out of reach; I decided to dig into some other cannabis related items I had been meaning to photograph and pulled out some THCa crystalline. I believe this was created using an everclear/alcohol based extraction to completely isolate the acid group from the other compounds in the plant.

What I thought would be a nice fun distraction turned into a chaotic game of cat and mouse...Asking myself if photographing something like this was even practical for me.

I've included some sample images below and knew that if I were to make any additional progress, I'd need to consult more seasoned minds.

My main issue is the haze that is created from so much depth- the added noise and grit just kills the image. I have to go fairly deep to try to pull focus on even the smallest sample sizes (I had a speck on the end of an insect pin). I tried a few 80x shots, but I wasn't able to to recover anything worth looking at.

Am I trying to go too deep with such a detailed subject or should I be trying something different in camera/with lighting?

-Mitutoyo BD Plan 20x (ISO 80)- I think I was stepping at 2-3um...I can't remember off the top of my head; 308, 240, and 206 image stack; slabbed at 25/15.

(Not great at downsizing and such for uploads here Embarassed )









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stefan



Joined: 17 Mar 2016
Posts: 9
Location: Scandinavia

PostPosted: Sat Dec 23, 2017 8:53 am    Post subject: Reply with quote

You may try monochromatic light and/or polarized light and less prisms. The prisms scatter the light in every direction again and again.
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rjlittlefield
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Joined: 01 Aug 2006
Posts: 19090
Location: Richland, Washington State, USA

PostPosted: Sat Dec 23, 2017 10:47 am    Post subject: Reply with quote

For what it's worth, I think the images you have here look pretty good, given the nature of the subject.

As a possible improvement, I suggest to aggressively noise-reduce your source images before stacking them. That will minimize the build-up of "grit" (pixel noise). To find an appropriate amount of noise-reduction, locate a single frame that contains the sharpest real detail you can find, then crank up the noise reduction settings until just before that real detail starts to be impacted. There is inevitably some judgement involved here, but we humans seem to be pretty good at distinguishing real detail from imaging artifacts, based largely on our knowledge of what the structure of the subject must really be.

Adding some background information...

I consider this sort of subject to be among the most challenging you will ever encounter.

The transparency and great depth of the subject means that at every focus position, at most pixel positions, the lens will see large amounts of light from out-of-focus parts of the subject both in front and behind whatever is focused. Whatever contrast remains is only provided by unusually bright reflections from the edges and favorably aligned facets of the crystals, and in some cases by unusually dark edges where the crystal simultaneously reflects black environment, prevents background light from getting through, and is not partially occluded by bright out-of-focus foreground. It is completely normal to end up with an image that consists of relatively few isolated bright & dark details floating in a cloud of haze.

--Rik
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concon



Joined: 01 Jun 2017
Posts: 87

PostPosted: Thu Jan 04, 2018 7:59 am    Post subject: Reply with quote

Appreciate the replies guys and will give both of these a try.

Rik, do you reduce noise from your source images often or just for very subjects that can be troublesome, like this?

When I first started stacking I used to edit a single source image for noise, color, sharpness, etc and then apply it to the rest - after that I would process the stack. As time went on I saw the disadvantages in this and read a few of your posts here and on Zerene - Now I only post process the final Zerene output...but I can see how removing noise ahead of time would be very beneficial for large stacks. Sometimes my normal stacks/work can get fairly deep and then grity/hazy; this can require plenty of extra care in PS to mask out.
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rjlittlefield
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PostPosted: Thu Jan 04, 2018 2:15 pm    Post subject: Reply with quote

Generally I reduce noise "to taste" whenever I shoot raw, but not when I shoot JPEG. I make no claim that this strategy is optimal in any sense.

Revisiting this thread, I realize that I'm unclear exactly how you're shooting and processing these stacks. I can see in the EXIF that you're using a Sony ILCE-7RM2 (a7R II) at low ISO (50 or 80), but I can't tell whether you're shooting at full resolution and/or shooting raw, whether you're processing in Zerene Stacker at full resolution, or how you're doing the reduction to posting size.

Short summary is that for best results you should be shooting and processing at full resolution, 42 megapixels, with smoothing applied in the final step just before resizing, as described at http://www.photomacrography.net/forum/viewtopic.php?t=19456 . The smoothing is described there as a method for minimizing moiré effects, but the same approach is very good at reducing noise also.

--Rik
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concon



Joined: 01 Jun 2017
Posts: 87

PostPosted: Fri Jan 05, 2018 11:06 am    Post subject: Reply with quote

Thanks again Smile

I generally shoot jpg nowadays for speed reasons and do my best to expose everything well enough that I'm not trying to recover too much and I can stay at lower ISOs (constantly working on improving upon this with my subjects [trichomes]). I shot RAW initially, but didn't find too much benefit when I exposed everything correctly and controlled my environment. There's also so much to shoot on a cut and with limited time before a subject drying, it's a race.

As for resolution, I'm embarrassed to say I don't believe I'm shooting in full. I use an old Vivitar 200mm as my relay lens and I have to put my camera in asp-c mode as there is definitely a noticeable ring/vignette- this causes me to shoot below max resolution for sure. I'm sure I could get away with the Raynox setup I was playing with, but I don't feel confident enough with it.

Ultimately though- shoot, transfer, move to Zerene, align, slab, combine slabs, retouch, move to PS- blacken out background with levels, color correct and recover anything I'd like to see more of, reduce noise (Topaz), sharpen (Topaz+High Pass) or MCP sharpening. I generally never downsize so I'm really inexperienced with that area, but definitely see the advantages and have been meaning to explore the process for IG posts; their normal compression engine isn't always that great to images.

*If I keep the background I'll generally create a gausian blur layer and mask in the areas I want untouched [this can yield good and bad results as I haven't perfected it].
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rjlittlefield
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PostPosted: Fri Jan 05, 2018 12:34 pm    Post subject: Reply with quote

APS-C at 5168 x 3448 is OK, though full frame would be better. APS-C at 2592 x 1728 would not be so good.

Quote:
I shot RAW initially, but didn't find too much benefit when I exposed everything correctly and controlled my environment.

I'm not surprised. I often shoot deep studio stacks in JPEG, same reason.

--Rik
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