Search found 19954 matches

by rjlittlefield
Mon Mar 18, 2024 7:14 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Hamuli
Replies: 13
Views: 384

Re: Hamuli

Bill and I have spent much time discussing his excellent images offline. I would like to add here a link to some external documentation that may clarify the structure. https://www.sciencedirect.com/science/article/abs/pii/S002219101930191X goes to "Structure, properties and functions of the forewing...
by rjlittlefield
Mon Mar 18, 2024 3:57 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: some scales
Replies: 121
Views: 5881

Re: some scales

Yes, like tiny waffles!

Doing a Google image search for pollen with waffle pattern produced one hit with a couple of very good matches:

GoogleImageForPollenWithWafflePattern.jpg

Unfortunately the full article is behind a paywall, and I don't care enough to pay.

--Rik
by rjlittlefield
Sat Mar 16, 2024 8:51 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Wasp, Nuthin' Fancy
Replies: 6
Views: 116

Re: Wasp, Nuthin' Fancy

On second study, I'm not seeing a bi-color mandible at all.

What's happening is that the mandible on the right side (critter's left) is tipped upward/inward at a very unusual angle, exposing a darker structure that would ordinarily be hidden behind it.

--Rik
by rjlittlefield
Sat Mar 16, 2024 5:07 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Wasp, Nuthin' Fancy
Replies: 6
Views: 116

Re: Wasp, Nuthin' Fancy

Interesting bi-color mandible on that beast!

--Rik
by rjlittlefield
Fri Mar 15, 2024 11:17 am
Forum: Equipment Discussions
Topic: Lens recomendation for film reproduction
Replies: 17
Views: 328

Re: Lens recomendation for film reproduction

I am currently scanning film with Sigma 70mm art. However, this lens has quite a high and unpleasant contrast, in which I have the impression that details are lost. This sounds to me like your darks are getting clipped at black, or at least pushed below the black threshold of your monitor. This oft...
by rjlittlefield
Wed Mar 13, 2024 10:04 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Hamuli
Replies: 13
Views: 384

Re: Hamuli

When the front to back distance exceeds the width, I get poor results. When I shoot something relatively flat and perpendicular to the lens, things go better. I agree, deeper stacks are tougher. The biggest problem I usually see is that the substantial width of the entrance cone allows the lens to ...
by rjlittlefield
Tue Mar 12, 2024 9:39 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Hamuli
Replies: 13
Views: 384

Re: Hamuli

In truth, it strikes me as a bit "synthetic" when we shoot a series and select each image as the sharpest since every image actually used in the final composite would be would have been taken at the same distance from the camera which destroys the natural perspective where things closer appear larg...
by rjlittlefield
Tue Mar 12, 2024 12:35 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Hamuli
Replies: 13
Views: 384

Re: Hamuli

I have not yet tried any false stereo from Zerene (actually, I resist the concept of false stereo I am curious to know what you consider "false" about Zerene Stacker's stereo images. They certainly are "synthetic", in the sense that off-axis views are derived from a single stack. But that synthesis...
by rjlittlefield
Fri Mar 08, 2024 7:45 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sensor size and depth of field
Replies: 24
Views: 630

Re: Sensor size and depth of field

Generally I prefer to avoid explanations that are based on pixel size because that opens another can of worms. https://clarkvision.com/articles/does.pixel.size.matter/#:~:text=The%20pixel%20size%20in%20digital,conversion%20limitations%2C%20and%20amplifier%20noise. That page of Clark's is exactly wh...
by rjlittlefield
Thu Mar 07, 2024 12:10 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: some scales
Replies: 121
Views: 5881

Re: some scales

Nice! That's very effective at contrasting the thin flat shape of the scales against the globular shape of the amber-colored mystery object.

--Rik
by rjlittlefield
Thu Mar 07, 2024 12:06 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sensor size and depth of field
Replies: 24
Views: 630

Re: Sensor size and depth of field

So for the same framing, a crop camera has to be further away than the full frame - with Nikon the crop factor is 1.5 so presumably that means 1.5x further away. And this gives more DOF. Feff increases the closer you get to the subject. So at 1:1, given Feff = Flens(mag+1), then Flens(1+1) = 2xFlen...
by rjlittlefield
Wed Mar 06, 2024 2:06 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: some scales
Replies: 121
Views: 5881

Re: some scales

Oh, I assumed it was more or less flat! Is it a spherical ball? If so then I'm reminded of silica gel. I have some larger balls that look exactly like that, but I have never checked to see if there are some small ones in the mix. Maybe a small ball of dried plant resin or nectar? Is it stuck to the ...
by rjlittlefield
Wed Mar 06, 2024 1:07 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: some scales
Replies: 121
Views: 5881

Re: some scales

Some exotic weevils have scales that look something like that.

Was this a purchased specimen? If so then it may have gotten contaminated in handling at the supplier.

--Rik
by rjlittlefield
Tue Mar 05, 2024 4:10 pm
Forum: Equipment Discussions
Topic: Mitutoyo 10x 0.42 M Plan APO HR lens adventure
Replies: 19
Views: 728

Re: Mitutoyo 10x 0.42 M Plan APO HR lens adventure

https://youtu.be/J16EeaibdNE?si=gqpHpwbMwxx4k17g&t=890 https://www.youtube.com/watch?v=tynfwPHzLiU If you watch closely, you can see in each video that the barrel of the objective has several small holes that are filled with white stuff. I've been told that those holes are used to provide access fo...
by rjlittlefield
Tue Mar 05, 2024 12:47 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sensor size and depth of field
Replies: 24
Views: 630

Re: Sensor size and depth of field

Tony, I hadn't given much thought to the diffraction effects - I need to do some tests to understand the trade off there. I'm guessing it will vary by lens etc. I normally shoot at around f/13 with my Nikon D500 and Nikon 105mm and manage to end up with sharp images, especially after a bit of proces...