Search found 19916 matches

by rjlittlefield
Thu Feb 22, 2024 8:22 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: some scales
Replies: 66
Views: 2967

Re: some scales

Lovely -- thank you for the stereo!

--Rik
by rjlittlefield
Thu Feb 22, 2024 8:21 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Debunking the high NA / coverslip correction myth
Replies: 73
Views: 31356

Re: Debunking the high NA / coverslip correction myth

High NA objectives are optimised for a certain coverslip thickness AND for focussing at a certain distance behind it - usually zero. On a scope, as you focus deeper into the mount and further from the underside of the coverslip, spherical aberration kicks in (haze and loss of contrast). Given that ...
by rjlittlefield
Wed Feb 21, 2024 3:39 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Book (2023): "Close-up and Macro Photography" by Lester Lefkowitz
Replies: 0
Views: 53

Book (2023): "Close-up and Macro Photography" by Lester Lefkowitz

This is to note with pleasure a new pair of books by Lester Lefkowitz. The 5-star rating is totally justified, and I do not say that lightly. I purchased through Amazon and consider the money well spent. Quoting the descriptions at Amazon: Book: The Manual of Close-up and Macro Photography, Volume I...
by rjlittlefield
Wed Feb 21, 2024 12:07 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: moth fly silhouette
Replies: 6
Views: 161

Re: moth fly silhouette

I had hoped to shoot a higher mag stack for the antenna, but the subject got too fidgety and I had to give up. I tried again later the same day, with more success. This is shot with Mitutoyo 20X NA 0.42 on Canon macro 100mm f/2.8L IS USM on Canon R7 camera, so 10X on APS-C sensor. https://janrik.ne...
by rjlittlefield
Tue Feb 20, 2024 9:12 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: moth fly silhouette
Replies: 6
Views: 161

Re: moth fly silhouette

The first stereo view is +-2%, with those values determined by inspection from a set of 11 different shifts rendered at resize 25% and stack every 3rd frame. But you prepared that manually, didn't you? Yes. I think of this technique as "old school", because it is what I used to do routinely before ...
by rjlittlefield
Mon Feb 19, 2024 5:59 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Bumblebee stinger
Replies: 2
Views: 96

Re: Bumblebee stinger

Nice image! There's some good discussion at https://www.reddit.com/r/evolution/comments/vknej8/why_were_bee_stings_being_fatal_selected_for/ . One poster notes that: It's literally only honey bees (Apis) that die once they have stung anything. Every other species of bee does not and can potentially ...
by rjlittlefield
Mon Feb 19, 2024 5:33 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: moth fly silhouette
Replies: 6
Views: 161

moth fly silhouette

This moth fly appeared in one of my bathroom sinks. It's still winter here, even snowed a couple of days ago, but I suppose this thing grew up someplace in the plumbing system and didn't know or care about the weather outdoors. Anyway, I trapped it in a tiny glass cage made of cover slips, put a dif...
by rjlittlefield
Mon Feb 19, 2024 11:40 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: kitchen ant
Replies: 23
Views: 1226

Re: kitchen ant

Thanks for the kudos! I showed your pictures in my fotoclub (on a beamer) but sadly most of the people did not get a stereo view. Have you ever tried to present your 3D work with something like the Loreo Stereo Viewer . And if yes could you share your experience on how to get the prints done? When I...
by rjlittlefield
Mon Feb 19, 2024 1:27 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: kitchen ant
Replies: 23
Views: 1226

Re: kitchen ant

More outstanding photographs! The stereos of the mouthparts are a treat and really rock! And you have even managed to capture the "eyelet" in a living specimen! I wonder why the picture of the petiolus in my key doesn't show it, and neither is it mentioned in the text. Thanks! The feature is not di...
by rjlittlefield
Mon Feb 19, 2024 1:14 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: kitchen ant
Replies: 23
Views: 1226

Re: kitchen ant

Several posts above ( HERE ), I showed a stereo view of the whole head of an ant. While talking with a friend on Zoom recently, we were exploring the images at higher resolution and noticed that the eye was confusing even in stereo. Here is that view: https://janrik.net/MiscSubj/2024/KitchenAnt_2024...
by rjlittlefield
Sun Feb 18, 2024 11:16 am
Forum: Beginners Micro
Topic: Down the rabbit hole… and some questions
Replies: 10
Views: 750

Re: Down the rabbit hole… and some questions

Those look great to my eye -- nice work!

Thanks for letting us know.

--Rik
by rjlittlefield
Sat Feb 17, 2024 5:26 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Debunking the high NA / coverslip correction myth
Replies: 73
Views: 31356

Re: Debunking the high NA / coverslip correction myth

P.S.: an interesting video about the 20/0.75 and the effect of coverslips is shown here (from minute 19) https://www.youtube.com/watch?v=n_dUgWDrYPw&ab_channel=HuygensOptics That's an excellent link, thanks. It is especially helpful for touching on the non-standard 20X NA 0.75's that are corrected ...
by rjlittlefield
Fri Feb 16, 2024 9:36 am
Forum: Equipment Discussions
Topic: Sharpest aperture for a given macro lens
Replies: 35
Views: 996

Re: Sharpest aperture for a given macro lens

RobertOToole wrote:
Fri Feb 16, 2024 9:33 am
I do have a link someplace where an optical engineer takes apart a D3, D300 and Canon 1DX and dissembles the AF arrays and sensors and how they work.
...
I did save the link if you are interested.
Yes please, definitely interested.

--Rik
by rjlittlefield
Fri Feb 16, 2024 1:28 am
Forum: Equipment Discussions
Topic: Sharpest aperture for a given macro lens
Replies: 35
Views: 996

Re: Sharpest aperture for a given macro lens

Pretty sure all Canon and Nikon AF systems stop down a bit to f/8 or so to AF and don't focus wide open. I tested just now, shining a flashlight down the barrel to watch the innards of Canon EF Macro 100mm f/2.8 L IS USM mounted on Canon R7 body with EF-EOS R adapter, manual mode set on f/11. It au...
by rjlittlefield
Thu Feb 15, 2024 11:02 pm
Forum: Equipment Discussions
Topic: Sharpest aperture for a given macro lens
Replies: 35
Views: 996

Re: Sharpest aperture for a given macro lens

Adding to Chris's excellent information...

Lenses at 1:1 often have some uncorrected spherical aberration that causes focus to shift when the lens is stopped down.

If you focus with aperture open, this can affect manual focusing as well as automatic.

--Rik