Search found 18162 matches

by rjlittlefield
Thu Apr 22, 2021 5:13 pm
Forum: Equipment Discussions
Topic: I built a fish-eye macro lens, but I need some advice
Replies: 17
Views: 345

Re: I built a fish-eye macro lens, but I need some advice

Thank you, Rik. Of course the fish eye virtual image goes to the other lens, and not to the sensor. But that would also be the case for my set up - the fisheye lens sending its image to the reversed lens. Only it doesn't... :? I think you missed the point about focus. The output of the clip-on fish...
by rjlittlefield
Thu Apr 22, 2021 12:48 pm
Forum: Equipment Discussions
Topic: Is it some kind of microscope?
Replies: 12
Views: 184

Re: Is it some kind of microscope?

For Nikon Small World Competition people it also is: "The homemade microscope is a new and growing sector of the contest and we are excited to collect and judge these images" Where did you find this quote? That was a personal communication from 2016, reported by Chris S. HERE . I guess the current ...
by rjlittlefield
Thu Apr 22, 2021 12:34 pm
Forum: Equipment Discussions
Topic: I built a fish-eye macro lens, but I need some advice
Replies: 17
Views: 345

Re: I built a fish-eye macro lens, but I need some advice

Perhaps its being designed to deliver an image to a cell phone sensor prevents its ability to deliver an aerial image to the necessary point in the reversed lens. More accurately, that clip-on fisheye is designed to deliver an image to the cell phone lens , not the cell phone sensor. The image crea...
by rjlittlefield
Tue Apr 20, 2021 11:00 pm
Forum: Equipment Discussions
Topic: I built a fish-eye macro lens, but I need some advice
Replies: 17
Views: 345

Re: I built a fish-eye macro lens, but I need some advice

For what is is worth, when I hold the entire lens rig up and peer out through it, from back to front, I see with my naked eye a lovely fish-eye image that seems focused from near to far. This is very easy to see, so it was a bit of a surprise that the camera sensor does not "see" it. Mysteries of o...
by rjlittlefield
Tue Apr 20, 2021 9:51 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Two wrongs can make a right
Replies: 6
Views: 195

Re: Two wrongs can make a right

Lou, this is a spectacular improvement! But on a quick test, I cannot reproduce your result by using DMap and PMax extracted from the posted image. I'm still left with a lot of CA around the big dust spots. I suppose this somehow disappears in the "selective color darkening", but I'm not sure what t...
by rjlittlefield
Tue Apr 20, 2021 6:38 pm
Forum: Equipment Discussions
Topic: I built a fish-eye macro lens, but I need some advice
Replies: 17
Views: 345

Re: I built a fish-eye macro lens, but I need some advice

So If I understand the situation (and I might not), one needs to get the 2nd lens to focus on that aerial image. Focus is only one requirement. A second requirement is that the light rays must be coming out of that front lens at an angle such that they succeed in entering the rear lens and working ...
by rjlittlefield
Sun Apr 18, 2021 9:58 am
Forum: Photography Through the Microscope
Topic: Daffodil pollen
Replies: 9
Views: 389

Re: Daffodil pollen

If I understand correctly, the point of Olympusman's "feathering" approach is to produce an asymmetric cone of light, which then gives a sort of 3D appearance. I assume the Expanding Stop would do the same thing if swung off-center, but that's because of the swing, not the expanding feature. Please ...
by rjlittlefield
Sat Apr 17, 2021 7:59 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Raynox DCR-250 adjustable magnification
Replies: 1
Views: 205

Re: Raynox DCR-250 adjustable magnification

The combination of DCR-250 and DCR-150 will be even stronger than the DCR-250 alone. Changing the separation between those two will change the overall power by a small amount, but I doubt that you would perceive it as anything "like a zoom lens". Separating the Raynox lenses will also introduce a st...
by rjlittlefield
Sat Apr 17, 2021 6:12 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: 1 - 1/2 inch mini pine cone
Replies: 2
Views: 229

Re: 1 - 1/2 inch mini pine cone

Macron, please check your "Private messages".

You can do that by using the link at the upper right corner of any forum page, next to your username.

--Rik
by rjlittlefield
Fri Apr 16, 2021 11:34 pm
Forum: Photography Through the Microscope
Topic: Daffodil pollen
Replies: 9
Views: 389

Re: Daffodil pollen

what is a ‘feathered darkfield stop’ (as opposed to a regular darkfield stop). I would guess Olympusman is referring to the technique he described at https://www.photomacrography.net/forum/viewtopic.php?p=245763#p245763 : In photographic lighting, a feathered edge from a light source is attained by...
by rjlittlefield
Fri Apr 16, 2021 11:26 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Photo of Ploum
Replies: 217
Views: 112353

Re: Photo of Ploum

Lovely! And I see that www.geoforum.fr is working again -- nice!

--Rik
by rjlittlefield
Thu Apr 15, 2021 9:18 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Photo of Ploum
Replies: 217
Views: 112353

Re: Photo of Ploum

As of this moment, all images at www.geoforum.fr are not accessible, because of an SSL certificate problem. Chrome reports the difficulty as "NET::ERR_CERT_DATE_INVALID". I do not know a good workaround, since it appears that www.geoforum.fr automatically upgrades an HTTP connection to HTTPS, which ...
by rjlittlefield
Wed Apr 14, 2021 8:29 am
Forum: Equipment Discussions
Topic: S21 ultra: 108mp in RAW
Replies: 13
Views: 960

Re: S21 ultra: 108mp in RAW

Here is another comparison that I find interesting. These are corresponding sections, the first from 12000x9000 as downloaded, the second from 6000x4500 upscaled to 12000x9000. The 6000x4500 was made by Photoshop's Image > Image Size..., with "Bicubic (smooth gradients)" resampling. Again, display u...
by rjlittlefield
Tue Apr 13, 2021 2:02 pm
Forum: Equipment Discussions
Topic: S21 ultra: 108mp in RAW
Replies: 13
Views: 960

Re: S21 ultra: 108mp in RAW

By the way, I looked again. If I go through https://flic.kr/s/aHsmVfrTBn to reach the album, then I cannot find any way to access camera-resolution versions of the images. For the scene corresponding to https://live.staticflickr.com/65535/51112917357_b3a566f9a8_o.jpg , Flickr offers me only up to "L...