Search found 13 matches

by nernelly
Fri Apr 24, 2020 10:26 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Trouble shooting butterfly wing scales
Replies: 6
Views: 5523

Hi ranstice,

I suggest you shoot in raw. Then make sure to expose to the right, so much that the jpeg histogram shows serious overexposure, but the raw histogram is still intact. During raw-development reduce the overall exposure, increase shadows and reduce highlights.
by nernelly
Sun Oct 05, 2014 5:02 pm
Forum: Equipment Exchange
Topic: For sale: Zeiss focus block for DIY automated stacker
Replies: 0
Views: 1037

For sale: Zeiss focus block for DIY automated stacker

For sale is a high precision focus block waiting for someone to incorporate it into an automated stacking setup. Travel distance is 28mm with a resolution of 0.5mm/rev, dimensions 13.7x 24.5x 6.3 cm. Mechanics run smootly. It comes with a mounting plate and a coupling disk so that it easily accepts ...
by nernelly
Thu May 08, 2014 2:48 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Rainbow rings (the secret revealed)
Replies: 42
Views: 15563

Remember that I'm using a lens. I had implicitly considered the lens+sensor combination as one system that images the diffraction pattern produced by the aperture. The phrasing "decreasing aperture-sensor distance" was very simplistic and thus probably misleading as it suggests a direct capturing o...
by nernelly
Wed May 07, 2014 5:44 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Rainbow rings (the secret revealed)
Replies: 42
Views: 15563

Rik, maybe two keywords: Fresnel and Fraunhofer? Did you, as a second modification, decrease the aperture-sensor distance? Physics says, you'll get Airy-disk patterns if the distance between sensor and aperture is large (compared to the aperture size). As the sensor is brought closer to the aperture...
by nernelly
Sat Apr 27, 2013 7:20 pm
Forum: Equipment Discussions
Topic: High precision positioner (from SEM)
Replies: 3
Views: 1240

Those interested in studying SEM stages might also be interested in item 190808413490 on ebay.de (completed auction). Presumably a five axis version.
by nernelly
Mon May 07, 2012 7:14 am
Forum: Equipment Discussions
Topic: Mitutoyo 2X M Plan Apo and MT-1 FOV problem
Replies: 24
Views: 9209

When I'm not sure about the centering/alignment in my setup, I replace the camera by a piece of opal glass or paper (just put it on the rear standard of the bellows setup and extend it until the sharp image appears). If the aperture of the standard is big enough, you'll get a pretty good estimate of...
by nernelly
Tue Apr 03, 2012 3:38 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Infinite objectives , tube lenses and questions ...
Replies: 25
Views: 7913

I completely agree with Rik, that the big pixel sizes will prevent an optimal use of the objective. But there also seems to be a flaw in your setup: This is done with the following settings: Nikon CF 10X / 0.30 > 36mm ext. tube > Tokina 90mm Macro focused at infinity > 10cm bellows extension, If the...
by nernelly
Sun Mar 11, 2012 4:21 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Two small contributions of new member from southern bavaria
Replies: 29
Views: 32770

Michael, my experiences in this magnification range are rather limited, but I do know that iridescent scales can be quite troublesome at higher magnifications (probably, because it gets very hard to avoid specular reflections). So, if you are still optimizing your setup you might consider using an e...
by nernelly
Thu Feb 02, 2012 6:08 am
Forum: Equipment Discussions
Topic: How many pixels are really needed?
Replies: 12
Views: 3096

Javier, image quality across the image field is certainly a point one has to take into consideration. I think Charles has pointed out before, that most of the microscope lenses we use were designed to deliver high image quality in an area of ~20mm diameter when used at their designed magnification. ...
by nernelly
Wed Feb 01, 2012 3:39 pm
Forum: Equipment Discussions
Topic: Pixels for use at 4-5X on an APS-sized sensor
Replies: 37
Views: 23637

I think there might be two points mainly contributing to the big difference in Mpix numbers mentioned above: 1) different resolution criteria and 2) the potentiation when converting pixel size into Mpix count. This reference discusses many relevant aspects of the topic http://luminous-landscape.com/...
by nernelly
Tue Jan 31, 2012 5:27 pm
Forum: Equipment Discussions
Topic: Pixels for use at 4-5X on an APS-sized sensor
Replies: 37
Views: 23637

Wow, great you also had the 10x image at hand. Just to make sure I got it right. When you speak of the "perfect" sensor this means perfect given its specific pixel size. When the next sensor generations will find their ways to our setups image detail at 5x might approach the current state of the art...
by nernelly
Tue Jan 31, 2012 3:36 pm
Forum: Equipment Discussions
Topic: Pixels for use at 4-5X on an APS-sized sensor
Replies: 37
Views: 23637

Pixels for use at 4-5X on an APS-sized sensor

Admin edit: This thread was originally a series of replies in "Lenses for use at 4-5X on an APS-sized sensor" . As suggested by other members, I have split them off from the original thread because this is really a separate and fundamental topic of its own: How many pixels are needed to capture all...
by nernelly
Tue Jan 17, 2012 7:01 am
Forum: Equipment Discussions
Topic: Adding teleconverters to microscope lenses
Replies: 17
Views: 7737

Hi Javier, you mention soft corners when using the mitutoyo inf. objectives on your full-frame sensor at lower than specified magnifications. Have you verified that these are worse than the loss in resolution you get when pushing the 5x up in comparison to pushing the 10x down? Using the morfanon an...