Re: Nikon D70 DSLR on microscope: Update
From: GTO (gregor_o_at_NOSPAMyahoo.com)
Date: 12/28/04
- Next message: Kevin Cunningham: "Re: Calibration"
- Previous message: GTO: "RRR microscopes"
- In reply to: KBob: "Re: Nikon D70 DSLR on microscope: Update"
- Next in thread: Richard J Kinch: "Re: Nikon D70 DSLR on microscope: Update"
- Messages sorted by: [ date ] [ thread ]
Date: Tue, 28 Dec 2004 21:41:23 GMT
The problem with adapters that include eyepieces or relay lenses is the
possible mismatch between objectives and adapter lens.
A Nikon CF-based scope (Labophot, Optiphot, Eclipse) requires CF relay
lenses (or eyepieces). These are fully corrected for lateral chromatic
aberration but not over-corrected.
A scope like the Leitz Ortholux with Fluor or APO lenses requires
compensating relay lenses (or eyepieces) that are over-corrected for lateral
chromatic aberration.
This is particularly important if most of the image is captured by the CCD
and not just the rays close to the optical main axis of the system. A
low-cost setup to connect a DSLR to a scope should include existing optical
components and not add new ones that might lead to a mismatch in optical
correction. After all, I want to use a DSLR to go beyond the performance
offered by a consumer grade digital camera, such as the Nikon Coolpix or
Canon Powershot digicams.
Gregor
"KBob" <KBob@nowhere.net> wrote in message
news:0o33t09r3h5vkd7vtd5dk555jt9egdjhvq@4ax.com...
> On Sun, 26 Dec 2004 05:18:10 GMT, "GTO" <gregor_o@NOSPAMyahoo.com>
> wrote:
>
>>I just want to give an update of my attempts to use a Nikon D70 DSLR on a
>>trinocular viewing body (see my previous posts regarding this subject).
>>
>>
>>
>>Using objectives that are fully corrected for lateral chromatic aberration
>>(no CDM), I found the following:
>>
>>
>>
>>1) At fast exposure settings, the mirror slap of the D70 (no mirror lockup
>>feature!) only contributes to the already existing vibration induced by
>>the
>>mechanical shutter curtain. I assume a D100 or D2H will not save the day.
>>I
>>might still get vibrations due to the mechanical shutter.
>>
>>2) At slow exposure settings using bulb mode, I get excellent images. They
>>are sharp and, of course, free from vibrations. Fast moving subjects can
>>easily be photographed with a flashlight moved into the illumination path
>>as
>>long as a collector lens is added in front of the flash for proper Koehler
>>illumination.
>>
>>3) The D70 can be connected to a regular eyepiece (with a spacer in front
>>of
>>the eyepiece). The necessary spacer is around 5mm in length. With this
>>setup, which is parfocal with the objectives, the D70 oversamples the
>>image
>>(too many pixels!). A relay lens (photo eyepiece) with a magnification
>>factor of 0.5x is recommended but such a relay lens can be rather
>>expensive.
>>
>>4) The D70 works great when its CCD is positioned into plane holding the
>>real image. In this case, vignetting occurs, but the D70 provides enough
>>pixels so that after cropping away the effect of vignetting a well-sampled
>>image remains of 3 to 4 Mpixels.
>>
>>
>>
>>The 12-bit RAW file format with the larger pixels of the D70, make this
>>camera an interesting solution for amateur photomicrography. The D70 is
>>very
>>strong for low light exposures. Remember, it is possible to combine this
>>digital camera with a scope with only a couple of lens-less adapters that
>>cost around US$80 to 100. Of course, this solution makes only sense for
>>people who are already enjoying using the D70 for photography :-)
>>
>>
>>Gregor
>
> Here's another idea. Someone on eBay has been selling microscope
> adapters that contain 10X WF eyepiece lenses and they come in both
> 23mm size (for standard microscopes) and 30mm sizes to fit binocular
> microscopes. These have 28mm male threads intended to couple with
> Nikon Coolpix cameras. All that's needed to make these work with
> other cameras (such as the D100, D70, etc.) I'm told is a 52-28mm
> stepdown ring, also readily available. I ordered these and will post
> shots after testing.
>
> I've been trying to use a Nikon microscope adapter (containing relay
> lens) with a Zeiss Standard microscope, but thus far the results
> haven't been all that great, at least with top-illuminated subjects.
> Loads of glare and chromatic aberration, and the photos look far worse
> than the objects appear visually. I'm trying to shoot the irregular
> surface of a silver amalgam filling, and the specular highlights from
> the mercury specks (or something) is making this task difficult. Has
> anyone tried anything like this?
> Thanks, kBob
>
>
- Next message: Kevin Cunningham: "Re: Calibration"
- Previous message: GTO: "RRR microscopes"
- In reply to: KBob: "Re: Nikon D70 DSLR on microscope: Update"
- Next in thread: Richard J Kinch: "Re: Nikon D70 DSLR on microscope: Update"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
