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InFocus replacement tube lens/SA corrector

 
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enricosavazzi



Joined: 21 Nov 2009
Posts: 995
Location: Stockholm, Sweden

PostPosted: Thu Jul 12, 2018 6:27 am    Post subject: InFocus replacement tube lens/SA corrector Reply with quote

I happened to see the web site of the InFocus "Dynamic Optical Focusing System" ( http://www.infinity-usa.com/products/InFocus/ , a couple of PDFs are also available for download). As far as I can understand, it is a replacement for the tube lens in infinity systems, and adds a collar for adjustable correction of spherical aberration. It claims in fact to replace the correction collar of microscope objectives.

The general claim makes sort of sense, although my impression is that they try to avoid giving specifics as much as possible. The sample images they present are not that convincing. I also have the general concerns that:

    variable SA correction in the objective is useful mainly in high magnification, high NA objectives (of which there are usually only one or two in a typical microscope)

    switching among objectives requires the InFocus device to be readjusted each time

    variable correction implemented in a high-end objective is more likely to be tailored to the specific objective than a one-size-fits-all solution

    a trinocular head apparently cannot be used with the InFocus device, only a camera with live view would be usable

    if it really was that revolutionary a device, Olympus, Nikon, Zeiss and Leitz would already be making equivalent devices


The cost of the device is also significant. The difference in price between a 40x high-end objective with or without correction collar is probably of the same order of magnitude, and a better overall choice.

Any opinions on this matter? I am not tempted to purchase the InFocus device, so this is only a technical curiosity for me.
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JohnyM



Joined: 24 Dec 2013
Posts: 248

PostPosted: Thu Jul 12, 2018 10:02 am    Post subject: Reply with quote

My wild guess is that it's just movable tube lens that changes distance between itself and camera - forcing you to change focus and correct for SA this way.
Basically a raynox with helicoid. But it's just a guess.
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