Starting out in photomacrography - noob questions and help

Starting out in microscopy? Post images and ask questions relating to the microscope and get answers from our more advanced users on the subject.

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rjlittlefield
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Post by rjlittlefield »

hayath wrote:Happened to read that the RMS to M42 cone causes some light issues which affects IQ -> contrast
Would that be true? If yes, any way of handling that?
Yes, there are sometimes reflections from the inside of the cone that cause loss of contrast. How bad they are depends on the particular cone and objective. Most people cover the inside of their cone with a black flocking material of some sort. Even just painting it flat black can help a lot. Another approach is to mask the reflections by cutting a piece of black paper to fit inside the cone, with a hole in it just big enough to let the sensor see the back of the objective and not the sides where the reflections occur.

--Rik

hayath
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Post by hayath »

Thanks for the reply again Rik :)

So if I get myself another set of ETs and reach 150mm...then using a "flat" Rms to m42 adapter should work better? (since the sides are not goin to be very obvious for reflections)

Cheers,
Hayath

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Post by rjlittlefield »

hayath wrote:So if I get myself another set of ETs and reach 150mm...then using a "flat" Rms to m42 adapter should work better? (since the sides are not going to be very obvious for reflections)
That's correct, assuming that the tubes are properly made. The downside of flat is that the cone provides a little better physical access to the specimen. It's tempting to think that the cone also provides better access for lighting, but this is a minor effect since with most objectives the limiting factor is the front of the objective itself, not anything close behind it. I now have both cone and flat adapters for finite objectives, but the cones are relatively new acquisitions and I didn't notice any great improvement in convenience when I got them.

--Rik

hayath
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Post by hayath »

Ah, then it does make sense to go in for the "normal" flat adapter.
Thanks Rik for being so patient and taking the time :)

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Post by naturephoto1 »

hayath wrote:Ah, then it does make sense to go in for the "normal" flat adapter.
Thanks Rik for being so patient and taking the time :)
The cone adapters will provide more extension if more magnification is required and can particularly valuable because of this when working with a bellow. In some instances you may also be able to work with lighting sources with the cone than the flat adapters. Like Rik and many others I too have both.

Rich

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Post by hayath »

Thank you Rich for the additional details :)

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Post by hayath »

"Yet another" question popped up in the head when I was trying a reversed 28mm on the 55-250

Would the objective mounted on the front of the lens give me vignetting and a smaller FoV compared to say a finite mounted on top of tubes/bellows?

Appreciate the patience and inputs :)

Cheers,
Hayath

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