FAQ: How can I hook a microscope objective to my camera?

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rjlittlefield
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Post by rjlittlefield »

Update: since I posted the DIY solution described above, two Chinese suppliers have come out with off-the-shelf packages that provide elegant engineered solutions:

https://www.wemacro.com/?product=raynox ... e-lens-pro

https://www.mjkzz.de/products/variable- ... 0380164211

--Rik

ckolluru
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Post by ckolluru »

Thanks for this post. I'm wondering if someone can draw a rough ray diagram for an infinity corrected objective attached to a telephoto lens.

Thanks again.
Chaitanya

len
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Re: FAQ: How can I hook a microscope objective to my camera?

Post by len »

Hi,
The post is wonderful and very informative. I understand the technical details of using both finite and infinite objectives but maybe I missed something? If we take two similar objectives with similar quality one is finite and the other is infinite which one will perform better? Can anyone explain the pro and cons of the two systems regards to macro photography?

Thanks,
Len

Adalbert
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Re: FAQ: How can I hook a microscope objective to my camera?

Post by Adalbert »

Hi Len,
two similar objectives with similar quality one is finite and the other is infinite
similar lens quality => similar image quality.
But you can mount the infinity lens to the AF photo lens and stack using focus bracketing.
Best, ADi

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Re: FAQ: How can I hook a microscope objective to my camera?

Post by rjlittlefield »

Can anyone explain the pro and cons of the two systems regards to macro photography?
The biggest difference is that all modern high end objectives are infinite. So, if you want the advantages of modern optical designs -- higher resolution, longer working distance, bigger image circles, better color correction -- you will eventually have to go infinite.

However, this is not to say that every infinite objective is better than every finite objective, or that you absolutely need an infinite objective to do good work. Some of the older finite objectives give excellent image quality. Many Nikon Small World awards have been won using finite objectives.

Finite objectives can be a good place to start, because:
  • in addition to the objective, all you need is some empty space such as bellows or extension tubes, and
  • there are some very good low cost finite objectives, both used and new.
But if you want to keep going, then eventually you'll end up infinite, for the reasons noted above. And as Adi notes, infinite objectives can play nicely with some forms of in-camera focus bracketing, which finite objectives do not.

You asked:
If we take two similar objectives with similar quality one is finite and the other is infinite which one will perform better?
I do not know how to answer this question.

As Adi points out, we usually judge the quality of a lens by the quality of the image that it makes. But by that criterion, it is essentially a truism that two objectives of similar quality will perform equally well.

So, I presume that you mean something else by "similar quality". Can you clarify?

--Rik

len
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Re: FAQ: How can I hook a microscope objective to my camera?

Post by len »

rjlittlefield wrote:
Sun Oct 24, 2021 10:27 am
Can anyone explain the pro and cons of the two systems regards to macro photography?
The biggest difference is that all modern high end objectives are infinite. So, if you want the advantages of modern optical designs -- higher resolution, longer working distance, bigger image circles, better color correction -- you will eventually have to go infinite.

However, this is not to say that every infinite objective is better than every finite objective, or that you absolutely need an infinite objective to do good work. Some of the older finite objectives give excellent image quality. Many Nikon Small World awards have been won using finite objectives.

Finite objectives can be a good place to start, because:
  • in addition to the objective, all you need is some empty space such as bellows or extension tubes, and
  • there are some very good low cost finite objectives, both used and new.
But if you want to keep going, then eventually you'll end up infinite, for the reasons noted above. And as Adi notes, infinite objectives can play nicely with some forms of in-camera focus bracketing, which finite objectives do not.
Got it :)
rjlittlefield wrote:
Sun Oct 24, 2021 10:27 am
You asked:
If we take two similar objectives with similar quality one is finite and the other is infinite which one will perform better?
I do not know how to answer this question.

As Adi points out, we usually judge the quality of a lens by the quality of the image that it makes. But by that criterion, it is essentially a truism that two objectives of similar quality will perform equally well.

So, I presume that you mean something else by "similar quality". Can you clarify?

--Rik
I understand what you are saying, each objective has its own specification and quality.
The thing that was on my mind was the additional glass. Let say, and I don't know if it's actually a valid example. Nikon produces two 10x Plan Achromat with the same NA and same working distance. one is finite and the other is infinity. Since the finite objective is mounted without any additional glass doesn't it mean better image quality compare to infinity which needs additional glass before the sensor?

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Re: FAQ: How can I hook a microscope objective to my camera?

Post by rjlittlefield »

len wrote:
Sun Oct 24, 2021 10:48 am
The thing that was on my mind was the additional glass. Let say, and I don't know if it's actually a valid example. Nikon produces two 10x Plan Achromat with the same NA and same working distance. one is finite and the other is infinity. Since the finite objective is mounted without any additional glass doesn't it mean better image quality compare to infinity which needs additional glass before the sensor?
Thanks for the clarification. I understand the worry, but I don't think it's productive. The attributes that you've mentioned do not totally describe the optics. The infinite objective, being newer, may well have better lens coatings and better corrections, so that even with the additional glass, the overall system performance is better with the infinite. The only way to tell for sure is by experiment.

Rather than trying to evaluate such issues by analysis -- which is doomed to failure -- you would do better to post a specific question in Equipment Discussions, describing what you want to do, what equipment you currently own, and what is your budget for new equipment, and ask for information about best ways forward under those particular circumstances.

For whatever it's worth, I started with finite objectives, then gradually switched to infinity for the most part, but have no hesitation about going back to finite for special cases where the objective in my kit that best fits the task happens to be finite.

--Rik

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Scarodactyl
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Re: FAQ: How can I hook a microscope objective to my camera?

Post by Scarodactyl »

The biggest advantage of infinity optics is being able to put accessories between the objective and head (or camera sensor) and not have to compensate for the added tube length. That matters more for some things than others.

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Re: FAQ: How can I hook a microscope objective to my camera?

Post by rjlittlefield »

Scarodactyl wrote:
Sun Oct 24, 2021 11:43 am
The biggest advantage of infinity optics is being able to put accessories between the objective and head (or camera sensor) and not have to compensate for the added tube length.
What makes an "advantage" is different for different people.

The accessories aspect is why the microscope manufacturers all shifted to infinity designs.

But for me personally, that aspect has been no advantage at all, because to date I have never needed to use such an accessory.

Instead, for me the main advantages for infinity designs are that I can more easily get the features I mentioned earlier (higher resolution, longer working distance, bigger image circles, better color correction), plus I can alter the magnification by changing tube lens FL without adding aberrations. On APS-C, the sharpest "5X" in my kit is an infinity 10X pushed down on 100 mm tube lens, and the sharpest "10X" is a 20X infinity pushed down in the same way.

In principle, the same reductions could be done with some special optics like a "speed booster" in combination with finite objectives. But such optics are hard to come by, and if found, the scheme would be foiled by the smaller fields of typical finite objectives.

Meanwhile, my only apochromatic NA 0.80 objective is finite, because I could buy that for much less money than any similar infinite I could find at the time.

--Rik

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