Any experiences with the Thorlabs 2x superapochromat?

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ray_parkhurst
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Post by ray_parkhurst »

Lou Jost wrote:Looking at their other spec sheets, the resolution is always 120 lp/mm regardless of lens or magnification. That means it must be the resolution on sensor, otherwise it should be roughly proportional to magnification.

But I am concerned that the spec sheet says that the resolution is appropriate for a 4.5 micron sensor. The Oly sensor is 3.3 microns.
I'm not sure how companies rate their lenses for sensor pitch, but it could be based on diffraction-limited performance. If so, this would imply an aperture of ~f7.

Edited to remove resolution calcs which I think were wrong...

dickb
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Post by dickb »

I was wondering about that micron rating as well. The largest - or actually smallest - claim I encountered so far is Qioptiq rating their MeVis C lenses for sub 2 micron pixel sensors and up to 200 lp/mm..

Lou Jost
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Post by Lou Jost »

Ray, I assume you mean effective aperture of f/7?

Dick, there are new astrophotography cameras with small 20Mp sensors that would be good for that series of lenses, the QHY183 series in monochrome and color, with 2.4 micron pixels:
http://www.qhyccd.com/MediumCOLDMOS.html

ray_parkhurst
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Post by ray_parkhurst »

Lou Jost wrote:Ray, I assume you mean effective aperture of f/7?
Yes.

Justwalking
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Post by Justwalking »

dickb wrote:I was wondering about that micron rating as well. The largest - or actually smallest - claim I encountered so far is Qioptiq rating their MeVis C lenses for sub 2 micron pixel sensors and up to 200 lp/mm..
There a lot of hi-reslution machine vision lenses, but very few of them is for macro and for 4/3 sensor. Mostly are just conventional lenses
and for 2/3" sensors. Btw my 16MP USB camera is also c-mount with 1.4 micron pixels. The advantage is simple. For FF (16MP) it need 5:1 magnification.
For my sensor it is not even macro - only 0,8X

Lou Jost
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Post by Lou Jost »

Yes, that is a great advantage, it is one of the reasons I chose 4/3" sensors. For infinity-corrected optics, it is a wonderful system, especially with effective 50Mp sensor due to pixel shifting. But there are many finite lenses which require larger sensors. So I am now adding a FF camera to my arsenal. I will also use medium and large format lenses on a view camera, using my FF sensor to scan their aerial images. This will be especially useful with my photolithography lenses; I have some 5x lenses with NA=0.30 and perfectly sharp image circles >125mm in diameter.

Justwalking
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Post by Justwalking »

Lou Jost wrote: This will be especially useful with my photolithography lenses; I have some 5x lenses with NA=0.30 and perfectly sharp image circles >125mm in diameter.
Probably very expensive, Lou?

Image

Lou Jost
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Post by Lou Jost »

They used to cost hundreds of thousands of dollars but now they are obsolete, because today semiconductors are being made with deep ultraviolet light and water immersion, with much higher NAs than were possible using visible light in air. The earlier-generation lenses (NA between 0.2 and 0.3) can be bought for a few hundred dollars now, except for those that collectors have noticed (Ultra-Micro-Nikkors), which still cost several thousand dollars.

Justwalking
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Post by Justwalking »

It's a miracle that it's prise drops so much to 1/1000 of new.

Lou Jost
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Post by Lou Jost »

Yes, it is the best bargain in photography. But these are not for everyone. They have no color correction, because they are designed to use monochromatic light produced by particular spectral lines of mercury, or lasers. They have very short working distances when used in reverse for macro work, around 1-2cm, and they are huge. They also have no camera mounts. But for the ultimate in black-and-white scientific photography, these can't be beat, when used with a monochrome cooled-sensor astrophotography camera.

Justwalking
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Post by Justwalking »

Lou, Did you tried ever cheap chinese clone varifocal tube lenses 0.7-4.5X ($60)?

Lou Jost
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Post by Lou Jost »

No, the most common zoom tube lenses I have seen are designed for small-sensor video or photo cameras and do not have acceptable resolution. Instead I use good ED zoom lenses designed for FF cameras. My current favorite is the Nikon 8-200mm f/2.8 ED-IF which does not extend for zooming or focusing. It is great for MFT.

Justwalking
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Post by Justwalking »

I'm interesting to try something like this on my sensor
http://www.seiwaopt.co.jp/products/mach ... f/0112.pdf
it is japan original.

Lou Jost
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Post by Lou Jost »

But the NA are small....

Lou Jost
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Post by Lou Jost »

For your small sensor, might an MFT zoom be good?

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