Improvements to my macro setup with various tests.

[fotoopa]

To solve vibration I made a better support for the lenses. A first improvement was for my 200mm macro lens:


Improved support for the AF200/F4 lens D20_0673 by fotoopa, on Flickr

The lens is supported now at 2 points. This gives a stable setup and reliable position determination. The lens is at the center of the linear stage. The front support is always given the correct position.
The second change was the 200mm tube version. Now this tube is fixed on the lineaire stage support:


200 mm tube support D20_0667 by fotoopa, on Flickr

Time to test a set reverse lenses. My first lens was an old small 50mm F4 component type which has a threaded end of M39x1mm. I had to turn an adapter to screw him in the front of the 200 mm macro lens. I made the adapter so that the componont lens comes 12mm into the macro lens, so both fronts are very close together.


DIY adaptor componon 50/4.0 M39x1 mm to M62mm D20_0690 by fotoopa, on Flickr


DIY adaptor componon 50/4.0 M39 x 1 mm to M62mm D20_0688 by fotoopa, on Flickr

After a few hours this adapter was ready for installation. Time in order to test the reverse 50mm componon lens. I have found an old image sensor, ideal for such measurements. The sensor contains a lot of small details and has a fairly correct geometry. You see the small picture cells. A disadvantage is that the sensor still has a transparent window and within the sensor, there is little contrast. It makes it possible to make measurements in a perfect sharpness. Here a picture of this image sensor:


Image sensor as picture object to test the resolution. by fotoopa, on Flickr

Now the results of this small componont lens:


componon 50mm F4 lens test by fotoopa, on Flickr

These results are not good, there is little sharpness and low contrast. All results are given via 100% crop at the centre and at the right corner at different apertures. Macro ratio is about 4:1. Due to the poor results I only have tested this lens at max wide focus of the AF200 mm lens.
The next step was the AF50/1.8 low cost standard lens. This low cost and low weight lens performs very well.


af50/1.8 reverse test tubelens at max wide focus. by fotoopa, on Flickr

The best results are F4 to F5.6, curiously, the corners are clearly sharper at F5.6. All crops at 100% are 200x200 pixels. I use the D300 DX camera with 4288x2848 pixels. So you can calculate the pixel dimension of the object sensor.
My next test was with the ais 35 mm F2.8 old lens. This reverse lens give 5:1 macro at max wide focus of the 200 mm tube lens. and the results are also nice. Again at F4 to F5.6 are the best results and the corners are pretty good.


ais 35 mm F4 reverse tests macro 5:1 by fotoopa, on Flickr

Now the same lens but the tube lens at max closeup focus, this gives 7:1 macro ratio:


ais 35 mm F4 reverse tests, max closeup 7:1 by fotoopa, on Flickr

Same results, you can choose between F4 and F5.6.
Now I have replaced the macro tube lens to the real 200mm tube. I have only the comparison here with the ais 35mm lens:


tube_versus_macro_lens by fotoopa, on Flickr

The 200 mm tube appears to be slightly less sharp also has less contrast and especially in the corners let them fail. This may indicate that the inside of the tube is not perfect black. I prefer my 200mm macro lens as tube lens. I also favor the macro ratio that can be changed. These tests are very time consuming. They give me a lot of insight to make everything even better.

Frans.

[pierre]

Hi Frans,

Many thanks for this pretty instructive demonstration.

[Chris S.]

Frans, it's very interesting to watch as your setup develops. As always with your rigs, the fabrication is art. I particularly admire the Componon adapter--how you engineered it to place the Componon as close to the 200mm lens as possible. Nicely done!

I'm curious to know more about your design goals. Some elements of your approach seem surprising to me, but no doubt make good sense given some aspect of what you're building toward.

For example, the lenses you've tested here, on your 200mm Micro-Nikkor and a plain tube, would have been predicted to be "maybe OK, but not top-notch." Since you're spending considerable time and--likely--money on this project, and are not using optics already demonstrated to deliver top-quality results, you probably have a good reason. I'm thinking, here, of microscope objectives such as the Mitutoyo M Plan 5x/0.14, Nikon N Plan 4x/0.20 (either the finite or infinite version), or Nikon CFI Plan Achromat 10x NA 0.25 on a 105mm converging lens. Could you explain?

Cheers,

--Chris

[fotoopa]

I'm curious to know more about your design goals. Some elements of your approach seem surprising to me, but no doubt make good sense given some aspect of what you're building toward.
For example, the lenses you've tested here, on your 200mm Micro-Nikkor and a plain tube, would have been predicted to be "maybe OK, but not top-notch." Since you're spending considerable time and--likely--money on this project, and are not using optics already demonstrated to deliver top-quality results, you probably have a good reason. I'm thinking, here, of microscope objectives such as the Mitutoyo M Plan 5x/0.14, Nikon N Plan 4x/0.20 (either the finite or infinite version), or Nikon CFI Plan Achromat 10x NA 0.25 on a 105mm converging lens. Could you explain?

Yes, I can easily explain, I do not own any microscope objective up to now. The intention is to have at least one or two of these lenses to purchase. But I work with buget planning. The costs should be spread over a period. The camera needs to be renewed too. My D300 has already over the 90,000 shutter clicks. I also have tree major objectives:

- The first is for a type of studio work, which can be done indoors and in all weather conditions. The weight is unimportant and generally takes even more magnification of the images. I like to make mechanical parts.
- The second is for outdoor work. Lower weight, lower magnification. This is the type to photograph small insects. For this I would build a special design for stacking shots. You know I like to make my own mechanics, electrical engineering, and any necessary adjustments or laser optical measurements. Both hardware and software are integrated together. This has been a hobby in itself.
- The third objective is for in-flight insects, closer then I have just now. For this, I would change my 3D setup for 2D shots with two synchronous shots with slightly shifted focus. Even with only two stacks that should give a shaper 2D picture for flying insects. You know I've developed a special laser detection system that very eficient works.

For microscope objectives I only want to buy new version. I would buy only some new objectiven, seen I buy nothing on Ebay. Hence also the buget should proceed as planned.

Update:
I found the sensor type number on the chip of my test sensor picture:
Image sensor CCD KC73129
• Number of Total Pixels: 537(H) ´ 597(V)
• Number of Effective Pixels: 500(H) ´ 582(V)
• Chip Size: 6.00mm(H) ´ 5.10mm(V)
• Unit Pixel Size: 9.80um(H) ´ 6.30um(V)
Into the previous test pixels of 200x200 you can calculate easy the macro ration view the photocells are 9.8 x 6.3 um.


sensor_KC73129 by fotoopa, on Flickr

Frans.