Microscope Lens Shootout

The Great Lens Shootout!

Our company's founder Jack Ross decided to take a closer look at the different types of National Optical objective lenses available for the 160 series microscopes. The objective lenses include the standard achromats, the super high contrast (ASC), semi-plan and plan objectives. Are the plan lenses really better as he once (unscientifically) deduced? Just because an objective lens costs more, is it really better? These are some questions he wanted to answer.

Microscope objective lenses

Jack went to work with a model 162 binocular researcher microscope, four sets of objective lenses (achromat, semi-plan, super high contrast, and plan), his Nikon coolpix digital camera (an old model 990) and a camera adapter.

His experimental plan was pretty simple: several co-workers and he would physically look at the same microscope slide using one each of the objective lenses. They would then try to determine visually if one image was better in quality than the others. Of course variables would remain the same: same microscope, same lighting and settings and always observing the same part of the slide.

He had a lot of fun looking at pine needle cross sections, bacteria, blood cells, insect parts and various tissue sections.

The RESULTS!

The pictures below were resized and compressed for the web but were not altered in any other way (for example they were not brightened, sharpened etc). All pictures are of a cross section of a pine needle and you can see a "stoma" or breathing hole (the small opening in the middle).

Achromat lens Standard Achromat Objective

Our analysis, the Achromatic lenses are a great buy for the money but, ...read on.

Semi-plan lens Semi-Plan Objective

Semi-Plan lenses are rated to 80% of the field of view (Achros are 60%, Plan are 100%). These lenses were consistently poor with all samples and since our test was conducted they have been discontinued.

ASC lens Super High Contrast Objective (ASC)

"ASC" stands for "Achromatic Super Contrast" and they live up to their name! Money versus quality, this is our favorite choice! Better contrast, sharper image and yet, the image retains brightness. Although the ASC lens is an achromat (rated to 60%), we saw very little field curvature effects at 1000x.

Thinking about the Standard Achromats above? We recommend you compare pictures 1 & 3, spend an additional $66, and choose these lenses.

Plan lens Plan Objective

We really couldn't tell much difference when comparing this 100x objective to the ASC lens. Some of our observers noted a bit more uniformity of brightness and some noted that the image was a bit sharper at the edges (being a Plan lens). Other observers actually preferred the ASC lens over the Plan as there was a slight increase in contrast.

Microscope Light Differences
This test was performed to see the difference between National Optical 150 series and 160 series microscopes. This test shows both the difference in optical quality as well as the difference between the lighting in National Optical's 150 series versus the 160 series.
achromat lens

157 Achromat Objective on 162 Microscope
Halogen Light Source

This image shows a 100x standard achromatic objective from National Optical model 157 on our test model 162 microscope to see how the 150 series lens compared.

The image does not look bad at all. Model 162 has a halogen light and this image is illuminated well.

achromat lens

157 Achromat Objective on 157 Microscope
Fluorescent Light Source

This images shows a 100x standard achromat objective from National Optical model 157 on model 157.

Overall quality is good and there is not much distortion on the outer edges (field curvature effects). This image is a bit dimmer in intensity though because model 157 has a fluorescent illuminator. Compare the four red structures at the top of the image. They are darker and show less detail than in the image above.

Conclusions

One of Microscope World's goals is to tell the consumer the facts as we see them. We want you to get the best product for your money and have as much information as possible to make an educated choice (and frankly, we doubt our competitors do these tests at their facilities). So, taking in all the data and factoring price into the equation, in our collective opinions, we have made the following conclusions:

  1. The standard achromats are good lenses but, factoring in price, we would recommend the ASC lenses over all others.
  2. If the price difference between the ASC and Plan lenses isn't that important to you and a flat field is, then choose the Plan lenses. The consensus was that the 100x Plan lenses had less distortion at the outer edges and a bit more uniformity of brightness. If you will be doing a lot of imaging or spending many hours looking into your microscope, the Plan would be a wise choice.
  3. The 150 series achromat objectives are of good quality however, having a bright halogen illuminator (such as in the 160 series) improves the image at 1000x.

Limitations of this study. No, it wasn't a double blind study and our sample size was extremely small. We only tested the 100x objectives on a model 162 binocular scope, but we assume that this data will carry through to all the 160 series microscopes as well (160, 161, 162, 163). We also think that the results will be the same when testing the 4x, 10x and 40x objectives too.

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