Contrast Enhancements

Frez · Post by **Frez** » Tue Aug 07, 2012 11:03 pm

Let's put the mutated N. lyra to bed with a series of contrast enhancements for comparison purposes. All images were obtained with an Olympus BHA and an Olympus DP-10 camera. All objectives were 40x.

This first one is Circular Oblique Lighting. It was obtained with an undersized 40x annulus aligned on the inner half of a 40x B&L DM phase plate.

This is dry dark field. The condenser is an older Swift that was made in Japan. It fits the 37mm sleeve of the BHA.

Hoffman Modulation Contrast was used here. The turret condenser is 1.25 Abbe.

In this example of oblique lighting an Olympus 1.4 na APL/ACH condenser was used for the offset.

Next is bright medium phase contrast. This is a negative phase contrast type. The condenser and objective were both Nikon. I did two separate series of stacked images and could not get the outer ends of the striae to line up.

The last one is dark low low phase contrast. This is a positive phase contrast. The condenser and objective were both Nikon.

All stacking was done with Helicon and post processing in Photoshop.
Thanks
Frez

Cactusdave · Post by **Cactusdave** » Wed Aug 08, 2012 12:19 am

Very nice illustration of the effects of different contrast techniques. The Circular Oblique in particular image looks great. It shows very well what can be achieved without resorting to wallet draining DIC.

Marek Mis · Post by **Marek Mis** » Wed Aug 08, 2012 4:13 am

Frez,

Very nice set there ! I like the 5 th the most. The sharpness and the ivisible details are very good. The colours are very nice for me too.

Marek

carlos.uruguay · Post by **carlos.uruguay** » Wed Aug 08, 2012 6:58 am

Excellent and beautiful images
carlos

Mitch640 · Post by **Mitch640** » Wed Aug 08, 2012 9:01 am

They are all beautiful, but I am drawn to the low-low phase contrast. It seem more 'real'.

RogelioMoreno · Post by **RogelioMoreno** » Wed Aug 08, 2012 9:03 am

Very nice set!

It is always nice to see a specimen under dif. illumination.

Rogelio

Frez · Post by **Frez** » Wed Aug 08, 2012 6:21 pm

Mitch640 wrote:They are all beautiful, but I am drawn to the low-low phase contrast. It seem more 'real'.

Me too. It has very little flare. The oblique is good for accuracy.

Frez

Jacek · Post by **Jacek** » Thu Aug 09, 2012 12:20 am

Beautiful photos and very interesting effects

Charles Krebs · Post by **Charles Krebs** » Sat Aug 11, 2012 6:27 pm

Frez,

Very nice comparison!

I like the way the COL (and oblique) can compete quite nicely with phase-contrast. (The COL might be my preference here.) Always nice when an essentially "no-cost" option can do well.