Experiments with a simple doublet lens

SXR_Mark · Joined: 12 Jun 2010 Posts: 506 Location: England

Recently, I was given a box of lenses (and by that I mean lens elements) that belonged to my Grandfather. Amongst them I found a couple of doublets (presumably achromats) of 2-inch diameter. I decided to see how they would work and so fastened one to the end of a bellows on my Oly EPL1. Focusing to infinity would suggest the focal length is 4-1/4 inches. The front surface of the lens has an anti-reflection coating of some sort, but the back is uncoated. Below is a picture of the lens on the bellows. the second lens is leaning against the bellows. As fitted, the lens is apertured down to about f3.5.

Below are some sample pictures taken indoors with available light. The cat pictures are ISO1600, so there is some noise, and are hand-held. The shooting distance was probably about 3 metres.

The other pictures were taken with the camera tripod mounted and with the aid of a bright lamp so the ISO is 100. The shooting distance is between 1 and 2 m. This is really too close for a simple doublet, so it's not surprising the results are a little on the soft side. I know my attempts at "still life" photography are rather feeble, but what do you think of my simple lens??

The only PP is white balance on the cat pictures, minor tweak to levels (surprisingly good saturation with this lens), but definitely no sharpening.