Low cost DIY extreme macro lens attachment

Step 7

To use it, you just screw the lens onto the filter, and then attache the assembly to your camera body. Set the aperture using the lens control ring as desired.

You can see two images I took to test the lens, using a full frame sensor. 1 and 3 are the full view, while 2 and 4 are 100% crops from the respective images.

Using the images of the ruler, I was able to do some math.

The lens has a reproduction ratio of about 6.78:1. On the full frame camera this means at most you could view a 5.3mm x 3.5mm area (that fills the frame), while on a typical 1.5x crop DSLR, it would be 3.5mm x 2.3mm.

Now the resolving power will depend on the resolution and sensor size of your camera. On a D3/D700, 1 pixel equals about 1.25um, while on a D90/D300, its about 0.82um. Yes - that is micro meters. This would mean, at least in theory, a human red blood cell would be about 6-8 pixels across. Not bad...

Realistically this is a bit too much magnification for much practical use. You really have to use this setup and a hard surface with both the body and lens extension supported, or getting a sharp image without shake is near impossible. Also, the depth of field is obscenely shallow. While I haven't measured or calculated it, you are probably talking on the order of 150-400um. I believe that making the extension shorter will reduce the magnification, but I'm not exactly sure how that works.

You can't focus this, you have to move the object to the focus point, which can take a lot of playing. Move the object, not the camera, if possible.

I recommend using this with a camera the supports live view over a USB cable, like a Nikon D90 paired with Nikon Camera Control Pro. There are also equivalent Canon solutions. This will help immensely in trying to focus and compose without accidentally moving the camera.