what they don’t tell you…
Copyright © 2011 by KV5R. Rev. July 21, 2011
Shop for Wide-angle Macro Lenses
The Digital Concepts 0.45x Wide-Angle Macro Lens goes by other names and descriptions, so look at the photos below and compare. They all go for about $15 on various eBay and Amazon shops. You can’t expect much quality from a $15 lens. Such are good purchases for the kids’ first camera, or anyone just wanting to play around without sinking a fortune into professional lenses. This lens comes in 58mm filter thread size and is usually supplied with one or more step-down rings. It unscrews into two sections, the rear section being the macro lens. The bad part about this lens is it’s deceptive and false advertising. It is widely sold as a .42 or .45 wide-angle lens, when in fact it is .75. When you put it on your camera you will see very little difference, just a bit wider.
The rear (macro) element is an uncoated 46mm spherical convex. It displays severe spherical, barrel, and chromatic aberrations, making only the center 30% or so usable. To use it, you remove (unscrew) the front half (the wide-angle lens), thread it onto your camera’s lens, and put the camera in normal (not macro) mode. You can zoom through it. It’s depth of field is extremely shallow. The focal length on my setup is about 4cm at 1x zoom, and 7cm at 5x and beyond. You need to mount the camera on a tripod with the mast inverted and use the mast to set the focus. With such a shallow depth of field, it is not really suited for hand-held macro work such as bees in flowers, but it’s okay for inverted tripod work such as small parts details like electronics or jewelry.
The front element is a 62mm coated concave, and alone it’s power is about .44x. But the front element cannot be used alone, because they stupidly made the back end of it female, so you either need to buy a 58mm male-male coupling, or remove the glass element from the macro section and use that as a 58mm male-male. This is where the deception comes in: the front element is ‘.45x,’ but it’s meant to be used with the back element attached, which makes it .75x. Not having a 58mm male-male handy, I removed the rear lens to see what it would look like at .45. Pretty bad, as you will see below; barrel distortion and spherical aberration. So remember, the two elements work well together, but that’s .75, not .45.
Update: I purchased a 58mm male-male (“reversing”) ring from China for $4.57 delivered. Took a couple weeks to get here, but now I can mount the wide-angle lens directly to the step-down ring, and put the macro lens back in its ring and use it as well. I really can’t imagine why the wide-angle/macro lens manufacturer reversed the genders between the macro and the wide-angle sections, but the male-male ring fixes that problem nicely.
Photos
These are cropped and then reduced to 800 pixels wide so they fit in a web page. They were taken at 12MP.
The Digital Concepts 0.45x wide-angle macro lens. Should be called 0.75x.
The rear element is a 46mm spherical convex in a 58mm male-male holder.
The ring on the right is a 46-58mm step-up.
The front element is a 62mm concave (~.45x) with 58mm rear female and 62mm front female threads.
It comes apart into 2 sections.
This is with my camera only (Aiptek H5 Extreme), 34 inches high, seeing 25 inches wide.
This is with both parts of the wide-angle lens, seeing 33 inches wide (~.75x).
To remove the rear element and leave a 58mm male-male ring, push each side of the
slots in the retainer with small screwdrivers. Be careful! It’s tight.
Rear element removed.
This is 34 inches high with only the front element, seeing 57 inches wide (~.44x).
Note the spherical and barrel aberrations, and the dark corners.
This is the Aiptek H5 camera in macro mode at 1cm. Hard to light.
Watch the shadow angles. Using an LED flashlight.
This is with the macro lens, 1x zoom, ~4cm. A little smaller but much easier to light.
The subject is the SMT diode, which is about .5x1mm.
This is with the macro lens, 5x zoom, ~7cm.
Note the chromatic aberration on the solder points, top and bottom.
This is with the macro lens, 20x zoom, ~7cm. (My camera has
5x optical and 4x digital zoom, hence the poor quality at 20x.)
Notes
- I was using auto-focus and adjusting the inverted tripod mast to get it in range. Probably better to lock the camera’s focus and just use the tripod mast.
- The lens of my camera is about 7mm inside the barrel, and is not threaded. I am using a 46mm female-female coupling on the outside of the barrel (see my filter threads article). The wide-angle and macro lens will likely work better on a threaded camera lens where you can mount it closer.
- They should make the front of the macro lens female and the back of the wide-angle lens male so you can screw the front half directly into a 58mm lens thread or adapter ring. You could then use the lens three ways without removing the rear glass or buying a 58mm male-male coupler.
- Yes, it’s cheap, and it’s fun. If you look at it that way, you’ll be satisfied with it. But it’s not for the pro or serious amateur.
Stay Tuned!
Next, I build a couple of DIY studio lights!
I’m still working on the 20-foot carry-around jib. It’s coming along slowly—so hot outside!
I’m still thinking about building another Merlin-style stabilizer using ¼″ 6061-T6 aluminum.
—KV5R