Having got my first DSLR and some lenses, I knew they were not intended for macro applications. So I have a gap in my capabilities having sold my old bridge camera. A dedicated macro lens is more than I want to spend at the moment, and I came across the closeup/macro lenses. These screw into the existing lens like a filter and provide magnification and reduce minimum focus distance.
The specific set I got are Camray
branded. They were found on ebay for £10 ($20) + £3 postage.
The set includes closeup +1, +2, +4, and macro (sometimes called +10). I got them in 62mm size to fit the SAL1680Z I have.
I did the following to see how they work. I didn't concentrate on great shots, but functional ones to show the effect. The lens was left at 80mm for all shots. I set the focus and exposure metering to spot, and centered the image on the coin.
The subject is a new South Korean 10 won coin which is about 18mm in diameter.
My first test was to experimentally find the minimum distance point I could focus on the coin. Keeping the coin and camera in the same position, I took pictures with +1, +2 and +4 closeup lenses attached in turn. I also tried the macro, but the camera wouldn't focus with it on.
Keeping the macro lens on, I had to move the camera closer in order to get it to focus. Again I found minimum focus distance and took a picture. This was repeated with the three closeup lenses, finding the minimum focus distance for each one.
Finally, just to see what happened, I did the same with ALL of them on the camera at once, with highest magnification closest to the camera.
The picture shows the relative sizes at the minimum focus distance for each configuration.
Top left: 80mm lens only
Top right: with closeup +1
Mid left: with closeup +2
Mid right: with closeup +4
Lower left: with macro
Lower right: with macro, +4, +2, +1
After downloading the pictures, I used imaging software to find the maximum width of the front for the coin in pixels for each configuration. This was then expressed as a percentage increase of the original size.
Keeping the distance between camera and coin the same:
closeup +1: +9.6%
closeup +2: +19.6%
closeup +4: +41.5%
So it looks like each "+" unit gives about 10% linear magnification.
Now if we do the same for the minimum focus distance as this gives the maximum practical magnification:
closeup +1: +17%
closeup +2: +33%
closeup +4: +60% (1.6x)
macro: +110% (2.1x)
all 4: +227% (3.3x)
Although it is not obvious in the small image above, when using all 4 lenses, the chromatic aberrations are very bad! Using a single lens appears to be ok.
Finally, I can do a quick calculation. The sensor in the A350 I used is apparently 23.5mm wide (from wikipedia). The pixel width of the coin with the macro lens fitted was approximately 40% of that width, giving an equivalent size at the sensor of 9.4mm. This puts the macro ability at about 1:2 or half size.
So in conclusion, they do what they claim, which is to let you get closer than you normally would without such a lens fitted. The macro ability is not up to the 1:1 of a true macro lens, but if you want something close at low cost, this is worth a look.
So now that I have an understanding of how they work, my next thing to do is use them for some interesting shots