Closeup Lens or Achromat?
I get alot of emails asking me the difference between an achromat and a closeup(macro) filter lens.
On the right side of this page is a picture showing an achromat and a closeup lens. A closeup lens is a single piece of glass that photographers use to shoot objects at very close distances.
This lens is cheap and easily available at any photographic supplier. It comes in a +1, +2, +4, and+10 diopter power. If you want to shoot even closer, you can stack the lenses up to give you the additional power. eg. put a +2 and +4 lens together and you get a +6 lens. The disadvantage is that this lens produces chromatic abberations and also some edge softness. The cheaper the lens, the worse is the edge softness and chromatic abberations. See here for defination of chromatic abberation http://en.wikipedia.org/wiki/Chromatic_aberration.
Achromatic lens are like closeup lenses but with 2 lenses made of different materials cemented together. These lenses are expensive but do a good job of correcting the chromatic abberations and spherical abberations. See the picture on the right.
The +5 Hoya achromat is much heavier and thicker than the no-name +10 closeup filter. It cost me $80 vs the $20 cheap version. For those who want excellent quality without CA (chromatic abberation), be prepared to pay anywhere around $150-$250 for a good quality achromat. If you are not fussy, you can get the cheap closeup which works well too.
Also note that the chromatic abberations are mostly visible in very high contrast pictures and away from the center. I will be testing 2 Hoya +5 achromat lenses stacked together and I might make that available to the more demanding users. Alternatively you can buy this excellent achromat available on Amazon-The Opteka 10x HD2 Macro. Tough luck to international buyers as they do not ship to most countries. However you can buy it from ebay for a much higher price.
After reading all this you might be wondering why do you need to use a macro lens with a DOF adapter. Here's the answer. Most camcorders need an achromat or macro lens as it needs to focus on the ground glass approximately 2 inches from the lens. Since all lens produce vignetting on the ground glass/focusing screen, you would have to zoom in past the dark edges. If you don't have a achromat or macro then you will get very heavy vignetting, if your camcorder can focus that close. See the wiki description here http://en.wikipedia.org/wiki/Vignetting
More good information regarding macro lenses and achromatic lenses with pictures and samples can be found here http://www.imperialrabbit.com/rescharttest.htm
On the right side of this page is a picture showing an achromat and a closeup lens. A closeup lens is a single piece of glass that photographers use to shoot objects at very close distances.
This lens is cheap and easily available at any photographic supplier. It comes in a +1, +2, +4, and+10 diopter power. If you want to shoot even closer, you can stack the lenses up to give you the additional power. eg. put a +2 and +4 lens together and you get a +6 lens. The disadvantage is that this lens produces chromatic abberations and also some edge softness. The cheaper the lens, the worse is the edge softness and chromatic abberations. See here for defination of chromatic abberation http://en.wikipedia.org/wiki/Chromatic_aberration.
Achromatic lens are like closeup lenses but with 2 lenses made of different materials cemented together. These lenses are expensive but do a good job of correcting the chromatic abberations and spherical abberations. See the picture on the right.
The +5 Hoya achromat is much heavier and thicker than the no-name +10 closeup filter. It cost me $80 vs the $20 cheap version. For those who want excellent quality without CA (chromatic abberation), be prepared to pay anywhere around $150-$250 for a good quality achromat. If you are not fussy, you can get the cheap closeup which works well too.
Also note that the chromatic abberations are mostly visible in very high contrast pictures and away from the center. I will be testing 2 Hoya +5 achromat lenses stacked together and I might make that available to the more demanding users. Alternatively you can buy this excellent achromat available on Amazon-The Opteka 10x HD2 Macro. Tough luck to international buyers as they do not ship to most countries. However you can buy it from ebay for a much higher price.
After reading all this you might be wondering why do you need to use a macro lens with a DOF adapter. Here's the answer. Most camcorders need an achromat or macro lens as it needs to focus on the ground glass approximately 2 inches from the lens. Since all lens produce vignetting on the ground glass/focusing screen, you would have to zoom in past the dark edges. If you don't have a achromat or macro then you will get very heavy vignetting, if your camcorder can focus that close. See the wiki description here http://en.wikipedia.org/wiki/Vignetting
More good information regarding macro lenses and achromatic lenses with pictures and samples can be found here http://www.imperialrabbit.com/rescharttest.htm
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