Canon DSLRs

As a pioneer of  the enhanced-camera provider, we have shipped thousands units all over the world since 1st camera – 300D. Since then, we have 3 options in Canon cameras, which might confuse people.  Each option has pros and cons. So I thought I should clarify here since we have same questions all the time. Before describing each option, please note imaging sensor is fairly sensitive from 700nm to 1000nm. I’m not sure the definition of infrared in wavelength. But let me consider this is near infrared(NIR) anyway and refractive optics are not well designed to correct chromatic aberrations. So NIR has to be blocked.

1) Option “T” :  This makes things quite simple. It doesn’t require any extra filter since UV/IR blocking filter is already built-in. So this is a ready-to-go kit. But the internal reflections are not avoidable. Bright stars gets larger. Another good thing is this allows to shoot regular daytime shots in custom white balance mode. So this is most economical way. Self-cleaning mode is still functional.

2) Option “E” : This is normally called performance-enhanced since this is the best performer.  This camera has no optical filters except CMOS cover glass. Since there is no such interference type of filters, image is cleanest among them. Virtually no internal reflections. So star edge is very clean even in bright stars. But since there is no UV/IR blocking filter, it requires extra filter for refractors and camera lenses. Otherwise image gets softer due to chromatic aberration in NIR region. Setting body-mounted filter is good idea to do so or simply set 2″ UV/IR blocking filter into telescopes. Also this camera allows to shoot UV or IR imaging. Especially ideal for UV imaging than following clear filter option. UV spectrum is considerably attenuated when the light goes through the glass. Minimal glass is advantage for UV. Another issue is no self-cleaning function. No way because of no filters. Fortunately, cover glass looks having the special coating to slip the dust out smoothly. As a real world,  this option works well too. This is good for scientific, forensic and nature photographers who are looking for maximum transmission.

3) Option “C” : Clear filter option. We replace two filters with clear ones. Modification process is most difficult because self-cleaning device is re-set on a filter glass. It’s challenging. This is why this option is most expensive. The internal reflection is less than T option but more than E option. It’s good for UV and IR imaging. However, UV is more attenuated because of two pieces of glass. This is the one for people who are concerned about the dust issue.  Like option E, it requires an extra filter to block UV or IR for astro and regular shots.

AF is still fully functional in above any of 3 options since all of flange back are set at 44.00mm – Canon specs.

If I’m asked “what is the best options?”, it is still difficult to say.  It depends on the budget, the optics you have and simplicity. But I would say option E and body-mounted filter. This combination creates  the cleanest image.  Yes, Newtonian optics doesn’t need to block IR. So if you have Newtonian telescope, this is it.


~ by tedishikawa on January 24, 2012.

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