Quote:
Originally Posted by skysurfer
Modding of DSLRs is not needed anymore with modern cameras.
I have an unmodded 6D and can take nice pictures of even faint red nebulas like Heart Nebula IC1805 and Elephants Trunk IC1396 (when using a UHC filter). Barnards Loop is displayed as well and Eta shows also many reds, in both cases I did not use filters.
Proper postprocessing does the trick.
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Of course Skysurfer's post is off the original topic, but it is important to not let comments like this pass through without remark. I suggest you read this, particularly Jon Rista's post #7:
https://www.cloudynights.com/topic/5...transmittance/
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Most DSLRs attenuate the reds such that they gradually fall off into IR (750nm) where transmittance is 1% or less. At the H-alpha line, transmittance is rarely more than 20% tops, and as little as 10%. For the 6D, given what I've seen with John Hayes can do with one, Ha transmission is probably around 20%. This limitation is ultimately imposed by the IR cutoff filter.*
For an unmodded DSLR, you then have 25% of the pixels passing 20% of he light. So its .25*.20, or a mere 5% Ha transmission. Throw in the quantum efficiency on top of that, which according to sensorgen is 47% (although that is for green, which is usually a bit higher than red or blue...but let's go ahead and use it), you then have .05*.47, or 2.35% actual sensitivity.
If you remove the IR cutoff filter, then you get significantly greater transmission. It's not perfect, but lets say it's 90%. So now you have 0.25*0.9*0.47, or 10.6% sensitivity.*
In comparison to a mono CCD camera, which is going to have no filtration at all and thus its entire Q.E.: For a KAF-8300 ~49% sensitivity; For a KAF-16200 ~55% sensitivity, for a Sony ICX834 ~70% sensitivity.*
No amount of post-processing mumbo jumbo is going to improve a 2,35% Ha sensitivity for an un-modded 6D.