Balance between "Exposing to the right" vs "Hot Pixel"

First thing first, I am a newbie who (so far) very keen on suck in as much information as possible.

Thanks to argyle: I now have basic understand of "Exposing to the right" - which is over explose pics in RAW format to allow the sensor capture as much data as possible (and modify it later)

Hot Pixel: open shutter for too long and certain point of sensor gets too HOT and generate unwanted noise.

Majority of time I am doing sea/landscape pics at night! There are couple of time I tried to do a 30+ minutes exposure (piror to go thru these 2 concepts) and they all turns out quite terrible. 1) under exposed and 2) full of noise dots.

So I like to ask the experts here, if I want to do a 30+ minutes exposure with my 500D, what is my best solution to avoid noise created by Hot Pixel?? (without crank up the ISO/Av setting) And of course I will expose a little longer to allows the effect of "Exposing to the right".

There are different kinds of noise and in normal photography the kind caused by heat buildup is not a significant factor. The difference in noise from heat between exposures done at 1/200 and 1/25 is tiny and this is what makes ETTR workable. Shooting at a slower speed and reducing the brightness later produces a reduction in noise much more significant than the tiny increase caused by the longer exposure. However, if the exposure times are long, heat becomes a much greater factor. 5 minutes has far less noise than 40 minutes, so much less that reducing brightness on a 40 minute exposure can't compensate for all that extra heat noise. If I were doing long exposures, I would forget about ETTR.

andylo wrote in post #10035364
First thing first, I am a newbie who (so far) very keen on suck in as much information as possible.

Thanks to argyle: I now have basic understand of "Exposing to the right" - which is over explose pics in RAW format to allow the sensor capture as much data as possible (and modify it later)

Hot Pixel: open shutter for too long and certain point of sensor gets too HOT and generate unwanted noise.

Majority of time I am doing sea/landscape pics at night! There are couple of time I tried to do a 30+ minutes exposure (piror to go thru these 2 concepts) and they all turns out quite terrible. 1) under exposed and 2) full of noise dots.

So I like to ask the experts here, if I want to do a 30+ minutes exposure with my 500D, what is my best solution to avoid noise created by Hot Pixel?? (without crank up the ISO/Av setting) And of course I will expose a little longer to allows the effect of "Exposing to the right".

The idea of exposing to the right is not to "overexpose" the image, which will result in blown highlights. The purpose of ETTR is to maximize the signal to noise ratio. You basically want to get the histogram as far to the right as possible without getting a "spike" on the right edge. In other words, the histogram should just snug up/touch the right side. Here's a better link to ETTR rather than relying on Wikipedia:

Luminous Landscape-Exposing to the Right

Most folks that do really long exposures (shooting star trails, for instance) take a series of 5-minute exposures and stack them afterwards in Photoshop or other similar program. A stack of multiple, shorter-duration exposures should help with the noise issue...not sure how this would relate to seascapes, however.