Taking pictures of waves on a gray bleak day

The other day I was taking pictures of waves coming in off the Gulf of Mexico. It was a gray day, just before sunset. Everything seemed black, white or gray. The sky was very cloudy. The water was very troubled, almost dirty looking. I was shooting off of a tripod with a pentax k-30 and a zoom lense. I began on auto-exposure, sort of let the camera do the work, but I was getting a lot of noise in my pics. My question is, when I switch over to manual which direction do I begin to correct the noise without effecting other things in my pic. Because, besides the noise, everything else was beautiful. Almost looked like I was shooting in black and white.

 

Sincerely,

 

800rate

Edited March 22, 2017 by blue_topaz

Why don't you post the shot in question with the exif data?

Lots of missing info....too much in fact fro anyone to give you an answer. First thing up though is you have to remember where that noise is generated. It is in the camera, more specifically the sensor. The sensor is an electronic device and so has energy applied at all times. this creates a certain level of heat which in turn causes spurious bursts of energy. It is latent, always there at a very low level. So when you have lots of light striking the sensor then the noise is drowned out since it resides only in the dark regions. Different sensors have differing sensitivities to light. the more sensitive they are the less noise appears because the sensor is grabbing that incoming light energy and over-riding the background levels....you pay more....much more the more sensitive your sensor is. So the sensor sets the inherent noise levels and sensitivity, noise is in the dark regions of the picture. too drop the noise in the picture you must increase the total amount of light absorbed. This means longer shutter times, wider apertures. Which in turn gives you less and less leeway against motion blur and ever decreasing DoF.s. That is a very mumbled explanation and if someone wants to jusmp in and correct or clarify please do so!