I'm an amateur photographer that would like to use software to get better images. My camera's pretty good so let's say I have a good landscape shot. I can easily manipulate the images to enhance the landscape to get perfect sky or perfect forest or perfect water but not all. Is there software out there that would let me take these 3 enhancements of the same shot and combine them into one perfect image? I can't justify buying a camera that has the "batch" mode that will probably do this for me.
I am not familiar with the software that is powerful enough to do as you suggest, though I suspect PhotoShop can do it. That program is out of my price range. So you would have to ask someone else about that in particular.
But I do have some thoughts. I am interpreting your question to mean you can take three pictures, each of which is properly exposed for part of the scene, but not the rest of it. Is this correct?
Since I have to make do with what I have, I have learned the following tricks for producing perfect or near-perfect exposure for a scene. First of all, at the scene, use a polarizing filter on your lens. It will tend to darken the sky a bit more than the land, so that the contrast is reduced. It will require a longer exposure than without that filter, but you can get very deep blue skies if you use a linear polarizer at right angles to the sun, turning it to get deeper color in the sky, and you can also get deeper color in the sky if you use a circular polarizer toward or away from the sun. You can also get graduated filters that will darken the sky and leave the land without darkening. The Cokin system has such filters available. Cokin makes square filters that are inserted in a holder which slips over a ring that is screwed onto the lens. The advantage is that you can buy one set of filters for many different size lenses. There are two sets of Cokin filters, one for smaller lenses, and one for larger. They have both a circular and a linear polarizer available, and they have graduated filters in many different hues. These just fade from intense color to no color at all.
After you load the photo into a program (I use Paint Shop Pro 5, because I happen to like it), you can then reduce the contrast to get the lighting more even over the entire scene. You can also lighten or darken the entire image with the gamma correction. If decreasing the contrast causes my color to wash out, I can use the hue/saturation/lightness provision to increase the color again.
If you want to combine more than one photo for best exposure, you can do it, but it is tedious. To make this successful, it is best if you have the camera on a tripod and use a shutter release so you get exactly the same scene each time. In your program, make separate copies of the photos for working; never use your originals. What you do is you take one of your new saved images, and you have to color one part of the scene entirely black. Let's say, the sky. You put a black edge around the top of the landscape, and then fill in the rest of the sky with black. There may be enough variation in the sky you can't simply use the fill tool, but you can paint it black, or use the fill tool with more than one color in the sky. Do this on an image that contains properly exposed landscape. Save the results as a new image with .png format. After you do this, you turn the black transparent. Then you can copy the entire image, and paste as transparent selection over a new copy of the picture with the sky properly exposed. Then save the results as yet another new image. At that point, you may need to use your soften tool to blend the edge of the land to the edge of the sky. That will straighten out a multitude of problems; it's just very tedious.
There is a lasso tool in Paint Shop Pro. I lack the manual skills to make it work. But it is supposed to surround something you want to copy and lift out of a photo to paste into a new photo. I can't tell you how to do that because I have never been able to do it myself. It is my understanding that PhotoShop has better tools for this purpose.
I hope this gives you some helpful ideas. If you find any of this explanation confusing, let me know. Take care.