Uploading images

eduncan46

I know that my D5100 camera is 16.2 mp but how does this translate to my images when I load them into my computer?

How many options does my camera have for file sizes and where are they located in the camera?

What is the ratio of width to height in my camera and can I change it?

bruto

The 16.2 megapixel figure means that the largest or densest image size you can obtain is going to be 4608 x 3264 pixels at the native sensor dimension, which is 24:16. I don't believe you can change the ratio in the camera. On some models, such as the D7100, there is the option to shoot in 4:3 ratio, but I don't think it exists in the D5100. In any case, changing that ratio even in the camera does not redistribute the pixels, it just crops the image, so a cropped image will never comprise as many pixels as the camera's sensor is capable of.

Exactly what file size that translates into in the computer will depend on various settings, and also on what is in the picture. I believe on the D5100 you can choose 12 or 14 bit Raw files, and three different sizes of JPG files.

The Raw formats include some compression, which means that a picture with large areas of a single color will store a bit smaller than more varied ones. I think the largest size for a Raw file will be in the 16 megabyte range. JPG files are always compressed and therefore will also vary in size depending on the content.

I am not sure exactly where you'll find the image size options on a D5100, but on the D3200, you can use the [i] button, and the image/file size options will appear at the top right. You can choose to shoot in Raw only, Raw + JPG, and JPG alone. Within the JPG range, you can choose among three different pixel dimensions and three different degrees of compression. On the D3200 one cannot choose different JPG options if shooting Raw +JPG, and all JPG are the largest available. I don't know whether this differs on the D5100.

You can also get at the file size and type in the shooting menu. There are two entries there, one for "Image Quality", and one for "Image size".

File sizes will diminish as you decrease the dimensions and increase the compression, with the smallest size and quality coming in at about 500 kilobytes.

Obviously, as you decrease size and increase compression, quality will also be lowered. These days with memory cards relatively cheap, and with computer memory so large, I see little point in shooting anything but the maximum file size and quality. There are many options for reducing size and increasing compression in the computer later. If you shoot a small compressed file in the camera, that's all you'll ever have. If you shoot a Raw file, you can alter it as you like in post processing, but you'll always have the best original to work from. The only reason I would choose a lower quality JPG file in the camera would be if I have forgotten to pack an extra memory card when traveling, or if I am shooting large sequences of still shots, where the large file size of Raw files can slow shooting down, especially with a low speed card. Otherwise, I'd stick with the biggest and best Raw files, and use any of a number of free post processing programs, such as Irfanview or Faststone Image Viewer, to reduce them as needed when needed.

If you use certain programs such as Nikon's View NX2 or Capture NXD, you'll find that Raw images provide a great deal more potential for post processing without losing track of the original. A number of options are available only for Raw images, such as changing the color set, altering white balance, and exposure compensation, which can also be undone at the touch of a button. Once you've got what you want, you can convert an image to JPG individually or in bulk processes.

You can, of course, also crop an image in post processing, and create whatever other formats you like. If you expect to crop to a squarer mode, for example, just make sure you leave a little extra room on the sides when you shoot. Faststone and the Nikon programs provide ready-made cropping ratios so that you can duplicate any ratio you like precisely, as well as freehand cropping.

eduncan46

An excellent reply and it contained the information I was looking for. Many thanks.