There has been a great deal of press about the extraordinary resolution of the D800 with its 36.3 bazillion mega-pixels. For those of us who at times may not need quite so much resolution, down-sampling is recommended. OK, I understand that down-sampling involves generating a smaller image file, but from a practical standpoint, how is that achieved? Reducing the image size (L, M, S), image quality (NEF, JPEG (fine, normal , basic)...), or image area (FX, 1.2, DX,...), all of the above?
Maybe this will be clearer once my dear D800 arrives!
Down-sampling - Practical how to....
(11 posts) (8 voices)-
Posted 1 year ago #
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To downsample means to reduce the image size after the picture is taken, on your computer using software such as Photoshop, Lightroom etc. A good start would be to get Photoshop Elements. Cropping is not the same as downsizing, so changing the image area is not gonna do it. That's the short answer, there's a learning curve when it comes to image resizing especially for print.
Posted 1 year ago # -
I asked this question several months ago. So, my hypothesis is that one uses the image resize menu in Photoshop, but not sure. I can't even guess how to do it in other software.
Posted 1 year ago # -
In the lightroom export menu you can select an output size, for example long edge 1000px. And you can also select an output sharpening for it. Almost any half serious software can do adequate re-sampling, although Photoshop's is pretty good.
Posted 1 year ago # -
Billder said:
Reducing the image size (L, M, S), image quality (NEF, JPEG (fine, normal , basic)...), or image area (FX, 1.2, DX,...), all of the above?
Maybe this will be clearer once my dear D800 arrives!Reducing image quality will compress the image data. So you will still have 36 MP, but the file on the card and your hard drive will be smaller. But as you already wrote, this will reduce the image quality.
Reducing the image size is down-sampling. You can do this in camera by using M or S instead of L or you can do this later in Aperture/Lightroom/Photoshop/whatever software you are using. Some people say that down-sampling the images later on the PC will give better quality because you can use a more powerful processor. I never tested this so I can't tell if this is correct or not.
Changing the image area will also reduce both the image size and the file size, but it is not the same as down-sampling as looon already said. This is just cropping.
I usually shoot full size (L) and down-sample later for whatever I need the images. This will give me the most options. But if I already know that I only need small files (etc. for an auction site) I would reduce the size to S. But this is just the way I do it and I don't have a 36 MP camera but "only" 12 MP.
Posted 1 year ago # -
It's not just the processor, the algorithms used are better. And also fine-tuning the output sharpening image by image can be very useful at times, for maximum quality, that's not something that an algorithm can detect properly in my experience. However for average users probably won't be any difference, especially if the output resolution is bigger than of the final print size.
Posted 1 year ago # -
Appreciate the comments. I use Aperture and am familiar with reducing image size in pp. As I mentioned, in-camera was something altogether different. Thanks
Posted 1 year ago # -
There are several ways you can set up the camera for a smaller filesize, but none of them will give you either the flexibility or IQ of doing it in pp. You could shoot in JPEG which gives you the 3 size options but you immediately lose quality and then if you're going to do a thing with it later you had better convert it to a lossless format before playing with it, because every time you save it as JPEG it loses more quality even at the highest setting. As for the crop modes, as a wildlife shooter coming from DX I first thought I was going to be shooting in DX, but discovered that shooting in FX opened up all kinds of new possibilities for me.. but that's a whole 'nother topic. Basically you lose all kinds of flexibility vs cropping it yourself in pp. I shoot in compressed 14-bit lossless raw, then in pp I crop and then sometimes downsample. That will give you max control and the best quality images, imho.
@Yetiibuddha - In Photoshop choose Image Size, make sure all 3 boxes are checked and choose a resample option (either bicubic for smooth gradients or bicubic sharper if you aren't doing your own sharpening). Change from pixels to percent unless you know what size you want, then change just the width to 80% or whatever and it will scale the height proportionately for you and off you go.
Posted 1 year ago # -
Another vote for just shooting raw and downsampling in post. If you feel you want a downsampled image after shooting, the newer Nikons have NEF processing in-camera (with exposure and white balance adjustments available, for example). The NEF processing will let you export a jpg to the card while keeping the raw file, too, and you can set the image size to be S, M, L as if you had shot the jpg (but with the added flexibility of keeping all the raw data). Good luck and congrats on the D800!
I have found this NEF processing with two card slots (I'm using a D7000) to be so handy for family gatherings because instead of the photos just sitting on my computer forever, I now just ask, say, my sister to lend me her SD card and I give her jpg copies of the files while I'm at the family dinner or whatever (used it for easter egg hunt last weekend).
Posted 1 year ago # -
great idea JA, never though about such a usage of SD card slot :)
Posted 1 year ago # -
For control freaks....From the camera... RAW, 14 BIT, Lossless, Compressed into Lightroom 4. Edit with a viciousness of the vampire. Then after processing, every one I will let out of my computer, export with JPEG settings either full size, or as suggested, with a specified size of the longest side. For example, I export the full size image of about 7-8 MB to Flicker, then download the 800Px size for PAD. Then the folks who want to really examine, and be critical, can look at the huge image on Flicker, wandering around and finding all the flaws.
Another example, for email, export with 500Px size and limit the size of the email. I usually have several different desktop folders with the exports in them so I can access the files for upload to the various websites, etc.
And this is the way an old lady does it....
Posted 1 year ago #
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