Monday, September 30, 2013

A D800 is a Privilege - Not an Obligation

If one buys an expensive camera, it seems logical to make sure one uses it fully. “If it has 36 megapixels, use the 36 megapixels.” “If it has 14-bit files, use every last bit.” “If it has splendid autofocus and perfect auto-whitebalance, use them.” “If it has a Pet Portrait scene mode, use it!” No, wait! Not the last one. Your expensive camera is unlikely to have a Pet Portrait scene mode.

However, if one thinks about it, the camera should not tell you what to do. You should be able to tell the camera what you want. I tell my camera what I want.
  • I use DX mode on my D800. Not all the time. When I need a really narrow depth of field or a lot of detail, I use FX. I'm glad it is there. However, when I do not need FX, I do not use it. With DX, my files are smaller; more of them fit on my harddisk, and they are quicker to edit.
  • I use small basic jpeg files with my D800. Not all the time. Usually I shoot RAW. However, when I just want to take photos of labels or signs to remember what they said, there is no reason to use anything but the smallest bad quality files one can get. And, to be honest, even small basic jpeg files are pretty good with a D800.
  • I use 12-bit lossy compression on my D800. I do that almost all the time. The average file size is less than 30 Mb. If I had used uncompressed 14-bit files, the average file sized had been around 75 Mb per picture. If there is a really delicate occasion, I can switch on lossless compression and 14-bit for a photo, but those delicate occasions are rare in my world.
  • I use cheap lenses on my D800. I happily use a Nikkor 50mm f/1.8D. Not all the time. I have specialised high-quality lenses, for things like macro, zooms and wide angle purposes. I use those lenses when I want to do macro, zooms or wide angle photos. But when I want to carry light, I can use a 50mm f/1.8D, which in many cases does a decent job.
  • I use manual focus on my D800. The D800 has a good auto-focus system, but sometimes I just feel I want to be in control, so I often twist the little focus ring on the lens instead of using the expensive auto-focus system built into the camera.
  • I use manual ISO on my D800. People praise the auto-ISO feature, but I want to be in control, so I rarely use auto-ISO.
All those things do not mean that I paid money for things I do not use. I do use them. I know the camera is there for me when I want it, and that's why I bought it - to know that it has what I need when I need it.

And what about the Pet Portrait mode? If I use a camera with a Pet Portrait mode, do I take advantage of it? No. The scene modes of cheaper cameras frighten me. I do not know how they work, and I do not know how to take advantage of them. I much prefer to use the standard PSAM modes. If I buy a camera with a Pet Portrait mode, I pay for something I will not use.


It is all a matter of finding the right level.



Saturday, May 11, 2013

What is the focal length equivalent for an iPhone? Or my Android phone?

That can change from one phone model to the next. The safest bet to get info about your phone is to open one of its photos in a tool that can read exif data.

For example, the iPhone 5 has "Focal length" 4.1 mm and "Focal length (35mm)" 33.0mm. That means that it is roughly as wide as your favourite 33mm prime lens on your FX camera. Or as wide as your 22mm on your DX camera.

A Galaxy S4 has "Focal length" 4.2mm and "Focal length (35mm)" 31mm.

An iPhone 6S plus has a "Focal length" 4.2mm and "Focal length (35mm)" 29mm. The reason the 35mm equivalent is different from the Galaxy S4 is certainly that it the size of the sensor is different.

To read exif data you can use for example:

  • Adobe Photoshop
  • Adobe Bridge
  • Aperture
  • Preview (Mac OS X)
  • exiftool
  • ... and many others.
The only snag is that not all exif-readers display the equivalent value for 35mm, and not all cameras actually store the 35mm equivalent. If it does not work for you, don't be too disappointed. Just make sure you try with at least one of the tools listed above. If you still have no luck, just buy a new phone. There is probably a new model on the market anyhow.

Friday, May 10, 2013

How do I extract an embedded JPEG from a RAW file?

Short answer:


exiftool -b -JpgFromRaw IMG0001.NEF > test.jpg

Long answer:

Most RAW files contain not only the raw data that was captured when the picture was taken, but also a jpeg file which can be used to quickly show the image before the RAW has been completely interpreted.

Some programs that pretend to handle RAW files actually just extract the jpeg and displays that one to the user.

There is rarely any reason to extract the jpeg manually, but if you want to, you can use the command tool above using exiftool which is a tool available for Windows, Mac OS and Unix/Linux.

Just replace "IMG0001.NEF" with the name of your RAW file and "test.jpg" with the name of the jpeg you want to create.

Update: The name of the preview is not the same for all RAW files. That's why Jener in the comment section succeeds with PreviewImage but not with JpgFromRaw. In general, if you have problems with the command, try the exiftool documentation page