Why isn't saving photos as TIFF files a popular choice by DSLR manufacturers?

Question

Why do many DSLRs have the option to save in RAW or JPEG but not in TIFF? It would be useful to save it as a TIFF file using lossless compression. It would be a midway between RAW and JPEG. Is it because the size of TIFF files is huge?

Asked by Akram Mellice

Answer

Noting other answers, and having had a bridge camera that did TIFFs, I'd suggest that for DSLRs TIFF is pointless except as an add on if it can be managed.

TIFF is a lossless way of saving an image, once an image is generated, BUT the image that it saves is an interpretation of what the sensor records.

RAW gives you the maximum possible flexibility in dealing with the available data. Software to convert to TIFF or JPG is provided by the camera maker plus the various commercial RAW converters are a small fraction of a good DSLR price.

JPG gives you user usable images at a compression level that suits the user.

RAW + JPG gives you all the advantages of RAW plus some of the advantages of JPG (as it usually does not allow selection of JPG compression level and the JPG provided may be not be the highest quality JPG the camera provides in pure JPG mode.
eg in a Sony A700, straight JPG comes in Extra Fine, Fine, Standard.
But with RAW + JPG, the provided JPG is "fine" and not "Extra Fine".

TIFF loses data relative to RAW and is far larger than any sensible JPG and has no great quality improvement over the best JPG. Once it is "not RAW" then it is subject to manufacturers decisions.

Useful where available is Compressed-RAW and Compressed RAW + JPG.
Available eg on Sony A700 but not on the newer A77 where it would be useful due to largr file sizes.
Compressed-RAW provides a lossless compression of the RAW file at the expense of processing time and a somewhat non-stanard format.

Answered by Russell McMahon

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How do I make sure my RAW files are readable in the future?

Question

I've recently started to use RAW with Lightroom. I'd like opinions on how I should make sure my images are readable (not necessarily editable) a few years hence. Heck, let's say a decade some decades.

Should I keep my archives in Nikon's raw format, in conjunction with the LR database? Should I convert them to TIFF? How about DNG?

Answer

Having finished scanning 40 year old film I can assure you that you need to think longer term than 10 years, in fact at least 40 years.

To know whether there is an answer one must understand the problem. These things can happen:

1. proprietary software makers stop supporting old formats, very possible after 40 years.
2. proprietary operating systems stop supporting old photographic programs, also very possible after 40 years.
3. a copy of the 40 year old proprietary operating system will no longer run on current hardware, highly probable.

So, there is a real possibility that in 40 years time you will no longer be able to read your RAW images, using proprietary software. This is not to criticise proprietary software makers. Their shareholders require them to generate profits and growth which can be incompatible with maintaining decades old software.

Can anything be done?

1. store your images as DNG. Support is coalescing around this format, making it rather more likely to survive over the long term.
2. store a copy as a high res jpeg. This will be readable for a long time.
3. keep a copy of your operating system and programs in a virtual machine. For example, for other reasons, I keep a copy of Windows 98 in a virtual box, allowing me to run it under more recent operating systems, on more recent hardware.

But, because I am involved in the open source world, I am confident there will always be an open source solution. I say this because:

1. it is a requirement of the GPL licence to keep the source code available. This means you can always locate the relevant program and recompile it to run in the current environment (or somebody else will do it).
2. there is an army of open source programmers who delight in supporting even the quaintest and most esoteric things. An example of this is that, right now, Linux supports a wider variety of hardware devices than MS Windows.
3. open source programmers are very active in supporting the various RAW formats.

You may remember the Commodore 64. It was introduced in Jan 1982, 28 years ago, but was quickly obsoleted by the then new IBM PC. But even today you can run programs for that machine thanks to the Commodore 64 emulators developed and maintained by the open source world. This is evidence that we will be able to depend on open source solutions for a long time.

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Is TIFF really of higher quality than PNG-24?

Question

I've been doing some research to try to figure out why more people do not store high-resolution image files as PNG-24. PNG has exactly-reversible, lossless compression, it is a net-friendly format so any web browser can view it, and it supports full transparency.

I've seen several people say that TIFF has a "higher quality" than PNG, but no one provides any details on exactly how it is of higher quality. PNG-24 is lossless, so when you "Save As" a TIFF to a PNG, how exactly are you losing quality?

Answer

You explicitly mentioned PNG-24 - that has eight bits per channel, whereas a TIFF file can have 16. That would be one reason the quality could be higher, from a RAW conversion especially but also if you are doing a lot of editing.

The PNG standard also supports 16-bits per channel (PNG-48) but I don't know how many applications support that, whereas pretty much anything that can read TIFF is going to be able to read a 16-bit TIFF file.

TIFF can also store layers in it, which is not a quality issue so much as a flexibility thing. PNG is really meant to hold an image, not a layered set (although APNG can hold a set, it's really not for the same purpose).

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