AboutLarry Maupin Expertise I am a published professional photographer specializing in landscape, garden and horticultural photography. My skills range from intimate floral macrophotography to grand landscapes. I have a complete "digital darkroom" for creating, enhancing and manipulating digital photos, and I would enjoy sharing what I know with anyone who wants to learn.
Experience
Past/Present clients I have several local and regional commercial clients, numerous portrait clients, newsletters, and several regional and national magazines among my clients.
Expert: Larry Maupin Date: 12/19/2007 Subject: RAW and Tiff
Question Hi Larry, was wondering about this, I'm a newbie. I'm beginning to shoot RAW in
my Canon 5D and my Mac tells me the RAW files are aprox. 12-15 MB. Why does
conversion to Tiff after editing on IPhoto 6 shoot the file up to 80-90 MB?? Is
this for real? Thanks VERY much!! Darrel
Answer Hello, Darrel -
I’m on a Mac too and have a Canon 5D, so I’m intimately familiar with your situation. A RAW file, as you probably know, is the unprocessed file created when you take a picture in RAW mode. Then you process it yourself – as if you were your own photo lab. RAW is compressed; files saved as TIFF are not compress at all, and files saved as JPEG are compressed a variable amount. JPEG is a “lossy” format – it throws away data as it compresses – the other formats do not (non-lossy).
My 5D (and yours) has a 12.5 MB sensor and makes a 10.7MB RAW file – not sure where you are seeing 12-15MB? I use Photoshop CS2, not iPhoto for processing, but the results should be about the same. A Canon 5D’s file in RGB mode has three channels – red, green, and blue – each 12.5 MB in size for a total of 32.5 MB. When you open a RAW file and save it as TIFF RGB, you get a 32.5 MB file (12.5 times 3).
Here again, not sure where you’re seeing 50-80 MB, unless you are looking at a layered file. Perhaps iPhoto is creating (or you are creating) additional layers in your photos? It is possible to save layered TIFF or Photoshop format (.psd) files, which can be huge. As 32 MB file w/ 2 layers becomes a 64MB file and 3 layers becomes 96MB, and so on.
So, to summarize this answer, yes, your numbers can be real but I think they are inflated somehow. Shooting RAW and saving as TIFF is your best route for quality and security.
FYI – several color printing experts I know (I work for the largest printing company in north Texas) including my pro color lab, tell me that they see no difference in print quality between TIFFs and high quality JPEGs. I can’t tell the difference either, though everyone says “don’t use JPEG.” For sure don’t repeatedly open and save the same file as JPEG – it will deteriorate.
I hope this answers your question sufficiently. If not just ask again.
BTW - I highly recommend Photoshop Elements - available for $89 to $99 many places. Has all the power of full blown PS but easier to learn.
