7D med/small raw

I realize that it's a smaller file size for the med and small raw files with med beign apx 10mega pixels and small 4.5. But how and /or what, would be a good reason for using it besides if you are running out of space on your card for whatever reason. (forgot extras at home, zombie attacks?)

would it help out while shooting at higer Iso's with noise at all.??

Does it just drop every third pixel to make it a smaller size file?

I searched for some old threads on this and most of them were just debating the proper way to type raw and didn't give much info

A good reason would be to get more shots in continuous drive mode since it will take longer to fill the buffer with the smaller file size. I can't really comment on the other questions, but I guess I'll have to check and see if I get less noise with the smaller file size, never thought to check.

I mainly use mRAW if Im trying to fit more into a card. thats about it. never really paid attention to noise or whatnot.

I have a 60D, which has the same sensor and MRaw, SRaw as the 7D. MRaw uses an interpolation technique like bicubic in Photoshop to reduce the number of pixels to 3/4 in each direction, and this results in the reduction to 10Mpixels in file size. SRaw reduces by 1/2 in each direction. So the answer is NO, MRaw does not just drop every fourth pixel, as that would result in ugly streaks running through the image. Instead, it interpolates.

In answer to your other question, I've done tests, and MRaw does reduce noise noticeably at both ISO 6400 and 12800, so I now use MRaw if I have to shoot at those very high ISOs. You get less noise due to the implicit averaging from the interpolation plus a smaller file size. To my taste SRaw is too small, and I would only suggest using it if you want very small Raw file sizes.

Wow thanks Hugh good info.

many thanks
G

Gaarryy wrote in post #13127799
would it help out while shooting at higer Iso's with noise at all?

Not in the slightest. If Canon were using actual hardware binning, it might be different. But they're not. All sRAW does is a normal raw conversion in-camera, but instead of saving that as a JPEG, it downsizes (like resizing in Photoshop) and saves it as a 15-bit file with chroma subsampling (one of the lossy types of compression used in JPEG).

At best, you will only get *equal* results by doing the same thing with your raw converter. But many raw converters can do slightly better (or a lot better, depending on your point of view) than the in-camera version.

I wrote more about in the following thread:

Canon sRAW considered harmful

(It also covers the many superior alternatives to sRAW that Canon chose not to implement.)

HughR wrote in post #13128370
You get less noise due to the implicit averaging from the interpolation plus a smaller file size.

Can't you just do the same thing using software in the computer rather than software in the camera? Or do you feel that Canon's in-camera demosaic and downsampling software are superior to anything we have available?

Daniel Browning wrote in post #13128812
Can't you just do the same thing using software in the computer rather than software in the camera? Or do you feel that Canon's in-camera demosaic and downsampling software are superior to anything we have available?

I have run both methods, and as you aptly identified, there is nothing special with the in-camera resizing, the only reason I do it is because when I shoot band competitions, it is faster to deal with smaller pictures and post them out on smugmug than to take the large files and mess with them. If a parent wants something more permanent than the X2 sizes I give them access to, I go back to the raw and rework it.

I am very positive that if anybody shoots large raw and sends me that file, then they shoot mraw or sraw with the same subject material and exposure and take those results, my end result from the large raw processed down to their image from the smaller raw file will look better. (I have tried it out several times in fact )

I found that, with my 7d, the difference between mRAW and RAW at iso6400 & iso12,800 were negligible when both were prepped for a 20x30 print @ 360ppi. As often as not, the mRAW file looked better than the RAW file. I chose those numbers because a) my printer likes 360ppi and b) 20x30 is the largest popular size I am asked to print for the college at which I work. So, in my mind, there was no reason to shoot RAW at those higher iso's when mRAW would do just as well. Also, to me, that meant that the 7d was no better than a 10.1MP aps-c body at those higher iso's. So that was the tipping point (along with the realization that the 1DmkIII was selling used for around $1800) for me. I sold my 7d and bought a clean, used mkIII (coincidentally, the mkIII has the exact same file size as the 7d's mRAW). I do miss the ability to crop the larger files at lower iso's, but I don't miss the 7d's noise at iso6400-iso12,800. Roughly half of my sports shooting is indoors, so the mkIII was a good overall move for me, I feel. YMMV

~Ian

Gaarryy wrote in post #13127799
But how and /or what, would be a good reason for using it

Useful for when you're making time-lapse movies. The frames that make up the final movie will only be 1920x1080 pixels, so using the full raw size isn't required. And you want to shoot in raw for the extra processing. So one may as well use S-raw and be able to store more images, use up less HD space, process faster etc.