CRAW burst on Canon R7, test, tries, results, photos, comments...

I've moved this thread from Tea Rooms to this forum, as it makes more sense.

The number of times I've used RAW burst can be counted on the fingers of one hand. I always forget it's there, and it takes time to set up on R7. RAW burst also generates massive files.

A combination of Mike B and Billysdad piqued my interest by mentioning CRAW files - Compressed RAW files. Mike B pointed them out, and Billysdad pointed out they are available on a Canon R7.

I decided to give CRAW and CRAW burst a go. Anything to reduce file sizes and decrease the time taken to write to a SD file.

Caveats, as always. I shot the following sequence through manky double glazed windows (why does it always rain shortly after I clean them?), with the subject under a large oak tree, with the added bonus of overcast conditions.

Findings.

Best used on bright sunny days or bright light, probably best in Tv mode, rather than my favoured Program mode.

DPP4 is pants when it comes to extracting images from RAW and CRAW burst files. Firstly, it produces image 1620x1080 pixels in size rather than 6960x4640 pixels of the original RAW image. There might be a setting I've missed to stop this, but I haven't invested the time to RTFM - I'm allergic to reading manuals. DPP4 doesn't appear to page or swap. All images are held in memory, resulting in 'out of memory' error message. It also screws up Windows 11, as I don't think it releases memory correctly when I close it down. Plus it's slow, and the extraction tool has a rubbish UI.

I found it far easier and quicker to extract images in camera. This process also leaves the image at its original size.

The resulting CRAW burst file seemed much smaller than the RAW burst file, about 50-60% smaller. Writing to SD card was definitely faster - as it's a smaller file. I think the individual CRAW files were smaller. Difficult 

Anyway, enough faff, on with the results. These are uncropped images. You'll also see No Mow May in full bloom.

That's it. Over and done with so quickly. Nine frames out of 48 images saved in burst mode.

One tiny issue with this sort of shot. The bird moves so fast, I can't track it. This means the focus point remains pretty much on where the bird started off. One reason the grass, buttercups and daisies are so crisp and clear. OK, another reason for the slightly blurred Jay is that it is moving fast, and I was using Program mode in less than ideal light. Tv mode with bright sun might have resulted in better sharpness.

Personally, I can't see much signs of rolling shutter. I also photographed a Magpie taking off and flying. Although there wasn't apparent signs of rolling shutter, the test was inconclusive as the bird was a fair distance away. However, Jays and Magpies are not noted for their fast wing beats. You would, though, expect fast movement when taking off, therefore more chance of rolling shutter. The last time I tried RAW burst (a year ago) I did get very bad rolling shutter with a Blue Tit.

Mike B did hint that he had read that rolling shutter had largely been removed by firmware upgrades. I hoped it would, but was unsure. Especially as certain learned gentlemen on the internet said it was impossible due to it being caused by hardware. Well, I shall have to try RAW burst on subjects like Tits or small ducks, whose wing beats are much faster.

90% luck, 5% field craft, 5% camera skills.

  • I believe you might be on the right track. The truth is even weirder. I never thought of this because I didn't think Canon's software engineers would be stupid enough to design a system like they have.

    I checked Canon's blurb. The alleged frame rate for High speed continuous + shooting and burst mode is the same, 30 fps. I'm a bit dubious about this, as I keep ending up with burst files containing between 32 and 37 images.

    I tried remote shooting with my R7 set at High speed continuous +, the same frame rate as burst.

    All worked as expected. Hover mouse pointer over EOS Utility's 'shutter button' and the R7 starts AF. Click on EOS Utility's shutter button and the R7 buzzes away taking photos.

    The R7 only allows me to take 2 seconds worth of photos. I don't know if this can be overridden, but suspect not as I guess the images are stored on some memory before being copied to a storage devise - normally a SD card.

    I'm happy with this, but what perplexes me is that the EOS utility will transfer the images to my Laptop. I don't want it written to my laptop. USB is slow. I want it written to a SD card.

    There is no option to override this behaviour.

    So, my reasoning is this...

    1) The frame rate of High speed continuous + is the same as burst mode.

    2) As I shoot with High speed continuous + I can see the same image through the R7's viewfinder as I do on the EOS utility remote shooting Liveview display. So far so good.

    3) The R7 buffers images taken with High speed continuous + in memory. I can't see any other sensible way of doing this.

    4) When shooting stops - either the photographer takes their finger off shutter release or the 2 second limit is reached (i.e. buffer full) - the contents of memory are written to a storage device, normally SD card.

    5) The R7 is locked up for the duration it takes to write images from memory to a storage devise - SD card on camera, disk file on laptop via USB.

    I would say that the circular buffer used to store RAW burst images is the same to store High Speed continuous + images i.e. on chip memory. Shooting rates are the same, 30 fps. Therefore, there is no reason why RAW burst mode should not be available for remote shooting via a USB connection.

    There may be other reasons, but I can't fathom them, except for one. The Canon software engineers haven't got around to updating the R7's firmware to allow remote shooting with RAW burst mode. Such functionality is probably low on their do to list.

    One big learning I have from this. I now know why RAW burst is so useful. High speed continuous photography is limited by the size of the temporary buffer (on chip memory) used to hold image temporarily.

    90% luck, 5% field craft, 5% camera skills.

  • Thanks for your research Angus. I have been following along with interest ... Thumbsup

  • A tale of 'should haves'...

    I should have

    Put my tripod up

    Removed my 1.4x extender

    Switched to Shutter priority

    Moved some plants closer to the table.

    Instead, I handheld my camera, left my extender on, left my R7 in Program mode, did not have plants closer to the table.

    I always leave meat trimmings, bones, etc on a 45cm plant dish placed on a table in the middle of our garden. Various birds, particularly Red Kites, know about this dish and will gather to take advantage of this free meal. On this occasion - chicken bones and skin, plus fat from a pork roast.

    Three of our local Red Kites turned up for a free for all. I saw them swooping down several times, but was in no position to photograph them. Until early evening when a couple turned up for a late feast of the pickings. I quickly grabbed my camera, opened our utility room door, placed myself as far back in the room as I could (the Red Kites are very wary), and pointed camera at table.

    The results are less than stellar as all the camera settings were wrong. Some heavy handed post processing was required.

    At this point, the glare from the Red Kite's wings totally, and I mean totally, washed out the photograph. Had to take a big cudgel to the image in FastStone. All remaining images had quite aggressive post processing.

    There was less glare from now on, requiring a lighter touch on the post processing.

    Next time ... Put up tripod. Remove extender. Set camera to shutter priority. Move plants nearer to table so camera focuses closer to the action.

    90% luck, 5% field craft, 5% camera skills.

  • You need to expose the picture manually or apply quite a bit of negative exposure compensation. . Your sensor is trying very hard to lighten the background, hence when the bird appears in the sunlit area its completely washed out. Personally I would go manual and put something light on the table to help you take some test shots to get the right exposure - other wise try the negative exposure compensation until the table an bowl are properly exposed. Good luck. Of course it is entirely possible that you won't have this problem again as that may well have been your quota of sunshine for the summer Slight smile

  • Another interesting finding as I experimented with Burst Mode. The Canon R7 does not retain the precious half second of photos taken before you press shutter release all the way in.

    What the R7 appears to do is to fill its circular buffer with as many photos as it can. It does not attempt to insert exactly half a seconds worth of photos.

    This makes a lot of sense. Why incur the extra cost of calculating an exact half seconds worth of photos? Just slam them in as fast as possible.

    All image file sizes are different by some considerable degree. The size of an image files depends on all sorts of factors e.g. how cluttered the background is, whether there are lots of differing tones and colours, light conditions etc. As an example, a photograph of a plain, white wall will require a smaller file size than a landscape photo with complex mixture of sky, cloud, water, colourful foliage and subjects.

    This is why I sometimes get as few as 25 photos in a burst. While other times I can get as many as 37 photos.

    I suspect the half second figure is a worse case scenario, where all stored image files are the largest that the R7 can produce. With smaller files sizes, the circular buffer may hold over a seconds worth of photos.

    90% luck, 5% field craft, 5% camera skills.