Best combination for highest shooting rate

Steve in Oz

Senior Member
I photograph airliners on approach and landing at our city's airport: everything from Dash-8 to A380.

I'm trying to get the best combination of setting to enable the best 'fps' shooting rate, without compromising image quality too much.

I understand shooting 'JPG-only' would enable the best 'fps' rate, but I'd like stick with RAW as I do a fair bit of tweaking in post.

I'd also like to stick with 6000x4000 resolution.

Would going from 14-bit RAW to 12-bit RAW only (i.e., not recording any JPG at all) give a noticeable difference in shooting speed or buffering?
 
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pforsell

Senior Member
Frame rate is 6 fps using 12 bit raw and 5 fps using 14 bit raw.

Buffer size is 18 to 35 images depending on bit depth and compression. It is 18 images using 14 bit and lossless compression and 35 images using 12 bits and lossy (image degrading) compression. The other two combinations fall in between these two extremes. Your camera does not offer uncompressed raw.

I believe there is also a possibility to shoot 7 fps using 1.3x crop mode that offers about 15 megapixel images.

I'd turn to the appendix pages of your user manual that has all these combinations spelled out.

Best image quality your camera can offer is 14 bit raw using lossless (reversible) compression, but that also means largest files that take more space to store and more time to process.
 
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Steve in Oz

Senior Member
I'm using the full image quality (14-bit lossless + JPG fine) at the moment and it's great.

With the airliners, depending on my vantage point, I've got about ten seconds with each aircraft to get as many shots as I can, so I'm looking for the best way to get as many shots as I can in that ten seconds.

DSC_2057.jpg
 

pforsell

Senior Member
I'm using the full image quality (14-bit lossless + JPG fine) at the moment and it's great.

Check your user manual if dropping the JPEG saves any buffer space.

Going from lossless 14 bit to lossless 12 bit increases the frame rate from 5 fps to 6 fps and increases the buffer from 18 to 27 images. Hence, 12 bit lossless gives 27 images at 6 frames per second allowing a 4.5 sec burst.

These are the best case scenario numbers. Things like noise reduction, vignette correction, image copyright etc. all eat into the buffer depth. Please refer to the manual for details.

I recommend you make a few tests to see if the 12 bit mode is much worse than the 14 bit mode. Mostly you'd expect to see the differences in the deep shadows. In many cameras the 14 bit mode is just a vanity mode doing nothing useful, but forced to be included in the camera specs by marketing department. Make a test, it's possible the 14 bit mode is just a waste of space. Slicing a bread into 14 slices instead of 12 gives no more bread, if nothing else changes.

(Of course there are exceptions, the D3X shoots vastly cleaner shadows in 14 bit mode, but I don't know whether that is the goodness of the 14 bit read chain or the badness of the 12 bit read chain. With D4S and D5 I can see a difference but not as large, and in D3S there's no difference.)
 
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Steve in Oz

Senior Member
Yes the bread analogy is a good one, and I do wonder if 14-bit is a 'vanity' mode.

I guess what I'm trying to do is maximise the fps by increasing the 'throughput' of the buffer by having it process smaller files. Do JPGs go through the buffer as well?
 

pforsell

Senior Member
Yes the bread analogy is a good one, and I do wonder if 14-bit is a 'vanity' mode.

I guess what I'm trying to do is maximise the fps by increasing the 'throughput' of the buffer by having it process smaller files. Do JPGs go through the buffer as well?

Yes. The buffer is the working memory. Most cameras capture the full raw data first into buffer, 12 or 14 bit. After that the processor makes a JPEG preview of the raw data into the buffer, and also the additional JPEG file. Then the raw data + the JPEG preview are written into a raw file onto the card as well as the JPEG file (if any).

Some operations require that two copies of the same raw data is temporarily held in the buffer, before the raw file is written to the card and the buffer space can be cleared. This is the reason why noise reduction, lens corrections, vignette corrections and some other operations reduce buffer space.
 

Steve in Oz

Senior Member
I just tried some manual shots at 1/1000 with 12-bit RAW only, distortion, vignetting, NR and HDR all turned off and it's noticeably faster.
 
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