I'm using Nikon D300. I've just switched image format from RAW to JPEG today. The sound of shutter seems different (faster than in RAW format) although they're as same shutter speed (I know that because I use Manual mode). In RAW format, I hear 2 separated sounds (I don't know what it's called), while in Jpeg, they're not clear and almost same as 1 sound only.

I wonder why they're different. Is RAW format needs to store more information, then it needs to open longer?

  • \$\begingroup\$ If the shutter opened more or less time depending on the files you are saving the images to there would be no point in controlling the shutter speed. Whithout a more accurate description or a video/audio recording there is little we can say about this. Maybe you have some feature turned on? \$\endgroup\$
    – user24295
    Dec 2, 2013 at 7:04
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    \$\begingroup\$ On my camera (Sony A77) I can select either mechanical 1st and 2nd shutter blind or the 1st can be performed electronically (sensor is turned on in a "wave" electronically). In the first case I hear a distinct "double tap" whereas in the latter I hear only the single mechanical shutter plus some related internal noises. The two are quite audibly distinct and sound very like what you are describing. IF your camera has this facility then you may be selecting electronic front curtain shutter in JPEG in some manner and not in RAW. \$\endgroup\$ Dec 2, 2013 at 8:25
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    \$\begingroup\$ I noticed this on my old D300 too, RAW takes longer than jpg, i can only assume its added processing time or some sort of anti-noise process. \$\endgroup\$ Dec 2, 2013 at 10:20
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    \$\begingroup\$ While I don't know why it might be, you are probably hearing a difference in the shutter lockup time rather than the shutter speed. When you take a photo, the mirror goes up, then the shutter actuates and then the mirror goes back down. It is possible it did the shutter snap and then opened back up to do some other processing before the mirror goes back down. \$\endgroup\$
    – AJ Henderson
    Dec 2, 2013 at 14:24
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    \$\begingroup\$ @TuTran - 14 bit is better than 12bit, try swapping to 12 bit and see if it still takes longer. According to this review: imaging-resource.com/PRODS/D300S/D300SA6.HTM it has a dramatic effect on processing time... \$\endgroup\$ Dec 2, 2013 at 16:10

1 Answer 1


This is an effect of being in 14 bit RAW mode - It takes longer to process the data from the sensor, which leads to a slight mechanical delay in the mirror / shutter mechanism (exact reason unknown)

Switch to 12 bit and it will take the same time to process as a JPG

Although in the spirit of pure quality 14 bit would be preferred if speed is not an issue.

  • \$\begingroup\$ Thank you. Speed is not a problem to me because I rarely use continuous shots. I just wonder why it is, and afraid that there is some bug on my camera. If you have more information why the mirror is delayed, please share it to me, too. \$\endgroup\$
    – Tu Tran
    Dec 3, 2013 at 9:23
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    \$\begingroup\$ Its discussed in GREAT LENGTH here :-) (with no definitive answer!) dpreview.com/forums/thread/2199848 \$\endgroup\$ Dec 3, 2013 at 9:45
  • \$\begingroup\$ Its certainly not a bug, they all do it! more a "quirk" \$\endgroup\$ Dec 3, 2013 at 10:03

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