EOS 5D Mark IV & EOS R5 Long Exposure Processing Time

[BillSD]

Why do long-exposures take longer to process than short exposures (Canon 5D MKIV and Canon R5)?

With a 30 second exposure and cable shutter release, each image will require about 33 seconds before the next image is taken. A full 3-second gap occurs between shots. The same if the internal intervalometer is used. It has to be set to 33 or 34 seconds, otherwise there are 30 second or so gaps between shots.

[wq9nsc]

Do you have long exposure noise reduction, lens correction, etc. options set?  Using RAW format with these options applied in post instead of at time of capture might help.

Rodger

[BillSD]

No lens corrections or noise reduction set. FYI - in bulb mode and an external intervalometer set to 1 second, the 30-second shots are 1 second apart. This also occurred on my 5D MkII as well as the Mk IV and R5.

[Waddizzle]

A couple of the noise reduction settings capture a second exposure using the same shutter seed as the initial image.  For example, if you capture a 30 second exposure, then Long Exposure NR will capture a second 30 second exposure to use as a reference for image sensor noise.

If you are shooting as RAW, then I would recommend disabling all Noise Reduction options, as suggested above.  The settings have no effect on RAW files, only in-camera produced JPGs.

[BillSD]

No lens corrections or noise reduction set. FYI - in bulb mode and an external intervalometer set to 1 second, the 30-second shots are 1 second apart. This also occurred on my 5D Mk II as well as the Mk IV and R5.

[Waddizzle]

Where is the 30 second exposure being set?  Your Intervalometer should be setting the exposure and the interval time.  

Also, depending on your intervalometer, the interval may or may not include the exposure time.  The “interval” may reflect the time that needs to elapse between shutter presses, not the down time between shots.

[BillSD]

Occurs with both internal intervalometer and cable release. In bulb mode and an external intervalometer it works just fine. At fast shutter speeds nothing like this occurs. Noticed this 10 years or so ago during star trails. 

[Waddizzle]

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@BillSD wrote:

Occurs with both internal intervalometer and cable release.. 

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In this mode of operation, the exposure time is defined by the normal camera settings.  The internal intervalometer must be set to allow for exposure time plus the delay interval between shots.  If you dial in 30-second exposure time, then your internal interval timer must be set to something longer than 30 seconds.

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@BillSD wrote:

In bulb mode and an external intervalometer it works just fine. At fast shutter speeds nothing like this occurs. 

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In this mode of operation the 30 second exposure time is defined within the external intervalometer. The external intervalometer defines a separate interval to set the delay between shots.

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These two modes of operation are very different from one another.

[BillSD]

Agreed that in theory the exp must be less than the interv time. With exp = 30 secs, and interv at 31 seconds it misses shots (timer tells camera to take a pic but the camera is busy doing the wierd 3 second stuff and ignores the request). At 32 seconds it misses shots, and 33 seconds it will not miss any shots - but then there is 3 seconds between shots.

Interestingly, with exp = 30 secs, if the interv time is 1 second then the camera will try to take a pic every second, but if the camera is busy taking a shot, the request is ignored. Doing this with a 30 sec exp yields a continuous set of images, all having the extra 3 seconds. 

[Waddizzle]

Are you writing to the SD card?  How long does the card slot LED light up between shots?