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I have a Canon 200D am I'm looking for a way to shoot a sequence of 10 pictures with a high exposure time (8s), minimizing the delay between the end of one exposure and the beginning of the following. For me would also be ok to record a movie with a very low framerate (< 1fps), given that I can have a 360° shutter.

Attempt 1:

I've set the camera in continuous mode, but there is a pretty high time of no exposure (0.5s)

Attempt 2:

I've kept the camera in continuous mode, but I've enabled the mirror lockup function to avoid at least the time needed to lower and raise the mirror at every frame. With the lockup enabled, I cannot shoot in continuous mode.

Attempt 3:

In video/timelapse mode, I've set the interval to 8s, but I cannot set the exposure time to 8s.

Attempt 4:

I've connected the camera to an OrangePI and, using gphoto2, I did the following:

gphoto2 --set-config-value /main/capturesettings/shutterspeed=8 \
        --set-config /main/capturesettings/meteringmode=1 \
        --set-config /main/capturesettings/drivemode=1 \
        --set-config /main/settings/capturetarget=1

gphoto2 --capture-image --frames 10 --force-overwrite

But I get:

ERROR: Could not capture image.                                                
ERROR: Could not capture.

I've tried also many other parameter combinations but without luck.

Attempt 5:

I've installed the INDI server and Ekos on my computer and I've configured the latter to take 10 photos in sequence, but the delay is even worse, as Ekos wants to download the current frame before starting capturing the next.

MarcoM
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  • I remember something about high iso noise reduction that forced the camera to take a dark frame, which effectively doubled the time before a camera could take the next photo. Perhaps that is going on with your camera as well? – Saaru Lindestøkke Jul 17 '23 at 06:59
  • The camera is not designed to do that kind of continuous shooting, pretty simple. Be sure to have set the camera to manual focus and manual exposure to reduce the interval as much as you can, and to potentially enable shooting with mirror lock-up. Even without mirror lock-up, once you set the camera to fully manual, the delay between shots will be shorter. It CANNOT be zero, obviously. Not even video cameras achieve zero. – FarO Jul 17 '23 at 07:57
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    It might help us to answer your question if you explained the photographic problem you're trying to solve - we may then be able to help you come up with a solution you haven't thought of yet. – Philip Kendall Jul 17 '23 at 10:59
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    Currently, I would like to do a timelapse of an ISS passage during the evening. Using a too-long exposure will saturate the landscape and a shorter exposure will not make the satellite not visible enough. So I would like to take multiple photos using an exposure that is right for the landscape and combine them. This is just an example, but I would like to have more control over the camera in general. – MarcoM Jul 17 '23 at 11:11
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    @MarcoM That explains what you want to do, but doesn't explain (For example) why 0.5s dead time between images in continuous mode is an issue. Also have you looked into something like Magic Lantern to see if it can hep? – Peter M Jul 17 '23 at 12:21
  • I don't know if it's an issue for your camera, but I tried something similar years ago with one of my cameras. It (thankfully) couldn't do it because of overheat protection logic. – End Anti-Semitic Hate Jul 17 '23 at 12:22
  • @PhilipKendall I used a similar technique to record lightning... You want to minimize the chances that a lightning happens while the camera isn't taking a shot. – xenoid Jul 17 '23 at 12:33
  • Given what you've tried, I suspect the realistic answer here may well be "you can't do what you're trying to do with entry-level kit". – Philip Kendall Jul 17 '23 at 13:42
  • 0.5s of dead time could be an issue because it could make the ISS light trail intensity inhomogeneous or even non-continuous. – MarcoM Jul 17 '23 at 19:49

2 Answers2

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The Canon 200D has a very small buffer, but a 0.5s delay during continuous shooting doesn't sound like it's clearing the buffer... that's typically more like 2-3 seconds. I think just using continuous mode should work.

Canon's long exposure noise reduction is applied to exposures longer than 1 second. You may want to ensure that is turned off because it may be adding processing delay.

If you are recording jpegs, any jpeg size/quality setting other than what is used for the raw file's embedded jpeg will add processing time/delay... IDK what that is for the 200D, but only recording raw files might be the better choice.

Most Canons do not drop the mirror in-between images when recording in live view. You could also switch the drive mode to silent continuous shooting which will use electronic shutter (no shutter or mirror). But I really doubt either is contributing significantly to the delay.

Steven Kersting
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  • On my 70D, using Liveview or Raw-only doesn't change the "blind time" (350ms between shots). Which by the way makes we wonder how I get 7 shots/seconds in burst mode when using shorter exposure... – xenoid Jul 18 '23 at 00:02
  • JPEG are faster than RAW because they require less writing time and less memory in the buffer. RAW is NEVER faster than JPEG. That said, @xenoid I also wondered the same. – FarO Jul 18 '23 at 07:29
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    Yes, Raw makes you more dependent on SD card performance, but at 8 seconds per shot, with a decent card, you can write the Raw faster than you produce them (at 7fps it is obviously a different matter). And we don't know where/when JPEG encoding happens. – xenoid Jul 18 '23 at 07:36
  • @FarO, jpegs are faster to write, not faster to create. The image always starts from the raw file, whether recorded or not. If the raw file is recorded a basic jpeg is also processed and embedded. If you want it to record a jpeg with a high quality setting, then that jpeg will also have to be processed. – Steven Kersting Jul 18 '23 at 12:01
  • @xenoid, that really sounds like noise reduction or similar is being applied. Apparently, even the off setting for NR doesn't actually turn it off for jpegs with Canons... at least with your 70D. I wonder if it is being applied to the raw file embedded jpeg as well. Even a camera with a slow readout speed is around 1/60th (17ms). So silent (rolling) shutter should allow many more FPS... i.e. video recording.

    https://www.imaging-resource.com/PRODS/canon-70d/canon-70dHI_ISO_NR.HTM

     – Steven Kersting Jul 18 '23 at 12:16
  • @StevenKersting I had disabled the long exposure noise reduction for the test... – xenoid Jul 18 '23 at 12:50
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Set focus before beginning the burst and then turning focus to manual. The largest portion of the half-second delay is most likely from autofocus taking time to lock onto the subject. Setting exposure manually will also slightly reduce the delay between frames in burst mode.

For other possible factors that can affect frame rates and the time gap between frames, please see: Canon 5D Mk II shoots only at 2.1 FPS burst instead of 3.9 claimed, why?

Michael C
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