Are there any issues I might experience if I leave the mirror up on my DSLR camera for a long time? My use mode would be "live view" mode connected to AC power, and using the HDMI output of the camera to a capture card to record raw 1080p frames to a computer. In this mode the mirror seems enter the "locked up" state for as long as I record and also the on-camera display turns off and then the mirror doesn't drop until shortly after I stop recording. So far I have only recorded for a few minutes at a time for testing purposes but I want to set up a possibly months long project where I record a time lapse in this mode. Assuming the camera is sufficiently protected from heat, moisture, etc. would there be any issues including potential damage to the camera with leaving the mirror locked up for this long? I know that my camera requires power to hold the lock up, so this may be a question of if the electromagnet or solenoid or whatever is rated for continuous use, but I have no idea if such a thing is known outside of the engineering team that designed a particular camera.

I had the thought of simply taking still images, but this is sub-optimal for several reasons: first, it's only possible to take a maximum of 999 pictures in a set using the built-in intervalometer, and I would be capturing something like 30,000 frames per day. It would also require extra workflows to frequently swap out memory cards, shuffle files around, and turn images into video, not to mention re-compression. This all needs to run mostly unattended.

Ideally I would like to use an old DSLR I'm not using for anything else for this project. However, I'm interested in this question for DSLRs in general, in case for instance older DSLRs are more (or less!) prone to some failure mode from leaving the mirror locked up for too long.

If it makes any difference, I'm not planning on shooting in a direction that has light from the sun directly (e.g. not by reflection) entering the lens at any part of the day.

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    Why don't you use a webcam for this? Or a dashcam (my dashcam has a function to take still pictures at 2 second intervals)?
    – xenoid
    Jun 23 at 10:08
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    I would be more concerned with the sensor overheating if you keep it active that long. Most cameras have a limit to how long they will allow live view to stay active for this reason. Jun 23 at 12:47
  • @xenoid I thought about this actually... I'm trying to repurpose old equipment to save some money and to get the same results new could be quite expensive, for instance to achieve similar quality with telephoto shots.
    – Michael
    Jun 23 at 16:11

3 Answers 3


It might depend on the specific DSLR.

  • Those that use springs for mirror return would be subject to eventual fatigue of the springs. The last time I checked (it's been a while), most of Nikons D3xxx and D5xxx series were still using springs in the mirror box as well as in the aperture control linkage. Even their top tier DSLRs still have springs for aperture control with lenses without electronic diaphragm control (almost all F-mount lens models introduced before around 2014 except for a very few higher end ones).
  • Those that use electric servo motors to move the mirror back down as well as up would not be subject to spring fatigue. Most of my upper tier Canon camera have no springs in the mirror and shutter assemblies, it's all done by servos. For those cameras, when the mirror is "locked up" there's a physical lever that holds the mirror in place so no continuous current need pass through the servo that actuates the mirrors.

There may be other design differences from one model to another that would also make a difference.

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    Possibly better anyway than the wear of actuating the mirror 30K times a day?
    – xenoid
    Jun 23 at 10:27
  • @xenoid That's the entire point of doing video frame capture instead. We're not arguing stills vs. video, The OP has already more or less decided that. I'm saying some (primarily) still camera models will be less subject to excessive wear doing video frame captures over very extended periods of time than others will.
    – Michael C
    Jun 24 at 15:43

Few points for further reconsideration:

  1. For semi-professional cameras of Canon (DSLR) usually the resource of shutter actuation is about 150k which mean you will reach it in 5 days. This do not mean the shutter will stop working, but maybe camera with electronic shutter will be better decision.
  2. Average size of files will be around 2MP*3/2 (from compressing) 3MB*30000=90GB. And SD cards have limited cycles of write so maybe will be better to use kind of tethering and store files directly on computer. Also tethering may help you with the limitation of timelapse software.
  3. Also managing 30k files (in one directory) on any filesystem can challenge. So you should develop kind of directory structure. Which lead to additional challenge when import the files in video software to convert them.
  4. Choosing the (computer) platform can be also challenge because for one month you will have around 1 million of files. So converting to video (on time) and remove old files is strictly necessary.
  • Yes, #2 is exactly one reason why I don't want to write to the SD card (along with all the hassle of moving files around). I've not heard that low of a number for #1 (I've heard something closer to 10x that)
    – Michael
    Jun 23 at 17:45
  • @Michael, I can't find now official source. But you can check here some statistic: shuttercheck.app/data/canon/eos-5d-mark-iii Jun 23 at 17:58
  • @Michael, you can check also this answer: photo.stackexchange.com/a/90510/34947 Here you can find another database (with old models): olegkikin.com/shutterlife One more source for the count: the-digital-picture.com/reviews/… Jun 23 at 18:08
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    neat site! was a long time ago I recall the 1M figure... may have misremembered, may have been for a higher end camera, or might just be a "you'll get this many shots if you're lucky" type thing.
    – Michael
    Jun 23 at 18:09

Basically, if the camera lets you do it without some kind of mechanical hack then you will not be causing disproportionate damage to the camera.

IMO, there is a very high likelihood that the camera will overheat and shut down in this scenario. But the thermal protection/shutdown is there to prevent any actual damage.

Having the mirror locked up is a lot less wear/strain on everything than 30k cycles...

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