# Leaving the camera ON, when changing lenses....Bad? Good? No Problem?



## cayenne (Oct 30, 2013)

Hi Guys,

Often in the heat of 'battle'...I've left the camera on while changing lenses....and this weekend, I'm shooting voodoo fest (http://www.worshipthemusic.com/) And I'll be at times in the pit or maybe onstage wanting to change lenses quickly.

I've been reading on some sites that promote changing without turning camera on/off to save time (also, in having your lenses in the bag with caps on both ends OFF)....

Anyway, from what I've read here and there, it shouldn't hurt to change your lenses with the camera on. I've even done this a few times with the camera in video mode...

I've not found anything yet official from Canon about this....for my 5D3.

What are your thoughts about this?

Bad? Good? No problem at all?

Thanks in advance,

cayenne


----------



## mackguyver (Oct 30, 2013)

It's not an issue, but turning it on and off during changes reduces dust. If you're using IS, make sure it stops before changing lenses and if you're using extenders, make sure you attach them to the lens first.


----------



## glongstaff (Oct 30, 2013)

I certainly would not put my lenses in the bag with the caps off....

1. However clean you think your bag is, there are always particles of one nature or another that will get on the lenses
2. Could lead to scratched lenses


I have changed lenses with the power on and had no ill effect, but sometime ago (can't remember where...maybe a camera manual) it promoted the turning off the camera (protecting the mirror / sensors etc) before changing the lens


----------



## kennephoto (Oct 30, 2013)

I change lenses all the time with the power on and never had an issue. I've heard that it makes dust more attracted to the lens and image sensor but I can't figure how that could happen and personally I haven't seen any dust on my sensor yet. Also the front elements are the only thing that gets dust, the rear element rarely gets dust. Maybe I'm lucky.


----------



## sunnyVan (Oct 30, 2013)

Yes keep the camera on while changing lenses. 

No caps are are necessary if your lenses are individually stored in a lens case or a compartment of your bag. I shoot with prime 90% of the time and I keep switching lenses. If I keep the caps on and the camera on it's gonna slow me down too much. 

There's no need to be overprotective of the lenses. Use them as much as possible to get your money's worth.


----------



## ajfotofilmagem (Oct 31, 2013)

Can be a problem if LIVE VIEW is enabled.


----------



## verysimplejason (Oct 31, 2013)

It would be better to change lens while turned off. At least the sensor cleaning will be triggered again after turning on. This minimizes dust accumulation if there's any while changing lens.


----------



## fugu82 (Oct 31, 2013)

It is generally advised to power down when you are changing lenses, because the sensor maintains a charge while on and can attract more dust. And, sure, you should cap the back of the lens before you chunk it in your bag. 

But, you know, I have a drawer full of lens + sensor cleaning goodies. So long as I avoid physical damage to the glass, I can clean it all up later, and not miss any shots. 8)


----------



## privatebydesign (Oct 31, 2013)

I have never turned any camera off to change lenses. The idea that you get more dust by not turning off is interesting, what about the shutter being in the way? There is no way I want to wait for a cleaning cycle to run before being able to use my camera every time I change a lens.

As for lens caps, if I am in a hurry I am happy to put them in pockets in my camera bag without caps, especially if I am going to be using them again shortly, again no bad happenings so far.


----------



## docholliday (Oct 31, 2013)

I've never turned off the camera to change lenses. Hell, never turned it off for anything (except for the tethered lock ups that occasionally happen when tethered to LR). Never had any problems with dust. And, I've changed lenses indoors, outdoors, in the rain, in the snow. I don't use caps, except on the rear element - I throw the front caps into a drawer and they're only seen again when trading lenses. I keep a Heliopan UV on the front of all lenses.

Dust on the sensor from a static charge? Never seen it, there is a shutter and mirror in the way. Of course, I wouldn't try it in a dustbowl, and I only take 3 seconds to change lenses at most. The way the contacts are laid out prevents any shorting or power application until grounding is completed anyways, so that won't hurt anything. 

Now, with that said, if you have an IS lens that you're taking off, I still don't power down, but I do let the IS unit go to sleep and lock in before removing the lens. If not, you get the loose element rattle from the IS unit.


----------



## sjschall (Oct 31, 2013)

I've never had an issue. My cameras are always on during lens changes, in stills or video mode. As far as caps, all come off as soon as I get to an event. I put them back on at the end.


----------



## Zv (Oct 31, 2013)

I always try and take my time during a lens change incase I muck it up and drop something. I use a table if possible or do the change in my bag to shield it from wind. I'm a super paranoid type and clumsy so I always keep all caps on when the lens is not in use. I think leaving the front cap off isn't a big deal if your camera bag or lens case has a smooth lining. You wouldn't want the front element smacking a zip or something. The rear element is more sensitive and if you scratch it your gubbed so for me rear caps are a must. 

I'm also extra careful because I tend to sell my lenses when I upgrade and scratches = lost $$$ on amazon. 

I change lenses with power off. It just seems more natural to me but I wonder if I am being too cautious and wasting time? Then again I mostly shoot with zoom lenses and I only occasionally change lenses when out and about. I like to chose one lens and stick with it throughout the day.


----------



## sunnyVan (Oct 31, 2013)

Getting dust on the sensor is really not such a big deal. Easy enough to clean.


----------



## iam2nd (Oct 31, 2013)

As a former hardware and firmware developer, I approach this from a technical perspective. Not turning off the camera implies that the camera firmware can dynamically detect when a lens has been removed and/or attached. In computer world, that is considered a hot-plug event. And for hot-plugs to work, it must be supported by both hardware and software.

Is it officially supported? I checked one of my camera's manuals (1D Mark IV) under the section "Attaching and Detaching a Lens", and none of the steps say to turn the camera off. Typically, when a particular operation is not supported or is important, manufacturers make a point of indicating that. I can't find where Canon says either way. So you are forced to assume.

I have chosen to operate on the safe-side and assume that the camera should be turned off, and I do so 99% of the time. Of course, I have (as you say, in the heat of the moment) forgotten and I couldn't find that it caused any direct issue. But just because the past 9 times nothing bad happened, it doesn't mean the 10th time 
is guaranteed success. If it's working for everyone else (meaning the newly attached lens is properly identified and both lens and camera function correctly), that means that either a) a lens attach/detach event generates an interrupt to the camera's CPU which tells it to automatically query the new lens for identification, or b) the camera is constantly polling (ex: ever 500ms) for an attached lens. My guess is a) , at least on modern Canons.


----------



## docholliday (Oct 31, 2013)

Of course, Canon bodies are never really off...they're soft-off. Pretty much the power switch is nothing more than a keylock. Hence, the reason that a body left in on, but sleeping and the "switched-off" body drains the batteries at the same rate.


----------

