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How to heat the EVF?

J

Jonas Rejman

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I am looking for elegant way on how to heat the EVF, as we observed, that below 5 degree celsius, it starts to show false colors.

I already read, that some wrap it in neoprene, so that it heats itself, some create some sort of micro-climate around the camera by wrapping the whole camera into a rescue-blanket.

I found some USB cup-warmers, but those are out of stock, some USB eye-heaters or USB gloves... but this are all gadgets that do not seem to be able to survive a shoot.

I would like to use a heat tape, that takes power from the D-tap of the battery plate. Before we create one ourself, I wanted to ask, if there is an already-made solution for that?

Thank you.
 
They make boxes with like a dozen of those air-activated hand warmers.
 
What about a heating pad. They make those small pads for warming hands. Or, potentially I think there a mittens that are electrically heated. If you just cut a hole in the other end you would have a perfect EVF wrap.
 
I read somewhere here before that there were wrist warmers that plugged in the USB port that worked for someone. It was a chinese company, I'll try and find it to post here.
 
Thanks for the link. Unfortunatelly, this is out of stock, as is this:
http://usb.brando.com.hk/prod_detai...35&PHPSESSID=80322e71fa8ea43c266aebcec0b32358
http://usb.brando.com.hk/prod_detail.php?prod_id=00046&dept_id=015&cat_id=035
http://usb.brando.com.hk/prod_detail.php?prod_id=00391&dept_id=015&cat_id=035


One might want to pimp those:
http://usb.brando.com.hk/prod_detail.php?prod_id=00009&dept_id=015&cat_id=035
http://usb.brando.com.hk/prod_detail.php?prod_id=00037&dept_id=015&cat_id=035


This surely won't work:
http://usb.brando.com.hk/prod_detail.php?prod_id=00224&dept_id=015&cat_id=035
http://usb.brando.com.hk/prod_detail.php?prod_id=00217&dept_id=015&cat_id=035

This will keep your clients away from the camera :shiftyph34r: :
http://usb.brando.com.hk/prod_detail.php?prod_id=00401&dept_id=015&cat_id=035

...

Honestly, those USB gadgets does not seem to cut it for me. Not rigid enough.

Actually dew removing products for telescopes might be the right direction:
http://www.kendrickastro.com/astro/dewremover.html

self-made solutions:
http://home.worldonline.dk/jsrsw/dewrem.html
http://www.backyard-astro.com/equipment/accessories/dewheater/dewheater.html#Anchor-49575
http://webhome.idirect.com/~rsnow/scopeheater.html

All nice, but nothing I can just order and try out.
Am I the only one, who's 2 EVFs are unusable at this time of the year?
How are the users from Norway solving this?
 
Jonas said:
...
All nice, but nothing I can just order and try out.
Am I the only one, who's 2 EVFs are unusable at this time of the year?
How are the users from Norway solving this?
Click to expand...


not from norway, but from poland - suffering also.

thinkig of DIY solution. i am not sure how interesting this thread is for other people, but i am ready to build something between usb camera blanket and blanket with heaters pockets - all custom tailored for red shape. includind EVF.

so Jonas, if you think this is ok - you can contact me thru P.M. so i can share some drawings and thoughts about this solution.

thank you,

filip
 
Jonas: This is Kevin from alamofilms here in Stockholm. I just had the same problem in Bucharest and the temp was actually above freezing. My plan is find some battery heated socks as is common in many hunting stores here in Sweden and convert them over to usb or a tap off the battery My theory is that they will not "warm" up the viewfinder just keep it from cooling down if it is also insulated with a sleeve of some sort.
The fix will be to warm up the viewfinders with full power batteries inside a house or car first
let me know if you come up with a better plan
kevin
 
USB-powered heating solutions will not generate enough BTU's to counter extreme cold situations. The bus cannot deliver enough current to generate the heat required. Items like the infra-red wrist strap are fine in a room-temperature office environment because they're only delivering a mild heat. Forget that solution in real cold.

http://en.wikipedia.org/wiki/USB#USB_connector_properties

"A unit load is defined as 100mA in USB 2.0, and was raised to 150mA in USB 3.0. A maximum of 5 unit loads can be drawn from a port in USB 2.0, and was raised to 6 in USB 3.0."

So, that's 0.1A to heat an EVF in sub-zero temperatures.

(And, a USB-powered heating blanket is a complete joke.)

The only viable solutions will draw power from a D-tap or off-board power source.
 
Hi
I use this one in the link with great success. I slip this over the EVF and have a cut down very heavy wool sock that fits over that. Worked great even last week here on the cape when the temp was -10 with the windchill, no problems, no banding in the EVF, but note - it does eat into the battery time, even when the Batteries are wrapped also.

Ron
 
It seems that I have found a solution for us:

Anti-dew devices for telescopes. Today, we bought a 10'' tape, and wrapped it around the EVF 3 times. We let it cool down to -10C. We turned on the EVF, and it was showing everything in pink/violet. We turned the heating device on, that was tapped into the same battery via D-TAP as the camera. After approx. 18 minutes, there were no posterizing issues in the EVF. We could literally see the issues "dissolving", as it got warmed up.

Of course, an EVF at this temperature is a little extreme, as one would keep it in warm as long as possible, but this scenario proved, that the anti-dew system was capable of heating up the EVF, so that it could operate normally. Of course, the battery will run about an hour, we will probably attach another battery onto the camera for that reason.

Also, note that you will loose the 3 buttons on the EVF, you might want to turn them of in the system menu, so that do not sent weird commands to the camera, while being pressed by the tape.
We chose this compromise, in order to have a working EVF in the cold. Let's hope later versions of the firmware will have programmable "A" "B" and "C" buttons on the back of the camera, to make up for that.

We will now add a rescue-space-blanket layer and a neoprene layer onto it, to enhance the efficiency of the system. I believe, that we could make it work till -15C - -20C that way.

My conclusion is, that one can forget about any USB solutions, if the temperatures are falling below -5, to have a reliable system, instead the telescope heating stripes (anti-dew systems) are the way to go.

The power-consumption of those stripes is about 2A, which resolves in about 17W. There is a regulator, where you can regulate the power.


Now to the system itself:
http://www.kendrickastro.com/astro/dewremover.html

We used the premier version, I advise against the firefly, which is quite fragile.

2012 9/10" Optic Heater as "tape" (wraps nicely 3x times at the EVF)
and the Kendrick P2100 controller, a 4-output with one regulator controller that does not seem to be on the page of the vendor anymore.
 
Michael Morlan said:
(And, a USB-powered heating blanket is a complete joke.)

The only viable solutions will draw power from a D-tap or off-board power source.
Click to expand...

just to make it clear (just in case above sentence is somehow also connected with my future solution :))

on post nr 10 in this thread i said :
i am ready to build something between usb camera blanket and blanket with heaters pockets - all custom tailored for red shape. includind EVF."
Click to expand...

this "between usb blanket and blanket with heater pockets" was more figurative info.
since i am not that good in electronics (i am working on this with my friend who is really top level in electronics). we will not use USB, but the shape of "blanket" is somehow common. hence the association. power is from external source of course.

the special pockets will stay of course - just for the electronics with special surface (already existing) which is somehow detecting temperature on it's surface, so it is reacting in a different way when certain part of it is cold and other parts are i.e. much warmer. so it has kind of "temperature brain" included. which is in our opinion rather interesting.

they are elastic, thin, and relativelly cheap, he, he...

will see,

all the best,

filip
 
200.jpg
 
there was supposed to be text with that picture. Oh well. Anyway, thanks jonas for finding that eyepiece heater solution for telescopes. I wonder if controller is maybe a bit clunky? hard to tell. I do like the firefly solution for its lightweight controller, but of course flimsy is no good. I also wonder if there is a specific part of the eyepiece that could benefit from the heat- maybe so whole thing doesn't need to be wrapped in heating element, blocking buttons.
My temorary low tech sloution is using chemical hand warmers and a neoprene kneee wrap (as seen in picture above) maun advantage- does not pull power from batt and neoprene holds in heat, maximizing your heat source, but what I like best is hole where your kneekap would go lets you acces at least some of eyepiece buttons....
 
@Natec
How long does your chemical pads solution hold? I was always under the impression, that this lasts only a couple of hours.

I personally prefer to burn more batteries, but to be able to turn that thing off, If I need to. Also, those pads needs to be either bought new, or put into hot water to "power up", no?

Also, I strongly advise against the firefly. I wanted to get it at first as well, but having it in my hand, the connectors from the tap into the controller are very tiny and will break! Also, the firefly tap pulls only 0.5A, and I did not see that heating this huge metallic cylinder of the EVF.

The controller is a little big, yes, but there are already so many boxes on the cam anyway, that it might not matter anymore.

I also think to implement this controller into our power distribution box, that will allow to connect all standard RS connectors from e.g. arri follow focus to be connected, as I do not want to strain the camera power output. This box will also accept 24V from a classical battery and pass that on to the accessories. Lets see, how this will work out.
 
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