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tomato

Using a fridge to help create darks

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This may sound a bit wacky but would it be OK?

I am keen to improve my library of darks at lower temperatures to see how my image processing could improve with them  but we have a bit of an Indian summer right now and I won't get the camera down to -30 in the current ambient conditions. So my plan is to put the camera in the fridge and take them while it's in there. 

Apart from the camera coming out maybe smelling of strawberries, is there any reason why this might not be a good idea?

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Hi Tomato.  Where are you getting strawberries this time of year?

Minus 30 seems a little extreme!  Most folk I know aim for around -20.  What about doing them in a garage?  Or, better yet, isn't your wine cellar reasonably cool?  

I don't know what camera you have - I would be a little reluctant to stick any of mine in the fridge (even the cheap ones).  But I am all for experimentation.  If you do plan on putting it in a fridge, I would be tempted to place it inside a freezer bag (or two) to stop any damage from spillages and such like.          

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The strawberries are from M&S and very nice too. Seriously I would protect the camera from liquids or risk of spillages. It's a G2-8300 and I thought the colder the better? I have taken recent subs at -30 with an ambient temp of about 7C, the camera was at 17C with the cooler running at 82% capacity. The humidity in the fridge would be no worse (probably better) than outside, it's the only environment I have available right now with single digit temperatures. My impatience coming through again.....

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You already mention controlling humidity, stick it in a bag with some dessicant jobbies and I don't see what you have to lose, except blowing up the fridge! A fridge can't run at -30 neither will a domestic freezer. If you are really serious, make friends with your local MCd's and ask the manager to help you out with their walk in freezer; waaaay back in a previous life I would have.

Currently I use a rather expensive but busted (de-gassed) fridge freezer to store all my photography gear when not in the ML. Effectively it is now a couple of sealed cupboards. I keep assorted bags of dessicant in it as well, but it seems to work well as an inert cabinet.

Rich

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I don’t really know, but I wonder if ‘colder the better’ (which has face validity) is offset somewhat by having the cooler running at what we scientists call ‘full tilt boogie’.  

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Hi Rich, I only need the fridge at 5C, the Peltier cooler in the camera will do the rest.

The Moravian manual recommends you don't run at more than about 80% cooling capacity to give you some leeway should the ambient temp rise during the session. So with single figure ambient temps I can run the chip at -30C. Every session so far it has been rock steady running under these conditions.

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At a fixed temperature and pressure, the humidity of the air inside the fridge is going to be pretty much the same as that outside it, I'd have thought.

I see no reason not to try it.  The only thing I can think of to watch out for is that the peltier could be kicking out a lot of heat and the fridge may not be able to maintain a stable temperature as a result.

James

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Well, it sort of worked. JamesF, you are spot on. The weak link in the heat transfer chain is the cooling capacity of the domestic fridge. The camera was at 17 C with the chip at -30C, but this just kept on rising steadily as I took the subs, meaning the internal cooler had to work harder. I pulled the plug (not literally) when the Peltier cooler was running at 90% and rising. Still I have 6 more dark frames in my library, and a picture to bemuse the grandkids.

IMG_0200.JPG

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Glad to see its not in a bag

Its a peltier cooler so the heat needs to get out  and air cooled by the fridge needs to get in so there is no point putting it in a bag.

the air air will be low in humidity inside the fridge its only when you open the door that the new air condensates.

The camera dissipates 40 watts at 100% cooling. Looking on the internet a Fridge will just about have enough heat extraction rate to cope. Perhaps putting a few frozen freezer packs next to the camera would be a good idea to take some of the load off the compressor.

 

Edited by Tomatobro
additional research data

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Well, with the way the weather is looking, this might be the only action the camera sees in the next week or so.

As you can see the fan was blowing warm air out onto a row of UHT milk cartons, I thought they might act  as a heat sink, but the foil lined cardboard must be a good insulator. 

All this physics in the fridge:icon_biggrin:

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You may not want to be using Darks with your Moravian G2-8300 (I have one) as per my current thread, something to consider...

 

 

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Agreed, but unless I am mistaken I still need a set of darks to create the Bad Pixel Map?

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21 hours ago, Tomatobro said:

 The moto. is :icon_biggrin:..."if some is good, more is better and too much is just about right"

I was going to use that quote in post about this:

IMG_0203.PNG

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