The D7i has a nice hand warming feature, but I'm afraid my camera might get a little bit too hot. What do you think?



Marko

It appears welder's gloves need to be a standard accessory

> It appears welder's gloves need to be a standard accessory

Indeed. The temperature of the hand grip might exceed 300 Kelvins, so be careful out there.

BTW, the picture was actually an infra-red image I've recolored. It shows quite nicely that the camera is indeed using the hand grip as a heat sink. There seems to be a hot spot right under the strap ring. Perhaps Minolta can't move the dreaded strap ring to a better place because it's an important part of the heat dissipation system

Here's another picture showing that the heat source is located really close to the CD card slot (the card door is open).



I was surprised to see how little heat the batteries seem to generate. Therefore, it was not a bad idea to place the battery compartment near the CCD.


A few more, uncolored IR pictures:




Marko

I've added a short explanation to the IR photo gallery. BTW, you are not going to find any beatuful photos from there, it's only for the tech-heads

http://www.pbase.com/mbjorkro/ir

Marko

I was guessing the batteries caused the most heat, but you seem to have blown that theory. It would be interesting to see if there was a difference in the heat sink when external battery pack (or dc adapter)
was being used in lieu of internal batteries.

Is your definition of "camera's grip" the front of the camera, the side of the camera, or both? It appears most of the heat is on the side of the camera, rather than in the front part of the grip.

When can we expect to see x-ray pictures?

William

here is the link to the disassembly of you camera for a inside look! If I was 4o years younger I might try this. Very interesting pictures.
Link: http://www.saunalahti.fi/~isoveli/

.

> I was guessing the batteries caused the most heat, but you seem to have blown that theory.

Well, the batteries were fresh and this was not a worst case situation, because the LCD was off and I didn't take any pictures. According to my own experience, the batteries get hot sometimes - probably when they are running out of power, but that does not seem to be the main heat source.

> It would be interesting to see if there was a difference in the heat sink when external battery pack (or dc adapter)was being used in lieu of internal batteries.

I won't get a change to take more IR pictures for a couple of months, but I could use a normal temperature probe instead... I've got a lab. power source, too, but I have to find an appropriate connector for the camera.

> Is your definition of "camera's grip" the front of the camera, the side of the camera, or both?

The whole area covered by black plastic.

> It appears most of the heat is on the side of the camera, rather than in the front part of the grip.

I think the front part is hollow. I suppose the "hot spots" are where there's heat-conducting metal structure right under the plastic.

> When can we expect to see x-ray pictures?

We have quite a few medical experts in this group, so we can always hope

BTW, Rolf, your link is very relewant. Too bad we don't get a good look of what's inside the grip. I don't think the real source of heat is visible in any of the pictures (but I'm a mechanical engineer, thought).

Marko

If the hand grip is supposed to be a heat sink, it sure doesn't seem to be a very good one.

I measured the temperature of the two CF cards with a small thermocouple sensor I taped on the underside (facing the rear side of the camera) of the CF cards.



I repeated the test twice. First with a 128 MB CF I card made by Kingston and again with a 1 GB Microdrive. During the first test the camera was sitting idle, but the EVF was forced on, for the first 20 minutes. After that I turned off the EVF, waited three minutes, turned on the LCD, snapped a few photos etc. As you can see, that had almost no impact on the temperature. After 30 minutes, it was still raising steadily. I don't know what the steady-state temperature is, but it seems to be near 55°C.

The results I got with the Microdrive are more interesting. The camera seemed to heat up slower, but I'm not sure if I managed to get the temperature probe into the same place as in previous test. The MD is a tight fit and I had to try several times before I managed to squeeze the MD into the CF slot with the probe. In any case, the MD heated up much faster as soon as I started shooting two full res. TIFFs per minute.

The temperatures were higher than I expected, but still well within the normal operating range of CF cards. The max. opertaing temperature of the Kingston card is 70°C and the max. operating temeprature of the MD is 65°C.

Marko

PS. Almost forgot... I measured also the temperature inside of the battery compartment right after my 30 min torture test. In both cases it was only about 28°C (27.4 / 27.9°C).

Your experimental results were quite interesting, but I suspect part of the heat-sink mechanism will also be the human hand which will impart moisture which then evaporates and gives some cooling onto the grip.
I wonder what your results may mean for the black-bodied 7Hi as opposed to the more reflective earlier models when being used in the hot sun?
John

> Your experimental results were quite interesting, but I suspect part of the heat-sink mechanism will also be the human hand which will impart moisture which then evaporates and gives some cooling onto the grip.

Well, I'm not sure. The surface temperature of the hand grip seems to be about the same as the temperature of the human hand -> minimal heat transfer and cooling effect. Have you read any of "the extreme shooting reports" written by Hans-Jürgen? He got less overheating problems when he got his hand off the hand grip whenever possible.

Check out this thread!
http://www.network54.com/Hide/Forum/message?forumid=151930&messageid=1045512773

Minolta clearly (and wisely) placed the heat-producing components as far from the CCD as possible, but it also looks like they simply stuffed all the components there and that's all. For example, the heat-producing components are not connected to the body of the camera in order to provide better heat dissipation. It works fine for a casual shooter (like I am) - I take less than one shot per minute, so the camera has plenty time to cool down (especially when it goes into power save mode) - but it's not sufficient when one shoots hundrets of photos in a row.

> I wonder what your results may mean for the black-bodied 7Hi as opposed to the more reflective earlier models when being used in the hot sun?

I guess it's safe to say that black body will absorb more solar radiation (visible light and short-wave IR) and, consequently, the camera will heat up faster and is more prone to lock up. In theory white paint would be the optimum solution. It does not absorb solar radiation but is also able to emit long-wave IR (in order to cool the camera) better than a metallic surface.

Marko