D7: a hands-on look

No 'values' but the camera did feel hot to me (compared to what I've experienced in the past) and certainly CF cards came out of the camera a lot hotter than I'm used to.

Giovanni said:

Thanks for this.

This statement is the thing more close to a real quantitative
measurement that we had about this issue.

Phil do you had different result in your test?

Click to expand...

Bryan,

Okay, then only some numbers without further theory

The best conductor in aspect of heat is silver ( 1 cal cm x s x K)
copper is still great (0.94 )
magnesium (0.4)
iron (0.2)
steel (0.03)

Regards,

Andreas

Bryan Biggers said:

Some heat theory...

Power, watts is I*I*R. In other words, power is proportional to the
square of the current.

Click to expand...

Well sort of.

Bryan Biggers said:

Lets compare the 990 and the D7.
same AA batteries in both of them), you can see that the 990 lasted
2h30m, and the D7 1h14m. Lets say that is exactly a factor of two.
That means that the D7 is drawing current at twice the rate as the
990, and that the power dissipated is 4 times as much in the D7.

Click to expand...

But not quite.

Disregarding the issue of the actual performance curves
of the batteries and assuming their lifetime to be proportional
to current drain:

P = VI

ie. if both are operating at the same voltage then power
is proportional to the the current -- not the square.

The formula P = I*I*R is correct but you're using it incorrectly
R = V/I -- so this is actually P = VI. Now if you had a simple
resistor and wanted to draw current through it the voltage
across the resistor would have to rise.

The camera doesn't operate as a simple resistor -- in effect
its resistance drops as it conumes more current because the
voltage supply will be maintained.

So the power dissipation is in effect approximately twice rather
than 4 times given the assumption about the battery life.

Figure that you're implying that a device which drains a
battery at twice the rate gets four times as much total
energy out of the battery!

--------------
Andrew.

Andrew Cruickshank said:

Bryan Biggers said:

Some heat theory...

Power, watts is I*I*R. In other words, power is proportional to the
square of the current.

Click to expand...

Well sort of.

Click to expand...

Yes, you are entirely right. I was thinking of the camera as a simple resistive load, but it isn't because it probably has a switching power supply, for one thing.
The camera should only dissipate twice the heat as the 990.
Bryan

We've been discussing this heat problem (if it is one) for quiet a while and as I still await my camera (not yet in the stores here in Germany) I wont be able to contribute any observations on my own instead hope that maybe someone with a D7 can help:

1. Did anyone try to shoot comparable motives with a cold D7 and one heated up / running for a while? If so what about the noise, did it increase significantly?? All heat obseravtions so far have been made only on the right side of the camera near the handle and the CF-cards ... maybe the cmaera is just able to direct most fo teh heat to that part of the camera actually keeping the chip even cooler than other cameras?? just maybe...

2. Did anyone so far use his D7 with a larger microdrive (maybe even 10GB)?? If so how bad / obvious was the heat problem?? Did it affect the microdrive? Was it very hot when taking it out of the camera?

Maybe someone can help - if not I guess I will post my observations if I get my hands on the D7 which still could take a few weeks :-(

Yours
Dirk

Bryan Biggers said:

Some heat theory...

Power, watts is I*I*R. In other words, power is proportional to the
square of the current. When power is consumed by a camera, almost
all of it ends up as heat (except for the small amound converted to
visible light by the displays).

Lets compare the 990 and the D7.
Assuming that the LCDs on both cameras have the same backlighting
level, so that we can ignore the amount converted to visible light,
and using Phil's battery life figures (fortunately Phil used the
same AA batteries in both of them), you can see that the 990 lasted
2h30m, and the D7 1h14m. Lets say that is exactly a factor of two.
That means that the D7 is drawing current at twice the rate as the
990, and that the power dissipated is 4 times as much in the D7.
It sure should get hotter! All that heat has to go somewhere. My
990 can get pretty hot if you leave it on for a while. The D7 has
slightly more mass, but not all of the outside of the case is metal
and plastic does not radiate heat as well, so I think that the D7
is really going to heat up.

Bryan

Click to expand...

Bryan:
I think there is a fault in your reasoning.

If the second camera draws twice as much current, then the resistance must be half of the first camera. The power consumed is then twice as much.
Do the calculation another way:

If the second camera is drawing twice as much current, and the voltage input is identical in both cases, the power input to the second camera is twice that of the first.
But there is no doubt that the second camera can be warmer.

One other item, the flash cards also draw current, and the current drawn is not a constant but depends on the operation being performed.
Yours for greater understanding of this whole situation.

bob manfredi

Bryan Biggers said:

Andrew Cruickshank said:

Bryan Biggers said:

Some heat theory...

Power, watts is I*I*R. In other words, power is proportional to the
square of the current.

Click to expand...

Well sort of.

Click to expand...

Yes, you are entirely right. I was thinking of the camera as a
simple resistive load, but it isn't because it probably has a
switching power supply, for one thing.
The camera should only dissipate twice the heat as the 990.
Bryan

Click to expand...

I'm by no means an expert on electronics. But isn't it reasonable to assume that the D7 has a much lower operating time because of the large amount of data it has to process and write to the CF card?

Maxven

Maxven said:

I'm by no means an expert on electronics. But isn't it reasonable
to assume that the D7 has a much lower operating time because of
the large amount of data it has to process and write to the CF card?

Maxven

Click to expand...

Yes, by all accounts it does do more. Compare to the Nikon 990 (sorry, I'm just very familiar with that camera. Figures from Phil's review).

First, the D7 can buffer 5 Fine mode shots where the 990 can buffer 2 or 3. The shots average 2.2 MB for the D7 and 1.2MB for the 990, so the D7 clearly has (a lot) more RAM buffer. It also requires more RAM to buffer the RAW shot because of the larger image size. More RAM takes more power to operate.

Second, the D7 appears to be at least as fast if not faster in most areas than the CP990. It turns on faster (3.6 vs 4.0 seconds), for example.

Thrid the D7 processes data faster. The 990 processes and saves a 1.2MB image in 7.9 seconds or 152KB/sec. The D7 saves a 2.2MB image in 9.8 seconds, or 207KB/sec. The D7 has to do more work because of the larger images just to keep up with the 990's rate. I suspect that the CPU is about 25% faster in the D7 than in the 990 (total guess, based on the times). That generates more heat too.

Fourth, the D7 has to run some extra stuff, like the EVF backlight (is it on at the same time as the LCD?) and the IR LED for the eye close approach sensor, plus it has to move a bigger lens around when it focuses than the 990 does so it needs a bigger motor to do that.

It does more, so it gets hotter! Makes sense. Bryan

Maxven said:

I'm by no means an expert on electronics. But isn't it reasonable
to assume that the D7 has a much lower operating time because of
the large amount of data it has to process and write to the CF card?

Click to expand...

I'd suspect the EVF + CPU and firmware to operate it as
prime suspects.

What is probably happening is that the D7's CPU is continually
active operating the EVF and handling the information updates.
That work translates into heat.

Without the EVF a passive viewfinder wouldn't require much
CPU power to operate. The backpanel LCD will normally drain
a camera quite quickly. The EVF lets it operate longer which
allows the heat to build up.

Upshot is it's doing a lot more continuous work than say an
E-10 or a D1 using their optical finders. Add to that the camera
has a conductive metal casing and frame and low mass to sink
the heat dissipated internally then it gets warm. The E-10 is
heavier, the D1 a lot heavier. Notably the D7's battery compartment
is not in the handgrip -- it appears that the electronics and CF
compartment are there.

------------------
Andrew.

The fellow whose comments on the D7 I reported earlier has recently e-mailed me, saying that he did not notice any particular heat problem. He had been aware of the potential problem and he said he checked several times during the hour in which he used the camera. (He checked by feeling the area around or under the battery housing, I guess.) He's in Arizona, where it is very hot right now. I would suppose that part of the time he was using the camera inside the store, which must have its air-conditioning switched on. He did use it outside, where the only air conditioning is in your mind.

Just got to spend 10 to 15 minutes with a demo D7 at Francis Camera Shop here in Hawaii. These are my impressions:

1. I did not find the build quality to be cheap. Camera was lighter than others, but to me that's all goodness. Camera also fit nicely in my smaller hands.

2. The rep left the camera on the whole time I was there. The body did get warm but not excessively so. There was no CF card in the camera so I did not get to take shots. I'm sure that would have generated more heat.

3. The evf does seem to lag and is somewhat jerky. If I compare it to my Sony PC-100 video camera, the Sony is much smoother.

4. The zoom is rather tight. As "The Man" says, you definitely need to use two fingers. My slr zooms are much smoother.

5. The autofocus does hunt some. Need to find a contrast or back off the zoom to help it some.

6. I would probably use the evf a lot when using this camera. I like that a lot better than trying to frame with the lcd. More like an slr and much better than trying to use the optical view finders on the range finder type digital cameras.

Still convinced it's the camera for me.

The same fellow tried a Photoshop action with some of the D7 test shots he made. The action, which I got from another forum here and then passed along to him, is as follows:

Step 1: Duplicate current layer
Step 2: Noise --> Median --> Radius 2
Step 3: Set current layer to Opacity 45%
Step 4: Select Background Layer
Step 5: Flatten Image
Step 6: Unsharp Mask : Radius 2, Amount 120, Threshold 16

He told me in some recent e-mail that this did a pretty good job of reducing noise in the sample D7 images.

(I tried it, using Photoshop Elements, with a C2100 shot. I didn't like the results -- too much detail was compromised. I need to tweak some of the settings given the lower resolution of the C2100, I guess. Not that I know enough about this yet to know which settings to tweak, or why...)

herb said:

4. The zoom is rather tight. As "The Man" says, you definitely
need to use two fingers. My slr zooms are much smoother.

Click to expand...

I suppose one "spin" that could be put onto this is: with the zoom ring being somewhat tight, it isn't as easy as it would otherwise be to turn the ring accidentally and re-frame the shot in progress in some way that you didn't like.

herb45374 said:

5. The autofocus does hunt some. Need to find a contrast or back
off the zoom to help it some.

Click to expand...

This seems to be characteristic even of the finest auto-focus systems. They're all going to "hunt" at some point. It's useful that with (at least some) Canon AF lenses, you can immediately over-ride the auto-focus mechanism by turning the focusing ring (though I don't know if then when you take the shot, pressing the shutter button causes the camera to try to re-focus...anyone know how that works with Canon or other AF "prime" lenses?).

herb45374 said:

6. I would probably use the evf a lot when using this camera.

Click to expand...

The guy whose message I paraphrased at the start of this thread uses his G1 quite a bit and uses only the LCD monitor for framing. But when he played with the D7, he found himself using only the EVF and not the monitor on the back of the camera. Much more SLR-like. He liked that part. (I knew he would.

As I already posted the D1 filter of QImage 2.5 seem to me to work suprising WELL with D7 - Monolta SW already processed images for some misterious reasons.

For me the noise is a NON-isssue if I will use QImage

MikeA said:

The same fellow tried a Photoshop action with some of the D7 test
shots he made. The action, which I got from another forum here and
then passed along to him, is as follows:

Step 1: Duplicate current layer
Step 2: Noise --> Median --> Radius 2
Step 3: Set current layer to Opacity 45%
Step 4: Select Background Layer
Step 5: Flatten Image
Step 6: Unsharp Mask : Radius 2, Amount 120, Threshold 16

He told me in some recent e-mail that this did a pretty good job of
reducing noise in the sample D7 images.

(I tried it, using Photoshop Elements, with a C2100 shot. I didn't
like the results -- too much detail was compromised. I need to
tweak some of the settings given the lower resolution of the C2100,
I guess. Not that I know enough about this yet to know which
settings to tweak, or why...)

Click to expand...

Giovanni said:

As I already posted the D1 filter of QImage 2.5 seem to me to work
suprising WELL with D7 - Monolta SW already processed images for
some misterious reasons.
For me the noise is a NON-isssue if I will use QImage

Click to expand...

I wish I could get accustomed to its interface. I played with the demo version a bit (now expired). Found it rather frustrating. Oh, well.

Nothing to do with the new one.
Same interface but now very quick.

MikeA said:

Giovanni said:

As I already posted the D1 filter of QImage 2.5 seem to me to work
suprising WELL with D7 - Monolta SW already processed images for
some misterious reasons.
For me the noise is a NON-isssue if I will use QImage

Click to expand...

I wish I could get accustomed to its interface. I played with the
demo version a bit (now expired). Found it rather frustrating. Oh,
well.

Click to expand...