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DorkUnderwater Feb 26, 2006 12:04 AM

I would simply like to know any major differences between these two cameras, not weight size as i know the 7D is considerably heftier and that difference is immaterial to me. I am more interested in differences that would allow for better pictures in low light situations. thanks.

JimC Feb 26, 2006 12:55 AM

Low light advantages, huh?

Well, it's debatable. But, IMO, the 5D has a slight advantage at the very highest ISO speeds (ISO 1600, 3200). It appears to be about 1/3 stop more sensitive to light compared to the 7D.

I looked at several sets of test photos to reach that conclusion, including one set taken of the same subjects, in the same conditions, with the same lenses, using manual exposure for both, right down to identical white balance settings.

The 5D images were exposed approximately 1/3 stop brighter at the highest ISO speed settings.

If you look at the 7D test photos here (not the set I'm referring to), you'll also see an exposure difference between the ISO 800 and ISO 1600 images, even though the exposure should have been linear (1/15 second at f/5.6 for the ISO 800, and 1/30 second at f/5.6 at ISO 1600, should have produced identical exposure). Steve didn't include an ISO 3200 image in the set.

In addition, Uwe Steinweller at Digital Outback Photo also noted a descrepancy in the sensitivity of the 7D at it's highest ISO speeds (calling it about 1/3 stop off).

After reviewing images, coupled with Uwe's opinion of the 7D's ISO speed rating, noting a descrepancy in sensitivity independently of the images I reviewed, I reached my conclusion about it. I think the 5D has a slight advantage at higher ISO speeds, and that's one of the reasons I decided on it, versus the 7D.

But, it's really not that much of a difference in real world use.

Now, Dave Etchells over at Imaging Resource noted that the 5D does a much better job of retaining detail at higher ISO speeds compared to the 7D, even though the noise graphs look identical. But, that could be a result of jpeg processing differences, and if you're shooting raw, you'd bypass the processing. You'll see Dave's comments about it under the noise graph:

One advantage the 7D would have in low light is a little better viewfinder. If light is very low, it could come in handy for manual focus purposes. Most people wouldn't use MF though.

The 7D has a number of advantages in some other areas (for example: manual mode for it's flash, better ergonomics, larger buffer, custom settings on the mode dial in place of the scene modes on the 5D, PC Sync Port for an external flash, more controls, higher resolution LCD).

But, the other differences weren't that important to me. I do wish I had the 7D's viewfinder at times, though (mostly because I wear eyeglasses and the 7D has better eye relief). But, IMO, the 5D viewfinder is better than competing models in it's market niche (Nikon D50, Canon Rebel XT).

The 7D's viewfinder is just much better than anything else around in it's market niche. So, it would have been nice if they put the same one on the 5D, too. But, you can't have everything in a smaller camera body.

kassandro Feb 26, 2006 8:45 AM

Interesting remark about the 1/3 stop advantage. I knew Steinmueller's comment about the KM 7D's iso 1600, but I thought that it applies for the KM 5D likewise. The KM 5D and the KM 7D also have a slightly different raw format. Thus their seems to have been some progress between the KM 7D and the KM 5D. On the other hand the KM developers certainly didn't want to destroy the KM 7D with the more recent KM 5D. The new 1.10 firmware took the performance level of the KM 7D up to that of the KM 5D. I don't know whether this applies also to the iso 1600 mode. After all both cameras have the same CCD and probably the same ampflifier chip, which converts the analog signals from the CCD into digital values for the image processor. There are also more problem reports about the KM 7D than about the KM 5D, although the sales of the KM 5D are considerably higher than that of KM 7D (the KM 7D was simply overpriced). Thus the KM 5D seems to be a somewhat more mature product. I would have bought the KM 5D on Ebay but not the KM 7D, though some new KM 7D bodies were sold there for 480€. I had both cameras in my hand and I looked through both view finders. The KM 7D is clearly better, but the KM 5D view finder would have been good enough for me, although I too wear eye glasses. The three custom modes of the KM 7D instead of the idiotic scene modes of the KM 5D impressed me more. Also that you do not have to surf through complicated menus was very important. Pressing the iso button and one time on the navigator button is about the most complicated operation on the KM 7D. I valued the better ergonomics of the KM 7D at around 100€ and then my buying decision was just a matter of opportunity. Fortunately after 430 raw shots my KM 7D didn't exhibit any of the quality issues, which were reported in this and other forums. Though I don't have yet the appropriate lenses, I initially bought the KM 7D only for low light use and sports, but I am now so impressed by the image quality (raw images processed with the free Raw Shooter Essentials are clearly better than the many jpegs, which I have seen on the net before) and the outstanding ergonomics, that I am now willing to carry around this heavy beast much more often than I thought initially.

JimC Feb 26, 2006 8:54 AM

kassandro wrote:

Interesting remark about the 1/3 stop advantage. I knew Steinmueller's comment about the KM 7D's iso 1600, but I thought that it applies for the 5D likewise.
Based on pohotos I've looked at, the 5D sensitivity appears to be linear. The 7D sensitivity does not appear to be linear (slightly more sensitive to light at it's lowest ISO speed setting, and slightly less sensitive to light at it's higher ISO speed settings than the settings should produce).

Given identical manual exposure settings, the 5D appears to expose about 1/3 stop brighter compared to the 7D at higher ISO speeds

That's a very small amount, and in real world use, I doubt you'd notice it, though (espcially since you're not going to be shooting at the highests ISO speeds all of the time). Many may value the brighter viewfinder of the 7D more in low light (especially if it gets low enough that MF may be preferable to AF).

As for the reason, who knows... It could be a more refined sensor, different supporting chipset, or even a more refined AA filter design.

We see the same thing with the newer Nikon D50 compared to the older D70 (the D50 has better high ISO speed performance).


Here is one set of test images taken of the same subjects, in the same conditions, using the same lenses, with the same manual exposure settings, right down to the WB. Note that the 7D is a bit brighter at ISO 100 compared to the rest of it's images (something else that Uwe noticed in his 7D review). Then, look at the exposure from the 7D get darker at it's highest ISO speeds (when exposure should have been linear).

You can also see this type of difference looking at the 7D review samples here going from ISO 800 to 1600. Steve didn't include an ISO 3200 image in the set.

Mercury694 Feb 26, 2006 10:57 AM

Interesting side by side, Jim. IMO though even if there is a 1/3 stop difference, the ease of holding the 7d vs the 5d may make up the difference to many, especially at the long telephoto ranges where the lens is stopped down. I got the 7d on ergonomics, it just feels right in my hands compared to the 5d which was just a bit smaller and not quite as "balanced feeling". I do think the 5d is a more mature product though and some of the rough edges that came to light when the 7d entered service have been addressed.

My recommendation to DorkUnderwater would be to go down to the local camera shop and put one in his hands for a few minutes. Check out the way it feels to you, mount a couple lenses and shoot a few shots. To me the biggest differences were the handling of the cameras and the price. The menu system of the 5d didn't bother me at all, nor did the build quality. If the 5d feels good in your hands and you are okay with the menu, I'd save the $ and buy a nice bright lens to go with it- enhancing your low light performance even more.

kassandro Feb 26, 2006 11:26 AM

The link
seems to be dead.

JimC Feb 26, 2006 11:40 AM

kassandro wrote:

The link
seems to be dead.
Works fine here. Your ISP may have a router or DNS problem somewhere (or be blocking your access to the URL for some reason).

kassandro Feb 26, 2006 12:05 PM

OK, I got it. It seems to be a slow korean site and I simply got timed out. The comparisons there show that the 5D is a tiny bit darker than the 7D at iso 100. Already at iso 200 the 7D is darker and the difference increases gradually until iso 3200.
Does the KM 5D have an iso 80 mode? I also wonder about the iso 200hi mode of the KM 5D. In the 7D menus there is a low/hi mode for more details in shadows/highlights. It seems to be a pure post prrocessing option, not relevant for raw shooting. Such a comparison should be made with raw shots, because we know that the image processors of both cameras are slightly different. It may very well be that the KM developers considered the 7D pictures a little bit dark and simply changed the postprocessing a little. That would not be a real gain.

JimC Feb 26, 2006 12:12 PM

Yea, I wish I could have tested it myself in raw with both cameras to see for sure.

I'm basing my assumptions on jpeg (and it could be due to some processing differences in the image pipeline). I think it's more likely improvements in the sensor and supporting chipset based on a lot of threads comparing the Nikon D50 and D70 elsewhere. Improvements do work their way into newer models, even when the sensor resolution remains the same.

I've seen some pretty darn clean images from my 5D at higher ISO speeds, even shooting in raw without any PP for noise reduction.

As for the "zone matching" choices, the KM 5D has a low 80 and high 200. But, I think this is primarily a curves function via in camera processing.

kassandro Feb 26, 2006 12:33 PM

I understand that the CCD manufacturer makes some progress over time and may even change the production if it doesn't require any change of the camera design. We have seen this from the Sony CCD disaster. Some copies of a camera model did have the malicious CCD others didn't. If that's the case, then also more recently produced 7D cameras should have the newer CCD. It simply doesn't make economic sense to maintain two production lines for very very similar products.

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