David - That comment is all over Dpreview. It's the biggest comparison between the 2 bodies. I have both the 40 and 50, but not by design. I was trying to get the flash fixed on my 10D but it was too expensive compared to the value of the body, so I stumbled upon Canon's Loyalty program and picked up a 50D for $629. (I'm not a camera whore ) Anyway, here's a summary of the differences between the 2:

Specific to your question about pixel density:
Canon EOS 50D Review: 20. Photographic tests: Digital Photography Review

And this one:

Canon 50D versus Canon 40D

Here's what is new compared to the 40D:

Canon EOS 50D Review: 3. What's New: Digital Photography Review


The biggest differences for me are the better seals (I'm not too particular about where I take pics, and if it's raining or I'm at the beach, the better weather sealing the better), and the new feature that lets you adjust focus on a lens by lens basis instead of having to send it to canon.

Keep in mind that the 17-85 lens that you're looking at is only F4 at it's widest, so using it indoors will probably mean pushing the ISO a bit, but both the 40D and 50D have incredible IQ with higher ISO settings, compared to my old 10D it's night and day. Until I got the 40D, I wouldn't shoot above ISO100 on the 10D, now I have no issues with going as high as 800 if I'm in a low light situation. I have a 17-40L F4 that is on the camera more than any other lens, and now I can use it indoors with the higher ISO useability of the 40D and 50D. It's also breathed new life into the 28-135IS.

You'll probably want an extra battery or 2, Digital Camera Batteries Chargers Memory Cards Readers is the place to buy them, their "knockoffs" work great and are 1/3rd the price of the OEM's. The other good thing about the 40/50D is that the pop up flash is now at a higher elevation when it's popped up, so the lens hood doesn't cast a shadow anymore (but be careful to check before you take that once in a lifetime pic ).

I also put one of these on my cameras, it's an eyepiece extender so you don't have your face smashed up against the back of the camera, it's good for people with glasses as well I'm told. You do have to be a bit careful with it though, I've knocked a couple off, and lost 1.

Canon | EP-EX15 Eyepiece Extender | 2444A001 | B&H Photo Video

All of that being said, trying to find a new in the box 40D right now is tough, the only place that has them is adorama. The listing doesn't say refurb and it includes the lens you want for $1099. NOTE: I just called and it's new in the box, the rep said you can call him direct x2276

1901B010 Canon EOS-40D Digital SLR Camera Body Kit with EF-S 17-85mm f/4-5.6 USM Image Stabilized Lens - USA Warranty

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The comparable 50D kit is ~ $300 more:

2807B012 Canon EOS 50D Digital SLR Camera Body Kit, 15.1 Megapixels, Black with EF-S 17-85mm f/4-5.6 USM Image Stabilized Lens - USA Warranty

__________________
You have your way. I have my way. As for the right way, the correct way, and the only way, it does not exist.

R/G,
Thank you very much for those links...I've been reading DP closely, but I must have
tunnel vision, or lack of "focus" in my info/rationale quest.

I've gotten the green light from the CEO, I have the fever, you know how it is.
Thank you again, for your, and other good posters efforts in giving me a hand.
Best Regards, TheOl'ShutterBug

Anytime.

So which one are you getting? the 40 or the 50?

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You have your way. I have my way. As for the right way, the correct way, and the only way, it does not exist.

R/G,
I'm torn...I haven't plowed through all the links you gave me, yet.
Probably the 50, though the 40 is not slouch, but the $ diff is
negligible. Funny how the 500D has practically the same specs as the
50D, for a lot less dough. I know it's a "cheaper" body...but, these
cam mfg'rs flood the channel with a dizzying array of nearly the same
species.

Digital Cameras Side-by-Side, 3 cameras: Digital Photography Review

I agree at first glance the differences between the 500D and 50D are very similar. I found this comparison on dpreview which sums up the big differences. So when you're trying to get those hummingbird pics, the 50D is going to be your best friend.

__________________________________________________ ______

The key differences between the 50D and T1i isn't about image quality rather being more likely to capture the image you want.

The 50D is much faster; 6.3 frames per second over 3.4

Much brighter, larger viewfinder as the 50D uses a Pentaprism rather than Pentamiror

50D offers 2 complete user configuration settings which can be accessed instantly via the mode dial. An example of usage; he's at a motorsports event and 1 configuration wold be for AIservo tracking the cars while the other is for shallow depth of field oneshot cacdids as a famous driver might just be walking by.

The controls to change settings is much easier to change as well as faster.

The 50D focus screen can be changed i.e. to one with a grid for easier alignment

The AF system is much faster and more accurate as well as having 9 Cross type AF points rather than just 1. The 50D centre AF point is a cross and X style for added accuracy.

The 50D AF sensors are also much smaller so you can more specific about the focusing spot.
ie. T1i

__________________
You have your way. I have my way. As for the right way, the correct way, and the only way, it does not exist.

Here's a good deal on 50D and it comes with nice picture printer and 2 GB CF card - all for $1299.

RIF my friend, he doesn't have a costco membership as they don't have any by his house

__________________
You have your way. I have my way. As for the right way, the correct way, and the only way, it does not exist.

This is online offer, so any of mD's friends can help him. My Mom doesn't have Costco membership either, but has tons of Costco stuff in her house. Thanks to her friends and kids.